Thermally-driven Coupled THM Processes in Shales

NASA Astrophysics Data System (ADS)

Rutqvist, J.

2017-12-01

Temperature changes can trigger strongly coupled thermal-hydrological-mechanical (THM) processes in shales that are important to a number of subsurface energy applications, including geologic nuclear waste disposal and hydrocarbon extraction. These coupled processes include (1) direct pore-volume couplings, by thermal expansion of trapped pore-fluid that triggers instantaneous two-way couplings between pore fluid pressure and mechanical deformation, and (2) indirect couplings in terms of property changes, such as changes in mechanical stiffness, strength, and permeability. Direct pore-volume couplings have been studied in situ during borehole heating experiments in shale (or clay stone) formations at Mont Terri and Bure underground research laboratories in Switzerland and France. Typically, the temperature changes are accompanied with a rapid increase in pore pressure followed by a slower decrease towards initial (pre-heating) pore pressure. Coupled THM modeling of these heater tests shows that the pore pressure increases because the thermal expansion coefficient of the fluid is much higher than that of the porous clay stone. Such thermal pressurization induces fluid flow away from the pressurized area towards areas of lower pressure. The rate of pressure increase and magnitude of peak pressure depends on the rate of heating, pore-compressibility, and permeability of the shale. Modeling as well as laboratory experiments have shown that if the pore pressure increase is sufficiently large it could lead to fracturing of the shale or shear slip along pre-existing bedding planes. Another set of data and observations have been collected associated with studies related to concentrated heating and cooling of oil-shales and shale-gas formations. Heating may be used to enhance production from tight oil-shale, whereas thermal stimulation has been attempted for enhanced shale-gas extraction. Laboratory experiments on shale have shown that strength and elastic deformation modulus decreases with temperature while the rate creep deformations increase with temperature. Such temperature dependency also affects the well stability and zonal sealing across shale layers.

Impact of Oxidative Dissolution on Black Shale Fracturing: Implication for Shale Fracturing Treatment Design

NASA Astrophysics Data System (ADS)

You, L.; Chen, Q.; Kang, Y.; Cheng, Q.; Sheng, J.

2017-12-01

Black shales contain a large amount of environment-sensitive compositions, e.g., clay minerals, carbonate, siderite, pyrite, and organic matter. There have been numerous studies on the black shales compositional and pore structure changes caused by oxic environments. However, most of the studies did not focus on their ability to facilitate shale fracturing. To test the redox-sensitive aspects of shale fracturing and its potentially favorable effects on hydraulic fracturing in shale gas reservoirs, the induced microfractures of Longmaxi black shales exposed to deionized water, hydrochloric acid, and hydrogen peroxide at room-temperature for 240 hours were imaged by scanning electron microscopy (SEM) and CT-scanning in this paper. Mineral composition, acoustic emission, swelling, and zeta potential of the untreated and oxidative treatment shale samples were also recorded to decipher the coupled physical and chemical effects of oxidizing environments on shale fracturing processes. Results show that pervasive microfractures (Fig.1) with apertures ranging from tens of nanometers to tens of microns formed in response to oxidative dissolution by hydrogen peroxide, whereas no new microfracture was observed after the exposure to deionized water and hydrochloric acid. The trajectory of these oxidation-induced microfractures was controlled by the distribution of phyllosilicate framework and flaky or stringy organic matter in shale. The experiments reported in this paper indicate that black shales present the least resistance to crack initiation and subcritical slow propagation in hydrogen peroxide, a process we refer to as oxidation-sensitive fracturing, which are closely related to the expansive stress of clay minerals, dissolution of redox-sensitive compositions, destruction of phyllosilicate framework, and the much lower zeta potential of hydrogen peroxide solution-shale system. It could mean that the injection of fracturing water with strong oxidizing aqueous solution may play an important role in improving hydraulic fracturing of shale formation by reducing the energy requirements for crack growth. However, additional work is needed to the selection of highly-effective, economical, and environmentally friendly oxidants.

A Transversely Isotropic Thermo-mechanical Framework for Oil Shale

NASA Astrophysics Data System (ADS)

Semnani, S. J.; White, J. A.; Borja, R. I.

2014-12-01

The present study provides a thermo-mechanical framework for modeling the temperature dependent behavior of oil shale. As a result of heating, oil shale undergoes phase transformations, during which organic matter is converted to petroleum products, e.g. light oil, heavy oil, bitumen, and coke. The change in the constituents and microstructure of shale at high temperatures dramatically alters its mechanical behavior e.g. plastic deformations and strength, as demonstrated by triaxial tests conducted at multiple temperatures [1,2]. Accordingly, the present model formulates the effects of changes in the chemical constituents due to thermal loading. It is well known that due to the layered structure of shale its mechanical properties in the direction parallel to the bedding planes is significantly different from its properties in the perpendicular direction. Although isotropic models simplify the modeling process, they fail to accurately describe the mechanical behavior of these rocks. Therefore, many researchers have studied the anisotropic behavior of rocks, including shale [3]. The current study presents a framework to incorporate the effects of transverse isotropy within a thermo-mechanical formulation. The proposed constitutive model can be readily applied to existing finite element codes to predict the behavior of oil shale in applications such as in-situ retorting process and stability assessment in petroleum reservoirs. [1] Masri, M. et al."Experimental Study of the Thermomechanical Behavior of the Petroleum Reservoir." SPE Eastern Regional/AAPG Eastern Section Joint Meeting. Society of Petroleum Engineers, 2008. [2] Xu, B. et al. "Thermal impact on shale deformation/failure behaviors---laboratory studies." 45th US Rock Mechanics/Geomechanics Symposium. American Rock Mechanics Association, 2011. [3] Crook, AJL et al. "Development of an orthotropic 3D elastoplastic material model for shale." SPE/ISRM Rock Mechanics Conference. Society of Petroleum Engineers, 2002.

Shale Gas Well, Hydraulic Fracturing, and Formation Data to Support Modeling of Gas and Water Flow in Shale Formations

NASA Astrophysics Data System (ADS)

Edwards, Ryan W. J.; Celia, Michael A.

2018-04-01

The potential for shale gas development and hydraulic fracturing to cause subsurface water contamination has prompted a number of modeling studies to assess the risk. A significant impediment for conducting robust modeling is the lack of comprehensive publicly available information and data about the properties of shale formations, shale wells, the process of hydraulic fracturing, and properties of the hydraulic fractures. We have collated a substantial amount of these data that are relevant for modeling multiphase flow of water and gas in shale gas formations. We summarize these data and their sources in tabulated form.

Leaching of polycyclic aromatic hydrocarbons from oil shale processing waste deposit: a long-term field study.

PubMed

Jefimova, Jekaterina; Irha, Natalya; Reinik, Janek; Kirso, Uuve; Steinnes, Eiliv

2014-05-15

The leaching behavior of selected polycyclic aromatic hydrocarbons (PAHs) from an oil shale processing waste deposit was monitored during 2005-2009. Samples were collected from the deposit using a special device for leachate sampling at field conditions without disturbance of the upper layers. Contents of 16 priority PAHs in leachate samples collected from aged and fresh parts of the deposit were determined by GC-MS. The sum of the detected PAHs in leachates varied significantly throughout the study period: 19-315 μg/l from aged spent shale, and 36-151 μg/l from fresh spent shale. Among the studied PAHs the low-molecular weight compounds phenanthrene, naphthalene, acenaphthylene, and anthracene predominated. Among the high-molecular weight PAHs benzo[a]anthracene and pyrene leached in the highest concentrations. A spent shale deposit is a source of PAHs that could infiltrate into the surrounding environment for a long period of time. Copyright © 2014 Elsevier B.V. All rights reserved.

Experimental Study and Numerical Modeling of Fracture Propagation in Shale Rocks During Brazilian Disk Test

NASA Astrophysics Data System (ADS)

Mousavi Nezhad, Mohaddeseh; Fisher, Quentin J.; Gironacci, Elia; Rezania, Mohammad

2018-06-01

Reliable prediction of fracture process in shale-gas rocks remains one of the most significant challenges for establishing sustained economic oil and gas production. This paper presents a modeling framework for simulation of crack propagation in heterogeneous shale rocks. The framework is on the basis of a variational approach, consistent with Griffith's theory. The modeling framework is used to reproduce the fracture propagation process in shale rock samples under standard Brazilian disk test conditions. Data collected from the experiments are employed to determine the testing specimens' tensile strength and fracture toughness. To incorporate the effects of shale formation heterogeneity in the simulation of crack paths, fracture properties of the specimens are defined as spatially random fields. A computational strategy on the basis of stochastic finite element theory is developed that allows to incorporate the effects of heterogeneity of shale rocks on the fracture evolution. A parametric study has been carried out to better understand how anisotropy and heterogeneity of the mechanical properties affect both direction of cracks and rock strength.

Methanogenic archaea in marcellus shale: a possible mechanism for enhanced gas recovery in unconventional shale resources.

PubMed

Tucker, Yael Tarlovsky; Kotcon, James; Mroz, Thomas

2015-06-02

Marcellus Shale occurs at depths of 1.5-2.5 km (5000 to 8000 feet) where most geologists generally assume that thermogenic processes are the only source of natural gas. However, methanogens in produced fluids and isotopic signatures of biogenic methane in this deep shale have recently been discovered. This study explores whether those methanogens are indigenous to the shale or are introduced during drilling and hydraulic fracturing. DNA was extracted from Marcellus Shale core samples, preinjected fluids, and produced fluids and was analyzed using Miseq sequencing of 16s rRNA genes. Methanogens present in shale cores were similar to methanogens in produced fluids. No methanogens were detected in injected fluids, suggesting that this is an unlikely source and that they may be native to the shale itself. Bench-top methane production tests of shale core and produced fluids suggest that these organisms are alive and active under simulated reservoir conditions. Growth conditions designed to simulate the hydrofracture processes indicated somewhat increased methane production; however, fluids alone produced relatively little methane. Together, these results suggest that some biogenic methane may be produced in these wells and that hydrofracture fluids currently used to stimulate gas recovery could stimulate methanogens and their rate of producing methane.

Inventory and evaluation of potential oil shale development in Kansas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Angino, E.; Berg, J.; Dellwig, L.

The University of Kansas Center for Research, Inc. was commissioned by the Kansas Energy Office and the US Department of Energy to conduct a review of certain oil shales in Kansas. The purpose of the study focused on making an inventory and assessing those oil shales in close stratigraphic proximity to coal beds close to the surface and containing significant reserves. The idea was to assess the feasibility of using coal as an economic window to aid in making oil shales economically recoverable. Based on this as a criterion and the work of Runnels, et al., (Runnels, R.T., Kulstead, R.O.,more » McDuffee, C. and Schleicher, J.A., 1952, Oil Shale in Kansas, Kansas Geological Survey Bulletin, No. 96, Part 3.) five eastern Kansas black shale units were selected for study and their areal distribution mapped. The volume of recoverable oil shale in each unit was calculated and translated to reserves. The report concludes that in all probability, extraction of oil shale for shale oil is not feasible at this time due to the cost of extraction, transportation and processing. The report recommends that additional studies be undertaken to provide a more comprehensive and detailed assessment of Kansas oil shales as a potential fuel resource. 49 references, 4 tables.« less

Research continues on Julia Creek shale oil project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-09-01

CSR Limited and the CSIRO Division of Mineral Engineering in Australia are working jointly on the development of a new retorting process for Julia Creek oil shale. This paper describes the retorting process which integrates a fluid bed combustor with a retort in which heat is transferred from hot shale ash to cold raw shale. The upgrading of shale oil into transport fuels is also described.

Development of a sintering process for recycling oil shale fly ash and municipal solid waste incineration bottom ash into glass ceramic composite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Zhikun; Zhang, Lei; Li, Aimin, E-mail: leeam@dlut.edu.cn

Highlights: • Glass ceramic composite is prepared from oil shale fly ash and MSWI bottom ash. • A novel method for the production of glass ceramic composite is presented. • It provides simple route and lower energy consumption in terms of recycling waste. • The vitrified slag can promote the sintering densification process of glass ceramic. • The performances of products decrease with the increase of oil shale fly ash content. - Abstract: Oil shale fly ash and municipal solid waste incineration bottom ash are industrial and municipal by-products that require further treatment before disposal to avoid polluting the environment.more » In the study, they were mixed and vitrified into the slag by the melt-quench process. The obtained vitrified slag was then mixed with various percentages of oil shale fly ash and converted into glass ceramic composites by the subsequent sintering process. Differential thermal analysis was used to study the thermal characteristics and determine the sintering temperatures. X-ray diffraction analysis was used to analyze the crystalline phase compositions. Sintering shrinkage, weight loss on ignition, density and compressive strength were tested to determine the optimum preparation condition and study the co-sintering mechanism of vitrified amorphous slag and oil shale fly ash. The results showed the product performances increased with the increase of sintering temperatures and the proportion of vitrified slag to oil shale fly ash. Glass ceramic composite (vitrified slag content of 80%, oil shale fly ash content of 20%, sintering temperature of 1000 °C and sintering time of 2 h) showed the properties of density of 1.92 ± 0.05 g/cm{sup 3}, weight loss on ignition of 6.14 ± 0.18%, sintering shrinkage of 22.06 ± 0.6% and compressive strength of 67 ± 14 MPa. The results indicated that it was a comparable waste-based material compared to previous researches. In particular, the energy consumption in the production process was reduced compared to conventional vitrification and sintering method. Chemical resistance and heavy metals leaching results of glass ceramic composites further confirmed the possibility of its engineering applications.« less

Application of petroleum demulsification technology to shale oil emulsions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robertson, R.E.

1983-01-01

Demulsification, the process of emulsion separation, of water-in-oil shale oil emulsions produced by several methods was accomplished using commercial chemical demulsifiers which are used typically for petroleum demulsification. The shale oil emulsions were produced from Green River shale by one in situ and three different above-ground retorts, an in situ high pressure/high temperature steam process, and by washing both retort-produced and hydrotreated shale oils.

Unconventional Liquid Flow in Low-Permeability Media: Theory and Revisiting Darcy's Law

NASA Astrophysics Data System (ADS)

Liu, H. H.; Chen, J.

2017-12-01

About 80% of fracturing fluid remains in shale formations after hydraulic fracturing and the flow back process. It is critical to understand and accurately model the flow process of fracturing fluids in a shale formation, because the flow has many practical applications for shale gas recovery. Owing to the strong solid-liquid interaction in low-permeability media, Darcy's law is not always adequate for describing liquid flow process in a shale formation. This non-Darcy flow behavior (characterized by nonlinearity of the relationship between liquid flux and hydraulic gradient), however, has not been given enough attention in the shale gas community. The current study develops a systematic methodology to address this important issue. We developed a phenomenological model for liquid flow in shale (in which liquid flux is a power function of pressure gradient), an extension of the conventional Darcy's law, and also a methodology to estimate parameters for the phenomenological model from spontaneous imbibition tests. The validity of our new developments is verified by satisfactory comparisons of theoretical results and observations from our and other research groups. The relative importance of this non-Darcy liquid flow for hydrocarbon production in unconventional reservoirs remains an issue that needs to be further investigated.

Lithologic Controls on Critical Zone Processes in a Variably Metamorphosed Shale-Hosted Watershed

NASA Astrophysics Data System (ADS)

Eldam Pommer, R.; Navarre-Sitchler, A.

2017-12-01

Local and regional shifts in thermal maturity within sedimentary shale systems impart significant variation in chemical and physical rock properties, such as pore-network morphology, mineralogy, organic carbon content, and solute release potential. Even slight variations in these properties on a watershed scale can strongly impact surface and shallow subsurface processes that drive soil formation, landscape evolution, and bioavailability of nutrients. Our ability to map and quantify the effects of this heterogeneity on critical zone processes is hindered by the complex coupling of the multi-scale nature of rock properties, geochemical signatures, and hydrological processes. This study addresses each of these complexities by synthesizing chemical and physical characteristics of variably metamorphosed shales in order to link rock heterogeneity with modern earth surface and shallow subsurface processes. More than 80 samples of variably metamorphosed Mancos Shale were collected in the East River Valley, Colorado, a headwater catchment of the Upper Colorado River Basin. Chemical and physical analyses of the samples show that metamorphism decreases overall rock porosity, pore anisotropy, and surface area, and introduces unique chemical signatures. All of these changes result in lower overall solute release from the Mancos Shale in laboratory dissolution experiments and a change in rock-derived solute chemistry with decreasing organic carbon and cation exchange capacity (Ca, Na, Mg, and K). The increase in rock competency and decrease in reactivity of the more thermally mature shales appear to subsequently control river morphology, with lower channel sinuosity associated with areas of the catchment underlain by metamorphosed Mancos Shale. This work illustrates the formative role of the geologic template on critical zone processes and landscape development within and across watersheds.

Baseline studies on the feasibility of detecting a coal/shale interface with a self-powered sensitized pick

NASA Technical Reports Server (NTRS)

Anderson, G. R., II

1981-01-01

The feasibility of utilizing a sensitized pick to discriminate between cutting coal and roof material during the longwall mining process was investigated. A conventional longwall mining pick was instrumented and cutting force magnitudes were determined for a variety of materials, including Illinois #6 coal, shale type materials, and synthetic coal/shale materials.

Process for oil shale retorting

DOEpatents

Jones, John B.; Kunchal, S. Kumar

1981-10-27

Particulate oil shale is subjected to a pyrolysis with a hot, non-oxygenous gas in a pyrolysis vessel, with the products of the pyrolysis of the shale contained kerogen being withdrawn as an entrained mist of shale oil droplets in a gas for a separation of the liquid from the gas. Hot retorted shale withdrawn from the pyrolysis vessel is treated in a separate container with an oxygenous gas so as to provide combustion of residual carbon retained on the shale, producing a high temperature gas for the production of some steam and for heating the non-oxygenous gas used in the oil shale retorting process in the first vessel. The net energy recovery includes essentially complete recovery of the organic hydrocarbon material in the oil shale as a liquid shale oil, a high BTU gas, and high temperature steam.

Oil shale derived pollutant control materials and methods and apparatuses for producing and utilizing the same

DOEpatents

Boardman, Richard D.; Carrington, Robert A.

2010-05-04

Pollution control substances may be formed from the combustion of oil shale, which may produce a kerogen-based pyrolysis gas and shale sorbent, each of which may be used to reduce, absorb, or adsorb pollutants in pollution producing combustion processes, pyrolysis processes, or other reaction processes. Pyrolysis gases produced during the combustion or gasification of oil shale may also be used as a combustion gas or may be processed or otherwise refined to produce synthetic gases and fuels.

Talaromyces sayulitensis, Acidiella bohemica and Penicillium citrinum in Brazilian oil shale by-products.

PubMed

de Goes, Kelly C G P; da Silva, Josué J; Lovato, Gisele M; Iamanaka, Beatriz T; Massi, Fernanda P; Andrade, Diva S

2017-12-01

Fine shale particles and retorted shale are waste products generated during the oil shale retorting process. These by-products are small fragments of mined shale rock, are high in silicon and also contain organic matter, micronutrients, hydrocarbons and other elements. The aims of this study were to isolate and to evaluate fungal diversity present in fine shale particles and retorted shale samples collected at the Schist Industrialization Business Unit (Six)-Petrobras in São Mateus do Sul, State of Paraná, Brazil. Combining morphology and internal transcribed spacer (ITS) sequence, a total of seven fungal genera were identified, including Acidiella, Aspergillus, Cladosporium, Ochroconis, Penicillium, Talaromyces and Trichoderma. Acidiella was the most predominant genus found in the samples of fine shale particles, which are a highly acidic substrate (pH 2.4-3.6), while Talaromyces was the main genus in retorted shale (pH 5.20-6.20). Talaromyces sayulitensis was the species most frequently found in retorted shale, and Acidiella bohemica in fine shale particles. The presence of T. sayulitensis, T. diversus and T. stolli in oil shale is described herein for the first time. In conclusion, we have described for the first time a snapshot of the diversity of filamentous fungi colonizing solid oil shale by-products from the Irati Formation in Brazil.

Preliminary view of geotechnical properties of soft rocks of Semanggol formation at Pokok Sena, Kedah

NASA Astrophysics Data System (ADS)

Ahmad, N. R.; Jamin, N. H.

2018-04-01

The research was inspired by series of geological studies on Semanggol formation found exposed at North Perak, South Kedah and North Kedah. The chert unit comprised interbedded chert-shale rocks are the main lithologies sampled in a small-scale outcrop of Pokok Sena area. Black shale materials were also observed associated with these sedimentary rocks. The well-known characteristics of shale that may swell when absorb water and leave shrinkage when dried make the formation weaker when load is applied on it. The presence of organic materials may worsen the condition apart from the other factors such as the history of geological processes and depositional environment. Thus, this research is important to find the preliminary relations of the geotechnical properties of soft rocks and the geological reasoning behind it. Series of basic soil tests and 1-D compression tests were carried out to obtain the soil parameters. The results obtained gave some preliminary insight to mechanical behaviour of these two samples. The black shale and weathered interbedded chert-shale were classified as sandy-clayey-SILT and clayey-silty-SAND respectively. The range of specific gravity of black shale and interbedded chert/shale 2.3 – 2.6 and fall in the common range of shale and chert specific gravity value. In terms of degree of plasticity, the interbedded chert/shale samples exhibit higher plastic degree compared to the black shale samples. Results from oedometer tests showed that black shale samples had higher overburden pressure (Pc) throughout its lifetime compare to weathered interbedded chert-shale, however the compression index (Cc) of black shale were 0.15 – 0.185 which was higher than that found in interbedded chert-shale. The geotechnical properties of these two samples were explained in correlation with their provenance and their history of geological processes involved which predominantly dictated the mechanical behaviour of these two samples.

16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

Code of Federal Regulations, 2014 CFR

2014-01-01

... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands together with... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands and associated... pipeline and pipeline system or processing facility which transports or processes oil and gas after it...

16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

Code of Federal Regulations, 2010 CFR

2010-01-01

... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands together with... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands and associated... pipeline and pipeline system or processing facility which transports or processes oil and gas after it...

16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

Code of Federal Regulations, 2013 CFR

2013-01-01

... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands together with... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands and associated... pipeline and pipeline system or processing facility which transports or processes oil and gas after it...

16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

Code of Federal Regulations, 2012 CFR

2012-01-01

... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands together with... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands and associated... pipeline and pipeline system or processing facility which transports or processes oil and gas after it...

16 CFR 802.3 - Acquisitions of carbon-based mineral reserves.

Code of Federal Regulations, 2011 CFR

2011-01-01

... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands together with... gas, shale or tar sands, or rights to reserves of oil, natural gas, shale or tar sands and associated... pipeline and pipeline system or processing facility which transports or processes oil and gas after it...

Preparation of grout for stabilization of abandoned in-situ oil shale retorts

DOEpatents

Mallon, Richard G.

1982-01-01

A process for the preparation of grout from burned shale by treating the burned shale in steam at approximately 700.degree. C. to maximize the production of the materials alite and larnite. Oil shale removed to the surface during the preparation of an in-situ retort is first retorted on the surface and then the carbon is burned off, leaving burned shale. The burned shale is treated in steam at approximately 700.degree. C. for about 70 minutes. The treated shale is then ground and mixed with water to produce a grout which is pumped into an abandoned, processed in-situ retort, flowing into the void spaces and then bonding up to form a rigid, solidified mass which prevents surface subsidence and leaching of the spent shale by ground water.

Noble Gas Signatures in Antrim Shale Gas in the Michigan Basin - Assessing Compositional Variability and Transport Processes

NASA Astrophysics Data System (ADS)

Wen, T.; Castro, M. C.; Ellis, B. R.; Hall, C. M.; Lohmann, K. C.; Bouvier, L.

2014-12-01

Recent studies in the Michigan Basin looked at the atmospheric and terrigenic noble gas signatures of deep brines to place constraints on the past thermal history of the basin and to assess the extent of vertical transport processes within this sedimentary system. In this contribution, we present noble gas data of shale gas samples from the Antrim shale formation in the Michigan Basin. The Antrim shale was one of the first economic shale-gas plays in the U.S. and has been actively developed since the 1980's. This study pioneers the use of noble gases in subsurface shale gas in the Michigan Basin to clarify the nature of vertical transport processes within the sedimentary sequence and to assess potential variability of noble gas signatures in shales. Antrim Shale gas samples were analyzed for all stable noble gases (He, Ne, Ar, Kr, Xe) from samples collected at depths between 300 and 500m. Preliminary results show R/Ra values (where R and Ra are the measured and atmospheric 3He/4He ratios, respectively) varying from 0.022 to 0.21. Although most samples fall within typical crustal R/Ra range values (~0.02-0.05), a few samples point to the presence of a mantle He component with higher R/Ra ratios. Samples with higher R/Ra values also display higher 20Ne/22Ne ratios, up to 10.4, and further point to the presence of mantle 20Ne. The presence of crustally produced nucleogenic 21Ne and radiogenic 40Ar is also apparent with 21Ne/22Ne ratios up to 0.033 and 40Ar/36Ar ratios up to 312. The presence of crustally produced 4He, 21Ne and 40Ar is not spatially homogeneous within the Antrim shale. Areas of higher crustal 4He production appear distinct to those of crustally produced 21Ne and 40Ar and are possibly related the presence of different production levels within the shale with varying concentrations of parent elements.

Method of operating an oil shale kiln

DOEpatents

Reeves, Adam A.

1978-05-23

Continuously determining the bulk density of raw and retorted oil shale, the specific gravity of the raw oil shale and the richness of the raw oil shale provides accurate means to control process variables of the retorting of oil shale, predicting oil production, determining mining strategy, and aids in controlling shale placement in the kiln for the retorting.

Development of a sintering process for recycling oil shale fly ash and municipal solid waste incineration bottom ash into glass ceramic composite.

PubMed

Zhang, Zhikun; Zhang, Lei; Li, Aimin

2015-04-01

Oil shale fly ash and municipal solid waste incineration bottom ash are industrial and municipal by-products that require further treatment before disposal to avoid polluting the environment. In the study, they were mixed and vitrified into the slag by the melt-quench process. The obtained vitrified slag was then mixed with various percentages of oil shale fly ash and converted into glass ceramic composites by the subsequent sintering process. Differential thermal analysis was used to study the thermal characteristics and determine the sintering temperatures. X-ray diffraction analysis was used to analyze the crystalline phase compositions. Sintering shrinkage, weight loss on ignition, density and compressive strength were tested to determine the optimum preparation condition and study the co-sintering mechanism of vitrified amorphous slag and oil shale fly ash. The results showed the product performances increased with the increase of sintering temperatures and the proportion of vitrified slag to oil shale fly ash. Glass ceramic composite (vitrified slag content of 80%, oil shale fly ash content of 20%, sintering temperature of 1000 °C and sintering time of 2h) showed the properties of density of 1.92 ± 0.05 g/cm(3), weight loss on ignition of 6.14 ± 0.18%, sintering shrinkage of 22.06 ± 0.6% and compressive strength of 67 ± 14 MPa. The results indicated that it was a comparable waste-based material compared to previous researches. In particular, the energy consumption in the production process was reduced compared to conventional vitrification and sintering method. Chemical resistance and heavy metals leaching results of glass ceramic composites further confirmed the possibility of its engineering applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Preparation of grout for stabilization of abandoned in-situ oil shale retorts. [Patent application

DOEpatents

Mallon, R.G.

1979-12-07

A process is described for the preparation of grout from burned shale by treating the burned shale in steam at approximately 700/sup 0/C to maximize the production of the materials alite and larnite. Oil shale removed to the surface during the preparation of an in-situ retort is first retorted on the surface and then the carbon is burned off, leaving burned shale. The burned shale is treated in steam at approximately 700/sup 0/C for about 70 minutes. The treated shale is then ground and mixed with water to produce a grout which is pumped into an abandoned, processed in-situ retort, flowing into the void spaces and then bonding up to form a rigid, solidified mass which prevents surface subsidence and leaching of the spent shale by ground water.

Rare earth element geochemistry of outcrop and core samples from the Marcellus Shale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noack, Clinton W.; Jain, Jinesh C.; Stegmeier, John

In this paper, we studied the geochemistry of the rare earth elements (REE) in eleven outcrop samples and six, depth-interval samples of a core from the Marcellus Shale. The REE are classically applied analytes for investigating depositional environments and inferring geochemical processes, making them of interest as potential, naturally occurring indicators of fluid sources as well as indicators of geochemical processes in solid waste disposal. However, little is known of the REE occurrence in the Marcellus Shale or its produced waters, and this study represents one of the first, thorough characterizations of the REE in the Marcellus Shale. In thesemore » samples, the abundance of REE and the fractionation of REE profiles were correlated with different mineral components of the shale. Namely, samples with a larger clay component were inferred to have higher absolute concentrations of REE but have less distinctive patterns. Conversely, samples with larger carbonate fractions exhibited a greater degree of fractionation, albeit with lower total abundance. Further study is necessary to determine release mechanisms, as well as REE fate-and-transport, however these results have implications for future brine and solid waste management applications.« less

Rare earth element geochemistry of outcrop and core samples from the Marcellus Shale

DOE PAGES

Noack, Clinton W.; Jain, Jinesh C.; Stegmeier, John; ...

2015-06-26

In this paper, we studied the geochemistry of the rare earth elements (REE) in eleven outcrop samples and six, depth-interval samples of a core from the Marcellus Shale. The REE are classically applied analytes for investigating depositional environments and inferring geochemical processes, making them of interest as potential, naturally occurring indicators of fluid sources as well as indicators of geochemical processes in solid waste disposal. However, little is known of the REE occurrence in the Marcellus Shale or its produced waters, and this study represents one of the first, thorough characterizations of the REE in the Marcellus Shale. In thesemore » samples, the abundance of REE and the fractionation of REE profiles were correlated with different mineral components of the shale. Namely, samples with a larger clay component were inferred to have higher absolute concentrations of REE but have less distinctive patterns. Conversely, samples with larger carbonate fractions exhibited a greater degree of fractionation, albeit with lower total abundance. Further study is necessary to determine release mechanisms, as well as REE fate-and-transport, however these results have implications for future brine and solid waste management applications.« less

Black shale - Its deposition and diagenesis.

USGS Publications Warehouse

Tourtelot, H.A.

1979-01-01

Black shale is a dark-colored mudrock containing organic matter that may have generated hydrocarbons in the subsurface or that may yield hydrocarbons by pyrolysis. Many black shale units are enriched in metals severalfold above expected amounts in ordinary shale. Some black shale units have served as host rocks for syngenetic metal deposits.Black shales have formed throughout the Earth's history and in all parts of the world. This suggests that geologic processes and not geologic settings are the controlling factors in the accumulation of black shale. Geologic processes are those of deposition by which the raw materials of black shale are accumulated and those of diagenesis in response to increasing depth of burial.Depositional processes involve a range of relationships among such factors as organic productivity, clastic sedimentation rate, and the intensity of oxidation by which organic matter is destroyed. If enough organic material is present to exhaust the oxygen in the environment, black shale results.Diagenetic processes involve chemical reactions controlled by the nature of the components and by the pressure and temperature regimens that continuing burial imposes. For a thickness of a few meters beneath the surface, sulfate is reduced and sulfide minerals may be deposited. Fermentation reactions in the next several hundred meters result in biogenic methane, followed successively at greater depths by decarboxylation reactions and thermal maturation that form additional hydrocarbons. Suites of newly formed minerals are characteristic for each of the zones of diagenesis.

Development of measures to improve technologies of energy recovery from gaseous wastes of oil shale processing

NASA Astrophysics Data System (ADS)

Tugov, A. N.; Ots, A.; Siirde, A.; Sidorkin, V. T.; Ryabov, G. A.

2016-06-01

Prospects of the use of oil shale are associated with its thermal processing for the production of liquid fuel, shale oil. Gaseous by-products, such as low-calorie generator gas with a calorific value up to 4.3MJ/m3 or semicoke gas with a calorific value up to 56.57 MJ/m3, are generated depending on the oil shale processing method. The main methods of energy recovery from these gases are either their cofiring with oil shale in power boilers or firing only under gaseous conditions in reconstructed or specially designed for this fuel boilers. The possible use of gaseous products of oil shale processing in gas-turbine or gas-piston units is also considered. Experiments on the cofiring of oil shale gas and its gaseous processing products have been carried out on boilers BKZ-75-39FSl in Kohtla-Järve and on the boiler TP-101 of the Estonian power plant. The test results have shown that, in the case of cofiring, the concentration of sulfur oxides in exhaust gases does not exceed the level of existing values in the case of oil shale firing. The low-temperature corrosion rate does not change as compared to the firing of only oil shale, and, therefore, operation conditions of boiler back-end surfaces do not worsen. When implementing measures to reduce the generation of NO x , especially of flue gas recirculation, it has been possible to reduce the emissions of nitrogen oxides in the whole boiler. The operation experience of the reconstructed boilers BKZ-75-39FSl after their transfer to the firing of only gaseous products of oil shale processing is summarized. Concentrations of nitrogen and sulfur oxides in the combustion products of semicoke and generator gases are measured. Technical solutions that made it possible to minimize the damage to air heater pipes associated with the low-temperature sulfur corrosion are proposed and implemented. The technological measures for burners of new boilers that made it possible to burn gaseous products of oil shale processing with low emissions of nitrogen oxides are developed.

Organic metamorphism in the Lower Mississippian-Upper Devonian Bakken shales-II: Soxhlet extraction.

USGS Publications Warehouse

Price, L.C.; Ging, T.; Love, A.; Anders, D.

1986-01-01

We report on Soxhlet extraction (and subsequent related analyses) of 39 Lower Mississippian-Upper Devonian Bakken shales from the North Dakota portion of the Williston Basin, and analyses of 28 oils from the Basin. Because of the influence of primary petroleum migration, no increase in the relative or absolute concentrations of hydrocarbons or bitumen was observed at the threshold of intense hydrocarbon generation (TIHG), or during mainstage hydrocarbon generation in the Bakken shales. Thus, the maturation indices that have been so useful in delineating the TIHG and mainstage hydrocarbon generation in other studies were of no use in this study, where these events could clearly be identified only by Rock-Eval pyrolysis data. The data of this study demonstrate that primary petroleum migration is a very efficient process. Four distinctive classes of saturated hydrocarbon gas chromatograms from the Bakken shales arose from facies, maturation, and primary migration controls. As a consequence of maturation, the % of saturated hydrocarbons increased in the shale extract at the expense of decreases in the resins and asphaltenes. Measurements involving resins and asphaltenes appear to be excellent maturation indices in the Bakken shales. Two different and distinct organic facies were present in immature Bakken shales. -from Authors

Implications of contact metamorphism of Mancos Shale for critical zone processes

NASA Astrophysics Data System (ADS)

Navarre-Sitchler, A.

2016-12-01

Bedrock lithology imparts control on some critical zone processes, for example rates and extent of chemical weathering, solute release though mineral dissolution, and water flow. Bedrock can be very heterogeneous resulting in spatial variability of these processes throughout a catchment. In the East River watershed outside of Crested Butte, Colorado, bedrock is dominantly comprised of the Mancos Shale; a Cretaceous aged, organic carbon rich marine shale. However, in some areas the Mancos Shale appears contact metamorphosed by nearby igneous intrusions resulting in a potential gradient in lithologic change in part of the watershed where impacts of lithology on critical zone processes can be evaluated. Samples were collected in the East River valley along a transect from the contact between the Tertiary Gothic Mountain laccolith of the Mount Carbon igneous system and the underlying Manocs shale. Porosity of these samples was analyzed by small-angle and ultra small-angle neutron scattering. Results indicate contact metamorphism decreases porosity of the shale and changes the pore shape from slightly anisotropic pores aligned with bedding in the unmetamorphosed shale to isotropic pores with no bedding alignment in the metamorphosed shales. The porosity analysis combined with clay mineralogy, surface area, carbon content and oxidation state, and solute release rates determined from column experiments will be used to develop a full understanding of the impact of contact metamorphism on critical zone processes in the East River.

Comparative acute toxicity of shale and petroleum derived distillates.

PubMed

Clark, C R; Ferguson, P W; Katchen, M A; Dennis, M W; Craig, D K

1989-12-01

In anticipation of the commercialization of its shale oil retorting and upgrading process, Unocal Corp. conducted a testing program aimed at better defining potential health impacts of a shale industry. Acute toxicity studies using rats and rabbits compared the effects of naphtha, Jet-A, JP-4, diesel and "residual" distillate fractions of both petroleum derived crude oils and hydrotreated shale oil. No differences in the acute oral (greater than 5 g/kg LD50) and dermal (greater than 2 g/kg LD50) toxicities were noted between the shale and petroleum derived distillates and none of the samples were more than mildly irritating to the eyes. Shale and petroleum products caused similar degrees of mild to moderate skin irritation. None of the materials produced sensitization reactions. The LC50 after acute inhalation exposure to Jet-A, shale naphtha, (greater than 5 mg/L) and JP-4 distillate fractions of petroleum and shale oils was greater than 5 mg/L. The LC50 of petroleum naphtha (greater than 4.8 mg/L) and raw shale oil (greater than 3.95 mg/L) also indicated low toxicity. Results demonstrate that shale oil products are of low acute toxicity, mild to moderately irritating and similar to their petroleum counterparts. The results further demonstrate that hydrotreatment reduces the irritancy of raw shale oil.

Process for oil shale retorting using gravity-driven solids flow and solid-solid heat exchange

DOEpatents

Lewis, A.E.; Braun, R.L.; Mallon, R.G.; Walton, O.R.

1983-09-21

A cascading bed retorting process and apparatus are disclosed in which cold raw crushed shale enters at the middle of a retort column into a mixer stage where it is rapidly mixed with hot recycled shale and thereby heated to pyrolysis temperature. The heated mixture then passes through a pyrolyzer stage where it resides for a sufficient time for complete pyrolysis to occur. The spent shale from the pyrolyzer is recirculated through a burner stage where the residual char is burned to heat the shale which then enters the mixer stage.

Process for oil shale retorting using gravity-driven solids flow and solid-solid heat exchange

DOEpatents

Lewis, Arthur E.; Braun, Robert L.; Mallon, Richard G.; Walton, Otis R.

1986-01-01

A cascading bed retorting process and apparatus in which cold raw crushed shale enters at the middle of a retort column into a mixer stage where it is rapidly mixed with hot recycled shale and thereby heated to pyrolysis temperature. The heated mixture then passes through a pyrolyzer stage where it resides for a sufficient time for complete pyrolysis to occur. The spent shale from the pyrolyzer is recirculated through a burner stage where the residual char is burned to heat the shale which then enters the mixer stage.

Oil-shale program

NASA Astrophysics Data System (ADS)

Bader, B. E.

1981-10-01

The principal activities of the Sandia National Laboratories in the Department of Energy Oil shale program during the period April 1 to June 30, 1981 are discussed. Currently, Sandia's activities are focused upon: the development and use of analytical and experimental modeling techniques to describe and predict the retort properties and retorting process parameters that are important to the preparation, operation, and stability of in situ retorts, and the development, deployment, and field use of instrumentation, data acquisition, and process monitoring systems to characterize and evaluate in site up shale oil recovery operations. In-house activities and field activities (at the Geokinetics Oil Shale Project and the Occidental Oil Shale Project) are described under the headings: bed preparation, bed characterization, retorting process, and structural stability.

Field studies on USBM and TOSCO II retorted oil shales: vegetation, moisture, salinity, and runoff, 1977-1980. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kilkelly, M.K.; Berg, W.A.; Harbert, H.P. III

1981-08-01

Field studies were initiated in 1973 to investigate the vegetative stabilization of processed oil shales and to follow moisture and soluble salt movement within the soil/shale profile. Research plots with two types of retorted shales (TOSCO II and USBM) with leaching and soil cover treatments were established at two locations: low-elevation (Anvil Points) and high-elevation (Piceance Basin) in western Colorado. Vegetation was established by intensive management including leaching, N and P fertilization, seeding, mulching, and irrigation. After seven growing seasons, a good vegetative cover remained with few differences between treatments, with the exception of the TOSCO retorted shale, south-aspect, whichmore » consistently supported less perennial vegetative cover than other treatments. With time, a shift from perennial grasses to dominance by shrubs was observed. Rodent activity on some treatments had a significantly negative effect on vegetative cover.« less

Porosity evolution during weathering of Marcellus shale

NASA Astrophysics Data System (ADS)

Gu, X.; Brantley, S.

2017-12-01

Weathering is an important process that continuously converts rock to regolith. Shale weathering is of particular interest because 1) shale covers about 25% of continental land mass; 2) recent development of unconventional shale gas generates large volumes of rock cuttings. When cuttings are exposed at earth's surface, they can release toxic trace elements during weathering. In this study, we investigated the evolution of pore structures and mineral transformation in an outcrop of Marcellus shale - one of the biggest gas shale play in North America - at Frankstown, Pennsylvania. A combination of neutron scattering and imaging was used to characterize the pore structures from nm to mm. The weathering profile of Marcellus shale was also compared to the well-studied Rose Hill shale from the Susquehanna Shale Hills critical zone observatory nearby. This latter shale has a similar mineral composition as Marcellus shale but much lower concentrations of pyrite and OC. The Marcellus shale formation in outcrop overlies a layer of carbonate at 10 m below land surface with low porosity (<3%). All the shale samples above the carbonate layer are almost completely depleted in carbonate, plagioclase, chlorite and pyrite. The porosities in the weathered Marcellus shale are twice as high as in protolith. The pore size distribution exhibits a broad peak for pores of size in the range of 10s of microns, likely due to the loss of OC and/or dissolution of carbonate during weathering. In the nearby Rose Hill shale, the pyrite and carbonate are sharply depleted close to the water table ( 15-20 m at ridgetop); while chlorite and plagioclase are gradually depleted toward the land surface. The greater weathering extent of silicates in the Marcellus shale despite the similarity in climate and erosion rate in these two neighboring locations is attributed to 1) the formation of micron-size pores increases the infiltration rate into weathered Marcellus shale and therefore promotes mineral weathering; 2) the pyrite/carbonate ratio is higher in the Marcellus shale than in Rose Hill shale, and thus excess acidity generated through pyrite oxidation enhances the dissolution of silicates. We seek to use these and other observations to develop a global model for shale weathering that incorporates both mineral composition and porosity change.

Liquid oil production from shale gas condensate reservoirs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheng, James J.

A process of producing liquid oil from shale gas condensate reservoirs and, more particularly, to increase liquid oil production by huff-n-puff in shale gas condensate reservoirs. The process includes performing a huff-n-puff gas injection mode and flowing the bottom-hole pressure lower than the dew point pressure.

Synthesis and analysis of jet fuel from shale oil and coal syncrudes

NASA Technical Reports Server (NTRS)

Gallagher, J. P.; Collins, T. A.; Nelson, T. J.; Pedersen, M. J.; Robison, M. G.; Wisinski, L. J.

1976-01-01

Thirty-two jet fuel samples of varying properties were produced from shale oil and coal syncrudes, and analyzed to assess their suitability for use. TOSCO II shale oil and H-COAL and COED syncrudes were used as starting materials. The processes used were among those commonly in use in petroleum processing-distillation, hydrogenation and catalytic hydrocracking. The processing conditions required to meet two levels of specifications regarding aromatic, hydrogen, sulfur and nitrogen contents at two yield levels were determined and found to be more demanding than normally required in petroleum processing. Analysis of the samples produced indicated that if the more stringent specifications of 13.5% hydrogen (min.) and 0.02% nitrogen (max.) were met, products similar in properties to conventional jet fuels were obtained. In general, shale oil was easier to process (catalyst deactivation was seen when processing coal syncrudes), consumed less hydrogen and yielded superior products. Based on these considerations, shale oil appears to be preferred to coal as a petroleum substitute for jet fuel production.

Review of rare earth element concentrations in oil shales of the Eocene Green River Formation

USGS Publications Warehouse

Birdwell, Justin E.

2012-01-01

Concentrations of the lanthanide series or rare earth elements and yttrium were determined for lacustrine oil shale samples from the Eocene Green River Formation in the Piceance Basin of Colorado and the Uinta Basin of Utah. Unprocessed oil shale, post-pyrolysis (spent) shale, and leached shale samples were examined to determine if oil-shale processing to generate oil or the remediation of retorted shale affects rare earth element concentrations. Results for unprocessed Green River oil shale samples were compared to data published in the literature on reference materials, such as chondritic meteorites, the North American shale composite, marine oil shale samples from two sites in northern Tibet, and mined rare earth element ores from the United States and China. The Green River oil shales had lower rare earth element concentrations (66.3 to 141.3 micrograms per gram, μg g-1) than are typical of material in the upper crust (approximately 170 μg g-1) and were also lower in rare earth elements relative to the North American shale composite (approximately 165 μg g-1). Adjusting for dilution of rare earth elements by organic matter does not account for the total difference between the oil shales and other crustal rocks. Europium anomalies for Green River oil shales from the Piceance Basin were slightly lower than those reported for the North American shale composite and upper crust. When compared to ores currently mined for rare earth elements, the concentrations in Green River oil shales are several orders of magnitude lower. Retorting Green River oil shales led to a slight enrichment of rare earth elements due to removal of organic matter. When concentrations in spent and leached samples were normalized to an original rock basis, concentrations were comparable to those of the raw shale, indicating that rare earth elements are conserved in processed oil shales.

The origin of Cretaceous black shales: a change in the surface ocean ecosystem and its triggers

PubMed Central

OHKOUCHI, Naohiko; KURODA, Junichiro; TAIRA, Asahiko

2015-01-01

Black shale is dark-colored, organic-rich sediment, and there have been many episodes of black shale deposition over the history of the Earth. Black shales are source rocks for petroleum and natural gas, and thus are both geologically and economically important. Here, we review our recent progress in understanding of the surface ocean ecosystem during periods of carbonaceous sediment deposition, and the factors triggering black shale deposition. The stable nitrogen isotopic composition of geoporphyrins (geological derivatives of chlorophylls) strongly suggests that N2-fixation was a major process for nourishing the photoautotrophs. A symbiotic association between diatoms and cyanobacteria may have been a major primary producer during episodes of black shale deposition. The timing of black shale formation in the Cretaceous is strongly correlated with the emplacement of large igneous provinces such as the Ontong Java Plateau, suggesting that black shale deposition was ultimately induced by massive volcanic events. However, the process that connects these events remains to be solved. PMID:26194853

Characterization of oil shale, isolated kerogen, and post-pyrolysis residues using advanced 13 solid-state nuclear magnetic resonance spectroscopy

USGS Publications Warehouse

Cao, Xiaoyan; Birdwell, Justin E.; Chappell, Mark A.; Li, Yuan; Pignatello, Joseph J.; Mao, Jingdong

2013-01-01

Characterization of oil shale kerogen and organic residues remaining in postpyrolysis spent shale is critical to the understanding of the oil generation process and approaches to dealing with issues related to spent shale. The chemical structure of organic matter in raw oil shale and spent shale samples was examined in this study using advanced solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Oil shale was collected from Mahogany zone outcrops in the Piceance Basin. Five samples were analyzed: (1) raw oil shale, (2) isolated kerogen, (3) oil shale extracted with chloroform, (4) oil shale retorted in an open system at 500°C to mimic surface retorting, and (5) oil shale retorted in a closed system at 360°C to simulate in-situ retorting. The NMR methods applied included quantitative direct polarization with magic-angle spinning at 13 kHz, cross polarization with total sideband suppression, dipolar dephasing, CHn selection, 13C chemical shift anisotropy filtering, and 1H-13C long-range recoupled dipolar dephasing. The NMR results showed that, relative to the raw oil shale, (1) bitumen extraction and kerogen isolation by demineralization removed some oxygen-containing and alkyl moieties; (2) unpyrolyzed samples had low aromatic condensation; (3) oil shale pyrolysis removed aliphatic moieties, leaving behind residues enriched in aromatic carbon; and (4) oil shale retorted in an open system at 500°C contained larger aromatic clusters and more protonated aromatic moieties than oil shale retorted in a closed system at 360°C, which contained more total aromatic carbon with a wide range of cluster sizes.

Methods for minimizing plastic flow of oil shale during in situ retorting

DOEpatents

Lewis, Arthur E.; Mallon, Richard G.

1978-01-01

In an in situ oil shale retorting process, plastic flow of hot rubblized oil shale is minimized by injecting carbon dioxide and water into spent shale above the retorting zone. These gases react chemically with the mineral constituents of the spent shale to form a cement-like material which binds the individual shale particles together and bonds the consolidated mass to the wall of the retort. This relieves the weight burden borne by the hot shale below the retorting zone and thereby minimizes plastic flow in the hot shale. At least a portion of the required carbon dioxide and water can be supplied by recycled product gases.

Jet fuels from synthetic crudes

NASA Technical Reports Server (NTRS)

Antoine, A. C.; Gallagher, J. P.

1977-01-01

An investigation was conducted to determine the technical problems in the conversion of a significant portion of a barrel of either a shale oil or a coal synthetic crude oil into a suitable aviation turbine fuel. Three syncrudes were used, one from shale and two from coal, chosen as representative of typical crudes from future commercial production. The material was used to produce jet fuels of varying specifications by distillation, hydrotreating, and hydrocracking. Attention is given to process requirements, hydrotreating process conditions, the methods used to analyze the final products, the conditions for shale oil processing, and the coal liquid processing conditions. The results of the investigation show that jet fuels of defined specifications can be made from oil shale and coal syncrudes using readily available commercial processes.

CONTROL OF SULFUR EMISSIONS FROM OIL SHALE RETORTING USING SPEND SHALE ABSORPTION

EPA Science Inventory

The paper gives results of a detailed engineering evaluation of the potential for using an absorption on spent shale process (ASSP) for controlling sulfur emissions from oil shale plants. The evaluation analyzes the potential effectiveness and cost of absorbing SO2 on combusted s...

Process for recovering products from oil shale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobs, H.R.; Udell, K.S.

A process is claimed for recovering hydrocarbon products from a body of fragmented or rubblized oil shale. The process includes initiating a combustion zone adjacent the lower end of a body of oil shale and using the thermal energy therefrom for volatilizing the shale oil from the oil shale above the combustion front. Improved recovery of hydrocarbon products is realized by refluxing the heavier fractions in the volatilized shale oil. The heavier fractions are refluxed by condensing the heavier fractions and allowing the resulting condensate to flow downwardly toward the combustion front. Thermal energy from the combustion zone cracks themore » condensate producing additional lower molecular weight fractions and a carbonaceous residue. The carbonaceous residue is burned in the combustion front to supply the thermal energy. The temperature of the combustion front is maintained by regulating input of oxygen to the combustion zone. The process also includes sweeping the volatilized products from the rubblized oil shale with a noncombustible gas. The flow rate of sweep gas is also controlled to regulate the temperature of the combustion front. The recovered products can be enriched with hydrogen by using water vapor as part of the noncombustible sweep gas and cracking the water vapor with the hot carbon in the combustion front to produce hydrogen and an oxide of carbon.« less

43 CFR 3922.10 - Application processing fee.

Code of Federal Regulations, 2012 CFR

2012-10-01

... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL SHALE LEASING Application Processing... process for a competitive oil shale lease is as follows: (1) The applicant nominating the tract for...

43 CFR 3922.10 - Application processing fee.

Code of Federal Regulations, 2011 CFR

2011-10-01

... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) OIL SHALE LEASING Application Processing... process for a competitive oil shale lease is as follows: (1) The applicant nominating the tract for...

43 CFR 3922.10 - Application processing fee.

Code of Federal Regulations, 2014 CFR

2014-10-01

... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL SHALE LEASING Application Processing... process for a competitive oil shale lease is as follows: (1) The applicant nominating the tract for...

43 CFR 3922.10 - Application processing fee.

Code of Federal Regulations, 2013 CFR

2013-10-01

... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL SHALE LEASING Application Processing... process for a competitive oil shale lease is as follows: (1) The applicant nominating the tract for...

A comparative study of removal of fluoride from contaminated water using shale collected from different coal mines in India.

PubMed

Biswas, Gargi; Dutta, Manjari; Dutta, Susmita; Adhikari, Kalyan

2016-05-01

Low-cost water defluoridation technique is one of the most important issues throughout the world. In the present study, shale, a coal mine waste, is employed as novel and low-cost adsorbent to abate fluoride from simulated solution. Shale samples were collected from Mahabir colliery (MBS) and Sonepur Bazari colliery (SBS) of Raniganj coalfield in West Bengal, India, and used to remove fluoride. To increase the adsorption efficiency, shale samples were heat activated at a higher temperature and samples obtained at 550 °C are denoted as heat-activated Mahabir colliery shale (HAMBS550) and heat-activated Sonepur Bazari colliery shale (HASBS550), respectively. To prove the fluoride adsorption onto different shale samples and ascertain its mechanism, natural shale samples, heat-activated shale samples, and their fluoride-loaded forms were characterized using scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction study, and Fourier transform infrared spectroscopy. The effect of different parameters such as pH, adsorbent dose, size of particles, and initial concentration of fluoride was investigated during fluoride removal in a batch contactor. Lower pH shows better adsorption in batch study, but it is acidic in nature and not suitable for direct consumption. However, increase of pH of the solution from 3.2 to 6.8 and 7.2 during fluoride removal process with HAMBS550 and HASBS550, respectively, confirms the applicability of the treated water for domestic purposes. HAMBS550 and HASBS550 show maximum removal of 88.3 and 88.5 %, respectively, at initial fluoride concentration of 10 mg/L, pH 3, and adsorbent dose of 70 g/L.

Geotechnical Properties of Oil Shale Retorted by the PARAHO and TOSCO Processes.

DTIC Science & Technology

1979-11-01

literature search was restricted to the Green River formation of oil shale in the tri-state area of Colorado (Piceance Basin ), Utah ( Uinta Basin ), and...it is preheated by combustion gases as it travels downward by gravity. Air and recycling gas are injected at midheight and are burned, bringing the oil ...REFERENCES..................................38 TABLES 1-5 APPENDIX A: OIL SHALE RETORTING PROCESSES................Al Tosco Process Gas Combustion

Continuous TDEM for monitoring shale hydraulic fracturing

NASA Astrophysics Data System (ADS)

Yan, Liang-Jun; Chen, Xiao-Xiong; Tang, Hao; Xie, Xing-Bing; Zhou, Lei; Hu, Wen-Bao; Wang, Zhong-Xin

2018-03-01

Monitoring and delineating the spatial distribution of shale fracturing is fundamentally important to shale gas production. Standard monitoring methods, such as time-lapse seismic, cross-well seismic and micro-seismic methods, are expensive, timeconsuming, and do not show the changes in the formation with time. The resistivities of hydraulic fracturing fluid and reservoir rocks were measured. The results suggest that the injection fluid and consequently the injected reservoir are characterized by very low resistivity and high chargeability. This allows using of the controlled-source electromagnetic method (CSEM) to monitor shale gas hydraulic fracturing. Based on the geoelectrical model which was proposed according to the well-log and seismic data in the test area the change rule of the reacted electrical field was studied to account for the change of shale resistivity, and then the normalized residual resistivity method for time lapse processing was given. The time-domain electromagnetic method (TDEM) was used to continuously monitor the shale gas fracturing at the Fulin shale gas field in southern China. A high-power transmitter and multi-channel transient electromagnetic receiver array were adopted. 9 h time series of Ex component of 224 sites which were laid out on the surface and over three fracturing stages of a horizontal well at 2800 m depth was recorded. After data processing and calculation of the normalized resistivity residuals, the changes in the Ex signal were determined and a dynamic 3D image of the change in resistivity was constructed. This allows modeling the spatial distribution of the fracturing fluid. The model results suggest that TDEM is promising for monitoring hydraulic fracturing of shale.

Investigation of sorption interactions between oil shale principal mineral phases and organic compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowen, J.M.

1988-09-01

The interactions between minerals representative of the bulk composition of oil shales and organic compounds that have been found in oil shale leachates were investigated. The method used to directly determine the type of interactions that could take place between organic compounds and oil shale mineral phases was Fourier transform infrared spectroscopy (FTIR) using several advanced detection methods, including diffuse reflectance (DRIFT) and photoacoustics (PAS). The minerals that were investigated include quartz, calcite, and dolomite, which are known to figure significantly in the composition of processed oil shales. The organic chemical compounds used were chosen from a list of compoundsmore » identified in spent oil shale leachates, and they include pyridine, phenol, p-cresol, and acetone. The sorption interactions for the study were prepared by exposing each of the minerals to the organic compounds by three different methods. These were vapor deposition, direct application, and immersion in an aqueous solution at pH 12. 41 refs., 3 figs., 4 tabs.« less

A study on the Jordanian oil shale resources and utilization

NASA Astrophysics Data System (ADS)

Sakhrieh, Ahmad; Hamdan, Mohammed

2012-11-01

Jordan has significant oil shale deposits occurring in 26 known localities. Geological surveys indicate that the existing deposits underlie more than 60% of Jordan's territory. The resource consists of 40 to 70 billion tones of oil shale, which may be equivalent to more than 5 million tones of shale oil. Since the 1960s, Jordan has been investigating economical and environmental methods for utilizing oil shale. Due to its high organic content, is considered a suitable source of energy. This paper introduces a circulating fluidized bed combustor that simulates the behavior of full scale municipal oil shale combustors. The inside diameter of the combustor is 500 mm, the height is 3000 mm. The design of the CFB is presented. The main parameters which affect the combustion process are elucidated in the paper. The size of the laboratory scale fluidized bed reactor is 3 kW, which corresponds to a fuel-feeding rate of approximately 1.5 kg/h.

The Oxidative Metabolism of Fossil Hydrocarbons and Sulfide Minerals by the Lithobiontic Microbial Community Inhabiting Deep Subterrestrial Kupferschiefer Black Shale.

PubMed

Włodarczyk, Agnieszka; Lirski, Maciej; Fogtman, Anna; Koblowska, Marta; Bidziński, Grzegorz; Matlakowska, Renata

2018-01-01

Black shales are one of the largest reservoirs of fossil organic carbon and inorganic reduced sulfur on Earth. It is assumed that microorganisms play an important role in the transformations of these sedimentary rocks and contribute to the return of organic carbon and inorganic sulfur to the global geochemical cycles. An outcrop of deep subterrestrial ~256-million-year-old Kupferschiefer black shale was studied to define the metabolic processes of the deep biosphere important in transformations of organic carbon and inorganic reduced sulfur compounds. This outcrop was created during mining activity 12 years ago and since then it has been exposed to the activity of oxygen and microorganisms. The microbial processes were described based on metagenome and metaproteome studies as well as on the geochemistry of the rock. The microorganisms inhabiting the subterrestrial black shale were dominated by bacterial genera such as Pseudomonas, Limnobacter, Yonghaparkia, Thiobacillus, Bradyrhizobium , and Sulfuricaulis . This study on black shale was the first to detect archaea and fungi, represented by Nitrososphaera and Aspergillus genera, respectively. The enzymatic oxidation of fossil aliphatic and aromatic hydrocarbons was mediated mostly by chemoorganotrophic bacteria, but also by archaea and fungi. The dissimilative enzymatic oxidation of primary reduced sulfur compounds was performed by chemolithotrophic bacteria. The geochemical consequences of microbial activity were the oxidation and dehydrogenation of kerogen, as well as oxidation of sulfide minerals.

Method for maximizing shale oil recovery from an underground formation

DOEpatents

Sisemore, Clyde J.

1980-01-01

A method for maximizing shale oil recovery from an underground oil shale formation which has previously been processed by in situ retorting such that there is provided in the formation a column of substantially intact oil shale intervening between adjacent spent retorts, which method includes the steps of back filling the spent retorts with an aqueous slurry of spent shale. The slurry is permitted to harden into a cement-like substance which stabilizes the spent retorts. Shale oil is then recovered from the intervening column of intact oil shale by retorting the column in situ, the stabilized spent retorts providing support for the newly developed retorts.

Spatial and stratigraphic distribution of water in oil shale of the Green River Formation using Fischer Assay, Piceance Basin, northwestern Colorado

USGS Publications Warehouse

Johnson, Ronald C.; Mercier, Tracey J.; Brownfield, Michael E.

2014-01-01

The spatial and stratigraphic distribution of water in oil shale of the Eocene Green River Formation in the Piceance Basin of northwestern Colorado was studied in detail using some 321,000 Fischer assay analyses in the U.S. Geological Survey oil-shale database. The oil-shale section was subdivided into 17 roughly time-stratigraphic intervals, and the distribution of water in each interval was assessed separately. This study was conducted in part to determine whether water produced during retorting of oil shale could provide a significant amount of the water needed for an oil-shale industry. Recent estimates of water requirements vary from 1 to 10 barrels of water per barrel of oil produced, depending on the type of retort process used. Sources of water in Green River oil shale include (1) free water within clay minerals; (2) water from the hydrated minerals nahcolite (NaHCO3), dawsonite (NaAl(OH)2CO3), and analcime (NaAlSi2O6.H20); and (3) minor water produced from the breakdown of organic matter in oil shale during retorting. The amounts represented by each of these sources vary both stratigraphically and areally within the basin. Clay is the most important source of water in the lower part of the oil-shale interval and in many basin-margin areas. Nahcolite and dawsonite are the dominant sources of water in the oil-shale and saline-mineral depocenter, and analcime is important in the upper part of the formation. Organic matter does not appear to be a major source of water. The ratio of water to oil generated with retorting is significantly less than 1:1 for most areas of the basin and for most stratigraphic intervals; thus water within oil shale can provide only a fraction of the water needed for an oil-shale industry.

Spatial and stratigraphic distribution of water in oil shale of the Green River Formation using Fischer assay, Piceance Basin, northwestern Colorado

USGS Publications Warehouse

Johnson, Ronald C.; Mercier, Tracey J.; Brownfield, Michael E.

2014-01-01

The spatial and stratigraphic distribution of water in oil shale of the Eocene Green River Formation in the Piceance Basin of northwestern Colorado was studied in detail using some 321,000 Fischer assay analyses in the U.S. Geological Survey oil-shale database. The oil-shale section was subdivided into 17 roughly time-stratigraphic intervals, and the distribution of water in each interval was assessed separately. This study was conducted in part to determine whether water produced during retorting of oil shale could provide a significant amount of the water needed for an oil-shale industry. Recent estimates of water requirements vary from 1 to 10 barrels of water per barrel of oil produced, depending on the type of retort process used. Sources of water in Green River oil shale include (1) free water within clay minerals; (2) water from the hydrated minerals nahcolite (NaHCO3), dawsonite (NaAl(OH)2CO3), and analcime (NaAlSi2O6.H20); and (3) minor water produced from the breakdown of organic matter in oil shale during retorting. The amounts represented by each of these sources vary both stratigraphically and areally within the basin. Clay is the most important source of water in the lower part of the oil-shale interval and in many basin-margin areas. Nahcolite and dawsonite are the dominant sources of water in the oil-shale and saline-mineral depocenter, and analcime is important in the upper part of the formation. Organic matter does not appear to be a major source of water. The ratio of water to oil generated with retorting is significantly less than 1:1 for most areas of the basin and for most stratigraphic intervals; thus water within oil shale can provide only a fraction of the water needed for an oil-shale industry.

Diagenetic variation at the lamina scale in lacustrine organic-rich shales: Implications for hydrocarbon migration and accumulation

NASA Astrophysics Data System (ADS)

Liang, Chao; Cao, Yingchang; Liu, Keyu; Jiang, Zaixing; Wu, Jing; Hao, Fang

2018-05-01

Lacustrine carbonate-rich shales are well developed within the Mesozoic-Cenozoic strata of the Bohai Bay Basin (BBB) of eastern China and across southeast Asia. Developing an understanding of the diagenesis of these shales is essential to research on mass balance, diagenetic fluid transport and exchange, and organic-inorganic interactions in black shales. This study investigates the origin and distribution of authigenic minerals and their diagenetic characteristics, processes, and pathways at the scale of lacustrine laminae within the Es4s-Es3x shale sequence of the BBB. The research presented in this study is based on thin sections, field emission scanning electron microscope (FESEM) and SEM-catholuminescence (CL) observations of well core samples combined with the use of X-ray diffraction (XRD), energy dispersive spectroscopy, electron microprobe analysis, and carbon and oxygen isotope analyses performed using a laser microprobe mass spectrometer. The dominant lithofacies within the Es4s-Es3x sequence are a laminated calcareous shale (LCS-1) and a laminated clay shale (LCS-2). The results of this study show that calcite recrystallization1 is the overarching diagenetic process affecting the LCS-1, related to acid generation from organic matter (OM) thermal evolution. This evolutionary transition is the key factor driving the diagenesis of this lithofacies, while the transformation of clay minerals is the main diagenetic attribute of the LCS-2. Diagenetic differences occur within different laminae and at variable locations within the same lamina level, controlled by variations in mineral composition and the properties of laminae interfaces. The diagenetic fluid migration scale is vertical and responses (dissolution and replacement) are limited to individual laminae, between zero and 100 μm in width. In contrast, the dominant migration pathway for diagenetic fluid is lateral, along the abrupt interfaces between laminae boundaries, which leads to the vertical transmission of diagenetic responses. The recrystallization boundaries between calcite laminae act as the main migration pathways for the expulsion of hydrocarbons from these carbonate-rich lacustrine shales. However, because the interaction between diagenetic fluids and the shales themselves is limited to the scale of individual lamina, this system is normally closed. The occurrence of abnormal pressure fractures can open the diagenetic system, however, and cause interactions to occur throughout laminae; in particular, the closed-open (C-O) diagenetic process at this scale is critical to this shale interval. Multi-scale C-O systems are ubiquitous and episodic ranging from the scale of laminae to the whole basin. Observations show that such small-scale systems are often superimposed onto larger ones to constitute the complex diagenetic system seen within the BBB combining fluid transport, material and energy exchange, and solid-liquid and organic-inorganic interactions.

Converting oil shale to liquid fuels: energy inputs and greenhouse gas emissions of the Shell in situ conversion process.

PubMed

Brandt, Adam R

2008-10-01

Oil shale is a sedimentary rock that contains kerogen, a fossil organic material. Kerogen can be heated to produce oil and gas (retorted). This has traditionally been a CO2-intensive process. In this paper, the Shell in situ conversion process (ICP), which is a novel method of retorting oil shale in place, is analyzed. The ICP utilizes electricity to heat the underground shale over a period of 2 years. Hydrocarbons are produced using conventional oil production techniques, leaving shale oil coke within the formation. The energy inputs and outputs from the ICP, as applied to oil shales of the Green River formation, are modeled. Using these energy inputs, the greenhouse gas (GHG) emissions from the ICP are calculated and are compared to emissions from conventional petroleum. Energy outputs (as refined liquid fuel) are 1.2-1.6 times greater than the total primary energy inputs to the process. In the absence of capturing CO2 generated from electricity produced to fuel the process, well-to-pump GHG emissions are in the range of 30.6-37.1 grams of carbon equivalent per megajoule of liquid fuel produced. These full-fuel-cycle emissions are 21%-47% larger than those from conventionally produced petroleum-based fuels.

Colorado oil shale: the current status, October 1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-01-01

A general background to oil shale and the potential impacts of its development is given. A map containing the names and locations of current oil shale holdings is included. The history, geography, archaeology, ecology, water resources, air quality, energy resources, land use, sociology, transportation, and electric power for the state of Colorado are discussed. The Colorado Joint Review Process Stages I, II, and III-oil shale are explained. Projected shale oil production capacity to 1990 is presented. (DC)

Physical and chemical characterization of Devonian gas shale. Quarterly status report, October 1-December 31, 1978

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zielinski, R.E.; Nance, S.W.

On shale samples from the WV-6 (Monongalia County, West Virginia) well, mean total gas yield was 80.4 ft/sup 3//ton. Mean hydrocarbon gas yield was 5.7 ft/sup 3//ton, 7% of total yield. Methane was the major hydrocarbon component and carbon dioxide the major nonhydrocarbon component. Oil yield was negligible. Clay minerals and organic matter were the dominant phases of the shale. Illite averages 76% of the total clay mineral content. This is detrital illite. Permeation of methane, parallel to the bedding direction for select samples from WV-5 (Mason County, West Virginia) well ranges from 10/sup -4/ to 10/sup -12/ darcys. Themore » permeability of these shales is affected by orgaic carbon content, density, particle orientation, depositional facies, etc. Preliminary studies of Devonian shale methane sorption rates suggest that these rates may be affected by shale porosity, as well as absorption and adsorption processes. An experimental system was designed to effectively simulate sorption of methane at natural reservoir conditions. The bulk density and color of select shales from Illinois, Appalachian and Michigan Basins suggest a general trend of decreasing density with increasing organic content. Black and grayish black shales have organic contents which normally exceed 1.0 wt %. Medium dark gray and gray shales generally have organic contents less than 1.0 wt %.« less

How lithology and climate affect REE mobility and fractionation along a shale weathering transect of the Susquehanna Shale Hills Critical Zone Observatory

NASA Astrophysics Data System (ADS)

Ma, L.; Jin, L.; Dere, A. L.; White, T.; Mathur, R.; Brantley, S. L.

2012-12-01

Shale weathering is an important process in global elemental cycles. Accompanied by the transformation of bedrock into regolith, many elements including rare earth elements (REE) are mobilized primarily by chemical weathering in the Critical Zone. Then, REE are subsequently transported from the vadose zone to streams, with eventual deposition in the oceans. REE have been identified as crucial and strategic natural resources; and discovery of new REE deposits will be facilitated by understanding global REE cycles. At present, the mechanisms and environmental factors controlling release, transport, and deposition of REE - the sources and sinks - at Earth's surface remain unclear. Here, we present a systematic study of soils, stream sediments, stream waters, soil water and bedrock in six small watersheds that are developed on shale bedrock in the eastern USA to constrain the mobility and fractionation of REE during early stages of chemical weathering. The selected watersheds are part of the shale transect established by the Susquehanna Shale Hills Observatory (SSHO) and are well suited to investigate weathering on shales of different compositions or within different climate regimes but on the same shale unit. Our REE study from SSHO, a small gray shale watershed in central Pennsylvania, shows that up to 65% of the REE (relative to parent bedrock) is depleted in the acidic and organic-rich soils due to chemical leaching. Both weathering soil profiles and natural waters show a preferential removal of middle REE (MREE: Sm to Dy) relative to light REE (La to Nd) and heavy REE (Ho to Lu) during shale weathering, due to preferential release of MREE from a phosphate phase (rhabdophane). Strong positive Ce anomalies observed in the regolith and stream sediments point to the fractionation and preferential precipitation of Ce as compared to other REE, in the generally oxidizing conditions of the surface environments. One watershed developed on the Marcellus black shale in Pennsylvania allows comparison of behaviors of REE in the organic-rich vs. organic-poor end members under the same climate conditions. Our study shows that black shale bedrock has much higher REE contents compared to the Rose Hill gray shale. The presence of reactive phases such as organic matter, carbonates and sulfides in black shale and their alteration greatly enhance the release of REE and other metals to surface environments. This observation suggests that weathering of black shale is thus of particular importance in the global REE cycles, in addition to other heavy metals that impact the health of terrestrial and aquatic ecosystems. Finally, our ongoing investigation of four more gray shale watersheds in Virginia, Tennessee, Alabama, and Puerto Rico will allow for a comparison of shale weathering along a climosequence. Such a systematic study will evaluate the control of air temperature and precipitation on REE release from gray shale weathering in eastern USA.

Combustion heater for oil shale

DOEpatents

Mallon, R.; Walton, O.; Lewis, A.E.; Braun, R.

1983-09-21

A combustion heater for oil shale heats particles of spent oil shale containing unburned char by burning the char. A delayed fall is produced by flowing the shale particles down through a stack of downwardly sloped overlapping baffles alternately extending from opposite sides of a vertical column. The delayed fall and flow reversal occurring in passing from each baffle to the next increase the residence time and increase the contact of the oil shale particles with combustion supporting gas flowed across the column to heat the shale to about 650 to 700/sup 0/C for use as a process heat source.

Combustion heater for oil shale

DOEpatents

Mallon, Richard G.; Walton, Otis R.; Lewis, Arthur E.; Braun, Robert L.

1985-01-01

A combustion heater for oil shale heats particles of spent oil shale containing unburned char by burning the char. A delayed fall is produced by flowing the shale particles down through a stack of downwardly sloped overlapping baffles alternately extending from opposite sides of a vertical column. The delayed fall and flow reversal occurring in passing from each baffle to the next increase the residence time and increase the contact of the oil shale particles with combustion supporting gas flowed across the column to heat the shale to about 650.degree.-700.degree. C. for use as a process heat source.

Restore the change process of Longmaxi shale pore structure during the diagenesis by the potassium and the magnesium

NASA Astrophysics Data System (ADS)

Zhou, W.

2016-12-01

The pore structure of Longmaxi shale was changing during the diagenetic process, mainly caused by the illitization and serpentinzation. The evolution of shale pore structure mainly relates to the element migration. Based on the result of electron microprobe analyser (EMPA), it is possible to find the distribution of element in shale directly and to distinguish the destroyed primary pore structure as element will remain in the migration way. The migration of potassium in Longmaxi shale mainly happened during early diagenesis phase to middle diagenesis phase (Geothermal temperature: 60°-140°). During the illitization, potassium mainly came from potassium feldspar, migrated though the connected pore structure and reacted with smectite. Illite and illite/smectite in Longmaxi shale distribute continuously in 10micron-level flocculent formation, which means that primary connective pore structure in Longmaxi shale has a same scale. The concentration of potassium has an obvious gradient that potassium content in middle of flocculation of Illite/smectite is about 6.8% and 4.8% in the boundary parts (Fig.). In addition, as SiO2 was generated during the illitization, which makes Longmaxi shale very compacted. The migration of magnesium in Longmaxi shale happened during low temperature serpentinization (Geothermal temperature: 140°-350°). Magnesium mainly came from dolomite and migrated in primary pores. According to the result of EMPA, it can be recognized that the migration path of magnesium is much simpler than potassium, which is caused as serpentinization do not have much reaction with clay minerals around (Fig.). Serpentine jams the primary pores of Longmaxi shale too. As reaction temperature of serpentinization is higher than illitization and serpentine is inserts in illite/smectite, the formation process of Longmaxi shale pore structure can be mainly divided into two phases: geothermal temperature˜140° and˜140°.

Apparatus for oil shale retorting

DOEpatents

Lewis, Arthur E.; Braun, Robert L.; Mallon, Richard G.; Walton, Otis R.

1986-01-01

A cascading bed retorting process and apparatus in which cold raw crushed shale enters at the middle of a retort column into a mixer stage where it is rapidly mixed with hot recycled shale and thereby heated to pyrolysis temperature. The heated mixture then passes through a pyrolyzer stage where it resides for a sufficient time for complete pyrolysis to occur. The spent shale from the pyrolyzer is recirculated through a burner stage where the residual char is burned to heat the shale which then enters the mixer stage.

Experimental Study on Longmaxi Shale Breaking Mechanism with Micro-PDC Bit

NASA Astrophysics Data System (ADS)

Wang, Teng; Xiao, Xiaohua; Zhu, Haiyan; Zhao, Jingying; Li, Yuheng; Lu, Ming

2017-10-01

China has abundant shale gas resource, but its geological conditions are complicated. This work sought to find the shale breaking mechanism with the polycrystalline diamond compact (PDC) bit when drilling the shale that is rich in stratification. Therefore, a laboratory-scale drilling device based on a drilling machine is developed. The influences of Longmaxi shale stratification on drilling parameters in the drilling process with micro-PDC bit are investigated. Six groups of drilling experiments with six inclination angles ( β = 0°, 15°, 30°, 45°, 60° and 90°), total thirty-six groups, are carried out. The weight on bit reaches the maximum value at β = 30° and reaches the minimum value at β = 0°. The biggest torque value is at β = 30°, and the smaller torque values are at β = 15°, β = 45° and β = 60°. When the inclination angle is between 30° and 60°, the shale fragmentation volume is larger. The inclination angle β = 0° is beneficial, and β = 15° and β = 60° are detrimental to controlling the drilling direction in the Longmaxi shale gas formation.

Vegetation canopy cover effects on sediment erosion processes in the upper Colorado River Basin mancos shale formation, Price, Utah

USDA-ARS?s Scientific Manuscript database

This study provides new parameterizations for applying the Rangeland Hydrology and Erosion Model (RHEM) on the highly erosive, rangeland saline soils of the Mancos Shale formation in the Price-San Rafael River Basin in east central Utah. Calibrated hydrologic parameters (Kss and K') values are gener...

Characterization of Unconventional Reservoirs: CO2 Induced Petrophysics

NASA Astrophysics Data System (ADS)

Verba, C.; Goral, J.; Washburn, A.; Crandall, D.; Moore, J.

2017-12-01

As concerns about human-driven CO2 emissions grow, it is critical to develop economically and environmentally effective strategies to mitigate impacts associated with fossil energy. Geologic carbon storage (GCS) is a potentially promising technique which involves the injection of captured CO2 into subsurface formations. Unconventional shale formations are attractive targets for GCS while concurrently improving gas recovery. However, shales are inherently heterogeneous, and minor differences can impact the ability of the shale to effectively adsorb and store CO2. Understanding GCS capacity from such endemic heterogeneities is further complicated by the complex geochemical processes which can dynamically alter shale petrophysics. We investigated the size distribution, connectivity, and type (intraparticle, interparticle, and organic) of pores in shale; the mineralogy of cores from unconventional shale (e.g. Bakken); and the changes to these properties under simulated GCS conditions. Electron microscopy and dual beam focused ion beam scanning electron microscopy were used to reconstruct 2D/3D digital matrix and pore structures. Comparison of pre and post-reacted samples gives insights into CO2-shale interactions - such as the mechanism of CO2 sorption in shales- intended for enhanced oil recovery and GCS initiatives. These comparisons also show how geochemical processes proceed differently across shales based on their initial diagenesis. Results show that most shale pore sizes fall within meso-macro pore classification (> 2 nm), but have variable porosity and organic content. The formation of secondary minerals (calcite, gypsum, and halite) may play a role in the infilling of fractures and pore spaces in the shale, which may reduce permeability and inhibit the flow of fluids.

Composition, diagenetic transformation and alkalinity potential of oil shale ash sediments.

PubMed

Mõtlep, Riho; Sild, Terje; Puura, Erik; Kirsimäe, Kalle

2010-12-15

Oil shale is a primary fuel in the Estonian energy sector. After combustion 45-48% of the oil shale is left over as ash, producing about 5-7 Mt of ash, which is deposited on ash plateaus annually almost without any reuse. This study focuses on oil shale ash plateau sediment mineralogy, its hydration and diagenetic transformations, a study that has not been addressed. Oil shale ash wastes are considered as the biggest pollution sources in Estonia and thus determining the composition and properties of oil shale ash sediment are important to assess its environmental implications and also its possible reusability. A study of fresh ash and drillcore samples from ash plateau sediment was conducted by X-ray diffractometry and scanning electron microscopy. The oil shale is highly calcareous, and the ash that remains after combustion is derived from the decomposition of carbonate minerals. It is rich in lime and anhydrite that are unstable phases under hydrous conditions. These processes and the diagenetic alteration of other phases determine the composition of the plateau sediment. Dominant phases in the ash are hydration and associated transformation products: calcite, ettringite, portlandite and hydrocalumite. The prevailing mineral phases (portlandite, ettringite) cause highly alkaline leachates, pH 12-13. Neutralization of these leachates under natural conditions, by rainwater leaching/neutralization and slow transformation (e.g. carbonation) of the aforementioned unstable phases into more stable forms, takes, at best, hundreds or even hundreds of thousands of years. Copyright © 2010 Elsevier B.V. All rights reserved.

Geochemical variations of rare earth elements in Marcellus shale flowback waters and multiple-source cores in the Appalachian Basin

NASA Astrophysics Data System (ADS)

Noack, C.; Jain, J.; Hakala, A.; Schroeder, K.; Dzombak, D. A.; Karamalidis, A.

2013-12-01

Rare earth elements (REE) - encompassing the naturally occurring lanthanides, yttrium, and scandium - are potential tracers for subsurface groundwater-brine flows and geochemical processes. Application of these elements as naturally occurring tracers during shale gas development is reliant on accurate quantitation of trace metals in hypersaline brines. We have modified and validated a liquid-liquid technique for extraction and pre-concentration of REE from saline produced waters from shale gas extraction wells with quantitative analysis by ICP-MS. This method was used to analyze time-series samples of Marcellus shale flowback and produced waters. Additionally, the total REE content of core samples of various strata throughout the Appalachian Basin were determined using HF/HNO3 digestion and ICP-MS analysis. A primary goal of the study is to elucidate systematic geochemical variations as a function of location or shale characteristics. Statistical testing will be performed to study temporal variability of inter-element relationships and explore associations between REE abundance and major solution chemistry. The results of these analyses and discussion of their significance will be presented.

Early diagenetic partial oxidation of organic matter and sulfides in the Middle Pennsylvanian (Desmoinesian) Excello Shale Member of the Fort Scott Limestone and equivalents, northern Midcontinent region, USA

USGS Publications Warehouse

Hatch, J.R.; Leventhal, M.S.

1997-01-01

A process of early diagenetic partial oxidation of organic matter and sulfides has altered the chemical composition of the Middle Pennsylvanian Excello Shale Member of the Fort Scott Limestone and equivalents in the northern Midcontinent region. This process was identified by comparison of organic carbon contents, Rock-Eval hydrogen indices, organic carbon ??13C and element compositions of core and surface mine samples of the Excello Shale Member with analyses of three other underlying and overlying organic-matter-rich marine shales (offshore shale lithofacies) from southern Iowa, northern Missouri, eastern Kansas and northeastern Oklahoma. The end product of the partial oxidation process is shale with relatively low contents of hydrogen-poor, C13-enriched organic matter, lower contents of sulfur and sulfide-forming elements, and relatively unchanged contents of phosphorus and many trace elements (e.g. Cr, Ni, and V). However, because of lower organic carbon contents, element/organic carbon ratios are greatly increased. The partial oxidation process apparently took place during subaerial exposure of the overlying marine carbonate member (Blackjack Creek Member of the Fort Scott Limestone) following a marine regression when meteoric waters percolated down to the level of the Excello muds allowing oxidation of organic matter and sulfides. This hypothesis is supported by earlier workers, who have identified meteoric carbonate cements within, and soil horizons at the top of the Blackjack Creek Member. The period of oxidation is constrained in that organic matter and sulfides in the Little Osage Shale Member of the Fort Scott Limestone and equivalents (immediately overlying the Blackjack Creek Member) appear unaltered. Similar alteration of other shales in the Middle and Upper Pennsylvanian sections may be local to regional in extent and would depend on the extent and duration of the marine regression and be influenced by local variations in permeability and topography. The partial oxidation process has likely led to a redistribution of sulfur and sulfide-forming elements into other organic-rich lithologies in the section. The altered/oxidized shales are nongenerative with respect to hydrocarbon generation.

Refining of Military Jet Fuels from Shale Oil. Part II. Volume II. (In Situ Shale Oil Process Data).

DTIC Science & Technology

1982-03-01

SPEC Meeting Specifications OXY Test Series on In Situ Shale Oil z P Pressure (P + N) Paraffins and Naphthenes PRO Test Series on Above Ground Shale Oil...LV 6/ 12.0 Naphthenes , LV% (Aromatics, LV %/ 11.8 Gross Heating Value, Btu/lb 19,720 19,068 -73- TABLE 111-29. CRUDE SHALE: OIL HYDROTREATING SERIES M...Wt % - Ramabottomn Carbon -1.34 IParaffins (P-IN), LV % (71.1) -IOlef ins, LV % 9.4 i ~ Naphthenes , LV% - Aromatics, LV % 19.5 - Gross Heating Value

Observations of the release of non-methane hydrocarbons from fractured shale.

PubMed

Sommariva, Roberto; Blake, Robert S; Cuss, Robert J; Cordell, Rebecca L; Harrington, Jon F; White, Iain R; Monks, Paul S

2014-01-01

The organic content of shale has become of commercial interest as a source of hydrocarbons, owing to the development of hydraulic fracturing ("fracking"). While the main focus is on the extraction of methane, shale also contains significant amounts of non-methane hydrocarbons (NMHCs). We describe the first real-time observations of the release of NMHCs from a fractured shale. Samples from the Bowland-Hodder formation (England) were analyzed under different conditions using mass spectrometry, with the objective of understanding the dynamic process of gas release upon fracturing of the shale. A wide range of NMHCs (alkanes, cycloalkanes, aromatics, and bicyclic hydrocarbons) are released at parts per million or parts per billion level with temperature- and humidity-dependent release rates, which can be rationalized in terms of the physicochemical characteristics of different hydrocarbon classes. Our results indicate that higher energy inputs (i.e., temperatures) significantly increase the amount of NMHCs released from shale, while humidity tends to suppress it; additionally, a large fraction of the gas is released within the first hour after the shale has been fractured. These findings suggest that other hydrocarbons of commercial interest may be extracted from shale and open the possibility to optimize the "fracking" process, improving gas yields and reducing environmental impacts.

The variation of molybdenum isotopes within the weathering system of the black shales

NASA Astrophysics Data System (ADS)

Jianming, Z.

2016-12-01

Jian-Ming Zhu 1,2, De-Can Tan 2, Liang Liang 2, Wang Jing21 State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing, 100083, China 2 State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China Molybdenum (Mo) stable isotopes have been developed as a tracer to indicate the evolution of the atmospheric and oceanic oxygenation related with continent weathering, and to reveal the extent of ancient oceanic euxinia. Molybdenum isotopic variation within the weathering system of basalts has been studied, and was presented the whole trend with heavier isotopes preferentially removed during weathering processes. However, there are few researches to study the variation of Mo isotopes during black shale weathering, especiall on the behavoir of Mo isotopes within the perfect shales' profiles. Here, the weathering profiles of Mo and selenium(Se)-rich carbonaceous rocks in Enshi southwest Hubei Province were selected. The Mo isotopes was measured on Nu Plasma II's MC-ICP-MS using 97Mo-100Mo double spike, and δ98/95Mo was reported relative to NIST 3134. A comprehensive set of Mo isotopic composition and concentration data from the unweathered, weakly and intensely weathered rocks were collected. The δ98/95Mo in fresh shales (220±248 mg/kg Mo, 1SD, n=41) from Shadi and Yutangba drill cores varies from 0.41‰ to 0.99‰ with an average of 0.67±0.16‰, while the strongly weathered shales (19.9±5.8 mg/kg Mo, 1SD, n=5) from Shadi profiles are isotopically heavier with average δ98/95Mo values of 1.03±0.10‰ (1SD, n=5). The Locally altered shales exposed in a quarry at Yutangba are highly enriched in Mo, varing from 31 to 2377 mg/kg with an average of 428 ±605mg/kg (1SD, n=24), approximately 2 times greater than that in fresh shales samples. These rocks are presented a significant variation in δ98/95Mo values varing from -0.24 ‰ to -3.99 ‰ with average -1.67±1.57‰, showing the extremely negative δ98/95Mo values existed in natural samples. This suggested that Mo isotopes can be fractionated during shales weathering processes, with lighter isotopes preferentially removed. This finding is in contrast to the previous knowledge from basalt weathering, and requires further study.

Shale Gas Implications for C2-C3 Olefin Production: Incumbent and Future Technology.

PubMed

Stangland, Eric E

2018-06-07

Substantial natural gas liquids recovery from tight shale formations has produced a significant boon for the US chemical industry. As fracking technology improves, shale liquids may represent the same for other geographies. As with any major industry disruption, the advent of shale resources permits both the chemical industry and the community an excellent opportunity to have open, foundational discussions on how both public and private institutions should research, develop, and utilize these resources most sustainably. This review summarizes current chemical industry processes that use ethane and propane from shale gas liquids to produce the two primary chemical olefins of the industry: ethylene and propylene. It also discusses simplified techno-economics related to olefins production from an industry perspective, attempting to provide a mutually beneficial context in which to discuss the next generation of sustainable olefin process development.

A Systematic Procedure to Describe Shale Gas Permeability Evolution during the Production Process

NASA Astrophysics Data System (ADS)

Jia, B.; Tsau, J. S.; Barati, R.

2017-12-01

Gas flow behavior in shales is complex due to the multi-physics nature of the process. Pore size reduces as the in-situ stress increases during the production process, which will reduce intrinsic permeability of the porous media. Slip flow/pore diffusion enhances gas apparent permeability, especially under low reservoir pressures. Adsorption not only increases original gas in place but also influences gas flow behavior because of the adsorption layer. Surface diffusion between free gas and adsorption phase enhances gas permeability. Pore size reduction and the adsorption layer both have complex impacts on gas apparent permeability and non-Darcy flow might be a major component in nanopores. Previously published literature is generally incomplete in terms of coupling of all these four physics with fluid flow during gas production. This work proposes a methodology to simultaneously take them into account to describe a permeability evolution process. Our results show that to fully describe shale gas permeability evolution during gas production, three sets of experimental data are needed initially: 1) intrinsic permeability under different in-situ stress, 2) adsorption isotherm under reservoir conditions and 3) surface diffusivity measurement by the pulse-decay method. Geomechanical effects, slip flow/pore diffusion, adsorption layer and surface diffusion all play roles affecting gas permeability. Neglecting any of them might lead to misleading results. The increasing in-situ stress during shale gas production is unfavorable to shale gas flow process. Slip flow/pore diffusion is important for gas permeability under low pressures in the tight porous media. They might overwhelm the geomechanical effect and enhance gas permeability at low pressures. Adsorption layer reduces the gas permeability by reducing the effective pore size, but the effect is limited. Surface diffusion increases gas permeability more under lower pressures. The total gas apparent permeability might keep increasing during the gas production process when the surface diffusivity is larger than a critical value. We believe that our workflow proposed in this study will help describe shale gas permeability evolution considering all the underlying physics altogether.

A study of pyrolysis of oil shale of the Leningrad deposit by solid heat carrier

NASA Astrophysics Data System (ADS)

Gerasimov, G. Ya; Khaskhachikh, V. V.; Potapov, O. P.

2017-11-01

The investigation of the oil shale pyrolysis with a solid heat carrier was carried out using the experimental retorting system that simulates the Galoter industrial process. This system allows verifying both fractional composition of the oil shale and solid heat carrier, and their ratio and temperature. The oil shale of the Leningradsky deposit was used in the work, and quartz sand was used as the solid heat carrier. It is shown that the yield of the shale oil under the pyrolysis with solid heat carrier exceeds by more than 20% the results received in the standard Fisher retort. Using ash as the solid heat carrier results in a decrease in the yield of oil and gas with simultaneous increase in the amount of the solid residue. This is due to the chemical interaction of the acid components of the vapor-gas mixture with the oxides of alkaline-earth metals that are part of the ash.

Estimation of anisotropy parameters in organic-rich shale: Rock physics forward modeling approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herawati, Ida, E-mail: ida.herawati@students.itb.ac.id; Winardhi, Sonny; Priyono, Awali

Anisotropy analysis becomes an important step in processing and interpretation of seismic data. One of the most important things in anisotropy analysis is anisotropy parameter estimation which can be estimated using well data, core data or seismic data. In seismic data, anisotropy parameter calculation is generally based on velocity moveout analysis. However, the accuracy depends on data quality, available offset, and velocity moveout picking. Anisotropy estimation using seismic data is needed to obtain wide coverage of particular layer anisotropy. In anisotropic reservoir, analysis of anisotropy parameters also helps us to better understand the reservoir characteristics. Anisotropy parameters, especially ε, aremore » related to rock property and lithology determination. Current research aims to estimate anisotropy parameter from seismic data and integrate well data with case study in potential shale gas reservoir. Due to complexity in organic-rich shale reservoir, extensive study from different disciplines is needed to understand the reservoir. Shale itself has intrinsic anisotropy caused by lamination of their formed minerals. In order to link rock physic with seismic response, it is necessary to build forward modeling in organic-rich shale. This paper focuses on studying relationship between reservoir properties such as clay content, porosity and total organic content with anisotropy. Organic content which defines prospectivity of shale gas can be considered as solid background or solid inclusion or both. From the forward modeling result, it is shown that organic matter presence increases anisotropy in shale. The relationships between total organic content and other seismic properties such as acoustic impedance and Vp/Vs are also presented.« less

Pore Characterization of Shale Rock and Shale Interaction with Fluids at Reservoir Pressure-Temperature Conditions Using Small-Angle Neutron Scattering

NASA Astrophysics Data System (ADS)

Ding, M.; Hjelm, R.; Watkins, E.; Xu, H.; Pawar, R.

2015-12-01

Oil/gas produced from unconventional reservoirs has become strategically important for the US domestic energy independence. In unconventional realm, hydrocarbons are generated and stored in nanopores media ranging from a few to hundreds of nanometers. Fundamental knowledge of coupled thermo-hydro-mechanical-chemical (THMC) processes that control fluid flow and propagation within nano-pore confinement is critical for maximizing unconventional oil/gas production. The size and confinement of the nanometer pores creates many complex rock-fluid interface interactions. It is imperative to promote innovative experimental studies to decipher physical and chemical processes at the nanopore scale that govern hydrocarbon generation and mass transport of hydrocarbon mixtures in tight shale and other low permeability formations at reservoir pressure-temperature conditions. We have carried out laboratory investigations exploring quantitative relationship between pore characteristics of the Wolfcamp shale from Western Texas and the shale interaction with fluids at reservoir P-T conditions using small-angle neutron scattering (SANS). We have performed SANS measurements of the shale rock in single fluid (e.g., H2O and D2O) and multifluid (CH4/(30% H2O+70% D2O)) systems at various pressures up to 20000 psi and temperature up to 150 oF. Figure 1 shows our SANS data at different pressures with H2O as the pressure medium. Our data analysis using IRENA software suggests that the principal changes of pore volume in the shale occurred on smaller than 50 nm pores and pressure at 5000 psi (Figure 2). Our results also suggest that with increasing P, more water flows into pores; with decreasing P, water is retained in the pores.

Effects of experimental parameters on the sorption of cesium, strontium, and uranium from saline groundwaters onto shales: Progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, R.E.; Arnold, W.D.; Case, F.I.

1988-11-01

This report concerns an extension of the first series of experiments on the sorption properties of shales and their clay mineral components reported earlier. Studies on the sorption of cesium and strontium were carried out on samples of Chattanooga (Upper Dowelltown), Pierre, Green River Formation, Nolichucky, and Pumpkin Valley Shales that had been heated to 120/degree/C in a 0.1-mol/L NaCl solution for periods up to several months and on samples of the same shales which had been heated to 250/degree/C in air for six months, to simulate limiting scenarios in a HLW repository. To investigate the kinetics of the sorptionmore » process in shale/groundwater systems, strontium sorption experiments were done on unheated Pierre, Green River Formation, Nolichucky, and Pumpkin Valley Shales in a diluted, saline groundwater and in 0.03-mol/L NaHCO/sub 3/, for periods of 0.25 to 28 days. Cesium sorption kinetics tests were performed on the same shales in a concentrated brine for the same time periods. The effect of the water/rock (W/R) ratio on sorption for the same combinations of unheated shales, nuclides, and groundwaters used in the kinetics experiments was investigated for a range of W/R ratios of 3 to 20 mL/g. Because of the complexity of the shale/groundwater interaction, a series of tests was conducted on the effects of contact time and W/R ratio on the pH of a 0.03-mol/L NaHCO/sub 3/ simulated groundwater in contact with shales. 8 refs., 12 figs., 15 tabs.« less

Heterogeneity of shale documented by micro-FTIR and image analysis.

PubMed

Chen, Yanyan; Mastalerz, Maria; Schimmelmann, Arndt

2014-12-01

In this study, four New Albany Shale Devonian and Mississippian samples, with vitrinite reflectance [Ro ] values ranging from 0.55% to 1.41%, were analyzed by micro-FTIR mapping of chemical and mineralogical properties. One additional postmature shale sample from the Haynesville Shale (Kimmeridgian, Ro = 3.0%) was included to test the limitation of the method for more mature substrates. Relative abundances of organic matter and mineral groups (carbonates, quartz and clays) were mapped across selected microscale regions based on characteristic infrared peaks and demonstrated to be consistent with corresponding bulk compositional percentages. Mapped distributions of organic matter provide information on the organic matter abundance and the connectivity of organic matter within the overall shale matrix. The pervasive distribution of organic matter mapped in the New Albany Shale sample MM4 is in agreement with this shale's high total organic carbon abundance relative to other samples. Mapped interconnectivity of organic matter domains in New Albany Shale samples is excellent in two early mature shale samples having Ro values from 0.55% to 0.65%, then dramatically decreases in a late mature sample having an intermediate Ro of 1.15% and finally increases again in the postmature sample, which has a Ro of 1.41%. Swanson permeabilities, derived from independent mercury intrusion capillary pressure porosimetry measurements, follow the same trend among the four New Albany Shale samples, suggesting that micro-FTIR, in combination with complementary porosimetric techniques, strengthens our understanding of porosity networks. In addition, image processing and analysis software (e.g. ImageJ) have the capability to quantify organic matter and total organic carbon - valuable parameters for highly mature rocks, because they cannot be analyzed by micro-FTIR owing to the weakness of the aliphatic carbon-hydrogen signal. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

Investigating GHGs and VOCs emissions from a shale gas industry in Germany and the UK

NASA Astrophysics Data System (ADS)

Cremonese, L.; Weger, L.; Denier Van Der Gon, H.; Bartels, M. P.; Butler, T. M.

2017-12-01

The shale gas and shale oil production boom experienced in the US led the country to a significant reduction of foreign fuel imports and an increase in domestic energy security. Several European countries are considering to extract domestic shale gas reserves that might serve as a bridge in the transition to renewables. Nevertheless, the generation of shale gas leads to emissions of CH4 and pollutants such as PM, NOx and VOCs, which in turn impact local and regional air quality and climate. Results from numerous studies investigating greenhouse gas and pollutant emissions from shale oil and shale gas extraction in North America can help in estimating the impact of such industrial activity elsewhere, when local regulations are taken into consideration. In order to investigate the extent of emissions and their distribution from a potential shale gas industry in Germany and the United Kingdom, we develop three drilling scenarios compatible with desired national gas outputs based on available geological information on potential productivity ranges of the reservoirs. Subsequently we assign activity data and emissions factors to wells under development, as well as to producing wells (from activities at the well site up until processing plants) to enable emissions quantification. We then define emissions scenarios to explore different shale gas development pathways: 1) implementation of "high-technology" devices and recovery practices (low emissions); 2) implementation of "low-technology" devices and recovery practices (high emissions), and 3) intermediate scenarios reflecting assumptions on local and national settings, or extremely high emission events (e.g. super-emitters); all with high and low boundaries of confidence driven by uncertainties. A comparison of these unconventional gas production scenarios to conventional natural gas production in Germany and the United Kingdom is also planned. The aim of this work is to highlight important variables and their ranges, to promote discussion and communication of potential impacts, and to construct possible visions for a future shale gas development in the two study countries. In a follow-up study, the impact of pollutant emissions from these scenarios on air quality will be explored using the Weather Research and Forecasting model with chemistry (WRF-Chem) model.

Selling 'Fracking': Legitimation of High Speed Oil and Gas Extraction in the Marcellus Shale Region

NASA Astrophysics Data System (ADS)

Matz, Jacob R.

The advent of horizontal hydraulic fracture drilling, or 'fracking,' a technology used to access oil and natural gas deposits, has allowed for the extraction of deep, unconventional shale gas and oil deposits in various shale seams throughout the United States and world. One such shale seam, the Marcellus shale, extends from New York State, across Pennsylvania, and throughout West Virginia, where shale gas development has significantly increased within the last decade. This boom has created a massive amount of economic activity surrounding the energy industry, creating jobs for workers, income from leases and royalties for landowners, and profits for energy conglomerates. However, this bounty comes with risks to environmental and public health, and has led to divisive community polarization over the issue in the Marcellus shale region. In the face of potential environmental and social disruption, and a great deal of controversy surrounding 'fracking,' the oil and gas industry has had to undertake a myriad of public relations campaigns and initiatives to legitimize their extraction efforts in the Marcellus shale region, and to project the oil and gas industry in a positive light to residents, policy makers, and landowners. This thesis describes one such public relations initiative, the Energy in Depth Northeast Marcellus Initiative. Through qualitative content analysis of Energy in Depth's online web material, this thesis examines the ways in which the oil and gas industry narrates the shale gas boom in the Marcellus shale region, and the ways in which the industry frames the discourse surrounding natural gas development. Through the use of environmental imagery, appeals to scientific reason, and appeals to patriotism, the oil and gas industry uses Energy in Depth to frame the shale gas extraction process in a positive way, all the while framing those who question or oppose the processes of shale gas extraction as irrational obstructionists.

Fundamental Understanding of Methane-Carbon Dioxide-Water (CH4-CO2-H2O) Interactions in Shale Nanopores under Reservoir Conditions: Quarterly Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yifeng

Shale is characterized by the predominant presence of nanometer-scale (1-100 nm) pores. The behavior of fluids in those pores directly controls shale gas storage and release in shale matrix and ultimately the wellbore production in unconventional reservoirs. Recently, it has been recognized that a fluid confined in nanopores can behave dramatically differently from the corresponding bulk phase due to nanopore confinement (Wang, 2014). CO 2 and H 2O, either preexisting or introduced, are two major components that coexist with shale gas (predominately CH 4) during hydrofracturing and gas extraction. Note that liquid or supercritical CO 2 has been suggested asmore » an alternative fluid for subsurface fracturing such that CO 2 enhanced gas recovery can also serve as a CO 2 sequestration process. Limited data indicate that CO 2 may preferentially adsorb in nanopores (particularly those in kerogen) and therefore displace CH 4 in shale. Similarly, the presence of water moisture seems able to displace or trap CH 4 in shale matrix. Therefore, fundamental understanding of CH 4-CO 2-H 2O behavior and their interactions in shale nanopores is of great importance for gas production and the related CO 2 sequestration. This project focuses on the systematic study of CH 4-CO 2-H 2O interactions in shale nanopores under high-pressure and high temperature reservoir conditions. The proposed work will help to develop new stimulation strategies to enable efficient resource recovery from fewer and less environmentally impactful wells.« less

Fundamental Understanding of Methane-Carbon Dioxide-Water (CH 4-CO 2-H 2O) Interactions in Shale Nanopores under Reservoir Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yifeng

2016-04-29

Shale is characterized by the predominant presence of nanometer-scale (1-100 nm) pores. The behavior of fluids in those pores directly controls shale gas storage and release in shale matrix and ultimately the wellbore production in unconventional reservoirs. Recently, it has been recognized that a fluid confined in nanopores can behave dramatically differently from the corresponding bulk phase due to nanopore confinement (Wang, 2014). CO 2 and H 2O, either preexisting or introduced, are two major components that coexist with shale gas (predominately CH 4) during hydrofracturing and gas extraction. Note that liquid or supercritical CO 2 has been suggested asmore » an alternative fluid for subsurface fracturing such that CO 2 enhanced gas recovery can also serve as a CO 2 sequestration process. Limited data indicate that CO 2 may preferentially adsorb in nanopores (particularly those in kerogen) and therefore displace CH 4 in shale. Similarly, the presence of water moisture seems able to displace or trap CH 4 in shale matrix. Therefore, fundamental understanding of CH 4-CO 2-H 2O behavior and their interactions in shale nanopores is of great importance for gas production and the related CO 2 sequestration. This project focuses on the systematic study of CH 4-CO 2-H 2O interactions in shale nanopores under high-pressure and high temperature reservoir conditions. The proposed work will help to develop new stimulation strategies to enable efficient resource recovery from fewer and less environmentally impactful wells.« less

Fundamental Understanding of Methane-Carbon Dioxide-Water (CH4-CO2-H2O) Interactions in Shale Nanopores under Reservoir Conditions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yifeng

Shale is characterized by the predominant presence of nanometer-scale (1-100 nm) pores. The behavior of fluids in those pores directly controls shale gas storage and release in shale matrix and ultimately the wellbore production in unconventional reservoirs. Recently, it has been recognized that a fluid confined in nanopores can behave dramatically differently from the corresponding bulk phase due to nanopore confinement (Wang, 2014). CO 2 and H 2O, either preexisting or introduced, are two major components that coexist with shale gas (predominately CH 4) during hydrofracturing and gas extraction. Note that liquid or supercritical CO 2 has been suggested asmore » an alternative fluid for subsurface fracturing such that CO 2 enhanced gas recovery can also serve as a CO 2 sequestration process. Limited data indicate that CO 2 may preferentially adsorb in nanopores (particularly those in kerogen) and therefore displace CH4 in shale. Similarly, the presence of water moisture seems able to displace or trap CH 4 in shale matrix. Therefore, fundamental understanding of CH 4-CO 2-H 2O behavior and their interactions in shale nanopores is of great importance for gas production and the related CO 2 sequestration. This project focuses on the systematic study of CH 4-CO 2-H 2O interactions in shale nanopores under high-pressure and high temperature reservoir conditions. The proposed work will help to develop new stimulation strategies to enable efficient resource recovery from fewer and less environmentally impactful wells.« less

Solar heated oil shale pyrolysis process

NASA Technical Reports Server (NTRS)

Qader, S. A. (Inventor)

1985-01-01

An improved system for recovery of a liquid hydrocarbon fuel from oil shale is presented. The oil shale pyrolysis system is composed of a retort reactor for receiving a bed of oil shale particules which are heated to pyrolyis temperature by means of a recycled solar heated gas stream. The gas stream is separated from the recovered shale oil and a portion of the gas stream is rapidly heated to pyrolysis temperature by passing it through an efficient solar heater. Steam, oxygen, air or other oxidizing gases can be injected into the recycle gas before or after the recycle gas is heated to pyrolysis temperature and thus raise the temperature before it enters the retort reactor. The use of solar thermal heat to preheat the recycle gas and optionally the steam before introducing it into the bed of shale, increases the yield of shale oil.

Feasibilities of a Coal-Biomass to Liquids Plant in Southern West Virginia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharyya, Debangsu; DVallance, David; Henthorn, Greg

This project has generated comprehensive and realistic results of feasibilities for a coal-biomass to liquids (CBTL) plant in southern West Virginia; and evaluated the sensitivity of the analyses to various anticipated scenarios and parametric uncertainties. Specifically the project has addressed economic feasibility, technical feasibility, market feasibility, and financial feasibility. In the economic feasibility study, a multi-objective siting model was developed and was then used to identify and rank the suitable facility sites. Spatial models were also developed to assess the biomass and coal feedstock availabilities and economics. Environmental impact analysis was conducted mainly to assess life cycle analysis and greenhousemore » gas emission. Uncertainty and sensitivity analysis were also investigated in this study. Sensitivity analyses on required selling price (RSP) and greenhouse gas (GHG) emissions of CBTL fuels were conducted according to feedstock availability and price, biomass to coal mix ratio, conversion rate, internal rate of return (IRR), capital cost, operational and maintenance cost. The study of siting and capacity showed that feedstock mixed ratio limited the CBTL production. The price of coal had a more dominant effect on RSP than that of biomass. Different mix ratios in the feedstock and conversion rates led to RSP ranging from $104.3 - $157.9/bbl. LCA results indicated that GHG emissions ranged from 80.62 kg CO 2 eq to 101.46 kg CO2 eq/1,000 MJ of liquid fuel at various biomass to coal mix ratios and conversion rates if carbon capture and storage (CCS) was applied. Most of water and fossil energy were consumed in conversion process. Compared to petroleum-derived-liquid fuels, the reduction in GHG emissions could be between -2.7% and 16.2% with CBTL substitution. As for the technical study, three approaches of coal and biomass to liquids, direct, indirect and hybrid, were considered in the analysis. The process models including conceptual design, process modeling and process validation were developed and validated for different cases. Equipment design and capital costs were investigated on capital coast estimation and economical model validation. Material and energy balances and techno-economic analysis on base case were conducted for evaluation of projects. Also, sensitives studies of direct and indirect approaches were both used to evaluate the CBTL plant economic performance. In this study, techno-economic analysis were conducted in Aspen Process Economic Analyzer (APEA) environment for indirect, direct, and hybrid CBTL plants with CCS based on high fidelity process models developed in Aspen Plus and Excel. The process thermal efficiency ranges from 45% to 67%. The break-even oil price ranges from $86.1 to $100.6 per barrel for small scale (10000 bbl/day) CBTL plants and from $65.3 to $80.5 per barrel for large scale (50000 bbl/day) CBTL plants. Increasing biomass/coal ratio from 8/92 to 20/80 would increase the break-even oil price of indirect CBTL plant by $3/bbl and decrease the break-even oil price of direct CBTL plant by about $1/bbl. The order of carbon capture penalty is direct > indirect > hybrid. The order of capital investment is hybrid (with or without shale gas utilization) > direct (without shale gas utilization) > indirect > direct (with shale gas utilization). The order of thermal efficiency is direct > hybrid > indirect. The order of break-even oil price is hybrid (without shale gas utilization) > direct (without shale gas utilization) > hybrid (with shale gas utilization) > indirect > direct (with shale gas utilization).« less

Systematic Investigation of REE Mobility and Fractionation During Continental Shale Weathering Along a Climate Gradient

NASA Astrophysics Data System (ADS)

Jin, L.; Ma, L.; Dere, A. L. D.; White, T.; Brantley, S. L.

2014-12-01

Rare earth elements (REE) have been identified as strategic natural resources and their demand in the United States is increasing rapidly. REE are relatively abundant in the Earth's crust, but REE deposits with minable concentrations are uncommon. One recent study has pointed to the deep-sea REE-rich muds in the Pacific Ocean as a new potential resource, related to adsorption and concentration of REE from seawater by hydrothermal iron-oxyhydroxides and phillipsite (Kato et al., 2010). Finding new REE deposits will be facilitated by understanding global REE cycles: during the transformation of bedrock into soils, REEs are leached into natural waters and transported to oceans. At present, the mechanisms and factors controlling release, transport, and deposition of REE - the sources and sinks - at Earth's surface remain unclear. Here, we systematically studied soil profiles and bedrock in seven watersheds developed on shale bedrock along a climate transect in the eastern USA, Puerto Rico and Wales to constrain the mobility and fractionation of REE during chemical weathering processes. In addition, one site on black shale (Marcellus) bedrock was included to compare behaviors of REEs in organic-rich vs. organic-poor shale end members under the same environmental conditions. Our investigation focused on: 1) the concentration of REEs in gray and black shales and the release rates of REE during shale weathering, 2) the biogeochemical and hydrological conditions (such as redox, dissolved organic carbon, and pH) that dictate the mobility and fractionation of REEs in surface and subsurface environments, and 3) the retention of dissolved REEs on soils, especially onto secondary Fe/Al oxyhydroxides and phosphate mineral phases. This systematic study sheds light on the geochemical behaviors and environmental pathways of REEs during shale weathering along a climosequence.

The Impact of a Potential Shale Gas Development in Germany and the United Kingdom on Pollutant and Greenhouse Gas Emissions

NASA Astrophysics Data System (ADS)

Weger, L.; Cremonese, L.; Bartels, M. P.; Butler, T. M.

2016-12-01

Several European countries with domestic shale gas reserves are considering extracting this natural gas resource to complement their energy transition agenda. Natural gas, which produces lower CO2 emissions upon combustion compared to coal or oil, has the potential to serve as a bridge in the transition from fossil fuels to renewables. However, the generation of shale gas leads to emissions of CH4 and pollutants such as PM, NOx and VOCs, which in turn impact climate as well as local and regional air quality. In this study, we explore the impact of a potential shale gas development in Europe, specifically in Germany and the United Kingdom, on emissions of greenhouse gases and pollutants. In order to investigate the effect on emissions, we first estimate a range of wells drilled per year and production volume for the two countries under examination based on available geological information and on regional infrastructural and economic limitations. Subsequently we assign activity data and emissions factors to the well development, gas production and processing stages of shale gas generation to enable emissions quantification. We then define emissions scenarios to explore different storylines of potential shale gas development, including low emissions (high level of regulation), high emissions (low level of regulation) and middle emissions scenarios, which influence fleet make-up, emission factor and activity data choices for emissions quantification. The aim of this work is to highlight important variables and their ranges, to promote discussion and communication of potential impacts, and to construct possible visions for a future shale gas development in the two study countries. In a follow-up study, the impact of pollutant emissions from these scenarios on air quality will be explored using the Weather Research and Forecasting model with chemistry (WRF-Chem) model.

Impact of emissions from natural gas production facilities on ambient air quality in the Barnett Shale area: a pilot study.

PubMed

Zielinska, Barbara; Campbell, Dave; Samburova, Vera

2014-12-01

Rapid and extensive development of shale gas resources in the Barnett Shale region of Texas in recent years has created concerns about potential environmental impacts on water and air quality. The purpose of this study was to provide a better understanding of the potential contributions of emissions from gas production operations to population exposure to air toxics in the Barnett Shale region. This goal was approached using a combination of chemical characterization of the volatile organic compound (VOC) emissions from active wells, saturation monitoring for gaseous and particulate pollutants in a residential community located near active gas/oil extraction and processing facilities, source apportionment of VOCs measured in the community using the Chemical Mass Balance (CMB) receptor model, and direct measurements of the pollutant gradient downwind of a gas well with high VOC emissions. Overall, the study results indicate that air quality impacts due to individual gas wells and compressor stations are not likely to be discernible beyond a distance of approximately 100 m in the downwind direction. However, source apportionment results indicate a significant contribution to regional VOCs from gas production sources, particularly for lower-molecular-weight alkanes (< C6). Although measured ambient VOC concentrations were well below health-based safe exposure levels, the existence of urban-level mean concentrations of benzene and other mobile source air toxics combined with soot to total carbon ratios that were high for an area with little residential or commercial development may be indicative of the impact of increased heavy-duty vehicle traffic related to gas production. Implications: Rapid and extensive development of shale gas resources in recent years has created concerns about potential environmental impacts on water and air quality. This study focused on directly measuring the ambient air pollutant levels occurring at residential properties located near natural gas extraction and processing facilities, and estimating the relative contributions from gas production and motor vehicle emissions to ambient VOC concentrations. Although only a small-scale case study, the results may be useful for guidance in planning future ambient air quality studies and human exposure estimates in areas of intensive shale gas production.

Field establishment of fourwing saltbush in processed oil shale and disturbed native soil as influenced by vesicular-arbuscular mycorrhizae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Call, C.A.; McKell, C.M.

1984-04-30

Seedlings of fourwing saltbush (Atriplex canescens (Pursh) Nutt.) were inoculated with indigenous vesicular-arbuscular mycorrhizal (VAM) fungi in a containerized system and transplanted into processed oil shale and disturbed native soil in a semiarid rangeland environment in northwestern Colorado. After two growing seasons in the field, plants inoculated with VAM had greater aboveground biomass, cover, and height than noninoculated plants. Mycorrhizal plants were more effective in the uptake of water and phosphorus. Infection levels of inoculated plants were greatly reduced in processed shale (from 13.0 at outplanting to 3.8 at harvest), but functional VAM associations could be found after two growingmore » seasons. Results indicate that VAM help make processed oil shale a more tractable medium for the establishment of plants representative of later successional stages by allowing these plants to make effective use of the natural resources that are limiting under conditions of high stress. 39 references, 1 figure.« less

Determining the locus of a processing zone in an in situ oil shale retort by sound monitoring

DOEpatents

Elkington, W. Brice

1978-01-01

The locus of a processing zone advancing through a fragmented permeable mass of particles in an in situ oil shale retort in a subterranean formation containing oil shale is determined by monitoring for sound produced in the retort, preferably by monitoring for sound at at least two locations in a plane substantially normal to the direction of advancement of the processing zone. Monitoring can be effected by placing a sound transducer in a well extending through the formation adjacent the retort and/or in the fragmented mass such as in a well extending into the fragmented mass.

Processing use, and characterization of shale oil products

PubMed Central

Decora, Andrew W.; Kerr, Robert D.

1979-01-01

Oil shale is a potential source of oil that will supplement conventional sources for oil as our needs for fossil fuels begin to exceed our supplies. The resource may be mined and processed on the surface or it may be processed in situ. An overview of the potential technologies and environmental issues is presented. PMID:446454

A review of the organic geochemistry of shales

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, P.C.; Meyer, R.E.

1987-06-01

Shale formations have been suggested as a potential site for a high level nuclear waste repository. As a first step in the study of the possible interaction of nuclides with the organic components of the shales, literature on the identification of organic compounds from various shales of the continent of the United States has been reviewed. The Green River shale of the Cenozoic era is the most studied shale followed by the Pierre shale of the Mesozoic era and the Devonian black shale of the Paleozoic era. Organic compounds that have been identified from these shales are hydrocarbons, fatty acids,more » fatty alcohols, steranes, terpanes, carotenes, carbohydrates, amino acids, and porphyrins. However, these organic compounds constitute only a small fraction of the organics in shales and the majority of the organic compounds in shales are still unidentified.« less

Environmental baselines: preparing for shale gas in the UK

NASA Astrophysics Data System (ADS)

Bloomfield, John; Manamsa, Katya; Bell, Rachel; Darling, George; Dochartaigh, Brighid O.; Stuart, Marianne; Ward, Rob

2014-05-01

Groundwater is a vital source of freshwater in the UK. It provides almost 30% of public water supply on average, but locally, for example in south-east England, it is constitutes nearly 90% of public supply. In addition to public supply, groundwater has a number of other uses including agriculture, industry, and food and drink production. It is also vital for maintaining river flows especially during dry periods and so is essential for maintaining ecosystem health. Recently, there have been concerns expressed about the potential impacts of shale gas development on groundwater. The UK has abundant shales and clays which are currently the focus of considerable interest and there is active research into their characterisation, resource evaluation and exploitation risks. The British Geological Survey (BGS) is undertaking research to provide information to address some of the environmental concerns related to the potential impacts of shale gas development on groundwater resources and quality. The aim of much of this initial work is to establish environmental baselines, such as a baseline survey of methane occurrence in groundwater (National methane baseline study) and the spatial relationships between potential sources and groundwater receptors (iHydrogeology project), prior to any shale gas exploration and development. The poster describes these two baseline studies and presents preliminary findings. BGS are currently undertaking a national survey of baseline methane concentrations in groundwater across the UK. This work will enable any potential future changes in methane in groundwater associated with shale gas development to be assessed. Measurements of methane in potable water from the Cretaceous, Jurassic and Triassic carbonate and sandstone aquifers are variable and reveal methane concentrations of up to 500 micrograms per litre, but the mean value is relatively low at < 10 micrograms per litre. These values compare with much higher levels of methane in aquicludes and thermal waters, for example from the Carboniferous and Triassic which have concentrations in excess of 1500 micrograms per litre. It is important to understand the spatial relationships between potential shale gas source rocks and overlying aquifers if shale gas is to be developed in a safe and sustainable manner. The BGS and the Environment Agency have undertaken a national-scale study of the UK to assess the vertical separation between potential shale gas source rocks and major aquifers (iHydrogeology project). Aquifer - shale separations have been documented in the range <200m to >2km. The geological modelling process will be presented and discussed along with maps combining the results of the methane baseline study, the distribution of Principal Aquifers and shale/clay units, and aquifer - shale separation maps for the UK.

Study on nickel and vanadium removal in thermal conversion of oil sludge and oil shale sludge

NASA Astrophysics Data System (ADS)

Sombral, L. G. S.; Pickler, A. C.; Aires, J. R.; Riehl, C. A.

2003-05-01

The petroleum refining processes and of oil shale industrialization generate solid and semi-solid residues. In those residues heavy metals are found in concentrations that vary according to the production sector. The destination of those residues is encouraging researches looking for new technologies that reach the specifications of environmental organisms, and are being developed and applied to the industry. In this work it is shown that the heavy metals concentrations, previously in the petroleum oily solid residues and in those of the oils shale, treated by low temperature thermal conversion, obtaining in both cases concentrations below Ippm to Nickel and below 5ppm to vanadium.

Perspective usage estimation of Volga region combustible shale as a power generating fuel alternative

NASA Astrophysics Data System (ADS)

Korolev, E.; Barieva, E.; Eskin, A.

2018-05-01

A comprehensive study of combustible shale, common within Tatarstan and Ulyanovsk region, is carried out. The rocks physicochemical parameters are found to meet the power generating fuels requirements. The predictive estimate of ash products properties of combustible shale burning is held. Minding furnace process technology it is necessary to know mineral and organic components behavior when combustible shale is burnt. Since the first will determine slagging properties of energy raw materials, the second – its calorific value. In consideration of this the main research methods were X-ray, thermal and X-ray fluorescence analyses. Summing up the obtained results, we can draw to the following conclusions: 1. The combustible shale in Tatarstan and the Ulyanovsk region has predominantly low calorific value (Qb d = 5-9 MJ/kg). In order to enhance its efficiency and to reduce cost it is possible to conduct rocks burning together with some other organic or organic mineral power generating fuels. 2. High ash content (Ad = 60-80%) that causes a high external ballast content in shale implies the appropriateness of using this fuel resource next to its exploitation site. The acceptable distance to a consumer will reduce unproductive transportation charges for large ash and moisture masses. 3. The performed fuel ash components characteristics, as well as the yield and volatiles composition allow us to specify the basic parameters for boiler units, designed for the Volga combustible shale burning. 4. The noncombustible residual components composition shows that shale ash can be used in manufacture of materials of construction.

A comprehensive method for the fracability evaluation of shale combined with brittleness and stress sensitivity

NASA Astrophysics Data System (ADS)

Wang, Xiaoqiong; Ge, Hongkui; Wang, Daobing; Wang, Jianbo; Chen, Hao

2017-12-01

An effective fracability evaluation on the fracture network is key to the whole process of shale gas exploitation. At present, neither a standard criteria nor a generally accepted evaluation method exist. Well log and laboratory results have shown that the commonly used brittleness index calculated from the mineralogy composition is not entirely consistent with that obtained from the elastic modulus of the rock, and is sometimes even contradictory. The brittle mineral reflects the brittleness of the rock matrix, and the stress sensitivity of the wave velocity reflects the development degree of the natural fracture system. They are both key factors in controlling the propagating fracture morphology. Thus, in this study, a novel fracability evaluation method of shale was developed combining brittleness and stress sensitivity. Based on this method, the fracability of three shale gas plays were evaluated. The cored cylindrical samples were loaded under uniaxial stress up to 30 MPa and the compressional wave velocities were obtained along the axis stress direction at each MPa stress. From the stress velocity evolution, the stress sensitivity coefficients could be obtained. Our results showed that the fracability of Niutitang shale is better than that of Lujiaping shale, and the fracability of Lujiaping shale is better than Longmaxi shale. This result is in good agreement with acoustic emission activity measurements. The new fracability evaluation method enables a comprehensive reflection of the characteristics of rock matrix brittleness and the natural fracture system. This work is valuable for the evaluation of hydraulic fracturing effects in unconventional oil and gas reservoirs in the future.

An exploratory study of air emissions associated with shale gas development and production in the Barnett Shale.

PubMed

Rich, Alisa; Grover, James P; Sattler, Melanie L

2014-01-01

Information regarding air emissions from shale gas extraction and production is critically important given production is occurring in highly urbanized areas across the United States. Objectives of this exploratory study were to collect ambient air samples in residential areas within 61 m (200 feet) of shale gas extraction/production and determine whether a "fingerprint" of chemicals can be associated with shale gas activity. Statistical analyses correlating fingerprint chemicals with methane, equipment, and processes of extraction/production were performed. Ambient air sampling in residential areas of shale gas extraction and production was conducted at six counties in the Dallas/Fort Worth (DFW) Metroplex from 2008 to 2010. The 39 locations tested were identified by clients that requested monitoring. Seven sites were sampled on 2 days (typically months later in another season), and two sites were sampled on 3 days, resulting in 50 sets of monitoring data. Twenty-four-hour passive samples were collected using summa canisters. Gas chromatography/mass spectrometer analysis was used to identify organic compounds present. Methane was present in concentrations above laboratory detection limits in 49 out of 50 sampling data sets. Most of the areas investigated had atmospheric methane concentrations considerably higher than reported urban background concentrations (1.8-2.0 ppm(v)). Other chemical constituents were found to be correlated with presence of methane. A principal components analysis (PCA) identified multivariate patterns of concentrations that potentially constitute signatures of emissions from different phases of operation at natural gas sites. The first factor identified through the PCA proved most informative. Extreme negative values were strongly and statistically associated with the presence of compressors at sample sites. The seven chemicals strongly associated with this factor (o-xylene, ethylbenzene, 1,2,4-trimethylbenzene, m- and p-xylene, 1,3,5-trimethylbenzene, toluene, and benzene) thus constitute a potential fingerprint of emissions associated with compression. Information regarding air emissions from shale gas development and production is critically important given production is now occurring in highly urbanized areas across the United States. Methane, the primary shale gas constituent, contributes substantially to climate change; other natural gas constituents are known to have adverse health effects. This study goes beyond previous Barnett Shale field studies by encompassing a wider variety of production equipment (wells, tanks, compressors, and separators) and a wider geographical region. The principal components analysis, unique to this study, provides valuable information regarding the ability to anticipate associated shale gas chemical constituents.

Organic-rich shale lithofacies geophysical prediction: A case study in the fifth organic-matter-rich interval of Paleogene Hetaoyuan Formation, Biyang Depression

NASA Astrophysics Data System (ADS)

Fei, S.; Xinong, X.

2017-12-01

The fifth organic-matter-rich interval (ORI 5) in the He-third Member of the Paleogene Hetaoyuan Formation is believed to be the main exploration target for shale oil in Biyang Depression, eastern China. An important part of successful explorating and producing shale oil is to identify and predict organic-rich shale lithofacies with different reservoir capacities and rock geomechanical properties, which are related to organic matter content and mineral components. In this study, shale lithofacies are defined by core analysis data, well-logging and seismic data, and the spatial-temporal distribution of various lithologies are predicted qualitatively by seismic attribute technology and quantitatively by geostatistical inversion analysis, and the prediction results are confirmed by the logging data and geological background. ORI 5 is present in lacustrine expanding system tract and can be further divided into four parasequence sets based on the analysis of conventional logs, TOC content and wavelet transform. Calcareous shale, dolomitic shale, argillaceous shale, silty shale and muddy siltstone are defined within ORI 5, and can be separated and predicted in regional-scale by root mean square amplitude (RMS) analysis and wave impedance. The results indicate that in the early expansion system tract, dolomitic shale and calcareous shale widely developed in the study area, and argillaceous shale, silty shale, and muddy siltstone only developed in periphery of deep depression. With the lake level rising, argillaceous shale and calcareous shale are well developed, and argillaceous shale interbeded with silty shale or muddy siltstone developed in deep or semi-deep lake. In the late expansion system tract, argillaceous shale is widely deposited in the deepest depression, calcareous shale presented band distribution in the east of the depression. Actual test results indicate that these methods are feasible to predict the spatial distribution of shale lithofacies.

Weathering of the New Albany Shale, Kentucky, USA: I. Weathering zones defined by mineralogy and major-element composition

USGS Publications Warehouse

Tuttle, M.L.W.; Breit, G.N.

2009-01-01

Comprehensive understanding of chemical and mineralogical changes induced by weathering is valuable information when considering the supply of nutrients and toxic elements from rocks. Here minerals that release and fix major elements during progressive weathering of a bed of Devonian New Albany Shale in eastern Kentucky are documented. Samples were collected from unweathered core (parent shale) and across an outcrop excavated into a hillside 40 year prior to sampling. Quantitative X-ray diffraction mineralogical data record progressive shale alteration across the outcrop. Mineral compositional changes reflect subtle alteration processes such as incongruent dissolution and cation exchange. Altered primary minerals include K-feldspars, plagioclase, calcite, pyrite, and chlorite. Secondary minerals include jarosite, gypsum, goethite, amorphous Fe(III) oxides and Fe(II)-Al sulfate salt (efflorescence). The mineralogy in weathered shale defines four weathered intervals on the outcrop-Zones A-C and soil. Alteration of the weakly weathered shale (Zone A) is attributed to the 40-a exposure of the shale. In this zone, pyrite oxidization produces acid that dissolves calcite and attacks chlorite, forming gypsum, jarosite, and minor efflorescent salt. The pre-excavation, active weathering front (Zone B) is where complete pyrite oxidation and alteration of feldspar and organic matter result in increased permeability. Acidic weathering solutions seep through the permeable shale and evaporate on the surface forming abundant efflorescent salt, jarosite and minor goethite. Intensely weathered shale (Zone C) is depleted in feldspars, chlorite, gypsum, jarosite and efflorescent salts, but has retained much of its primary quartz, illite and illite-smectite. Goethite and amorphous FE(III) oxides increase due to hydrolysis of jarosite. Enhanced permeability in this zone is due to a 14% loss of the original mass in parent shale. Denudation rates suggest that characteristics of Zone C were acquired over 1 Ma. Compositional differences between soil and Zone C are largely attributed to illuvial processes, formation of additional Fe(III) oxides and incorporation of modern organic matter.

Multi-scale Multi-dimensional Imaging and Characterization of Oil Shale Pyrolysis

NASA Astrophysics Data System (ADS)

Gao, Y.; Saif, T.; Lin, Q.; Al-Khulaifi, Y.; Blunt, M. J.; Bijeljic, B.

2017-12-01

The microstructural evaluation of fine grained rocks is challenging which demands the use of several complementary methods. Oil shale, a fine-grained organic-rich sedimentary rock, represents a large and mostly untapped unconventional hydrocarbon resource with global reserves estimated at 4.8 trillion barrels. The largest known deposit is the Eocene Green River Formation in Western Colorado, Eastern Utah, and Southern Wyoming. An improved insight into the mineralogy, organic matter distribution and pore network structure before, during and after oil shale pyrolysis is critical to understanding hydrocarbon flow behaviour and improving recovery. In this study, we image Mahogany zone oil shale samples in two dimensions (2-D) using scanning electron microscopy (SEM), and in three dimensions (3-D) using focused ion beam scanning electron microscopy (FIB-SEM), laboratory-based X-ray micro-tomography (µCT) and synchrotron X-ray µCT to reveal a complex and variable fine grained microstructure dominated by organic-rich parallel laminations which are tightly bound in a highly calcareous and heterogeneous mineral matrix. We report the results of a detailed µCT study of the Mahogany oil shale with increasing pyrolysis temperature. The physical transformation of the internal microstructure and evolution of pore space during the thermal conversion of kerogen in oil shale to produce hydrocarbon products was characterized. The 3-D volumes of pyrolyzed oil shale were reconstructed and image processed to visualize and quantify the volume and connectivity of the pore space. The results show a significant increase in anisotropic porosity associated with pyrolysis between 300-500°C with the formation of micron-scale connected pore channels developing principally along the kerogen-rich lamellar structures.

The effect of long-term regional pumping on hydrochemistry and dissolved gas content in an undeveloped shale-gas-bearing aquifer in southwestern Ontario, Canada

NASA Astrophysics Data System (ADS)

Hamilton, Stewart M.; Grasby, Stephen E.; McIntosh, Jennifer C.; Osborn, Stephen G.

2015-02-01

Baseline groundwater geochemical mapping of inorganic and isotopic parameters across 44,000 km2 of southwestern Ontario (Canada) has delineated a discreet zone of natural gas in the bedrock aquifer coincident with an 8,000-km2 exposure of Middle Devonian shale. This study describes the ambient geochemical conditions in these shales in the context of other strata, including Ordovician shales, and discusses shale-related natural and anthropogenic processes contributing to hydrogeochemical conditions in the aquifer. The three Devonian shales—the Kettle Point Formation (Antrim equivalent), Hamilton Group and Marcellus Formation—have higher DOC, DIC, HCO3, CO2(aq), pH and iodide, and much higher CH4(aq). The two Ordovician shales—the Queenston and Georgian-Bay/Blue Mountain Formations—are higher in Ca, Mg, SO4 and H2S. In the Devonian shale region, isotopic zones of Pleistocene-aged groundwater have halved in size since first identified in the 1980s; potentiometric data implicate regional groundwater extraction in the shrinkage. Isotopically younger waters invading the aquifer show rapid increases in CH4(aq), pH and iodide with depth and rapid decrease in oxidized carbon species including CO2, HCO3 and DIC, suggesting contemporary methanogenesis. Pumping in the Devonian shale contact aquifer may stimulate methanogenesis by lowering TDS, removing products and replacing reactants, including bicarbonate, derived from overlying glacial sedimentary aquifers.

Purifying contaminated water

DOEpatents

Daughton, Christian G.

1983-01-01

Process for removing biorefractory compounds from contaminated water (e.g., oil shale retort waste-water) by contacting same with fragmented raw oil shale. Biorefractory removal is enhanced by preactivating the oil shale with at least one member of the group of carboxylic, acids, alcohols, aldehydes, ketones, ethers, amines, amides, sulfoxides, mixed ether-esters and nitriles. Further purification is obtained by stripping, followed by biodegradation and removal of the cells.

Organic Substances from Unconventional Oil and Gas Production in Shale

NASA Astrophysics Data System (ADS)

Orem, W. H.; Varonka, M.; Crosby, L.; Schell, T.; Bates, A.; Engle, M.

2014-12-01

Unconventional oil and gas (UOG) production has emerged as an important element in the US and world energy mix. Technological innovations in the oil and gas industry, especially horizontal drilling and hydraulic fracturing, allow for the enhanced release of oil and natural gas from shale compared to conventional oil and gas production. This has made commercial exploitation possible on a large scale. Although UOG is enormously successful, there is surprisingly little known about the effects of this technology on the targeted shale formation and on environmental impacts of oil and gas production at the surface. We examined water samples from both conventional and UOG shale wells to determine the composition, source and fate of organic substances present. Extraction of hydrocarbon from shale plays involves the creation and expansion of fractures through the hydraulic fracturing process. This process involves the injection of large volumes of a water-sand mix treated with organic and inorganic chemicals to assist the process and prop open the fractures created. Formation water from a well in the New Albany Shale that was not hydraulically fractured (no injected chemicals) had total organic carbon (TOC) levels that averaged 8 mg/L, and organic substances that included: long-chain fatty acids, alkanes, polycyclic aromatic hydrocarbons, heterocyclic compounds, alkyl benzenes, and alkyl phenols. In contrast, water from UOG production in the Marcellus Shale had TOC levels as high as 5,500 mg/L, and contained a range of organic chemicals including, solvents, biocides, scale inhibitors, and other organic chemicals at thousands of μg/L for individual compounds. These chemicals and TOC decreased rapidly over the first 20 days of water recovery as injected fluids were recovered, but residual organic compounds (some naturally-occurring) remained up to 250 days after the start of water recovery (TOC 10-30 mg/L). Results show how hydraulic fracturing changes the organic composition of shale formation water, and that some injected organic substances are retained on the shale and slowly released. Thus, appropriate safe disposal of produced water is needed long into production. Changes in organic substances in formation water may impact microbial communities. Current work is focused on UOG production in the Permian Basin, Texas.

Geology of the Devonian black shales of the Appalachian basin

USGS Publications Warehouse

Roen, J.B.

1983-01-01

Black shales of Devonian age in the Appalachian basin are a unique rock sequence. The high content of organic matter, which imparts the characteristic lithology, has for years attracted considerable interest in the shales as a possible source of energy. Concurrent with periodic and varied economic exploitations of the black shales are geologic studies. The recent energy shortage prompted the U.S. Department of Energy through the Eastern Gas Shales Project of the Morgantown Energy Technology Center to underwrite a research program to determine the geologic, geochemical, and structural characteristics of the Devonian black shales in order to enhance the recovery of gas from the shales. Geologic studies produced a regional stratigraphic network that correlates the 15-foot sequence in Tennessee with 3,000 feet of interbedded black and gray shales in central New York. The classic Devonian black-shale sequence in New York has been correlated with the Ohio Shale of Ohio and Kentucky and the Chattanooga Shale of Tennessee and southwestern Virginia. Biostratigraphic and lithostratigraphic markers in conjunction with gamma-ray logs facilitated long range correlations within the Appalachian basin and provided a basis for correlations with the black shales of the Illinois and Michigan basins. Areal distribution of selected shale units along with paleocurrent studies, clay mineralogy, and geochemistry suggests variations in the sediment source and transport directions. Current structures, faunal evidence, lithologic variations, and geochemical studies provide evidence to support interpretation of depositional environments. In addition, organic geochemical data combined with stratigraphic and structural characteristics of the shale within the basin allow an evaluation of the resource potential of natural gas in the Devonian shale sequence.

Clean and Secure Energy from Domestic Oil Shale and Oil Sands Resources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spinti, Jennifer; Birgenheier, Lauren; Deo, Milind

This report summarizes the significant findings from the Clean and Secure Energy from Domestic Oil Shale and Oil Sands Resources program sponsored by the Department of Energy through the National Energy Technology Laboratory. There were four principle areas of research; Environmental, legal, and policy issues related to development of oil shale and oil sands resources; Economic and environmental assessment of domestic unconventional fuels industry; Basin-scale assessment of conventional and unconventional fuel development impacts; and Liquid fuel production by in situ thermal processing of oil shale Multiple research projects were conducted in each area and the results have been communicated viamore » sponsored conferences, conference presentations, invited talks, interviews with the media, numerous topical reports, journal publications, and a book that summarizes much of the oil shale research relating to Utah’s Uinta Basin. In addition, a repository of materials related to oil shale and oil sands has been created within the University of Utah’s Institutional Repository, including the materials generated during this research program. Below is a listing of all topical and progress reports generated by this project and submitted to the Office of Science and Technical Information (OSTI). A listing of all peer-reviewed publications generated as a result of this project is included at the end of this report; Geomechanical and Fluid Transport Properties 1 (December, 2015); Validation Results for Core-Scale Oil Shale Pyrolysis (February, 2015); and Rates and Mechanisms of Oil Shale Pyrolysis: A Chemical Structure Approach (November, 2014); Policy Issues Associated With Using Simulation to Assess Environmental Impacts (November, 2014); Policy Analysis of the Canadian Oil Sands Experience (September, 2013); V-UQ of Generation 1 Simulator with AMSO Experimental Data (August, 2013); Lands with Wilderness Characteristics, Resource Management Plan Constraints, and Land Exchanges (March, 2012); Conjunctive Surface and Groundwater Management in Utah: Implications for Oil Shale and Oil Sands Development (May, 2012); Development of CFD-Based Simulation Tools for In Situ Thermal Processing of Oil Shale/Sands (February, 2012); Core-Based Integrated Sedimentologic, Stratigraphic, and Geochemical Analysis of the Oil Shale Bearing Green River Formation, Uinta Basin, Utah (April, 2011); Atomistic Modeling of Oil Shale Kerogens and Asphaltenes Along with their Interactions with the Inorganic Mineral Matrix (April, 2011); Pore Scale Analysis of Oil Shale/Sands Pyrolysis (March, 2011); Land and Resource Management Issues Relevant to Deploying In-Situ Thermal Technologies (January, 2011); Policy Analysis of Produced Water Issues Associated with In-Situ Thermal Technologies (January, 2011); and Policy Analysis of Water Availability and Use Issues for Domestic Oil Shale and Oil Sands Development (March, 2010)« less

43 CFR 3922.40 - Tract delineation.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL SHALE LEASING Application Processing § 3922.40... development of the oil shale resource. (b) The BLM may delineate more or less lands than were covered by an...

43 CFR 3922.40 - Tract delineation.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL SHALE LEASING Application Processing § 3922.40... development of the oil shale resource. (b) The BLM may delineate more or less lands than were covered by an...

Military jet fuel from shale oil

NASA Technical Reports Server (NTRS)

Coppola, E. N.

1980-01-01

Investigations leading to a specification for aviation turbine fuel produced from whole crude shale oil are described. Refining methods involving hydrocracking, hydrotreating, and extraction processes are briefly examined and their production capabilities are assessed.

43 CFR 3922.40 - Tract delineation.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) OIL SHALE LEASING Application Processing § 3922.40 Tract... the oil shale resource. (b) The BLM may delineate more or less lands than were covered by an...

43 CFR 3922.40 - Tract delineation.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL SHALE LEASING Application Processing § 3922.40... development of the oil shale resource. (b) The BLM may delineate more or less lands than were covered by an...

Effects of acid-volatile sulfide on metal bioavailability and toxicity to midge (Chironomus tentans) larvae in black shale sediments

USGS Publications Warehouse

Ogendi, G.M.; Brumbaugh, W.G.; Hannigan, R.E.; Farris, J.L.

2007-01-01

Metal bioavailability and toxicity to aquatic organisms are greatly affected by variables such as pH, hardness, organic matter, and sediment acid-volatile sulfide (AVS). Sediment AVS, which reduces metal bioavailability and toxicity by binding and immobilizing metals as insoluble sulfides, has been studied intensely in recent years. Few studies, however, have determined the spatial variability of AVS and its interaction with simultaneously extracted metals (SEM) in sediments containing elevated concentrations of metals resulting from natural geochemical processes, such as weathering of black shales. We collected four sediment samples from each of four headwater bedrock streams in northcentral Arkansa (USA; three black shale-draining streams and one limestone-draining stream). We conducted 10-d acute whole-sediment toxicity tests using the midge Chironomus tentans and performed analyses for AVS, total metals, SEMs, and organic carbon. Most of the sediments from shale-draining streams had similar total metal and SEM concentrations but considerable differences in organic carbon and AVS. Zinc was the leading contributor to the SEM molar sum, averaging between 68 and 74%, whereas lead and cadmium contributed less than 3%. The AVS concentration was very low in all but two samples from one of the shale streams, and the sum of the SEM concentrations was in molar excess of AVS for all shale stream sediments. No significant differences in mean AVS concentrations between sediments collected from shale-draining or limestone-draining sites were noted (p > 0.05). Midge survival and growth in black shale-derived sediments were significantly less (p < 0.001) than that of limestone-derived sediments. On the whole, either SEM alone or SEM-AVS explained the total variation in midge survival and growth about equally well. However, survival and growth were significantly greater (p < 0.05) in the two sediment samples that contained measurable AVS compared with the two sediments from the same stream that contained negligible AVS. ?? 2007 SETAC.

Lower Silurian `hot shales' in North Africa and Arabia: regional distribution and depositional model

NASA Astrophysics Data System (ADS)

Lüning, S.; Craig, J.; Loydell, D. K.; Štorch, P.; Fitches, B.

2000-03-01

Lowermost Silurian organic-rich (`hot') shales are the origin of 80-90% of Palaeozoic sourced hydrocarbons in North Africa and also played a major role in petroleum generation on the Arabian Peninsula. In most cases, the shales were deposited directly above upper Ordovician (peri-) glacial sandstones during the initial early Silurian transgression that was a result of the melting of the late Ordovician icecap. Deposition of the main organic-rich shale unit in the North African/Arabian region was restricted to the earliest Silurian Rhuddanian stage ( acuminatus, atavus and probably early cyphus graptolite biozones). During this short period (1-2 m.y.), a favourable combination of factors existed which led to the development of exceptionally strong oxygen-deficiency in the area. In most countries of the study area, the post-Rhuddanian Silurian shales are organically lean and have not contributed to petroleum generation. The distribution and thickness of the basal Silurian `hot' shales have been mapped in detail for the whole North African region, using logs from some 300 exploration wells in Libya, Tunisia, Algeria and Morocco. In addition, all relevant, accessible published and unpublished surface and subsurface data of the lower Silurian shales in North Africa and Arabia have been reviewed, including sedimentological, biostratigraphic and organic geochemical data. The lowermost Silurian hot shales of northern Gondwana are laterally discontinuous and their distribution and thickness were controlled by the early Silurian palaeorelief which was shaped mainly by glacial processes of the late Ordovician ice age and by Pan-African and Infracambrian compressional and extensional tectonism. The thickest and areally most extensive basal Silurian organic-rich shales in North Africa occur in Algeria, Tunisia and western Libya, while on the Arabian Peninsula they are most prolific in Saudi Arabia, Oman, Jordan and Iraq. The hot shales were not deposited in Egypt, which was a large palaeohigh at that time. The depositional model presented may help in better understanding the source potential of the basal Silurian shales in less-explored regions of North Africa and Arabia including Morocco, northern Niger and the Kufra Basin in southeast Libya.

Oil shale as an energy source in Israel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fainberg, V.; Hetsroni, G.

1996-01-01

Reserves, characteristics, energetics, chemistry, and technology of Israeli oil shales are described. Oil shale is the only source of energy and the only organic natural resource in Israel. Its reserves of about 12 billion tons will be enough to meet Israel`s requirements for about 80 years. The heating value of the oil shale is 1,150 kcal/kg, oil yield is 6%, and sulfur content of the oil is 5--7%. A method of oil shale processing, providing exhaustive utilization of its energy and chemical potential, developed in the Technion, is described. The principal feature of the method is a two-stage pyrolysis ofmore » the oil shale. As a result, gas and aromatic liquids are obtained. The gas may be used for energy production in a high-efficiency power unit, or as a source for chemical synthesis. The liquid products can be an excellent source for production of chemicals.« less

Study of gas production from shale reservoirs with multi-stage hydraulic fracturing horizontal well considering multiple transport mechanisms.

PubMed

Guo, Chaohua; Wei, Mingzhen; Liu, Hong

2018-01-01

Development of unconventional shale gas reservoirs (SGRs) has been boosted by the advancements in two key technologies: horizontal drilling and multi-stage hydraulic fracturing. A large number of multi-stage fractured horizontal wells (MsFHW) have been drilled to enhance reservoir production performance. Gas flow in SGRs is a multi-mechanism process, including: desorption, diffusion, and non-Darcy flow. The productivity of the SGRs with MsFHW is influenced by both reservoir conditions and hydraulic fracture properties. However, rare simulation work has been conducted for multi-stage hydraulic fractured SGRs. Most of them use well testing methods, which have too many unrealistic simplifications and assumptions. Also, no systematical work has been conducted considering all reasonable transport mechanisms. And there are very few works on sensitivity studies of uncertain parameters using real parameter ranges. Hence, a detailed and systematic study of reservoir simulation with MsFHW is still necessary. In this paper, a dual porosity model was constructed to estimate the effect of parameters on shale gas production with MsFHW. The simulation model was verified with the available field data from the Barnett Shale. The following mechanisms have been considered in this model: viscous flow, slip flow, Knudsen diffusion, and gas desorption. Langmuir isotherm was used to simulate the gas desorption process. Sensitivity analysis on SGRs' production performance with MsFHW has been conducted. Parameters influencing shale gas production were classified into two categories: reservoir parameters including matrix permeability, matrix porosity; and hydraulic fracture parameters including hydraulic fracture spacing, and fracture half-length. Typical ranges of matrix parameters have been reviewed. Sensitivity analysis have been conducted to analyze the effect of the above factors on the production performance of SGRs. Through comparison, it can be found that hydraulic fracture parameters are more sensitive compared with reservoir parameters. And reservoirs parameters mainly affect the later production period. However, the hydraulic fracture parameters have a significant effect on gas production from the early period. The results of this study can be used to improve the efficiency of history matching process. Also, it can contribute to the design and optimization of hydraulic fracture treatment design in unconventional SGRs.

Study of gas production from shale reservoirs with multi-stage hydraulic fracturing horizontal well considering multiple transport mechanisms

PubMed Central

Wei, Mingzhen; Liu, Hong

2018-01-01

Development of unconventional shale gas reservoirs (SGRs) has been boosted by the advancements in two key technologies: horizontal drilling and multi-stage hydraulic fracturing. A large number of multi-stage fractured horizontal wells (MsFHW) have been drilled to enhance reservoir production performance. Gas flow in SGRs is a multi-mechanism process, including: desorption, diffusion, and non-Darcy flow. The productivity of the SGRs with MsFHW is influenced by both reservoir conditions and hydraulic fracture properties. However, rare simulation work has been conducted for multi-stage hydraulic fractured SGRs. Most of them use well testing methods, which have too many unrealistic simplifications and assumptions. Also, no systematical work has been conducted considering all reasonable transport mechanisms. And there are very few works on sensitivity studies of uncertain parameters using real parameter ranges. Hence, a detailed and systematic study of reservoir simulation with MsFHW is still necessary. In this paper, a dual porosity model was constructed to estimate the effect of parameters on shale gas production with MsFHW. The simulation model was verified with the available field data from the Barnett Shale. The following mechanisms have been considered in this model: viscous flow, slip flow, Knudsen diffusion, and gas desorption. Langmuir isotherm was used to simulate the gas desorption process. Sensitivity analysis on SGRs’ production performance with MsFHW has been conducted. Parameters influencing shale gas production were classified into two categories: reservoir parameters including matrix permeability, matrix porosity; and hydraulic fracture parameters including hydraulic fracture spacing, and fracture half-length. Typical ranges of matrix parameters have been reviewed. Sensitivity analysis have been conducted to analyze the effect of the above factors on the production performance of SGRs. Through comparison, it can be found that hydraulic fracture parameters are more sensitive compared with reservoir parameters. And reservoirs parameters mainly affect the later production period. However, the hydraulic fracture parameters have a significant effect on gas production from the early period. The results of this study can be used to improve the efficiency of history matching process. Also, it can contribute to the design and optimization of hydraulic fracture treatment design in unconventional SGRs. PMID:29320489

Shale Oil Value Enhancement Research

DOE Office of Scientific and Technical Information (OSTI.GOV)

James W. Bunger

2006-11-30

Raw kerogen oil is rich in heteroatom-containing compounds. Heteroatoms, N, S & O, are undesirable as components of a refinery feedstock, but are the basis for product value in agrochemicals, pharmaceuticals, surfactants, solvents, polymers, and a host of industrial materials. An economically viable, technologically feasible process scheme was developed in this research that promises to enhance the economics of oil shale development, both in the US and elsewhere in the world, in particular Estonia. Products will compete in existing markets for products now manufactured by costly synthesis routes. A premium petroleum refinery feedstock is also produced. The technology is nowmore » ready for pilot plant engineering studies and is likely to play an important role in developing a US oil shale industry.« less

Updated methodology for nuclear magnetic resonance characterization of shales

NASA Astrophysics Data System (ADS)

Washburn, Kathryn E.; Birdwell, Justin E.

2013-08-01

Unconventional petroleum resources, particularly in shales, are expected to play an increasingly important role in the world's energy portfolio in the coming years. Nuclear magnetic resonance (NMR), particularly at low-field, provides important information in the evaluation of shale resources. Most of the low-field NMR analyses performed on shale samples rely heavily on standard T1 and T2 measurements. We present a new approach using solid echoes in the measurement of T1 and T1-T2 correlations that addresses some of the challenges encountered when making NMR measurements on shale samples compared to conventional reservoir rocks. Combining these techniques with standard T1 and T2 measurements provides a more complete assessment of the hydrogen-bearing constituents (e.g., bitumen, kerogen, clay-bound water) in shale samples. These methods are applied to immature and pyrolyzed oil shale samples to examine the solid and highly viscous organic phases present during the petroleum generation process. The solid echo measurements produce additional signal in the oil shale samples compared to the standard methodologies, indicating the presence of components undergoing homonuclear dipolar coupling. The results presented here include the first low-field NMR measurements performed on kerogen as well as detailed NMR analysis of highly viscous thermally generated bitumen present in pyrolyzed oil shale.

Shale Gas in Europe: pragmatic perspectives and actions

NASA Astrophysics Data System (ADS)

Hübner, A.; Horsfield, B.; Kapp, I.

2012-10-01

Natural gas will continue to play a key role in the EU's energy mix in the coming years, with unconventional gas' role increasing in importance as new resources are exploited worldwide. As far as Europe's own shale gas resources are concerned, it is especially the public's perception and level of acceptance that will make or break shale gas in the near-term. Both the pros and cons need to be discussed based on factual argument rather than speculation. Research organizations such as ours (GFZ German Research Centre for Geosciences) have an active and defining role to play in remedying this deficiency. As far as science and technology developments are concerned, the project "Gas Shales in Europe" (GASH) and the shale gas activities of "GeoEnergie" (GeoEn) are the first major initiatives in Europe focused on shale gas. Basic and applied geoscientific research is conducted to understand the fundamental nature and interdependencies of the processes leading to shale gas formation. When it comes to knowledge transfer, the perceived and real risks associated with shale gas exploitation need immediate evaluation in Europe using scientific analysis. To proactively target these issues, the GFZ and partners are launching the European sustainable Operating Practices (E-SOP) Initiative for Unconventional Resources. The web-based Shale Gas Information Platform (SHIP) brings these issues into the public domain.

Updated methodology for nuclear magnetic resonance characterization of shales

USGS Publications Warehouse

Washburn, Kathryn E.; Birdwell, Justin E.

2013-01-01

Unconventional petroleum resources, particularly in shales, are expected to play an increasingly important role in the world’s energy portfolio in the coming years. Nuclear magnetic resonance (NMR), particularly at low-field, provides important information in the evaluation of shale resources. Most of the low-field NMR analyses performed on shale samples rely heavily on standard T1 and T2 measurements. We present a new approach using solid echoes in the measurement of T1 and T1–T2 correlations that addresses some of the challenges encountered when making NMR measurements on shale samples compared to conventional reservoir rocks. Combining these techniques with standard T1 and T2 measurements provides a more complete assessment of the hydrogen-bearing constituents (e.g., bitumen, kerogen, clay-bound water) in shale samples. These methods are applied to immature and pyrolyzed oil shale samples to examine the solid and highly viscous organic phases present during the petroleum generation process. The solid echo measurements produce additional signal in the oil shale samples compared to the standard methodologies, indicating the presence of components undergoing homonuclear dipolar coupling. The results presented here include the first low-field NMR measurements performed on kerogen as well as detailed NMR analysis of highly viscous thermally generated bitumen present in pyrolyzed oil shale.

Purifying contaminated water. [DOE patent application

DOEpatents

Daughton, C.G.

1981-10-27

Process is presented for removing biorefactory compounds from contaminated water (e.g., oil shale retort waste-water) by contacting same with fragmented raw oil shale. Biorefractory removal is enhanced by preactivating the oil shale with at least one member of the group of carboxylic acids, alcohols, aldehydes, ketones, ethers, amines, amides, sulfoxides, mixed ether-esters and nitriles. Further purification is obtained by stripping, followed by biodegradation and removal of the cells.

System for utilizing oil shale fines

DOEpatents

Harak, Arnold E.

1982-01-01

A system is provided for utilizing fines of carbonaceous materials such as particles or pieces of oil shale of about one-half inch or less diameter which are rejected for use in some conventional or prior surface retorting process, which obtains maximum utilization of the energy content of the fines and which produces a waste which is relatively inert and of a size to facilitate disposal. The system includes a cyclone retort (20) which pyrolyzes the fines in the presence of heated gaseous combustion products, the cyclone retort having a first outlet (30) through which vapors can exit that can be cooled to provide oil, and having a second outlet (32) through which spent shale fines are removed. A burner (36) connected to the spent shale outlet of the cyclone retort, burns the spent shale with air, to provide hot combustion products (24) that are carried back to the cyclone retort to supply gaseous combustion products utilized therein. The burner heats the spent shale to a temperature which forms a molten slag, and the molten slag is removed from the burner into a quencher (48) that suddenly cools the molten slag to form granules that are relatively inert and of a size that is convenient to handle for disposal in the ground or in industrial processes.

CO2 Sequestration within Spent Oil Shale

NASA Astrophysics Data System (ADS)

Foster, H.; Worrall, F.; Gluyas, J.; Morgan, C.; Fraser, J.

2013-12-01

Worldwide deposits of oil shales are thought to represent ~3 trillion barrels of oil. Jordanian oil shale deposits are extensive and of high quality, and could represent 100 billion barrels of oil, leading to much interest and activity in the development of these deposits. The exploitation of oil shales has raised a number of environmental concerns including: land use, waste disposal, water consumption, and greenhouse gas emissions. The dry retorting of oil shales can overcome a number of the environmental impacts, but this leaves concerns over management of spent oil shale and CO2 production. In this study we propose that the spent oil shale can be used to sequester CO2 from the retorting process. Here we show that by conducting experiments using high pressure reaction facilities, we can achieve successful carbonation of spent oil shale. High pressure reactor facilities in the Department of Earth Sciences, Durham University, are capable of reacting solids with a range of fluids up to 15 MPa and 350°C, being specially designed for research with supercritical fluids. Jordanian spent oil shale was reacted with high pressure CO2 in order to assess whether there is potential for sequestration. Fresh and reacted materials were then examined by: Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Thermogravimetric Analysis (TGA), X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD) methods. Jordanian spent oil shale was found to sequester up to 5.8 wt % CO2, on reacting under supercritical conditions, which is 90% of the theoretical carbonation. Jordanian spent oil shale is composed of a large proportion of CaCO3, which on retorting decomposes, forming CaSO4 and Ca-oxides which are the focus of carbonation reactions. A factorially designed experiment was used to test different factors on the extent of carbonation, including: pressure; temperature; duration; and the water content. Analysis of Variance (ANOVA) techniques were then used to determine the significance of each of these. Results show that the duration; temperature; pressure; and the interactions between these significantly affect the extent of carbonation. Reactions carried out for at least 4 hours show significantly more carbonation than those under supercritical conditions for 2 hours or less. However, reacting for 24 hours does not show a significant increase in the extent of reaction, indicating that the reaction has reached equilibrium within a few hours. Maximum carbonation occurred within 4 hours, at higher temperatures and pressures of 80°C and 100 bar although results also show that there is a significant amount of carbonation achieved within 30 minutes, at 40°C and 70 bar. The magnitude of the CO2 sequestration achieved was sufficient that it could lower CO2 emissions by up to 30 kg CO2 /bbl, thereby bringing the emissions from oil shale processing in line with those from conventional oil extraction methods. The determination of optimum conditions to allow for: maximum carbonation, oil recovery and sufficient calcination, is also of importance and is currently under investigation.

Reservoir properties of submarine- fan facies: Great Valley sequence, California.

USGS Publications Warehouse

McLean, H.

1981-01-01

Submarine-fan sandstones of the Great Valley sequence west of the Sacramento Valley, California, have low porosities and permeabilities. However, petrography and scanning electron microscope studies indicate that most sands in almost all submarine-fan environments are originally porous and permeable. Thin turbidite sandstones deposited in areas dominated by shale in the outer-fan and basin-plain are cemented mainly by calcite; shale dewatering is inferred to contribute to rapid cementation early in the burial process. Sands deposited in inner- and middle-fan channels with only thin shale beds have small percentrages of intergranular cement. The original porosity is reduced mechanically at shallow depths and by pressure solution at deeperlevels. Permeability decreases with increasing age of the rocks, as a result of increasing burial depths. Computer-run stepwise regression analyses show that the porosity is inversely related to the percentage of calcite cement. The results reported here indicate original porosity and permeability can be high in deep-water submarine fans and that fan environments dominated by sand (with high sand/shale ratios) are more likely to retain higher porosity and permeability to greater depths than sand interbedded with thick shale sequences.-from Author

Shale-oil-recovery systems incorporating ore beneficiation. Final report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weiss, M.A.; Klumpar, I.V.; Peterson, C.R.

This study analyzed the recovery of oil from oil shale by use of proposed systems which incorporate beneficiation of the shale ore (that is concentration of the kerogen before the oil-recovery step). The objective was to identify systems which could be more attractive than conventional surface retorting of ore. No experimental work was carried out. The systems analyzed consisted of beneficiation methods which could increase kerogen concentrations by at least four-fold. Potentially attractive low-enrichment methods such as density separation were not examined. The technical alternatives considered were bounded by the secondary crusher as input and raw shale oil as output.more » A sequence of ball milling, froth flotation, and retorting concentrate is not attractive for Western shales compared to conventional ore retorting; transporting the concentrate to another location for retorting reduces air emissions in the ore region but cost reduction is questionable. The high capital and energy cost s results largely from the ball milling step which is very inefficient. Major improvements in comminution seem achievable through research and such improvements, plus confirmation of other assumptions, could make high-enrichment beneficiation competitive with conventional processing. 27 figures, 23 tables.« less

Water pollution potential of spent oil shale residues. [From USBM, UOC, and TOSCO processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1971-12-01

Physical properties, including porosity, permeability, particle size distribution, and density of spent shale from three different retorting operations, (TOSCO, USBM, and UOC) have been determined. Slurry experiments were conducted on each of the spent shales and the slurry analyzed for leachable dissolved solids. Percolation experiments were conducted on the TOSCO spent shale and the quantities of dissolved solids leachable determined. The concentrations of the various ionic species in the initial leachate from the column were high. The major constituents, SO/sub 4//sup 2 -/ and Na/sup +/, were present in concentrations of 90,000 and 35,000 mg/l in the initial leachate; howevermore » the succeeding concentrations dropped markedly during the course of the experiment. A computer program was utilized to predict equilibrium concentrations in the leachate from the column. The extent of leaching and erosion of spent shale and the composition and concentration of natural drainage from spent shale have been determined using oil shale residue and simulated rainfall. Concentrations in the runoff from the spent shale have been correlated with runoff rate, precipitation intensity, flow depth, application time, slope, and water temperature. 18 tables, 32 figures.« less

Mineralogy and Geochemistry of Vanadium-Bearing Black Shales at Zhangcun and Zhengfang, Eastern Jiangxi Province, China

NASA Astrophysics Data System (ADS)

Long, H.; Long, H.; Nekvasil, H.; Liu, Y.

2001-12-01

As a member of Hetang Formation, lower Cambrian, the Zhangcun-Zhengfang vanadium-bearing black shales are spread in the sea basin outside of the Ancient Jiangnan Island Arc. The composition of black shales is silicalite + siltstone + detrital carbonate. A large amount of hyalophane has been discovered in the shales and the hyalophane-rich rock is the major type of vanadium-host rock. The barium content in the hyalophane is up to 18.91%. The vanadium mainly exists in vanadiferous illite and several Ti-V oxides, possibly including a new mineral. The chemical formula of this kind of Ti-V oxide is V2O3¡nTiO2, n=4¡ª9, according to the electronic microprobe studies. The micro X-ray diffraction studies show the new mineral may be triclinic. The shales are rich in Ba, K, V and contain only trace Na and Mn while all the compositions of the shales except carbonate have a low content of Mg and Ca. According to the authors¡_ study, V obviously has a relationship with Ba and Se, which are from the volcano or hydrothermal activities, and the basic elements Cr, Co, Ni, Ti and Fe. It may present that they are from the same source. Thus, it seems that they are not from the ¡rnormal¡_ sedimentary environment and may be from the hydrothermal deposition. The REE models show that silicalite may be the hydrothermal deposit that does not mix with seawater while the REE models of hyalopahne-rich rock is similar to some modern hydrothermal deposits in the seafloor. The subtle negative anomaly of Yb may reflect the REE model of basalt in the seafloor. The geology and geochemistry of the shales indicate that the shales may be of hydrothermal genesis. Silicalite may be the typical ¡r pure¡_ hydrothermal sediment and hyalophane-rich rock may be the product of hydrothermal activity while the hydrothermal fluid passes the continent source material in the sedimentary process. V, Ti, Ba and Si may be from the volcanic rock in the seafloor and the Al and K may be from the continent.

Desalination and reuse of high-salinity shale gas produced water: drivers, technologies, and future directions.

PubMed

Shaffer, Devin L; Arias Chavez, Laura H; Ben-Sasson, Moshe; Romero-Vargas Castrillón, Santiago; Yip, Ngai Yin; Elimelech, Menachem

2013-09-03

In the rapidly developing shale gas industry, managing produced water is a major challenge for maintaining the profitability of shale gas extraction while protecting public health and the environment. We review the current state of practice for produced water management across the United States and discuss the interrelated regulatory, infrastructure, and economic drivers for produced water reuse. Within this framework, we examine the Marcellus shale play, a region in the eastern United States where produced water is currently reused without desalination. In the Marcellus region, and in other shale plays worldwide with similar constraints, contraction of current reuse opportunities within the shale gas industry and growing restrictions on produced water disposal will provide strong incentives for produced water desalination for reuse outside the industry. The most challenging scenarios for the selection of desalination for reuse over other management strategies will be those involving high-salinity produced water, which must be desalinated with thermal separation processes. We explore desalination technologies for treatment of high-salinity shale gas produced water, and we critically review mechanical vapor compression (MVC), membrane distillation (MD), and forward osmosis (FO) as the technologies best suited for desalination of high-salinity produced water for reuse outside the shale gas industry. The advantages and challenges of applying MVC, MD, and FO technologies to produced water desalination are discussed, and directions for future research and development are identified. We find that desalination for reuse of produced water is technically feasible and can be economically relevant. However, because produced water management is primarily an economic decision, expanding desalination for reuse is dependent on process and material improvements to reduce capital and operating costs.

On the origin of a phosphate enriched interval in the Chattanooga Shale (Upper Devonian) of Tennessee-A combined sedimentologic, petrographic, and geochemical study

NASA Astrophysics Data System (ADS)

Li, Yifan; Schieber, Juergen

2015-11-01

The Devonian Chattanooga Shale contains an uppermost black shale interval with dispersed phosphate nodules. This interval extends from Tennessee to correlative strata in Kentucky, Indiana, and Ohio and represents a significant period of marine phosphate fixation during the Late Devonian of North America. It overlies black shales that lack phosphate nodules but otherwise look very similar in outcrop. The purpose of this study is to examine what sets these two shales apart and what this difference tells us about the sedimentary history of the uppermost Chattanooga Shale. In thin section, the lower black shales (PBS) show pyrite enriched laminae and compositional banding. The overlying phosphatic black shales (PhBS) are characterized by phosbioclasts, have a general banded to homogenized texture with reworked layers, and show well defined horizons of phosphate nodules that are reworked and transported. In the PhBS, up to 8000 particles of P-debris per cm2 occur in reworked beds, whereas the background black shale shows between 37-88 particles per cm2. In the PBS, the shale matrix contains between 8-16 phosphatic particles per cm2. The shale matrix in the PhBS contains 5.6% inertinite, whereas just 1% inertinite occurs in the PBS. The shale matrix in both units is characterized by flat REE patterns (shale-normalized), whereas Phosbioclast-rich layers in the PhBS show high concentrations of REEs and enrichment of MREEs. Negative Ce-anomalies are common to all samples, but are best developed in association with Phosbioclasts. Redox-sensitive elements (Co, U, Mo) are more strongly enriched in the PBS when compared to the PhBS. Trace elements associated with organic matter (Cu, Zn, Cd, Ni) show an inverse trend of enrichment. Deposited atop a sequence boundary that separates the two shale units, the PhBS unit represents a transgressive systems tract and probably was deposited in shallower water than the underlying PBS interval. The higher phosphate content in the PhBS is interpreted as the result of a combination of lower sedimentation rates with reworking/winnowing episodes. Three types of phosphatic beds that reflect different degrees of reworking intensity are observed. Strong negative Ce anomalies and abundant secondary marcasite formation in the PhBS suggests improved aeration of the water column, and improved downward diffusion of oxygen into the sediment. The associated oxidation of previously formed pyrite resulted in a lowering of pore water pH and forced dissolution of biogenic phosphate. Phosphate dissolution was followed by formation of secondary marcasite and phosphate. Repeated, episodic reworking caused repetitive cycles of phosphatic dissolution and reprecipitation, enriching MREEs in reprecipitated apatite. A generally "deeper" seated redox boundary favored P-remineralization within the sediment matrix, and multiple repeats of this process in combination with wave and current reworking at the seabed led to the formation of larger phosphatic aggregates and concentration of phosphate nodules in discrete horizons.

Study of shale reservoir nanometer-sized pores in Member 1 of Shahejie Formation in JX area, Liaozhong sag

NASA Astrophysics Data System (ADS)

Cheng, Yong; Zhang, Yu; Wen, Yiming

2018-02-01

The microscopic pore structure is the key of the shale reservoir study; however, traditional Scanning Electron Microscopy (SEM) methods cannot identify the irregular morphology caused by mechanical polishing. In this work, Scanning Electron Microscopy combined argon ion polishing technology was taken to study the characteristics of shale reservoir pores of Member 1 of Shahejie Formation (E3s1) located in JX1-1 area of Liaozhong Sag. The results show that pores between clay platelets, intraplatelet pores within clay aggregates and organic-matter pores are very rich in the area and with good pore connectivity, so these types of pores are of great significance for oil-gas exporation. Pores between clay platelets are formed by directional or semi-directional contact between edge and surface, edge and edge or surface and surface of laminated clay minerals, whose shapes are linear, mesh, and irregular with the size of 500 nm to 5 μm. The intraplatelet pores within clay aggregates are formed in the process of the transformation and compaction of clay minerals, whose shapes are usually linear with the width of 30 to 500 nm and the length of 2 to 50 μm. The organic-matter pores are from the process of the conversion from organic matters to the hydrocarbon under thermal evolution, whose shapes are gneissic, irregular, pitted and elliptical with the size of 100 nm to 2 μm. This study is of certain guiding significance to selecting target zones, evaluating resource potential and exploring & developing of shale gas in this region.

Oil shale processing as a source of aquatic pollution: monitoring of the biologic effects in caged and feral freshwater fish.

PubMed Central

Tuvikene, A; Huuskonen, S; Koponen, K; Ritola, O; Mauer, U; Lindström-Seppä, P

1999-01-01

The biologic effects of the oil shale industry on caged rainbow trout (Oncorhynchus mykiss) as well as on feral perch (Perca fluviatilis) and roach (Rutilus rutilus) were studied in the River Narva in northeast Estonia. The River Narva passes the oil shale mining and processing area and thus receives elevated amounts of polycyclic aromatic hydrocarbons (PAHs), heavy metals, and sulfates. The effects of the chemical load were monitored by measuring cytochrome P4501A (CYP1A)-dependent monooxygenase (MO) activities [7-ethoxyresorufin O-deethylase and aryl hydrocarbon hydroxylase (AHH)] as well as conjugation enzyme activities [glutathione S-transferase (GST) and UDP-glucuronosyltransferase] in the liver of fish. CYP1A induction was further studied by detecting the amount and occurrence of the CYP1A protein. Histopathology of tissues (liver, kidney, spleen, and intestine) and the percentage of micronuclei in fish erythrocytes were also determined. Selected PAHs and heavy metals (Cd, Cu, Hg, and Pb) were measured from fish muscle and liver. In spite of the significant accumulation of PAHs, there was no induction of MO activities in any studied fish species. When compared to reference samples, AHH activities were even decreased in feral fish at some of the exposed sites. Detection of CYP1A protein content and the distribution of the CYP1A enzyme by immunohistochemistry also did not show extensive CYP1A induction. Instead, GST activities were significantly increased at exposed sites. Detection of histopathology did not reveal major changes in the morphology of tissues. The micronucleus test also did not show any evidence of genotoxicity. Thus, from the parameters studied, GST activity was most affected. The lack of catalytic CYP1A induction in spite of the heavy loading of PAHs was not studied but has been attributed to the elevated content of other compounds such as heavy metals, some of which can act as inhibitors for MOs. Another possible explanation of this lack of induction is that through adaptation processes the fish could have lost some of their sensitivity to PAHs. Either complex pollution caused by oil shale processing masked part of the harmful effects measured in this study, or oil shale industry did not have any severe effects on fish in the River Narva. Our study illustrates the difficulties in estimating risk in cases where there are numerous various contaminants affecting the biota. Images Figure 1 Figure 2 PMID:10464075

Life-cycle analysis of shale gas and natural gas.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, C.E.; Han, J.; Burnham, A.

2012-01-27

The technologies and practices that have enabled the recent boom in shale gas production have also brought attention to the environmental impacts of its use. Using the current state of knowledge of the recovery, processing, and distribution of shale gas and conventional natural gas, we have estimated up-to-date, life-cycle greenhouse gas emissions. In addition, we have developed distribution functions for key parameters in each pathway to examine uncertainty and identify data gaps - such as methane emissions from shale gas well completions and conventional natural gas liquid unloadings - that need to be addressed further. Our base case results showmore » that shale gas life-cycle emissions are 6% lower than those of conventional natural gas. However, the range in values for shale and conventional gas overlap, so there is a statistical uncertainty regarding whether shale gas emissions are indeed lower than conventional gas emissions. This life-cycle analysis provides insight into the critical stages in the natural gas industry where emissions occur and where opportunities exist to reduce the greenhouse gas footprint of natural gas.« less

The Description of Shale Reservoir Pore Structure Based on Method of Moments Estimation

PubMed Central

Li, Wenjie; Wang, Changcheng; Shi, Zejin; Wei, Yi; Zhou, Huailai; Deng, Kun

2016-01-01

Shale has been considered as good gas reservoir due to its abundant interior nanoscale pores. Thus, the study of the pore structure of shale is of great significance for the evaluation and development of shale oil and gas. To date, the most widely used approaches for studying the shale pore structure include image analysis, radiation and fluid invasion methods. The detailed pore structures can be studied intuitively by image analysis and radiation methods, but the results obtained are quite sensitive to sample preparation, equipment performance and experimental operation. In contrast, the fluid invasion method can be used to obtain information on pore size distribution and pore structure, but the relative simple parameters derived cannot be used to evaluate the pore structure of shale comprehensively and quantitatively. To characterize the nanoscale pore structure of shale reservoir more effectively and expand the current research techniques, we proposed a new method based on gas adsorption experimental data and the method of moments to describe the pore structure parameters of shale reservoir. Combined with the geological mixture empirical distribution and the method of moments estimation principle, the new method calculates the characteristic parameters of shale, including the mean pore size (x¯), standard deviation (σ), skewness (Sk) and variation coefficient (c). These values are found by reconstructing the grouping intervals of observation values and optimizing algorithms for eigenvalues. This approach assures a more effective description of the characteristics of nanoscale pore structures. Finally, the new method has been applied to analyze the Yanchang shale in the Ordos Basin (China) and Longmaxi shale from the Sichuan Basin (China). The results obtained well reveal the pore characteristics of shale, indicating the feasibility of this new method in the study of the pore structure of shale reservoir. PMID:26992168

The Description of Shale Reservoir Pore Structure Based on Method of Moments Estimation.

PubMed

Li, Wenjie; Wang, Changcheng; Shi, Zejin; Wei, Yi; Zhou, Huailai; Deng, Kun

2016-01-01

Shale has been considered as good gas reservoir due to its abundant interior nanoscale pores. Thus, the study of the pore structure of shale is of great significance for the evaluation and development of shale oil and gas. To date, the most widely used approaches for studying the shale pore structure include image analysis, radiation and fluid invasion methods. The detailed pore structures can be studied intuitively by image analysis and radiation methods, but the results obtained are quite sensitive to sample preparation, equipment performance and experimental operation. In contrast, the fluid invasion method can be used to obtain information on pore size distribution and pore structure, but the relative simple parameters derived cannot be used to evaluate the pore structure of shale comprehensively and quantitatively. To characterize the nanoscale pore structure of shale reservoir more effectively and expand the current research techniques, we proposed a new method based on gas adsorption experimental data and the method of moments to describe the pore structure parameters of shale reservoir. Combined with the geological mixture empirical distribution and the method of moments estimation principle, the new method calculates the characteristic parameters of shale, including the mean pore size (mean), standard deviation (σ), skewness (Sk) and variation coefficient (c). These values are found by reconstructing the grouping intervals of observation values and optimizing algorithms for eigenvalues. This approach assures a more effective description of the characteristics of nanoscale pore structures. Finally, the new method has been applied to analyze the Yanchang shale in the Ordos Basin (China) and Longmaxi shale from the Sichuan Basin (China). The results obtained well reveal the pore characteristics of shale, indicating the feasibility of this new method in the study of the pore structure of shale reservoir.

Magnetic anisotropy of Silurian organic-rich shale rocks and calcareous concretions from Northern Poland

NASA Astrophysics Data System (ADS)

Niezabitowska, Dominika; Szaniawski, Rafał

2017-04-01

The research has been performed on Wenlockian shales of Pelplin formation from the Pomerania region located in Northern Poland. These organic-rich marine shales were deposited on the western shelf of the Baltica paleo-continent and currently they constitute the cover of East European Platform. The studied shales lie almost completely flat without signs of tectonic deformations. Rock magnetic studies were carried out with the aim of recognizing ferro- and paramagnetic minerals in shales and thus fully understanding the origin of the magnetic anisotropy. The typical dark shales and spherical calcareous concretions from two boreholes were sampled. Based on deflection of shales beds bordered with a concretions, we deduce that such concretions were formed in the early stage of diagenesis, before the final compaction and lithification of surrounding shales. We obtained similar rockmagnetic results for both of rock types. The results of thermal variation of magnetic susceptibility and hysteresis loops show that the magnetic susceptibility is mainly controlled by paramagnetic minerals, due to domination of phyllosilicate minerals, with a smaller impact of ferromagnetic phase. The results of the hysteresis studies documented the domination of low coercivity ferromagnetic minerals, that is magnetite and pyrrhotite. The deposition alignment of flocculated phyllosilicates and further compaction determine distinct bedding parallel foliation of the AMS (Anisotropy of Magnetic Susceptibility) in the both drill cores. In one of the drill core the maximal AMS axes are almost randomly distributed in the bedding plane and show only a weak tendency for grouping. In the second drill core the magnetic lineation is better defined. In the case of concretions the bedding parallel magnetic foliation is also evident but it is much weaker than in shales. In turn, the magnetic lineation in the both drill cores is well developed and the maximal AMS axes are well grouped. In both of the cores the orientation of lineation from concretions complies with site mean lineation from shale rocks. To summarize, the results imply that the phyllosilicate minerals from shales are typically well aligned in the bedding plane by compaction processes. In the case of calcareous concretions the foliation is less developed due to their earlier cementation of flocculated phyllosicates in the calcareous matrix, which occurred before the end of sediments compaction. A good grouping of the maximal AMS axes within the early cemented concretions suggest that the magnetic lineation is rather sedimentary than tectonic in origin. We suggest that the magnetic lineation is probably related to the orientation of flocculated phyllosilicates due to transportation. This work has been funded by the Polish National Centre for Research and Development within the Blue Gas project (No BG2/SHALEMECH/14). Samples were provided by the PGNiG SA.

Depositional Architecture of Late Cambrian-Early Ordovician Siliciclastic Barik Formation; Al Huqf Area, Oman

NASA Astrophysics Data System (ADS)

Abbasi, Iftikhar Ahmed

2017-04-01

Early Paleozoic siliciclastics sediments of the Haima Supergroup are subdivided into a number of formations and members based on lithological characteristics of various rock sequences. One of the distinct sandstone sequence, the Barik Formation (Late Cambrian-Early Ordovician) of the Andam Group is a major deep gas reservoir in central Oman. The sandstone bodies are prospective reservoir rocks while thick shale and clay interbeds act as effective seal. Part of the Barik Formation (lower and middle part) is exposed in isolated outcrops in Al Huqf area as interbedded multistoried sandstone, and green and red shale. The sandstone bodies are up to 2 meters thick and can be traced laterally for 300 m to over 1 km. Most of sandstone bodies show both lateral and vertical stacking. Two types of sandstone lithofacies are identified on the basis of field characteristics; a plane-bedded sandstone lithofacies capping thick red and green color shale beds, and a cross-bedded sandstone lithofacies overlying the plane-bedded sandstone defining coarsening upward sequences. The plane-bedded sandstone at places contains Cruziana ichnofacies and bivalve fragments indicating deposition by shoreface processes. Thick cross-bedded sandstone is interpreted to be deposited by the fluvial dominated deltaic processes. Load-casts, climbing ripples and flaser-bedding in siltstone and red shale indicate influence of tidal processes at times during the deposition of the formation. This paper summarizes results of a study carried out in Al Huqf area outcrops to analyze the characteristics of the sandstone-body geometry, internal architecture, provenance and diagenetic changes in the lower and middle part of the formation. The study shows build-up of a delta complex and its progradation over a broad, low-angle shelf where fluvial processes operate beside shoreface processes in a vegetation free setting. Keywords: Andam Group, Barik Formation, Ordovician sandstone, Al Huqf, Central Oman,

POLICY ANALYSIS OF PRODUCED WATER ISSUES ASSOCIATED WITH IN-SITU THERMAL TECHNOLOGIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robert Keiter; John Ruple; Heather Tanana

2011-02-01

Commercial scale oil shale and oil sands development will require water, the amount of which will depend on the technologies adopted and the scale of development that occurs. Water in oil shale and oil sands country is already in scarce supply, and because of the arid nature of the region and limitations on water consumption imposed by interstate compacts and the Endangered Species Act, the State of Utah normally does not issue new water rights in oil shale or oil sands rich areas. Prospective oil shale and oil sands developers that do not already hold adequate water rights can acquiremore » water rights from willing sellers, but large and secure water supplies may be difficult and expensive to acquire, driving oil shale and oil sands developers to seek alternative sources of supply. Produced water is one such potential source of supply. When oil and gas are developed, operators often encounter ground water that must be removed and disposed of to facilitate hydrocarbon extraction. Water produced through mineral extraction was traditionally poor in quality and treated as a waste product rather than a valuable resource. However, the increase in produced water volume and the often-higher quality water associated with coalbed methane development have drawn attention to potential uses of produced water and its treatment under appropriations law. This growing interest in produced water has led to litigation and statutory changes that must be understood and evaluated if produced water is to be harnessed in the oil shale and oil sands development process. Conversely, if water is generated as a byproduct of oil shale and oil sands production, consideration must be given to how this water will be disposed of or utilized in the shale oil production process. This report explores the role produced water could play in commercial oil shale and oil sands production, explaining the evolving regulatory framework associated with produced water, Utah water law and produced water regulation, and the obstacles that must be overcome in order for produced water to support the nascent oil shale and oil sands industries.« less

A nuclear wind/solar oil-shale system for variable electricity and liquid fuels production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forsberg, C.

2012-07-01

The recoverable reserves of oil shale in the United States exceed the total quantity of oil produced to date worldwide. Oil shale contains no oil, rather it contains kerogen which when heated decomposes into oil, gases, and a carbon char. The energy required to heat the kerogen-containing rock to produce the oil is about a quarter of the energy value of the recovered products. If fossil fuels are burned to supply this energy, the greenhouse gas releases are large relative to producing gasoline and diesel from crude oil. The oil shale can be heated underground with steam from nuclear reactorsmore » leaving the carbon char underground - a form of carbon sequestration. Because the thermal conductivity of the oil shale is low, the heating process takes months to years. This process characteristic in a system where the reactor dominates the capital costs creates the option to operate the nuclear reactor at base load while providing variable electricity to meet peak electricity demand and heat for the shale oil at times of low electricity demand. This, in turn, may enable the large scale use of renewables such as wind and solar for electricity production because the base-load nuclear plants can provide lower-cost variable backup electricity. Nuclear shale oil may reduce the greenhouse gas releases from using gasoline and diesel in half relative to gasoline and diesel produced from conventional oil. The variable electricity replaces electricity that would have been produced by fossil plants. The carbon credits from replacing fossil fuels for variable electricity production, if assigned to shale oil production, results in a carbon footprint from burning gasoline or diesel from shale oil that may half that of conventional crude oil. The U.S. imports about 10 million barrels of oil per day at a cost of a billion dollars per day. It would require about 200 GW of high-temperature nuclear heat to recover this quantity of shale oil - about two-thirds the thermal output of existing nuclear reactors in the United States. With the added variable electricity production to enable renewables, additional nuclear capacity would be required. (authors)« less

Data set for Journal article "The shale gas revolution: barriers, sustainability, and emerging opportunities"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Middleton, Richard Stephen

Shale gas and hydraulic refracturing has revolutionized the US energy sector in terms of prices, consumption, and CO 2 emissions. However, key questions remain including environmental concerns and extraction efficiencies that are leveling off. For the first time, we identify key discoveries, lessons learned, and recommendations from this shale gas revolution through extensive data mining and analysis of 23 years of production from 20,000 wells. Discoveries include identification of a learning-bydoing process where disruptive technology innovation led to a doubling in shale gas extraction, how refracturing with emerging technologies can transform existing wells, and how overall shale gas production ismore » actually dominated by long-term tail production rather than the high-profile initial exponentially-declining production in the first 12 months. We hypothesize that tail production can be manipulated, through better fracturing techniques and alternative working fluids such as CO 2, to increase shale gas recovery and minimize environmental impacts such as through carbon sequestration.« less

The shale gas revolution: Barriers, sustainability, and emerging opportunities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Middleton, Richard S.; Gupta, Rajan; Hyman, Jeffrey D.

Shale gas and hydraulic refracturing has revolutionized the US energy sector in terms of prices, consumption, and CO 2 emissions. However, key questions remain including environmental concerns and extraction efficiencies that are leveling off. For the first time, we identify key discoveries, lessons learned, and recommendations from this shale gas revolution through extensive data mining and analysis of 23 years of production from 20,000 wells. Discoveries include identification of a learning-by-doing process where disruptive technology innovation led to a doubling in shale gas extraction, how refracturing with emerging technologies can transform existing wells, and how overall shale gas production ismore » actually dominated by long-term tail production rather than the high-profile initial exponentially-declining production in the first 12 months. We hypothesize that tail production can be manipulated, through better fracturing techniques and alternative working fluids such as CO 2, to increase shale gas recovery and minimize environmental impacts such as through carbon sequestration.« less

The shale gas revolution: Barriers, sustainability, and emerging opportunities

DOE PAGES

Middleton, Richard S.; Gupta, Rajan; Hyman, Jeffrey D.; ...

2017-08-01

Shale gas and hydraulic refracturing has revolutionized the US energy sector in terms of prices, consumption, and CO 2 emissions. However, key questions remain including environmental concerns and extraction efficiencies that are leveling off. For the first time, we identify key discoveries, lessons learned, and recommendations from this shale gas revolution through extensive data mining and analysis of 23 years of production from 20,000 wells. Discoveries include identification of a learning-by-doing process where disruptive technology innovation led to a doubling in shale gas extraction, how refracturing with emerging technologies can transform existing wells, and how overall shale gas production ismore » actually dominated by long-term tail production rather than the high-profile initial exponentially-declining production in the first 12 months. We hypothesize that tail production can be manipulated, through better fracturing techniques and alternative working fluids such as CO 2, to increase shale gas recovery and minimize environmental impacts such as through carbon sequestration.« less

GIS-and Web-based Water Resource Geospatial Infrastructure for Oil Shale Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Wei; Minnick, Matthew; Geza, Mengistu

2012-09-30

The Colorado School of Mines (CSM) was awarded a grant by the National Energy Technology Laboratory (NETL), Department of Energy (DOE) to conduct a research project en- titled GIS- and Web-based Water Resource Geospatial Infrastructure for Oil Shale Development in October of 2008. The ultimate goal of this research project is to develop a water resource geo-spatial infrastructure that serves as “baseline data” for creating solutions on water resource management and for supporting decisions making on oil shale resource development. The project came to the end on September 30, 2012. This final project report will report the key findings frommore » the project activity, major accomplishments, and expected impacts of the research. At meantime, the gamma version (also known as Version 4.0) of the geodatabase as well as other various deliverables stored on digital storage media will be send to the program manager at NETL, DOE via express mail. The key findings from the project activity include the quantitative spatial and temporal distribution of the water resource throughout the Piceance Basin, water consumption with respect to oil shale production, and data gaps identified. Major accomplishments of this project include the creation of a relational geodatabase, automated data processing scripts (Matlab) for database link with surface water and geological model, ArcGIS Model for hydrogeologic data processing for groundwater model input, a 3D geological model, surface water/groundwater models, energy resource development systems model, as well as a web-based geo-spatial infrastructure for data exploration, visualization and dissemination. This research will have broad impacts of the devel- opment of the oil shale resources in the US. The geodatabase provides a “baseline” data for fur- ther study of the oil shale development and identification of further data collection needs. The 3D geological model provides better understanding through data interpolation and visualization techniques of the Piceance Basin structure spatial distribution of the oil shale resources. The sur- face water/groundwater models quantify the water shortage and better understanding the spatial distribution of the available water resources. The energy resource development systems model reveals the phase shift of water usage and the oil shale production, which will facilitate better planning for oil shale development. Detailed descriptions about the key findings from the project activity, major accomplishments, and expected impacts of the research will be given in the sec- tion of “ACCOMPLISHMENTS, RESULTS, AND DISCUSSION” of this report.« less

Rehabilitation potential and practices of Colorado oil shale lands. Progress report, June 1, 1978--May 31, 1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, C.W.

The following document is a third-year progress report for the period June 1, 1978 to May 31, 1979. The overall objective of the project is to study the effects of seeding techniques, species mixtures, fertilizer, ecotypes, improved plant materials, mycorrhizal fungi, and soil microorganisms on the initial and final stages of reclamation obtained through seeding and subsequent succession on disturbed oil shale lands. Plant growth medias that are being used in field-established test plots include retorted shale, soil over retorted shale, subsoil materials, and surface disturbed topsoils. Because of the long-term nature of successional and ecologically oriented studies the projectmore » is just beginning to generate significant publications. Several of the studies associated with the project have some phases being conducted principally in the laboratories and greenhouses at Colorado State Univerisity. The majority of the research, however, is being conducted on a 20 hectare Intensive Study Site located near the focal points of oil shale activity in the Piceance Basin. The site is at an elevation of 2,042 m, receives approximately 30 to 55 cm of precipitation annually, and encompasses the plant communities most typical of the Piceance Basin. Most of the information contained in this report originated from the monitoring and sampling of research plots established in either the fall of 1976 or 1977. Therefore, data that have been obtained from the Intensive Study Site represent only first- or second-year results. However, many trends have been identified in thesuccessional process and the soil microorganisms and mycorrhizal studies continue to contribute significant information to the overall results. The phytosociological study has progressed to a point where field sampling is complete and the application and publication of this materials will be forthcoming in 1979.« less

United States Air Force Shale Oil to Fuels. Phase II.

DTIC Science & Technology

1981-11-01

and modified so that any off-gas from the LPS, stripper column, product drums, spent caustic drums, and sample ports would be sent to the caustic ...product, or in the spent caustic . After the desalted Paraho shale oil was processed in Production Run No. 2, the catalyst bed was flushed with light cycle...58 20 First-Stage Hydrotreating of Occidental Shale Oil -- Spent Catalyst Analysis - Run 1 ....... 59 21 First-Stage Hydrotreating of Occidental

Method of rubblization for in-situ oil shale processing

NASA Technical Reports Server (NTRS)

Yang, Lien C. (Inventor)

1985-01-01

A method that produces a uniformly rubblized oil shale bed of desirable porosity for underground, in-situ heat extraction of oil. Rubblization is the generation of rubble of various sized fragments. The method uses explosive loadings lying at different levels in adjacent holes and detonation of the explosives at different levels in sequence to achieve the fracturing and the subsequent expansion of the fractured oil shale into excavated rooms both above and below the hole pattern.

Tectono-thermal Evolution of the Lower Paleozoic Petroleum Source Rocks in the Southern Lublin Trough: Implications for Shale Gas Exploration from Maturity Modelling

NASA Astrophysics Data System (ADS)

Botor, Dariusz

2018-03-01

The Lower Paleozoic basins of eastern Poland have recently been the focus of intensive exploration for shale gas. In the Lublin Basin potential unconventional play is related to Lower Silurian source rocks. In order to assess petroleum charge history of these shale gas reservoirs, 1-D maturity modeling has been performed. In the Łopiennik IG-1 well, which is the only well that penetrated Lower Paleozoic strata in the study area, the uniform vitrinite reflectance values within the Paleozoic section are interpreted as being mainly the result of higher heat flow in the Late Carboniferous to Early Permian times and 3500 m thick overburden eroded due to the Variscan inversion. Moreover, our model has been supported by zircon helium and apatite fission track dating. The Lower Paleozoic strata in the study area reached maximum temperature in the Late Carboniferous time. Accomplished tectono-thermal model allowed establishing that petroleum generation in the Lower Silurian source rocks developed mainly in the Devonian - Carboniferous period. Whereas, during Mesozoic burial, hydrocarbon generation processes did not develop again. This has negative influence on potential durability of shale gas reservoirs.

Modeling of gas generation from the Barnett Shale, Fort Worth Basin, Texas

USGS Publications Warehouse

Hill, R.J.; Zhang, E.; Katz, B.J.; Tang, Y.

2007-01-01

The generative gas potential of the Mississippian Barnett Shale in the Fort Worth Basin, Texas, was quantitatively evaluated by sealed gold-tube pyrolysis. Kinetic parameters for gas generation and vitrinite reflectance (Ro) changes were calculated from pyrolysis data and the results used to estimate the amount of gas generated from the Barnett Shale at geologic heating rates. Using derived kinetics for Ro evolution and gas generation, quantities of hydrocarbon gas generated at Ro ??? 1.1% are about 230 L/t (7.4 scf/t) and increase to more that 5800 L/t (186 scf/t) at Ro ??? 2.0% for a sample with an initial total organic carbon content of 5.5% and Ro = 0.44%. The volume of shale gas generated will depend on the organic richness, thickness, and thermal maturity of the shale and also the amount of petroleum that is retained in the shale during migration. Gas that is reservoired in shales appears to be generated from the cracking of kerogen and petroleum that is retained in shales, and that cracking of the retained petroleum starts by Ro ??? 1.1%. This result suggests that the cracking of petroleum retained in source rocks occurs at rates that are faster than what is predicted for conventional siliciclastic and carbonate reservoirs, and that contact of retained petroleum with kerogen and shale mineralogy may be a critical factor in shale-gas generation. Shale-gas systems, together with overburden, can be considered complete petroleum systems, although the processes of petroleum migration, accumulation, and trap formation are different from what is defined for conventional petroleum systems. Copyright ?? 2007. The American Association of Petroleum Geologists. All rights reserved.

Israeli co-retorting of coal and oil shale would break even at 22/barrel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

Work is being carried out at the Hebrew University of Jerusalem on co-retorting of coal and oil shale. The work is funded under a cooperative agreement with the US Department of Energy. The project is exploring the conversion of US eastern high-sulfur bituminous coal in a split-stage, fluidized-bed reactor. Pyrolysis occurs in the first stage and char combustion in the second stage. These data for coal will be compared with similar data from the same reactor fueled by high-sulfur eastern US oil shale and Israeli oil shales. The project includes research at three major levels: pyrolysis in lab-scale fluidized-bed reactor;more » retorting in split-stage, fluidized-bed bench-scale process (1/4 tpd); and scale-up, preparation of full-size flowchart, and economic evaluation. In the past year's research, a preliminary economic evaluation was completed for a scaled-up process using a feed of high-sulfur coal and carbonate-containing Israeli oil shale. A full-scale plant in Israel was estimated to break even at an equivalent crude oil price of $150/ton ($22/barrel).« less

Eastern Devonian shales: Organic geochemical studies, past and present

USGS Publications Warehouse

Breger, I.A.; Hatcher, P.G.; Romankiw, L.A.; Miknis, F.P.

1983-01-01

The Eastern Devonian shales are represented by a sequence of sediments extending from New York state, south to the northern regions of Georgia and Alabama, and west into Ohio and to the Michigan and Ilinois Basins. Correlatives are known in Texas. The shale is regionally known by a number of names: Chattanooga, Dunkirk, Rhinestreet, Huron, Antrim, Ohio, Woodford, etc. These shales, other than those in Texas, have elicited much interest because they have been a source of unassociated natural gas. It is of particular interest, however, that most of these shales have no associated crude oil, in spite of the fact that they have some of the characteristics normally attributed to source beds. This paper addresses some of the organic geochemical aspects of the kerogen in these shales, in relation to their oil generating potential. Past organic geochemical studies on Eastern Devonian shales will be reviewed. Recent solid state 13C NMR studies on the nature of the organic matter in Eastern Devonian shales show that Eastern Devonian shales contain a larger fraction of aromatic carbon in their chemical composition. Thus, despite their high organic matter contents, their potential as a petroleum source rock is low, because the kerogen in these shales is of a "coaly" nature and hence more prone to producing natural gas.

Eastern Devonian shales: Organic geochemical studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berger, I.A.; Hatchner, P.G.; Miknis, F.P.

The Eastern Devonian shales are represented by a sequence of sediments extending from New York state, south to the northern regions of Georgia and Alabama, and west into Ohio and to the Michigan and Illinois Basins. Correlatives are known in Texas. The shale is regionally known by a number of names: Chattanooga, Dunkirk, Rhinestreet, Huron, Antrim, Ohio, Woodford, etc. These shales, other than those in Texas, have elicited much interest because they have been a source of unassociated natural gas. It is of particular interest, however, that most of these shales have no associated crude oil, in spite of themore » fact that they have some of the characteristics normally attributed to source beds. This paper addresses some of the organic geochemical aspects of the kerogen in these shales, in relation to their oil generating potential. Past organic geochemical studies on Eastern Devonian shales are reviewed. Recent solid state /sup 13/C NMR studies on the nature of the organic matter in Eastern Devonian shales show that Eastern Devonian shales contain a larger fraction of aromatic carbon in their chemical composition. Thus, despite their high organic matter contents, their potential as a petroleum source rock is low, because the kerogen in these shales is of a ''coaly'' nature and hence more prone to producing natural gas.« less

Bacterial communities associated with hydraulic fracturing fluids in thermogenic natural gas wells in North Central Texas, USA.

PubMed

Struchtemeyer, Christopher G; Elshahed, Mostafa S

2012-07-01

Hydraulic fracturing is used to increase the permeability of shale gas formations and involves pumping large volumes of fluids into these formations. A portion of the frac fluid remains in the formation after the fracturing process is complete, which could potentially contribute to deleterious microbially induced processes in natural gas wells. Here, we report on the geochemical and microbiological properties of frac and flowback waters from two newly drilled natural gas wells in the Barnett Shale in North Central Texas. Most probable number studies showed that biocide treatments did not kill all the bacteria in the fracturing fluids. Pyrosequencing-based 16S rRNA diversity analyses indicated that the microbial communities in the flowback waters were less diverse and completely distinct from the communities in frac waters. These differences in frac and flowback water communities appeared to reflect changes in the geochemistry of fracturing fluids that occurred during the frac process. The flowback communities also appeared well adapted to survive biocide treatments and the anoxic conditions and high temperatures encountered in the Barnett Shale. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Sediment Sources, Depositional Environment, and Diagenetic Alteration of the Marcellus Shale, Appalachian Basin, USA: Nd, Sr, Li and U Isotopic Constraints

NASA Astrophysics Data System (ADS)

Phan, T. T.; Capo, R. C.; Gardiner, J. B.; Stewart, B. W.

2017-12-01

The organic-rich Middle Devonian Marcellus Shale in the Appalachian Basin, eastern USA, is a major target of natural gas exploration. Constraints on local and regional sediment sources, depositional environments, and post-depositional processes are essential for understanding the evolution of the basin. In this study, multiple proxies, including trace metals, rare earth elements (REE), the Sm-Nd and Rb-Sr isotope systems, and U and Li isotopes were applied to bulk rocks and authigenic fractions of the Marcellus Shale and adjacent limestone/sandstone units from two locations separated by 400 km. The range of ɛNd values (-7.8 to -6.4 at 390 Ma) is consistent with a clastic sedimentary component derived from a well-mixed source of fluvial and eolian material of the Grenville orogenic belt. The Sm-Nd isotope system and bulk REE distributions appear to have been minimally affected by post-depositional processes, while the Rb-Sr isotope system shows evidence of limited post-depositional redistribution. While REE are primarily associated with silicate minerals (80-95%), REE patterns of sequentially extracted fractions reflect post-depositional alteration at the intergranular scale. Although the chemical index of alteration (CIA = 54 to 60) suggests the sediment source was not heavily weathered, Li isotope data are consistent with progressively increasing weathering of the source region during Marcellus Shale deposition. δ238U values in bulk shale and reduced phases (oxidizable fraction) are higher than those of modern seawater and upper crust. The isotopically heavy U accumulated in these authigenic phases can be explained by the precipitation of insoluble U in anoxic/euxinic bottom water. Unlike carbonate cement within the shale, the similarity between δ238U values and REE patterns of the limestone units and those of modern seawater indicates that the limestone formed under open ocean (oxic) conditions.

Oil shale combustor model developed by Greek researchers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-09-01

Work carried out in the Department of Chemical Engineering at the University of Thessaloniki, Thessaloniki, Greece has resulted in a model for the combustion of retorted oil shale in a fluidized bed combustor. The model is generally applicable to any hot-solids retorting process, whereby raw oil shale is retorted by mixing with a hot solids stream (usually combusted spent shale), and then the residual carbon is burned off the spent shale in a fluidized bed. Based on their modelling work, the following conclusions were drawn by the researchers. (1) For the retorted particle size distribution selected (average particle diameter 1600more » microns) complete carbon conversion is feasible at high pressures (2.7 atmosphere) and over the entire temperature range studied (894 to 978 K). (2) Bubble size was found to have an important effect, especially at conditions where reaction rates are high (high temperature and pressure). (3) Carbonate decomposition increases with combustor temperature and residence time. Complete carbon conversion is feasible at high pressures (2.7 atmosphere) with less than 20 percent carbonate decomposition. (4) At the preferred combustor operating conditions (high pressure, low temperature) the main reaction is dolomite decomposition while calcite decomposition is negligible. (5) Recombination of CO/sub 2/ with MgO occurs at low temperatures, high pressures, and long particle residence times.« less

Baseflow recession analysis across the Eagle Ford shale play (Texas, USA)

NASA Astrophysics Data System (ADS)

Arciniega, Saul; Brena-Naranjo, Agustin; Hernandez-Espriu, Jose Antonio; Pedrozo-Acuña, Adrian

2016-04-01

Baseflow is an important process of the hydrological cycle as it can be related to aquatic ecosystem health and groundwater recharge. The temporal and spatial dynamics of baseflow are typically governed by fluctuations in the water table of shallow aquifers hence groundwater pumping and return flow can greatly modify baseflow patterns. More recently, in some regions of the world the exploitation of gas trapped in shale formations by means of hydraulic fracturing (fracking) has raised major concerns on the quantitative and qualitative groundwater impacts. Although fracking implies massive amounts of groundwater withdrawals, its contribution on baseflow decline has not yet been fully investigated. Furthermore, its impact with respect to other human activities or climate extremes such as irrigation or extreme droughts, respectively, remain largely unknown. This work analyzes baseflow recession time-space patterns for a set of watersheds located across the largest shale producer in the world, the Eagle Ford shale play in Texas (USA). The period of study (1985-2014) includes a pre-development and post-development period. The dataset includes 56 hydrometric time series located inside and outside the shale play. Results show that during the development and expansion of the Eagle Ford play, around 70 % of the time series displayed a significant decline wheras no decline was observed during the pre-development)

Introduction to special section: China shale gas and shale oil plays

USGS Publications Warehouse

Jiang, Shu; Zeng, Hongliu; Zhang, Jinchuan; Fishman, Neil; Bai, Baojun; Xiao, Xianming; Zhang, Tongwei; Ellis, Geoffrey S.; Li, Xinjing; Richards-McClung, Bryony; Cai, Dongsheng; Ma, Yongsheng

2015-01-01

Even though China shale gas and shale oil exploration is still in an early stage, limited data are already available. We are pleased to have selected eight high-quality papers from fifteen submitted manuscripts for this timely section on the topic of China shale gas and shale oil plays. These selected papers discuss various subject areas including regional geology, resource potentials, integrated and multidisciplinary characterization of China shale reservoirs (geology, geophysics, geochemistry, and petrophysics) China shale property measurement using new techniques, case studies for marine, lacustrine, and transitional shale deposits in China, and hydraulic fracturing. One paper summarizes the regional geology and different tectonic and depositional settings of the major prospective shale oil and gas plays in China. Four papers concentrate on the geology, geochemistry, reservoir characterization, lithologic heterogeneity, and sweet spot identification in the Silurian Longmaxi marine shale in the Sichuan Basin in southwest China, which is currently the primary focus of shale gas exploration in China. One paper discusses the Ordovician Salgan Shale in the Tarim Basin in northwest China, and two papers focus on the reservoir characterization and hydraulic fracturing of Triassic lacustrine shale in the Ordos Basin in northern China. Each paper discusses a specific area.

Mongolian Oil Shale, hosted in Mesozoic Sedimentary Basins

NASA Astrophysics Data System (ADS)

Bat-Orshikh, E.; Lee, I.; Norov, B.; Batsaikhan, M.

2016-12-01

Mongolia contains several Mesozoic sedimentary basins, which filled >2000 m thick non-marine successions. Late Triassic-Middle Jurassic foreland basins were formed under compression tectonic conditions, whereas Late Jurassic-Early Cretaceous rift valleys were formed through extension tectonics. Also, large areas of China were affected by these tectonic events. The sedimentary basins in China host prolific petroleum and oil shale resources. Similarly, Mongolian basins contain hundreds meter thick oil shale as well as oil fields. However, petroleum system and oil shale geology of Mongolia remain not well known due to lack of survey. Mongolian oil shale deposits and occurrences, hosted in Middle Jurassic and Lower Cretaceous units, are classified into thirteen oil shale-bearing basins, of which oil shale resources were estimated to be 787 Bt. Jurassic oil shale has been identified in central Mongolia, while Lower Cretaceous oil shale is distributed in eastern Mongolia. Lithologically, Jurassic and Cretaceous oil shale-bearing units (up to 700 m thick) are similar, composed mainly of alternating beds of oil shale, dolomotic marl, siltstone and sandstone, representing lacustrine facies. Both Jurassic and Cretaceous oil shales are characterized by Type I kerogen with high TOC contents, up to 35.6% and low sulfur contents ranging from 0.1% to 1.5%. Moreover, S2 values of oil shales are up to 146 kg/t. The numbers indicate that the oil shales are high quality, oil prone source rocks. The Tmax values of samples range from 410 to 447, suggesting immature to early oil window maturity levels. PI values are consistent with this interpretation, ranging from 0.01 to 0.03. According to bulk geochemistry data, Jurassic and Cretaceous oil shales are identical, high quality petroleum source rocks. However, previous studies indicate that known oil fields in Eastern Mongolia were originated from Lower Cretaceous oil shales. Thus, further detailed studies on Jurassic oil shale and its petroleum potential are required.

Geology of the Devonian black shales of the Appalachian Basin

USGS Publications Warehouse

Roen, J.B.

1984-01-01

Black shales of Devonian age in the Appalachian Basin are a unique rock sequence. The high content of organic matter, which imparts the characteristic lithology, has for years attracted considerable interest in the shales as a possible source of energy. The recent energy shortage prompted the U.S. Department of Energy through the Eastern Gas Shales Project of the Morgantown Energy Technology Center to underwrite a research program to determine the geologic, geochemical, and structural characteristics of the Devonian black shales in order to enhance the recovery of gas from the shales. Geologic studies by Federal and State agencies and academic institutions produced a regional stratigraphic network that correlates the 15 ft black shale sequence in Tennessee with 3000 ft of interbedded black and gray shales in central New York. These studies correlate the classic Devonian black shale sequence in New York with the Ohio Shale of Ohio and Kentucky and the Chattanooga Shale of Tennessee and southwestern Virginia. Biostratigraphic and lithostratigraphic markers in conjunction with gamma-ray logs facilitated long-range correlations within the Appalachian Basin. Basinwide correlations, including the subsurface rocks, provided a basis for determining the areal distribution and thickness of the important black shale units. The organic carbon content of the dark shales generally increases from east to west across the basin and is sufficient to qualify as a hydrocarbon source rock. Significant structural features that involve the black shale and their hydrocarbon potential are the Rome trough, Kentucky River and Irvine-Paint Creek fault zone, and regional decollements and ramp zones. ?? 1984.

Mixed integer simulation optimization for optimal hydraulic fracturing and production of shale gas fields

NASA Astrophysics Data System (ADS)

Li, J. C.; Gong, B.; Wang, H. G.

2016-08-01

Optimal development of shale gas fields involves designing a most productive fracturing network for hydraulic stimulation processes and operating wells appropriately throughout the production time. A hydraulic fracturing network design-determining well placement, number of fracturing stages, and fracture lengths-is defined by specifying a set of integer ordered blocks to drill wells and create fractures in a discrete shale gas reservoir model. The well control variables such as bottom hole pressures or production rates for well operations are real valued. Shale gas development problems, therefore, can be mathematically formulated with mixed-integer optimization models. A shale gas reservoir simulator is used to evaluate the production performance for a hydraulic fracturing and well control plan. To find the optimal fracturing design and well operation is challenging because the problem is a mixed integer optimization problem and entails computationally expensive reservoir simulation. A dynamic simplex interpolation-based alternate subspace (DSIAS) search method is applied for mixed integer optimization problems associated with shale gas development projects. The optimization performance is demonstrated with the example case of the development of the Barnett Shale field. The optimization results of DSIAS are compared with those of a pattern search algorithm.

Gold and platinum in shales with evidence against extraterrestrial sources of metals

USGS Publications Warehouse

Coveney, R.M.; Murowchick, J.B.; Grauch, R.I.; Glascock, M.D.; Denison, J.R.

1992-01-01

Few black shales contain concentrations of precious metals higher than average continental crust (i.e. ???5 ppb Au). Yet Au and Pt alloys have been reported from the Kupferschiefer in Poland. Moreover, thin sulfide beds in certain Chinese and Canadian shales contain several hundred ppb Au, Pd and Pt and average ???4% Mo and ???2.5% Ni in an association that is difficult to explain. Volcanic and non-volcanic exhalations, hydrothermal epigenesis involving either igneous or sedex fluids, biogenic processes and low-temperature secondary enrichment are among the possible factors involved in deriving Ni, PGE and Au for black shales and sulfide beds in black shales. Extraterrestrial sources have been invoked in some cases (e.g., the Cambrian of China). However, available data on abundances of PGE indicate relatively low values for Ir (<0.02-2 ppb) in comparison with amounts for other PGE (up to 700 ppb Pt and 1255 ppb Pd). These data and high contents for Mo are not consistent with extraterrestrial sources of metals for Chinese shales and Ni-Mo-sulfide beds. Data are less complete for the U.S. shales, but nevertheless are suggestive of earthly origins for PGE. ?? 1992.

Morbidity and mortality study of shale oil workers in the United States.

PubMed

Costello, J

1979-06-01

The study of the carcinogenic potential of domestic U. S. shale oil has increased significantly in importance because of the present energy problem and resulting research into alternative sources of fuel. With the increased scope of planned oil shale activity on the Colorado Plateau, it is important that an attempt be made to determine the health effects, if any, of occupational exposure to shale oil. This paper briefly reviews some past work of Soviet and British investigators concerning potential health hazards of shale oil. It reviews the results and conclusions of the 1952-1955 dermatological study of oil shale workers by the U. S. Public Health Service, and it discusses in detail the plans of a NIOSH morbidity and mortality study currently under way.

Upper Paleozoic Marine Shale Characteristics and Exploration Prospects in the Northwestern Guizhong Depression, South China

NASA Astrophysics Data System (ADS)

Zhu, Zhenhong; Yao, Genshun; Lou, Zhanghua; Jin, Aimin; Zhu, Rong; Jin, Chong; Chen, Chao

2018-05-01

Multiple sets of organic-rich shales developed in the Upper Paleozoic of the northwestern Guizhong Depression in South China. However, the exploration of these shales is presently at a relatively immature stage. The Upper Paleozoic shales in the northwestern Guizhong Depression, including the Middle Devonian Luofu shale, the Nabiao shale, and the Lower Carboniferous Yanguan shale, were investigated in this study. Mineral composition analysis, organic matter analysis (including total organic carbon (TOC) content, maceral of kerogen and the vitrinite reflection (Ro)), pore characteristic analysis (including porosity and permeability, pore type identification by SEM, and pore size distribution by nitrogen sorption), methane isothermal sorption test were conducted, and the distribution and thickness of the shales were determined, Then the characteristics of the two target shales were illustrated and compared. The results show that the Upper Paleozoic shales have favorable organic matter conditions (mainly moderate to high TOC content, type I and II1 kerogen and high to over maturity), good fracability potential (brittleness index (BI) > 40%), multiple pore types, stable distribution and effective thickness, and good methane sorption capacity. Therefore, the Upper Paleozoic shales in the northern Guizhong Depression have good shale gas potential and exploration prospects. Moreover, the average TOC content, average BI, thickness of the organic-rich shale (TOC > 2.0 wt%) and the shale gas resources of the Middle Devonian shales are better than those of the Lower Carboniferous shale. The Middle Devonian shales have better shale gas potential and exploration prospects than the Lower Carboniferous shales.

Refining of Military Jet Fuels from Shale Oil. Volume I. Part II. Preparation of Laboratory-Scale Fuel Samples.

DTIC Science & Technology

1982-03-01

ON SPEC Meeting Specifications *1 OXY Test Series on In Situ Shale Oil P Pressure (P + N) Paraffins and Naphthenes PHO Test Series on Above-Ground...material, the crude shale is heated and processed through caustic desalt- ing similar to conventional technology. The desalted oil is mixed with recycle...with hot regenerated catalyst. Spent catalyst and oil vapors are disengaqed by -.eans of high temperature cyclones. The spent catalyst first passes

The Water-Energy-Food Nexus of Unconventional Fossil Fuels.

NASA Astrophysics Data System (ADS)

Rosa, L.; Davis, K. F.; Rulli, M. C.; D'Odorico, P.

2017-12-01

Extraction of unconventional fossil fuels has increased human pressure on freshwater resources. Shale formations are globally abundant and widespread. Their extraction through hydraulic fracturing, a water-intensive process, may be limited by water availability, especially in arid and semiarid regions where stronger competition is expected to emerge with food production. It is unclear to what extent and where shale resource extraction could compete with local water and food security. Although extraction of shale deposits materializes economic gains and increases energy security, in some regions it may exacerbate the reliance on food imports, thereby decreasing regional food security. We consider the global distribution of known shale deposits suitable for oil and gas extraction and evaluate their impacts on water resources for food production and other human and environmental needs. We find that 17% of the world's shale deposits are located in areas affected by both surface water and groundwater stress, 50% in areas with surface water stress, and about 30% in irrigated areas. In these regions shale oil and shale gas production will likely threaten water and food security. These results highlight the importance of hydrologic analyses in the extraction of fossil fuels. Indeed, neglecting water availability as one of the possible factors constraining the development of shale deposits around the world could lead to unaccounted environmental impacts and business risks for firms and investors. Because several shale deposits in the world stretch across irrigated agricultural areas in arid regions, an adequate development of these resources requires appropriate environmental, economic and political decisions.

Microstructural and mineralogical characterization of selected shales in support of nuclear waste repository studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S.Y.; Hyder, L.K.; Alley, P.D.

1988-01-01

Five shales were examined as part of the Sedimentary Rock Program evaluation of this medium as a potential host for a US civilian nuclear waste repository. The units selected for characterization were the Chattanooga Shale from Fentress County, Tennessee; the Pierre Shale from Gregory County, South Dakota; the Green River Formation from Garfield County, Colorado; and the Nolichucky Shale and Pumpkin Valley Shale from Roane County, Tennessee. The micromorphology and structure of the shales were examined by petrographic, scanning electron, and high-resolution transmission electron microscopy. Chemical and mineralogical compositions were studied through the use of energy-dispersive x-ray, neutron activation, atomicmore » absorption, thermal, and x-ray diffraction analysis techniques. 18 refs., 12 figs., 2 tabs.« less

Mineralogical characterization of selected shales in support of nuclear waste repository studies: Progress report, October 1987--September 1988

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S. Y.; Hyder, L. K.; Baxter, P. M.

1989-07-01

One objective of the Sedimentary Rock Program at the Oak Ridge National Laboratory has been to examine end-member shales to develop a data base that will aid in evaluations if shales are ever considered as a repository host rock. Five end-member shales were selected for comprehensive characterization: the Chattanooga Shale from Fentress County, Tennessee; the Pierre Shale from Gregory County, South Dakota; the Green River Formation from Garfield County, Colorado; and the Nolichucky Shale and Pumpkin Valley Shale from Roane County, Tennessee. Detailed micromorphological and mineralogical characterizations of the shales were completed by Lee et al. (1987) in ORNL/TM-10567. Thismore » report is a supplemental characterization study that was necessary because second batches of the shale samples were needed for additional studies. Selected physical, chemical, and mineralogical properties were determined for the second batches; and their properties were compared with the results from the first batches. Physical characterization indicated that the second-batch and first-batch samples had a noticeable difference in apparent-size distributions but had similar primary-particle-size distributions. There were some differences in chemical composition between the batches, but these differences were not considered important in comparison with the differences among the end-member shales. The results of x-ray diffraction analyses showed that the second batches had mineralogical compositions very similar to the first batches. 9 refs., 9 figs., 4 tabs.« less

Coupled Fracture and Flow in Shale in Hydraulic Fracturing

NASA Astrophysics Data System (ADS)

Carey, J. W.; Mori, H.; Viswanathan, H.

2014-12-01

Production of hydrocarbon from shale requires creation and maintenance of fracture permeability in an otherwise impermeable shale matrix. In this study, we use a combination of triaxial coreflood experiments and x-ray tomography characterization to investigate the fracture-permeability behavior of Utica shale at in situ reservoir conditions (25-50 oC and 35-120 bars). Initially impermeable shale core was placed between flat anvils (compression) or between split anvils (pure shear) and loaded until failure in the triaxial device. Permeability was monitored continuously during this process. Significant deformation (>1%) was required to generate a transmissive fracture system. Permeability generally peaked at the point of a distinct failure event and then dropped by a factor of 2-6 when the system returned to hydrostatic failure. Permeability was very small in compression experiments (< 1 mD), possibly because of limited fracture connectivity through the anvils. In pure share experiments, shale with bedding planes perpendicular to shear loading developed complex fracture networks with narrow apertures and peak permeability of 30 mD. Shale with bedding planes parallel to shear loading developed simple fractures with large apertures and a peak permeability as high as 1 D. Fracture systems held at static conditions for periods of several hours showed little change in effective permeability at hydrostatic conditions as high as 140 bars. However, permeability of fractured systems was a function of hydrostatic pressure, declining in a pseudo-linear, exponential fashion as pressure increased. We also observed that permeability decreased with increasing fluid flow rate indicating that flow did not follow Darcy's Law, possibly due to non-laminar flow conditions, and conformed to Forscheimer's law. The coupled deformation and flow behavior of Utica shale, particularly the large deformation required to initiate flow, indicates the probable importance of activation of existing fractures in hydraulic fracturing and that these fractures can have adequate permeability for the production of hydrocarbon.

Evaluating the oxidation of shale during hydraulic fracturing using SEM-EDS and spectrocolorimetry

NASA Astrophysics Data System (ADS)

Tan, X. Y.; Nakashima, S.

2017-12-01

During hydraulic fracturing (fracking) for shale gas/oil extraction, oxygen is introduced into deep oxygen-poor environments, and Fe2+-bearing minerals in rocks can be oxidized thus leading to the degradation of rock quality. Akita diatomaceous shale is considered to be one of the source rocks for oil and gas fields in northwestern Japan. Outcrops of Akita shale often show presence of jarosite (Fe sulfate: yellow) and/or goethite (Fe hydroxide: brown to orange) as oxidation products of pyrite (FeS2). Several series of oxidation experiments of Akita shale under dry, humid, and wet conditions were conducted at temperatures of around 30 oC and 50oC for 30-40 days. Portable color spectro-colorimeters were used to monitor color changes of the rock surfaces every hour. SEM-EDS, UV-Vis, and Raman spectroscopic analyses were performed on the rock sample surface to examine the chemical and mineralogical compositions of Akita shale before and after the dry, humid, and wet experiments. In SEM-EDS analyses before the humid experiment, Fe and S containing phases show their atomic ratio close to 1:2 indicating that this is pyrite (FeS2). After the experiment, the ratio changed to around 1:1 suggesting a conversion from pyrite (FeS2) to mackinawite-like mineral (FeS). In addition, the formation of Ca sulfate (possibly gypsum: CaSO4.2H2O) and goethite-like Fe hydroxide were identified which were not present initially. Therefore, oxidation pathways of iron sulfide (pyrite: FeS2) via FeS to sulfate is confirmed by our humid experiments around 30oC on Akita shale. These oxidation processes might occur during the fracking of shale within relatively short time periods associated with precipitation of sulfates and hydroxides. Therefore, further studies are needed for their effects on rock properties and gas/oil production.

Retardation effect of nitrogen compounds and condensed aromatics on shale oil catalytic cracking processing and their characterization.

PubMed

Li, Nan; Chen, Chen; Wang, Bin; Li, Shaojie; Yang, Chaohe; Chen, Xiaobo

Untreated shale oil, shale oil treated with HCl aqueous solution and shale oil treated with HCl and furfural were used to do comparative experiments in fixed bed reactors. Nitrogen compounds and condensed aromatics extracted by HCl and furfural were characterized by electrospray ionization Fourier transform cyclotron resonance mass spectrometry and gas chromatography and mass spectrometry, respectively. Compared with untreated shale oil, the conversion and yield of liquid products increased considerably after removing basic nitrogen compounds by HCl extraction. Furthermore, after removing nitrogen compounds and condensed aromatics by both HCl and furfural, the conversion and yield of liquid products further increased. In addition, N 1 class species are predominant in both basic and non-basic nitrogen compounds, and they are probably indole, carbazole, cycloalkyl-carbazole, pyridine and cycloalkyl-pyridine. As for the condensed aromatics, most of them possess aromatic rings with two to three rings and zero to four carbon atom.

Discussion on upper limit of maturity for marine shale gas accumulation

NASA Astrophysics Data System (ADS)

Huang, Jinliang; Dong, Dazhong; Zhang, Chenchen; Wang, Yuman; Li, Xinjing; Wang, Shufang

2017-04-01

The sedimentary formations of marine shale in China are widely distributed and are characterized by old age, early hydrocarbon-generation and high thermal evolution degree, strong tectonic deformation and reformation and poor preservation conditions. Therefore whether commercial shale gas reservoirs can be formed is a critical issue to be studied. The previous studies showed that the upper threshold of maturity (Ro%) for the gas generation of marine source rocks is 3.0%. Based on comparative studies of marine shale gas exploration practices at home and abroad and reservoir experimental analysis results, we proposed in this paper that the upper threshold of maturity (Ro%) for marine shale gas accumulation is 3.5%. And the main proofs are as follows: (1) There is still certain commercial production in the area with the higher than 3.0% in Marcellus and Woodford marine shale gas plays in North America; (2) The Ro of the Silurian Longmaxi shale in the Sichuan Basin in China is between 2.5% and 3.3%. However, the significant breakthrough has been made in shale gas exploration and the production exceeds 7 billion m3 in 2016; (3) The TOC of the Cambrian Qiongzhusi organic-rich shale in Changning Region in the Sichuan Basin ranges 2% to 7.1% and the Ro is greater than 3.5%. And the resistivity logging of organic-rich shale appears low-ultra low resistivity and inversion of Rt curve. It's suggested that the organic matters in Qiongzhusi organic-rich shale occurs partial carbonization which leads to stronger conductivity; (4) Thermal simulation experiments showed that the specific surface of shale increases with Ro. And the specific surface and adsorptive capacity both reach maximum when the Ro is 3.5%; (5) The analysis of physical properties and SEM images of shale reservoirs indicated that when Ro is higher than 3.5%, the dominant pores of Qiongzhusi shale are micro-pores while the organic pores are relatively poor-developed, and the average porosity is less than 2%.

Recycling of Ammonia Wastewater During Vanadium Extraction from Shale

NASA Astrophysics Data System (ADS)

Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing

2018-03-01

In the vanadium metallurgical industry, massive amounts of ammonia hydroxide or ammonia salt are added during the precipitation process to obtain V2O5; therefore, wastewater containing a high level of NH4 + is generated, which poses a serious threat to environmental and hydrologic safety. In this article, a novel process was developed to recycle ammonia wastewater based on a combination of ammonia wastewater leaching and crystallization during vanadium extraction from shale. The effects of the NH4 + concentration, temperature, time and liquid-to-solid ratio on the leaching efficiencies of vanadium, aluminum and potassium were investigated, and the results showed that 93.2% of vanadium, 86.3% of aluminum and 96.8% of potassium can be leached from sulfation-roasted shale. Subsequently, 80.6% of NH4 + was separated from the leaching solution via cooling crystallization. Vanadium was recovered via a combined method of solvent extraction, precipitation and calcination. Therefore, ammonia wastewater was successfully recycled during vanadium extraction from shale.

Evolution of water chemistry during Marcellus Shale gas development: A case study in West Virginia.

PubMed

Ziemkiewicz, Paul F; Thomas He, Y

2015-09-01

Hydraulic fracturing (HF) has been used with horizontal drilling to extract gas and natural gas liquids from source rock such as the Marcellus Shale in the Appalachian Basin. Horizontal drilling and HF generates large volumes of waste water known as flowback. While inorganic ion chemistry has been well characterized, and the general increase in concentration through the flowback is widely recognized, the literature contains little information relative to organic compounds and radionuclides. This study examined the chemical evolution of liquid process and waste streams (including makeup water, HF fluids, and flowback) in four Marcellus Shale gas well sites in north central West Virginia. Concentrations of organic and inorganic constituents and radioactive isotopes were measured to determine changes in waste water chemistry during shale gas development. We found that additives used in fracturing fluid may contribute to some of the constituents (e.g., Fe) found in flowback, but they appear to play a minor role. Time sequence samples collected during flowback indicated increasing concentrations of organic, inorganic and radioactive constituents. Nearly all constituents were found in much higher concentrations in flowback water than in injected HF fluids suggesting that the bulk of constituents originate in the Marcellus Shale formation rather than in the formulation of the injected HF fluids. Liquid wastes such as flowback and produced water, are largely recycled for subsequent fracturing operations. These practices limit environmental exposure to flowback. Copyright © 2015 Elsevier Ltd. All rights reserved.

BER balanced program plan: oil shale technology. [23 suggested biomedical and environmental research projects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schulte, H.F.; Stoker, A.K.; Campbell, E.E.

1976-06-01

Oil shale technology has been divided into two sub-technologies: surface processing and in-situ processing. Definition of the research programs is essentially an amplification of the five King-Muir categories: (A) pollutants: characterization, measurement, and monitoring; (B) physical and chemical processes and effects; (C) health effects; (D) ecological processes and effects; and (E) integrated assessment. Twenty-three biomedical and environmental research projects are described as to program title, scope, milestones, technolgy time frame, program unit priority, and estimated program unit cost.

Balanced program plan: analysis for biomedical and environmental research. Volume 5. Oil shale technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1976-06-01

Oil shale technology has been divided into two sub-technologies: surfaceprocessing and in-situ processing. Definition of the research programs is essentially an amplification of the five King-Muir categories: (A) pollutants: characterization, measurement, and monitoring; (B) physical and chemical processes and effects; (C) health effects; (D) ecological processes and effects; and (E) integrated assessment. Twenty-three biomedical and environmental research projects are described as to program title, scope, milestones, technology time frame, program unit priority, and estimated program unit cost.

Reaction rate kinetics for in situ combustion retorting of Michigan Antrim oil shale

USGS Publications Warehouse

Rostam-Abadi, M.; Mickelson, R.W.

1984-01-01

The intrinsic reaction rate kinetics for the pyrolysis of Michigan Antrim oil shale and the oxidation of the carbonaceous residue of this shale have been determined using a thermogravimetric analysis method. The kinetics of the pyrolysis reaction were evaluated from both isothermal and nonisothermal rate data. The reaction was found to be second-order with an activation energy of 252.2 kJ/mole, and with a frequency factor of 9.25 ?? 1015 sec-1. Pyrolysis kinetics were not affected by heating rates between 0.01 to 0.67??K/s. No evidence of any reactions among the oil shale mineral constituents was observed at temperatures below 1173??K. However, it was found that the presence of pyrite in oil shale reduces the primary devolatilization rate of kerogen and increases the amount of residual char in the spent shale. Carbonaceous residues which were prepared by heating the oil shale at a rate of 0.166??K/s to temperatures between 923??K and 1073??K, had the highest reactivities when oxidized at 0.166??K/s in a gas having 21 volume percent oxygen. Oxygen chemisorption was found to be the initial precursor to the oxidation process. The kinetics governing oxygen chemisorption is (Equation Presented) where X is the fractional coverage. The oxidation of the carbonaceous residue was found also to be second-order. The activation energy and the frequency factor determined from isothermal experiments were 147 kJ/mole and 9.18??107 sec-1 respectively, while the values of these parameters obtained from a nonisothermal experiment were 212 kJ/mole and 1.5??1013 sec-1. The variation in the rate constants is attributed to the fact that isothermal and nonisothermal analyses represent two different aspects of the combustion process.

Micro Mechanics and Microstructures of Major Subsurface Hydraulic Barriers: Shale Caprock vs Wellbore Cement

NASA Astrophysics Data System (ADS)

Radonjic, M.; Du, H.

2015-12-01

Shale caprocks and wellbore cements are two of the most common subsurface impermeable barriers in the oil and gas industry. More than 60% of effective seals for geologic hydrocarbon bearing formations as natural hydraulic barriers constitute of shale rocks. Wellbore cements provide zonal isolation as an engineered hydraulic barrier to ensure controlled fluid flow from the reservoir to the production facilities. Shale caprocks were deposited and formed by squeezing excess formation water and mineralogical transformations at different temperatures and pressures. In a similar process, wellbore cements are subjected to compression during expandable tubular operations, which lead to a rapid pore water propagation and secondary mineral precipitation within the cement. The focus of this research was to investigate the effect of wellbore cement compression on its microstructure and mechanical properties, as well as a preliminary comparison of shale caprocks and hydrated cement. The purpose of comparative evaluation of engineered vs natural hydraulic barrier materials is to further improve wellbore cement durability when in contact with geofluids. The micro-indentation was utilized to evaluate the change in cement mechanical properties caused by compression. Indentation experiments showed an overall increase in hardness and Young's modulus of compressed cement. Furthermore, SEM imaging and Electron Probe Microanalysis showed mineralogical alterations and decrease in porosity. These can be correlated with the cement rehydration caused by microstructure changes as a result of compression. The mechanical properties were also quantitatively compared to shale caprock samples in order to investigate the similarities of hydraulic barrier features that could help to improve the subsurface application of cement in zonal isolation. The comparison results showed that the poro-mechanical characteristics of wellbore cement appear to be improved when inherent pore sizes are shifted to predominantly nano-scale range as characteristic of pore-size distribution typical for shale rocks. The effect of compression on cement appears to petrophysically alter cement towards the properties of shale caprocks, although the process is achieved much faster than in the case of shale diagenesis over geological times.

Ecological risks of shale oil and gas development to wildlife, aquatic resources and their habitats

USGS Publications Warehouse

Brittingham, Margaret C.; Maloney, Kelly O.; Farag, Aïda M.; Harper, David D.; Bowen, Zachary H.

2014-01-01

Technological advances in hydraulic fracturing and horizontal drilling have led to the exploration and exploitation of shale oil and gas both nationally and internationally. Extensive development of shale resources has occurred within the United States over the past decade, yet full build out is not expected to occur for years. Moreover, countries across the globe have large shale resources and are beginning to explore extraction of these resources. Extraction of shale resources is a multistep process that includes site identification, well pad and infrastructure development, well drilling, high-volume hydraulic fracturing and production; each with its own propensity to affect associated ecosystems. Some potential effects, for example from well pad, road and pipeline development, will likely be similar to other anthropogenic activities like conventional gas drilling, land clearing, exurban and agricultural development and surface mining (e.g., habitat fragmentation and sedimentation). Therefore, we can use the large body of literature available on the ecological effects of these activities to estimate potential effects from shale development on nearby ecosystems. However, other effects, such as accidental release of wastewaters, are novel to the shale gas extraction process making it harder to predict potential outcomes. Here, we review current knowledge of the effects of high-volume hydraulic fracturing coupled with horizontal drilling on terrestrial and aquatic ecosystems in the contiguous United States, an area that includes 20 shale plays many of which have experienced extensive development over the past decade. We conclude that species and habitats most at risk are ones where there is an extensive overlap between a species range or habitat type and one of the shale plays (leading to high vulnerability) coupled with intrinsic characteristics such as limited range, small population size, specialized habitat requirements, and high sensitivity to disturbance. Examples include core forest habitat and forest specialists, sagebrush habitat and specialists, vernal pond inhabitants and stream biota. We suggest five general areas of research and monitoring that could aid in development of effective guidelines and policies to minimize negative impacts and protect vulnerable species and ecosystems: (1) spatial analyses, (2) species-based modeling, (3) vulnerability assessments, (4) ecoregional assessments, and (5) threshold and toxicity evaluations.

Ecological risks of shale oil and gas development to wildlife, aquatic resources and their habitats.

PubMed

Brittingham, Margaret C; Maloney, Kelly O; Farag, Aïda M; Harper, David D; Bowen, Zachary H

2014-10-07

Technological advances in hydraulic fracturing and horizontal drilling have led to the exploration and exploitation of shale oil and gas both nationally and internationally. Extensive development of shale resources has occurred within the United States over the past decade, yet full build out is not expected to occur for years. Moreover, countries across the globe have large shale resources and are beginning to explore extraction of these resources. Extraction of shale resources is a multistep process that includes site identification, well pad and infrastructure development, well drilling, high-volume hydraulic fracturing and production; each with its own propensity to affect associated ecosystems. Some potential effects, for example from well pad, road and pipeline development, will likely be similar to other anthropogenic activities like conventional gas drilling, land clearing, exurban and agricultural development and surface mining (e.g., habitat fragmentation and sedimentation). Therefore, we can use the large body of literature available on the ecological effects of these activities to estimate potential effects from shale development on nearby ecosystems. However, other effects, such as accidental release of wastewaters, are novel to the shale gas extraction process making it harder to predict potential outcomes. Here, we review current knowledge of the effects of high-volume hydraulic fracturing coupled with horizontal drilling on terrestrial and aquatic ecosystems in the contiguous United States, an area that includes 20 shale plays many of which have experienced extensive development over the past decade. We conclude that species and habitats most at risk are ones where there is an extensive overlap between a species range or habitat type and one of the shale plays (leading to high vulnerability) coupled with intrinsic characteristics such as limited range, small population size, specialized habitat requirements, and high sensitivity to disturbance. Examples include core forest habitat and forest specialists, sagebrush habitat and specialists, vernal pond inhabitants and stream biota. We suggest five general areas of research and monitoring that could aid in development of effective guidelines and policies to minimize negative impacts and protect vulnerable species and ecosystems: (1) spatial analyses, (2) species-based modeling, (3) vulnerability assessments, (4) ecoregional assessments, and (5) threshold and toxicity evaluations.

Accelerated weathering of tough shales : final report.

DOT National Transportation Integrated Search

1977-01-01

The purpose of this study was to find or develop a test that would identify a very tough but relatively rapid weathering type of shale that has caused problems when used in embankments as rock. Eight shales, including the problem shale, were collecte...

Minor-element composition and organic carbon content of marine and nonmarine shales of Late Cretaceous age in the western interior of the United States

USGS Publications Warehouse

Tourtelot, H.A.

1964-01-01

The composition of nonmarine shales of Cretaceous age that contain less than 1 per cent organic carbon is assumed to represent the inherited minor-element composition of clayey sediments delivered to the Cretaceous sea that occupied the western interior region of North America. Differences in minor-element content between these samples and samples of 1. (a) nonmarine carbonaceous shales (1 to 17 per cent organic carbon), 2. (b) nearshore marine shales (less than 1 per cent organic carbon), and 3. (c) offshore marine shales (as much as 8 per cent organic carbon), all of the same age, reveal certain aspects of the role played by clay minerals and organic materials in affecting the minor-element composition of the rocks. The organic carbon in the nonmarine rocks occurs in disseminated coaly plant remains. The organic carbon in the marine rocks occurs predominantly in humic material derived from terrestrial plants. The close similarity in composition between the organic isolates from the marine samples and low-rank coal suggests that the amount of marine organic material in these rocks is small. The minor-element content of the two kinds of nonmarine shales is the same despite the relatively large amount of organic carbon in the carbonaceous shales. The nearshore marine shales, however, contain larger median amounts of arsenic, boron, chromium, vanadium and zinc than do the nonmarine rocks; and the offshore marine shales contain even larger amounts of these elements. Cobalt, molybdenum, lead and zirconium show insignificant differences in median content between the nonmarine and marine rocks, although as much as 25 ppm molybdenum is present in some offshore marine samples. The gallium content is lower in the marine than in the nonmarine samples. Copper and selenium contents of the two kinds of nonmarine rocks and the nearshore marine samples are the same, but those of the offshore samples are larger. In general, arsenic, chromium, copper, molybdenum, selenium, vanadium and zinc are concentrated in those offshore marine samples having the largest amounts of organic carbon, but samples with equal amounts of vanadium, for instance, may differ by a factor of 3 in their amount of organic carbon. Arsenic and molybdenum occur in some samples chiefly in syngenetic pyrite but also are present in relatively large amounts in samples that contain little pyrite. The data on nonmarine carbonaceous shales indicate that organic matter of terrestrial origin in marine shales contributes little to the minor-element content of such rocks. It is possible that marine organic matter, even though seemingly small in amount in marine shales, contributes to the minor-element composition of the shales. In addition to any such contribution, however, the great effectiveness in sorption processes of humic materials in conjunction with clay minerals suggests that such processes must have played an important role as these materials moved from the relatively dilute solutions of the nonmarine environment to the relatively concentrated solution of sea water. The volumes of sea water sufficient to supply for sorption the amounts of most minor elements in the offshore marine samples are insignificant compared to the volumes of water with which the clay and organic matter were in contact during their transportation and sedimentation. Consequently, the chemical characteristics of the environment in which the clay minerals and organic matter accumulated and underwent diagenesis probably were the most important factors in controlling the degree to which sorption processes and the formation of syngenetic minerals affected the final composition of the rocks. ?? 1969.

Effect of depletion rate on solution gas drive in shale

NASA Astrophysics Data System (ADS)

Zhang, Mingshan; Sang, Qian; Gong, Houjian; Li, Yajun; Dong, Mingzhe

2018-01-01

Solution gas drive process has been studied extensively in sand rocks and heavy oil reservoirs for a long time. Oil recovery is affected by several factors, such as depletion rate, initial GOR (gas oil ratio), oil viscosity, and temperature and so on. Before the solution gas drive tests, elastic drive without dissolved gas was carried out as a reference, which shows a limited oil recovery. Solution gas drive experiments were conducted in shale to study oil recovery with various depletion rates. Results show that oil recovery increases with the decrease of depletion rates because of the low permeability and desorption of methane.

Biological markers from Green River kerogen decomposition

NASA Astrophysics Data System (ADS)

Burnham, A. K.; Clarkson, J. E.; Singleton, M. F.; Wong, C. M.; Crawford, R. W.

1982-07-01

Isoprenoid and other carbon skeletons that are formed in living organisms and preserved essentially intact in ancient sediments are often called biological markers. The purpose of this paper is to develop improved methods of using isoprenoid hydrocarbons to relate petroleum or shale oil to its source rock. It is demonstrated that most, but not all, of the isoprenoid hydrocarbon structures are chemically bonded in kerogen (or to minerals) in Green River oil shale. The rate constant for thermally producing isoprenoid, cyclic, and aromatic hydrocarbons is substantially greater than for the bulk of shale oil. This may be related to the substantial quantity of CO 2 which is evolved coincident with the isoprenoid hydrocarbons but prior to substantial oil evolution. Although formation of isoprenoid alkenes is enhanced by rapid heating and high pyrolysis temperatures, the ratio of isoprenoid alkenes plus alkanes to normal alkenes plus alkanes is independent of heating rate. High-temperature laboratory pyrolysis experiments can thus be used to predict the distribution of aliphatic hydrocarbons in low temperature processes such as in situ shale oil production and perhaps petroleum formation. Finally, we demonstrate that significant variation in biological marker ratios occurs as a function of stratigraphy in the Green River formation. This information, combined with methods for measuring process yield from oil composition, enables one to relate time-dependent processing conditions to the corresponding time-dependent oil yield in a vertical modified- in situ retort even if there is a substantial and previously undetermined delay in drainage of shale oil from the retort.

Spontaneous Imbibition Process in Micro-Nano Fractal Capillaries Considering Slip Flow

NASA Astrophysics Data System (ADS)

Shen, Yinghao; Li, Caoxiong; Ge, Hongkui; Guo, Xuejing; Wang, Shaojun

An imbibition process of water into a matrix is required to investigate the influences of large-volume fracturing fluids on gas production of unconventional formations. Slip flow has been recognized by recent studies as a major mechanism of fluid transport in nanotubes. For nanopores in shale, a slip boundary is nonnegligible in the imbibition process. In this study, we established an analytic equation of spontaneous imbibition considering slip effects in capillaries. A spontaneous imbibition model that couples the analytic equation considering the slip effect was constructed based on fractal theory. We then used a model for various conditions, such as slip boundary, pore structure, and fractal dimension of pore tortuosity, to capture the imbibition characteristics considering the slip effect. A dynamic contact angle was integrated into the modeling. Results of our study verify that the slip boundary influences water imbibition significantly. The imbibition speed is significantly improved when slip length reaches the equivalent diameter of a tube. Therefore, disregarding the slip effect will underestimate the imbibition speed in shale samples.

Do Shale Pore Throats Have a Threshold Diameter for Oil Storage?

PubMed Central

Zou, Caineng; Jin, Xu; Zhu, Rukai; Gong, Guangming; Sun, Liang; Dai, Jinxing; Meng, Depeng; Wang, Xiaoqi; Li, Jianming; Wu, Songtao; Liu, Xiaodan; Wu, Juntao; Jiang, Lei

2015-01-01

In this work, a nanoporous template with a controllable channel diameter was used to simulate the oil storage ability of shale pore throats. On the basis of the wetting behaviours at the nanoscale solid-liquid interfaces, the seepage of oil in nano-channels of different diameters was examined to accurately and systematically determine the effect of the pore diameter on the oil storage capacity. The results indicated that the lower threshold for oil storage was a pore throat of 20 nm, under certain conditions. This proposed pore size threshold provides novel, evidence-based criteria for estimating the geological reserves, recoverable reserves and economically recoverable reserves of shale oil. This new understanding of shale oil processes could revolutionize the related industries. PMID:26314637

Do Shale Pore Throats Have a Threshold Diameter for Oil Storage?

PubMed

Zou, Caineng; Jin, Xu; Zhu, Rukai; Gong, Guangming; Sun, Liang; Dai, Jinxing; Meng, Depeng; Wang, Xiaoqi; Li, Jianming; Wu, Songtao; Liu, Xiaodan; Wu, Juntao; Jiang, Lei

2015-08-28

In this work, a nanoporous template with a controllable channel diameter was used to simulate the oil storage ability of shale pore throats. On the basis of the wetting behaviours at the nanoscale solid-liquid interfaces, the seepage of oil in nano-channels of different diameters was examined to accurately and systematically determine the effect of the pore diameter on the oil storage capacity. The results indicated that the lower threshold for oil storage was a pore throat of 20 nm, under certain conditions. This proposed pore size threshold provides novel, evidence-based criteria for estimating the geological reserves, recoverable reserves and economically recoverable reserves of shale oil. This new understanding of shale oil processes could revolutionize the related industries.

Shale hydrocarbon reservoirs: some influences of tectonics and paleogeography during deposition: Chapter 2

USGS Publications Warehouse

Eoff, Jennifer D

2014-01-01

Fundamental to any of the processes that acted during deposition, however, was active tectonism. Basin type can often distinguish self-sourced shale plays from other types of hydrocarbon source rocks. The deposition of North American self-sourced shale was associated with the assembly and subsequent fragmentation of Pangea. Flooded foreland basins along collisional margins were the predominant depositional settings during the Paleozoic, whereas deposition in semirestricted basins was responsible along the rifted passive margin of the U.S. Gulf Coast during the Mesozoic. Tectonism during deposition of self-sourced shale, such as the Upper Jurassic Haynesville Formation, confined (re)cycling of organic materials to relatively closed systems, which promoted uncommonly thick accumulations of organic matter.

Wellbore stability in oil and gas drilling with chemical-mechanical coupling.

PubMed

Yan, Chuanliang; Deng, Jingen; Yu, Baohua

2013-01-01

Wellbore instability in oil and gas drilling is resulted from both mechanical and chemical factors. Hydration is produced in shale formation owing to the influence of the chemical property of drilling fluid. A new experimental method to measure diffusion coefficient of shale hydration is given, and the calculation method of experimental results is introduced. The diffusion coefficient of shale hydration is measured with the downhole temperature and pressure condition, then the penetration migrate law of drilling fluid filtrate around the wellbore is calculated. Furthermore, the changing rules of shale mechanical properties affected by hydration and water absorption are studied through experiments. The relationships between shale mechanical parameters and the water content are established. The wellbore stability model chemical-mechanical coupling is obtained based on the experimental results. Under the action of drilling fluid, hydration makes the shale formation softened and produced the swelling strain after drilling. This will lead to the collapse pressure increases after drilling. The study results provide a reference for studying hydration collapse period of shale.

Wellbore Stability in Oil and Gas Drilling with Chemical-Mechanical Coupling

PubMed Central

Deng, Jingen

2013-01-01

Wellbore instability in oil and gas drilling is resulted from both mechanical and chemical factors. Hydration is produced in shale formation owing to the influence of the chemical property of drilling fluid. A new experimental method to measure diffusion coefficient of shale hydration is given, and the calculation method of experimental results is introduced. The diffusion coefficient of shale hydration is measured with the downhole temperature and pressure condition, then the penetration migrate law of drilling fluid filtrate around the wellbore is calculated. Furthermore, the changing rules of shale mechanical properties affected by hydration and water absorption are studied through experiments. The relationships between shale mechanical parameters and the water content are established. The wellbore stability model chemical-mechanical coupling is obtained based on the experimental results. Under the action of drilling fluid, hydration makes the shale formation softened and produced the swelling strain after drilling. This will lead to the collapse pressure increases after drilling. The study results provide a reference for studying hydration collapse period of shale. PMID:23935430

Multiscale model reduction for shale gas transport in poroelastic fractured media

NASA Astrophysics Data System (ADS)

Akkutlu, I. Yucel; Efendiev, Yalchin; Vasilyeva, Maria; Wang, Yuhe

2018-01-01

Inherently coupled flow and geomechanics processes in fractured shale media have implications for shale gas production. The system involves highly complex geo-textures comprised of a heterogeneous anisotropic fracture network spatially embedded in an ultra-tight matrix. In addition, nonlinearities due to viscous flow, diffusion, and desorption in the matrix and high velocity gas flow in the fractures complicates the transport. In this paper, we develop a multiscale model reduction approach to couple gas flow and geomechanics in fractured shale media. A Discrete Fracture Model (DFM) is used to treat the complex network of fractures on a fine grid. The coupled flow and geomechanics equations are solved using a fixed stress-splitting scheme by solving the pressure equation using a continuous Galerkin method and the displacement equation using an interior penalty discontinuous Galerkin method. We develop a coarse grid approximation and coupling using the Generalized Multiscale Finite Element Method (GMsFEM). GMsFEM constructs the multiscale basis functions in a systematic way to capture the fracture networks and their interactions with the shale matrix. Numerical results and an error analysis is provided showing that the proposed approach accurately captures the coupled process using a few multiscale basis functions, i.e. a small fraction of the degrees of freedom of the fine-scale problem.

Study of Cetane Properties of ATJ Blends Based on World Survey of Jet Fuels

DTIC Science & Technology

2016-01-28

49.84 N/A N/A N/A 46.92 N/A N/A N/A 12 (100% Syn.) 1 57.79 N/A N/A N/A 53.48 N/A N/A N/A a - Conventional petroleum based jet fuel; b - Oil Shale ...Australia (% Nitrogen content unknown) c - Oil Shale , Australia (Low Nitrogen); d - Oil Shale , Australia (High Nitrogen) U/A – Unavailable in PQIS...fuel b - Oil Shale , Australia (% Nitrogen content unknown) c - Oil Shale , Australia (Low Nitrogen) d - Oil Shale , Australia (High Nitrogen) U/A

Sedimentary processes and depositional environments of the Horn River Shale in British Columbia, Canada

NASA Astrophysics Data System (ADS)

Yoon, Seok-Hoon; Koh, Chang-Seong; Joe, Young-Jin; Woo, Ju-Hwan; Lee, Hyun-Suk

2017-04-01

The Horn River Basin in the northeastern British Columbia, Canada, is one of the largest unconventional gas accumulations in North America. It consists mainly of Devonian shales (Horn River Formation) and is stratigraphically divided into three members, the Muskwa, Otterpark and Evie in descending order. This study focuses on sedimentary processes and depositional environments of the Horn River shale based on sedimentary facies analysis aided by well-log mineralogy (ECS) and total organic carbon (TOC) data. The shale formation consists dominantly of siliceous minerals (quartz, feldspar and mica) and subordinate clay mineral and carbonate materials, and TOC ranging from 1.0 to 7.6%. Based on sedimentary structures and micro texture, three sedimentary facies were classified: homogeneous mudstone (HM), indistinctly laminated mudstone (ILM), and planar laminated mudstone (PLM). Integrated interpretation of the sedimentary facies, lithology and TOC suggests that depositional environment of the Horn River shale was an anoxic quiescent basin plain and base-of-slope off carbonate platform or reef. In this deeper marine setting, organic-rich facies HM and ILM, dominant in the Muskwa (the upper part of the Horn River Formation) and Evie (the lower part of the Horn River Formation) members, may have been emplaced by pelagic to hemipelagic sedimentation on the anoxic sea floor with infrequent effects of low-density gravity flows (turbidity currents or nepheloid flows). In the other hand, facies PLM typifying the Otterpark Member (the middle part of the Horn River Formation) suggests more frequent inflow of bottom-hugging turbidity currents punctuating the hemipelagic settling of the background sedimentation process. The stratigraphic change of sedimentary facies and TOC content in the Horn River Formation is most appropriately interpreted to have been caused by the relative sea-level change, that is, lower TOC and frequent signal of turbidity current during the sea-level lowstand and vice versa. Therefore, the Horn River Formation represents an earlier upward shallowing environmental change from a deep basin (Evie) to shallower marginal slope (middle Otterpark), then turning back to the deeper marine environment (Muskwa) in association with overall regression-lowstand-transgression of the sea level. (This study is supported by "Research on Exploration Technologies and an Onsite Verification to Enhance the Fracturing Efficiency of a Shale Gas Formation" of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea.)

Paleozoic shale gas resources in the Sichuan Basin, China

USGS Publications Warehouse

Potter, Christopher J.

2018-01-01

The Sichuan Basin, China, is commonly considered to contain the world’s most abundant shale gas resources. Although its Paleozoic marine shales share many basic characteristics with successful United States gas shales, numerous geologic uncertainties exist, and Sichuan Basin shale gas production is nascent. Gas retention was likely compromised by the age of the shale reservoirs, multiple uplifts and orogenies, and migration pathways along unconformities. High thermal maturities raise questions about gas storage potential in lower Paleozoic shales. Given these uncertainties, a new look at Sichuan Basin shale gas resources is advantageous. As part of a systematic effort to quantitatively assess continuous oil and gas resources in priority basins worldwide, the US Geological Survey (USGS) completed an assessment of Paleozoic shale gas in the Sichuan Basin in 2015. Three organic-rich marine Paleozoic shale intervals meet the USGS geologic criteria for quantitative assessment of shale gas resources: the lower Cambrian Qiongzhusi Formation, the uppermost Ordovician Wufeng through lowermost Silurian Longmaxi Formations (currently producing shale gas), and the upper Permian Longtan and Dalong Formations. This study defined geologically based assessment units and calculated probabilistic distributions of technically recoverable shale gas resources using the USGS well productivity–based method. For six assessment units evaluated in 2015, the USGS estimated a mean value of 23.9 tcf (677 billion cubic meters) of undiscovered, technically recoverable shale gas. This result is considerably lower than volumes calculated in previous shale gas assessments of the Sichuan Basin, highlighting a need for caution in this geologically challenging setting.

Preliminary Results from Outcrop-Based Spectral Gamma-Ray Measurements on the Lower Silurian Longmaxi Shale, in Chongqing and Its Adjacent Areas

NASA Astrophysics Data System (ADS)

Zou, C.; Nie, X.; Qiao, L.; Pan, L.; Hou, S.

2013-12-01

The Longmaxi Shale in the Lower Silurian has been recognized as a favorable target of shale gas exploration in Sichuan basin, China. One important feature of shale gas reservoirs is of high total organic carbon (TOC). Many studies have shown that the spectral gamma-ray measurements are positively correlated to the TOC contents. In this study, the spectral gamma ray responses of five shale outcrop profiles are measured in Chongqing and its adjacent areas, Sichuan basin. Three of the five profiles are located in Qijiang, Qianjiang and Changning in Chongqing, and the other two are located in Qilong and Houtan in Guizhou. The main lithologies of the profiles include mainly black shale, gray shale and silty shale. The spectral gamma-ray measurements provide the contents of potassium (K), uranium (U), and thorium (Th). The result of the five profiles shows that the K and Th contents of gray shale are close to the ones of black shale, while the U contents in the black shale are significantly higher than that in the other rocks. The TOC contents are estimated by using the outcrop-based measurements with an empirical formula. The result shows that the TOC contents are the highest in black shale of Changning profile. It indicates that there is a most promising exploration potential for shale gas in this area. In the future, the outcrop data will be used to construct detailed lithofacies profiles and establish relationships between lithofacies both in outcrop and the subsurface gamma-ray logs. Acknowledgment: We acknowledge the financial support of the National Natural Science Foundation of China (41274185) and the Fundamental Research Funds for the Central Universities.

Characterization of raw and burnt oil shale from Dotternhausen: Petrographical and mineralogical evolution with temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thiéry, Vincent, E-mail: vincent.thiery@mines-douai.fr; Université de Lille; Bourdot, Alexandra, E-mail: alexandra.bourdot@gmail.com

The Toarcian Posidonia shale from Dotternhausen, Germany, is quarried and burnt in a fluidized bed reactor to produce electricity. The combustion residue, namely burnt oil shale (BOS), is used in the adjacent cement work as an additive in blended cements. The starting material is a typical laminated oil shale with an organic matter content ranging from 6 to 18%. Mineral matter consists principally of quartz, feldspar, pyrite and clays. After calcination in the range, the resulting product, burnt oil shale, keeps the macroscopic layered texture however with different mineralogy (anhydrite, lime, iron oxides) and the formation of an amorphous phase.more » This one, studied under STEM, reveals a typical texture of incipient partial melting due to a long retention time (ca. 30 min) and quenching. An in-situ high temperature X-ray diffraction (HTXRD) allowed studying precisely the mineralogical changes associated with the temperature increase. - Highlights: • We present oil shale/burnt oil shale characterization. • The Posidonia Shale is burnt in a fluidized bed. • Mineralogical evolution with temperature is complex. • The burnt oil shale is used in composite cements.« less

Experimental and theoretical studies of the effect of temperature on supercritical CO2 adsorption on illite

NASA Astrophysics Data System (ADS)

Joewondo, N.; Zhang, Y.; Prasad, M.

2016-12-01

Sequestration of carbon dioxide in shale has been a subject of interest as the result of the technological advancement in gas shale production. The process involves injection of CO2 to enhance methane recovery and storing CO2 in depleted shale reservoir at elevated pressures. To better understand both shale production and carbon storage one must study the physical phenomena acting at different scales that control the in situ fluid flow. Shale rocks are complex systems with heterogeneous structures and compositions. Pore structures of these systems are in nanometer scales and have significant gas storage capacity and surface area. Adsorption is prominent in nanometer sized pores due to the high attraction between gas molecules and the surface of the pores. Recent studies attempt to find correlation between storage capacity and the rock composition, particularly the clay content. This study, however, focuses on the study of supercritical adsorption of CO2 on pure clay sample. We have built an in-house manometric experimental setup that can be used to study both the equilibrium and kinetics of adsorption. The experiment is conducted at isothermal condition. The study of equilibrium of adsorption gives insight on the storage capacity of these systems, and the study of the kinetics of adsorption is essential in understanding the resistance to fluid transport. The diffusion coefficient, which can be estimated from the dynamic experimental results, is a parameter which quantify diffusion mobility, and is affected by many factors including pressure and temperature. The first part of this paper briefly discusses the study of both equilibrium and kinetics of the CO2 adsorption on illite. Both static and dynamic measurements on the system are compared to theoretical models available in the literature to estimate the storage capacity and the diffusion time constants. The main part of the paper discusses the effect of varying temperature on the static and dynamic experimental results.

A new laboratory approach to shale analysis using NMR relaxometry

USGS Publications Warehouse

Washburn, Kathryn E.; Birdwell, Justin E.; Baez, Luis; Beeney, Ken; Sonnenberg, Steve

2013-01-01

Low-field nuclear magnetic resonance (LF-NMR) relaxometry is a non-invasive technique commonly used to assess hydrogen-bearing fluids in petroleum reservoir rocks. Measurements made using LF-NMR provide information on rock porosity, pore-size distributions, and in some cases, fluid types and saturations (Timur, 1967; Kenyon et al., 1986; Straley et al., 1994; Brown, 2001; Jackson, 2001; Kleinberg, 2001; Hurlimann et al., 2002). Recent improvements in LF-NMR instrument electronics have made it possible to apply methods used to measure pore fluids to assess highly viscous and even solid organic phases within reservoir rocks. T1 and T2 relaxation responses behave very differently in solids and liquids; therefore the relationship between these two modes of relaxation can be used to differentiate organic phases in rock samples or to characterize extracted organic materials. Using T1-T2 correlation data, organic components present in shales, such as kerogen and bitumen, can be examined in laboratory relaxometry measurements. In addition, implementation of a solid-echo pulse sequence to refocus T2 relaxation caused by homonuclear dipolar coupling during correlation measurements allows for improved resolution of solid-phase protons. LF-NMR measurements of T1 and T2 relaxation time distributions were carried out on raw oil shale samples from the Eocene Green River Formation and pyrolyzed samples of these shales processed by hydrous pyrolysis and techniques meant to mimic surface and in-situ retorting. Samples processed using the In Situ Simulator approach ranged from bitumen and early oil generation through to depletion of petroleum generating potential. The standard T1-T2 correlation plots revealed distinct peaks representative of solid- and liquid-like organic phases; results on the pyrolyzed shales reflect changes that occurred during thermal processing. The solid-echo T1 and T2 measurements were used to improve assessment of the solid organic phases, specifically kerogen, thermally degraded kerogen, and char. Integrated peak areas from the LF-NMR results representative of kerogen and bitumen were found to be well correlated with S1 and S2 parameters from Rock-Eval programmed pyrolysis. This study demonstrates that LFNMR relaxometry can provide a wide range of information on shales and other reservoir rocks that goes well beyond porosity and pore-fluid analysis.

Energy trump for Morocco: the oil shales (in French)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosa, S.D.

1981-10-01

The mainstays of the economy in Morocco are still agriculture and phosphates; the latter represent 34% of world exports. Energy demand in 1985 will be probably 3 times that in 1975. Most of the oil, which covers 82% of its energy needs, must be imported. Other possible sources are the rich oil shale deposits and nuclear energy. Four nuclear plants with a total of 600 MW are projected, but shale oil still will play an important role. A contract for building a pilot plant has been met recently. The plant is to be located at Timahdit and cost $13 million,more » for which a loan from the World Bank has been requested. If successful in the pilot plant, the process will be used in full scale plants scheduled to produce 400,000 tons/yr of oil. Tosco also has a contract for a feasibility study.« less

The Supercritical CO2 Huff-n-puff Experiment of Shale Oil Utilizing Isopropanol

NASA Astrophysics Data System (ADS)

Shang, Shengxiang; Dong, Mingzhe; Gong, Houjian

2018-01-01

In this study, the supercritical CO2 huff-n-puff experiment of shale oil has been investigated. Experimental data shows that the addition of isopropanol can greatly improve the recovery of shale oil. And this provides a new way to improve the recovery of shale oil. In this paper, it is also tried to analyze the influencing factor of isopropanol on the recovery of shale oil by analyzing the MMP.

The environmental consequences of the oil shale utilization in Jordan: The effect of combustion processes

NASA Astrophysics Data System (ADS)

El-Hasan, Tayel

2015-04-01

The geochemical analysis of the upper Cretaceous organic rich oil shale of El-Lajjoun revealed that it contains considerable concentrations of trace element when compared to the average world shale. The aim of this study was to deduce the effect of various combustion processes on the geochemical and mineralogical characteristics of the produced ashes.The oil shale powder samples were burned under Aerobic Combustion Process (ACP) at 700˚C, 850˚C and 1000˚C respectively, beside the anaerobic (pyrolysis) combustion process (PCP) at 600, 650, 700, 750 and 800˚C respectively.The ashes produced from the (ACP) caused almost all major oxides contents to increase with increasing burning temperature, particularly SiO2 and CaO were nearly doubled at temperature 1000 ˚C. Moreover, trace elements showed the same trend where ashes at higher temperatures (i.e. 1000 ˚C) have doubled its contents of trace elements such as Cr, Ni, Zn, Cu and U. This was reflected through enrichment of calcite and quartz beside the anhydrite as the main mineral phases in the ACP ashes. As for the PCP ash show similar trend but relatively with lower concentrations as evident from its lowerEnrichment Factor (EF) values. This might be due to the higher organic matter remained in the PCP ashes compared with ACP ashes. However, PCP is more likely associated with toxic Cd and Asgasses as evident from their lowerconcentrations in the ashes.Moreover, recent results using the synchrotron-based XANES technique confirm that toxic elements are found in higher oxidation state due to ACP. The investigation was concerned on As and Cr. Thechromium in the original shales was in the form of Cr (III) and then it was converted to Cr(VI) in the ashes due of the ACP. Similarly, As (III) the XANES results showed that it was converted into As(V) too. These findingsare alarming and should be taken seriously. Because elements with higher oxidation states became more mobile, thus they can easily leached from the ash tailing into the nearby water resources. The most important species is Cr(VI) because itis easily leachable and very harmful species. It could cause pollution to surface and ground water resources.Therefore, allot of concerns should be paid on the ongoing oil shale utilization enterprises due to its pollution potential.Further investigation regarding the speciation of vanadium and cadmium are on the way.

The flux of radionuclides in flowback fluid from shale gas exploitation.

PubMed

Almond, S; Clancy, S A; Davies, R J; Worrall, F

2014-11-01

This study considers the flux of radioactivity in flowback fluid from shale gas development in three areas: the Carboniferous, Bowland Shale, UK; the Silurian Shale, Poland; and the Carboniferous Barnett Shale, USA. The radioactive flux from these basins was estimated, given estimates of the number of wells developed or to be developed, the flowback volume per well and the concentration of K (potassium) and Ra (radium) in the flowback water. For comparative purposes, the range of concentration was itself considered within four scenarios for the concentration range of radioactive measured in each shale gas basin, the groundwater of the each shale gas basin, global groundwater and local surface water. The study found that (i) for the Barnett Shale and the Silurian Shale, Poland, the 1 % exceedance flux in flowback water was between seven and eight times that would be expected from local groundwater. However, for the Bowland Shale, UK, the 1 % exceedance flux (the flux that would only be expected to be exceeded 1 % of the time, i.e. a reasonable worst case scenario) in flowback water was 500 times that expected from local groundwater. (ii) In no scenario was the 1 % exceedance exposure greater than 1 mSv-the allowable annual exposure allowed for in the UK. (iii) The radioactive flux of per energy produced was lower for shale gas than for conventional oil and gas production, nuclear power production and electricity generated through burning coal.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Negus-De Wys, J.; Dixon, J. M.; Evans, M. A.

This document consists of the following papers: inorganic geochemistry studies of the Eastern Kentucky Gas Field; lithology studies of upper Devonian well cuttings in the Eastern Kentucky Gas Field; possible effects of plate tectonics on the Appalachian Devonian black shale production in eastern Kentucky; preliminary depositional model for upper Devonian Huron age organic black shale in the Eastern Kentucky Gas Field; the anatomy of a large Devonian black shale gas field; the Cottageville (Mount Alto) Gas Field, Jackson County, West Virginia: a case study of Devonian shale gas production; the Eastern Kentucky Gas Field: a geological study of the relationshipsmore » of Ohio Shale gas occurrences to structure, stratigraphy, lithology, and inorganic geochemical parameters; and a statistical analysis of geochemical data for the Eastern Kentucky Gas Field.« less

Life Cycle Water Consumption for Shale Gas and Conventional Natural Gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, Corrie E.; Horner, Robert M.; Harto, Christopher B.

2013-10-15

Shale gas production represents a large potential source of natural gas for the nation. The scale and rapid growth in shale gas development underscore the need to better understand its environmental implications, including water consumption. This study estimates the water consumed over the life cycle of conventional and shale gas production, accounting for the different stages of production and for flowback water reuse (in the case of shale gas). This study finds that shale gas consumes more water over its life cycle (13–37 L/GJ) than conventional natural gas consumes (9.3–9.6 L/GJ). However, when used as a transportation fuel, shale gasmore » consumes significantly less water than other transportation fuels. When used for electricity generation, the combustion of shale gas adds incrementally to the overall water consumption compared to conventional natural gas. The impact of fuel production, however, is small relative to that of power plant operations. The type of power plant where the natural gas is utilized is far more important than the source of the natural gas.« less

Life cycle water consumption for shale gas and conventional natural gas.

PubMed

Clark, Corrie E; Horner, Robert M; Harto, Christopher B

2013-10-15

Shale gas production represents a large potential source of natural gas for the nation. The scale and rapid growth in shale gas development underscore the need to better understand its environmental implications, including water consumption. This study estimates the water consumed over the life cycle of conventional and shale gas production, accounting for the different stages of production and for flowback water reuse (in the case of shale gas). This study finds that shale gas consumes more water over its life cycle (13-37 L/GJ) than conventional natural gas consumes (9.3-9.6 L/GJ). However, when used as a transportation fuel, shale gas consumes significantly less water than other transportation fuels. When used for electricity generation, the combustion of shale gas adds incrementally to the overall water consumption compared to conventional natural gas. The impact of fuel production, however, is small relative to that of power plant operations. The type of power plant where the natural gas is utilized is far more important than the source of the natural gas.

Shale oil recovery process

DOEpatents

Zerga, Daniel P.

1980-01-01

A process of producing within a subterranean oil shale deposit a retort chamber containing permeable fragmented material wherein a series of explosive charges are emplaced in the deposit in a particular configuration comprising an initiating round which functions to produce an upward flexure of the overburden and to initiate fragmentation of the oil shale within the area of the retort chamber to be formed, the initiating round being followed in a predetermined time sequence by retreating lines of emplaced charges developing further fragmentation within the retort zone and continued lateral upward flexure of the overburden. The initiating round is characterized by a plurality of 5-spot patterns and the retreating lines of charges are positioned and fired along zigzag lines generally forming retreating rows of W's. Particular time delays in the firing of successive charges are disclosed.

Methane baseline concentrations and sources in shallow aquifers from the shale gas-prone region of the St. Lawrence lowlands (Quebec, Canada).

PubMed

Moritz, Anja; Hélie, Jean-Francois; Pinti, Daniele L; Larocque, Marie; Barnetche, Diogo; Retailleau, Sophie; Lefebvre, René; Gélinas, Yves

2015-04-07

Hydraulic fracturing is becoming an important technique worldwide to recover hydrocarbons from unconventional sources such as shale gas. In Quebec (Canada), the Utica Shale has been identified as having unconventional gas production potential. However, there has been a moratorium on shale gas exploration since 2010. The work reported here was aimed at defining baseline concentrations of methane in shallow aquifers of the St. Lawrence Lowlands and its sources using δ(13)C methane signatures. Since this study was performed prior to large-scale fracturing activities, it provides background data prior to the eventual exploitation of shale gas through hydraulic fracturing. Groundwater was sampled from private (n = 81), municipal (n = 34), and observation (n = 15) wells between August 2012 and May 2013. Methane was detected in 80% of the wells with an average concentration of 3.8 ± 8.8 mg/L, and a range of <0.0006 to 45.9 mg/L. Methane concentrations were linked to groundwater chemistry and distance to the major faults in the studied area. The methane δ(1)(3)C signature of 19 samples was > -50‰, indicating a potential thermogenic source. Localized areas of high methane concentrations from predominantly biogenic sources were found throughout the study area. In several samples, mixing, migration, and oxidation processes likely affected the chemical and isotopic composition of the gases, making it difficult to pinpoint their origin. Energy companies should respect a safe distance from major natural faults in the bedrock when planning the localization of hydraulic fracturation activities to minimize the risk of contaminating the surrounding groundwater since natural faults are likely to be a preferential migration pathway for methane.

On wettability of shale rocks.

PubMed

Roshan, H; Al-Yaseri, A Z; Sarmadivaleh, M; Iglauer, S

2016-08-01

The low recovery of hydraulic fracturing fluid in unconventional shale reservoirs has been in the centre of attention from both technical and environmental perspectives in the last decade. One explanation for the loss of hydraulic fracturing fluid is fluid uptake by the shale matrix; where capillarity is the dominant process controlling this uptake. Detailed understanding of the rock wettability is thus an essential step in analysis of loss of the hydraulic fracturing fluid in shale reservoirs, especially at reservoir conditions. We therefore performed a suit of contact angle measurements on a shale sample with oil and aqueous ionic solutions, and tested the influence of different ion types (NaCl, KCl, MgCl2, CaCl2), concentrations (0.1, 0.5 and 1M), pressures (0.1, 10 and 20MPa) and temperatures (35 and 70°C). Furthermore, a physical model was developed based on the diffuse double layer theory to provide a framework for the observed experimental data. Our results show that the water contact angle for bivalent ions is larger than for monovalent ions; and that the contact angle (of both oil and different aqueous ionic solutions) increases with increase in pressure and/or temperature; these increases are more pronounced at higher ionic concentrations. Finally, the developed model correctly predicted the influence of each tested variable on contact angle. Knowing contact angle and therefore wettability, the contribution of the capillary process in terms of water uptake into shale rocks and the possible impairment of hydrocarbon production due to such uptake can be quantified. Copyright © 2016 Elsevier Inc. All rights reserved.

A Numerical Study of Factors Affecting Fracture-Fluid Cleanup and Produced Gas/Water in Marcellus Shale: Part II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seales, Maxian B.; Dilmore, Robert; Ertekin, Turgay

Horizontal wells combined with successful multistage-hydraulic-fracture treatments are currently the most-established method for effectively stimulating and enabling economic development of gas-bearing organic-rich shale formations. Fracture cleanup in the stimulated reservoir volume (SRV) is critical to stimulation effectiveness and long-term well performance. But, fluid cleanup is often hampered by formation damage, and post-fracture well performance frequently falls to less than expectations. A systematic study of the factors that hinder fracture-fluid cleanup in shale formations can help optimize fracture treatments and better quantify long-term volumes of produced water and gas. Fracture-fluid cleanup is a complex process influenced by mutliphase flow through porousmore » media (relative permeability hysteresis, capillary pressure), reservoir-rock and -fluid properties, fracture-fluid properties, proppant placement, fracture-treatment parameters, and subsequent flowback and field operations. Changing SRV and fracture conductivity as production progresses further adds to the complexity of this problem. Numerical simulation is the best and most-practical approach to investigate such a complicated blend of mechanisms, parameters, their interactions, and subsequent effect on fracture-fluid cleanup and well deliverability. Here, a 3D, two-phase, dual-porosity model was used to investigate the effect of mutliphase flow, proppant crushing, proppant diagenesis, shut-in time, reservoir-rock compaction, gas slippage, and gas desorption on fracture-fluid cleanup and well performance in Marcellus Shale. Our findings have shed light on the factors that substantially constrain efficient fracture-fluid cleanup in gas shales, and we have provided guidelines for improved fracture-treatment designs and water management.« less

A Numerical Study of Factors Affecting Fracture-Fluid Cleanup and Produced Gas/Water in Marcellus Shale: Part II

DOE PAGES

Seales, Maxian B.; Dilmore, Robert; Ertekin, Turgay; ...

2017-04-01

Horizontal wells combined with successful multistage-hydraulic-fracture treatments are currently the most-established method for effectively stimulating and enabling economic development of gas-bearing organic-rich shale formations. Fracture cleanup in the stimulated reservoir volume (SRV) is critical to stimulation effectiveness and long-term well performance. But, fluid cleanup is often hampered by formation damage, and post-fracture well performance frequently falls to less than expectations. A systematic study of the factors that hinder fracture-fluid cleanup in shale formations can help optimize fracture treatments and better quantify long-term volumes of produced water and gas. Fracture-fluid cleanup is a complex process influenced by mutliphase flow through porousmore » media (relative permeability hysteresis, capillary pressure), reservoir-rock and -fluid properties, fracture-fluid properties, proppant placement, fracture-treatment parameters, and subsequent flowback and field operations. Changing SRV and fracture conductivity as production progresses further adds to the complexity of this problem. Numerical simulation is the best and most-practical approach to investigate such a complicated blend of mechanisms, parameters, their interactions, and subsequent effect on fracture-fluid cleanup and well deliverability. Here, a 3D, two-phase, dual-porosity model was used to investigate the effect of mutliphase flow, proppant crushing, proppant diagenesis, shut-in time, reservoir-rock compaction, gas slippage, and gas desorption on fracture-fluid cleanup and well performance in Marcellus Shale. Our findings have shed light on the factors that substantially constrain efficient fracture-fluid cleanup in gas shales, and we have provided guidelines for improved fracture-treatment designs and water management.« less

Comparison of formation mechanism of fresh-water and salt-water lacustrine organic-rich shale

NASA Astrophysics Data System (ADS)

Lin, Senhu

2017-04-01

Based on the core and thin section observation, major, trace and rare earth elements test, carbon and oxygen isotopes content analysis and other geochemical methods, a detailed study was performed on formation mechanism of lacustrine organic-rich shale by taking the middle Permian salt-water shale in Zhungaer Basin and upper Triassic fresh-water shale in Ordos Basin as the research target. The results show that, the middle Permian salt-water shale was overall deposited in hot and dry climate. Long-term reductive environment and high biological abundance due to elevated temperature provides favorable conditions for formation and preservation of organic-rich shale. Within certain limits, the hotter climate, the organic-richer shale formed. These organic-rich shale was typically distributed in the area where palaeosalinity is relatively high. However, during the upper Triassic at Ordos Basin, organic-rich shale was formed in warm and moist environment. What's more, if the temperature, salinity or water depth rises, the TOC in shale decreases. In other words, relatively low temperature and salinity, stable lake level and strong reducing conditions benefits organic-rich shale deposits in fresh water. In this sense, looking for high-TOC shale in lacustrine basin needs to follow different rules depends on the palaeoclimate and palaeoenvironment during sedimentary period. There is reason to believe that the some other factors can also have significant impact on formation mechanism of organic-rich shale, which increases the complexity of shale oil and gas prediction.

Reservoir characteristics of coal-shale sedimentary sequence in coal-bearing strata and their implications for the accumulation of unconventional gas

NASA Astrophysics Data System (ADS)

Wang, Yang; Zhu, Yanming; Liu, Yu; Chen, Shangbin

2018-04-01

Shale gas and coalbed methane (CBM) are both considered unconventional natural gas and are becoming increasingly important energy resources. In coal-bearing strata, coal and shale are vertically adjacent as coal and shale are continuously deposited. Research on the reservoir characteristics of coal-shale sedimentary sequences is important for CBM and coal-bearing shale gas exploration. In this study, a total of 71 samples were collected, including coal samples (total organic carbon (TOC) content >40%), carbonaceous shale samples (TOC content: 6%-10%), and shale samples (TOC content <6%). Combining techniques of field emission scanning electron microscopy (FE-SEM), x-ray diffraction, high-pressure mercury intrusion porosimetry, and methane adsorption, experiments were employed to characterize unconventional gas reservoirs in coal-bearing strata. The results indicate that in the coal-shale sedimentary sequence, the proportion of shale is the highest at 74% and that of carbonaceous shale and coal are 14% and 12%, respectively. The porosity of all measured samples demonstrates a good positive relationship with TOC content. Clay and quartz also have a great effect on the porosity of shale samples. According to the FE-SEM image technique, nanoscale pores in the organic matter of coal samples are much more developed compared with shale samples. For shales with low TOC, inorganic minerals provide more pores than organic matter. In addition, TOC content has a positive relationship with methane adsorption capacity, and the adsorption capacity of coal samples is more sensitive than the shale samples to temperature.

Organoporosity Evaluation of Shale: A Case Study of the Lower Silurian Longmaxi Shale in Southeast Chongqing, China

PubMed Central

Chen, Fangwen; Lu, Shuangfang; Ding, Xue

2014-01-01

The organopores play an important role in determining total volume of hydrocarbons in shale gas reservoir. The Lower Silurian Longmaxi Shale in southeast Chongqing was selected as a case to confirm the contribution of organopores (microscale and nanoscale pores within organic matters in shale) formed by hydrocarbon generation to total volume of hydrocarbons in shale gas reservoir. Using the material balance principle combined with chemical kinetics methods, an evaluation model of organoporosity for shale gas reservoirs was established. The results indicate that there are four important model parameters to consider when evaluating organoporosity in shale: the original organic carbon (w(TOC0)), the original hydrogen index (I H0), the transformation ratio of generated hydrocarbon (F(R o)), and the organopore correction coefficient (C). The organoporosity of the Lower Silurian Longmaxi Shale in the Py1 well is from 0.20 to 2.76%, and the average value is 1.25%. The organoporosity variation trends and the residual organic carbon of Longmaxi Shale are consistent in section. The residual organic carbon is indicative of the relative levels of organoporosity, while the samples are in the same shale reservoirs with similar buried depths. PMID:25184155

43 CFR 3000.12 - What is the fee schedule for fixed fees?

Code of Federal Regulations, 2012 CFR

2012-10-01

... Processing and Filing Fee Table Document/action FY 2013 fee Oil & Gas (parts 3100, 3110, 3120, 3130, 3150... 320 Lease or lease interest transfer 65 Leasing of Solid Minerals Other Than Coal and Oil Shale (parts...) Adverse claim 105 Protest 65 Oil Shale Management (parts 3900, 3910, 3930) Exploration license application...

Cocarcinogenicity of phenols from Estonian shale tars (oils).

PubMed Central

Bogovski, P A; Mirme, H I

1979-01-01

Many phenols have carcinogenic activity. The Estonian shale oils contain up to 40 vol % phenols. The promoting activity after initiation of phenols of Estonian shale oils was tested in mice with a single subthreshold dose (0.36 mg) of benzo(a)pyrene. C57Bl and CC57Br mice were used in skin painting experiments. Weak carcinogenic activity was found in the total crude water-soluble phenols recovered from the wastewater of a shale processing plant. In two-stage experiments a clear promoting action of the total crude phenols was established, whereas the fractions A and B (training reagents), obtained by selective crystallization of the total phenols exerted a considerably weaker promoting action. Epo-glue, a commercial epoxy product produced from unfractionated crude phenols, had no promoting activity, which may be due to the processing of the phenols involving polymerization. The mechanism of action of phenols is not clear. According to some data from the literature, phenol and 5-methylresorcinol reduce the resorption speed of BP in mouse skin, causing prolongation of the action fo the carcinogen. PMID:446449

Cocarcinogenicity of phenols from Estonian shale tars (oils).

PubMed

Bogovski, P A; Mirme, H I

1979-06-01

Many phenols have carcinogenic activity. The Estonian shale oils contain up to 40 vol % phenols. The promoting activity after initiation of phenols of Estonian shale oils was tested in mice with a single subthreshold dose (0.36 mg) of benzo(a)pyrene. C57Bl and CC57Br mice were used in skin painting experiments. Weak carcinogenic activity was found in the total crude water-soluble phenols recovered from the wastewater of a shale processing plant. In two-stage experiments a clear promoting action of the total crude phenols was established, whereas the fractions A and B (training reagents), obtained by selective crystallization of the total phenols exerted a considerably weaker promoting action. Epo-glue, a commercial epoxy product produced from unfractionated crude phenols, had no promoting activity, which may be due to the processing of the phenols involving polymerization. The mechanism of action of phenols is not clear. According to some data from the literature, phenol and 5-methylresorcinol reduce the resorption speed of BP in mouse skin, causing prolongation of the action fo the carcinogen.

Transport and geotechnical properties of porous media with applications to retorted oil shale. Volume 4. Appendix D. Temperature and toe erosion effects on spent oil shale embankment stability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, N.Y.; Wu, T.H.

1986-01-01

To evaluate the engineering property of spent shale at elevated temperatures, high temperature triaxial cells were designed and manufactured. The cells were then used in the test program designed to provide the physical and engineering properties of spent shale (TOSCO-II) at elevated temperatures. A series of consolidated drained triaxial tests were conducted at high temperatures. Duncan-Chang hyperbolic model was adopted to simulate the laboratory stress versus strain behavior of spent shale at various temperatures. This model provides very good fit to the laboratory stress-strain-volumetric strain characteristics of spent shale at various temperatures. The parameters of this model were then formulatedmore » as functions of temperatures and the Duncan-Chang model was implemented in a finite element analysis computer code for predicting the stress-deformation behavior of large spent shale embankments. Modified Bishop method was also used in analyzing the stability of spent shale embankments. The stability of three different spent shale embankments at three different temperatures were investigated in the study. Additionally the stability of embankments with different degrees of toe erosion was also studied. Results of this study indicated that (1) the stress-strain-strength properties of soils are affected by temperature variation; (2) the stress-strain-strength behavior of spent shale can be simulated by Duncan-Chang hyperbolic model, (3) the factor of safety of embankment slope decreases with rising temperatures; (4) the embankment deformation increases with rising temperatures; and (5) the toe erosion induced by floods causes the embankment slope to become less stable. It is strongly recommended, to extend this study to investigate the effect of internal seepage on the stability of large spent shale embankment. 68 refs., 53 figs., 16 tabs.« less

Dynamic compressive properties obtained from a split Hopkinson pressure bar test of Boryeong shale

NASA Astrophysics Data System (ADS)

Kang, Minju; Cho, Jung-Woo; Kim, Yang Gon; Park, Jaeyeong; Jeong, Myeong-Sik; Lee, Sunghak

2016-09-01

Dynamic compressive properties of a Boryeong shale were evaluated by using a split Hopkinson pressure bar, and were compared with those of a Hwangdeung granite which is a typical hard rock. The results indicated that the dynamic compressive loading reduced the resistance to fracture. The dynamic compressive strength was lower in the shale than in the granite, and was raised with increasing strain rate by microcracking effect as well as strain rate strengthening effect. Since the number of microcracked fragments increased with increasing strain rate in the shale having laminated weakness planes, the shale showed the better fragmentation performance than the granite at high strain rates. The effect of transversely isotropic plane on compressive strength decreased with increasing strain rate, which was desirable for increasing the fragmentation performance. Thus, the shale can be more reliably applied to industrial areas requiring good fragmentation performance as the striking speed of drilling or hydraulic fracturing machines increased. The present dynamic compressive test effectively evaluated the fragmentation performance as well as compressive strength and strain energy density by controlling the air pressure, and provided an important idea on which rock was more readily fragmented under dynamically processing conditions such as high-speed drilling and blasting.

Fracture-permeability behavior of shale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carey, J. William; Lei, Zhou; Rougier, Esteban

The fracture-permeability behavior of Utica shale, an important play for shale gas and oil, was investigated using a triaxial coreflood device and X-ray tomography in combination with finite-discrete element modeling (FDEM). Fractures generated in both compression and in a direct-shear configuration allowed permeability to be measured across the faces of cylindrical core. Shale with bedding planes perpendicular to direct-shear loading developed complex fracture networks and peak permeability of 30 mD that fell to 5 mD under hydrostatic conditions. Shale with bedding planes parallel to shear loading developed simple fractures with peak permeability as high as 900 mD. In addition tomore » the large anisotropy in fracture permeability, the amount of deformation required to initiate fractures was greater for perpendicular layering (about 1% versus 0.4%), and in both cases activation of existing fractures are more likely sources of permeability in shale gas plays or damaged caprock in CO₂ sequestration because of the significant deformation required to form new fracture networks. FDEM numerical simulations were able to replicate the main features of the fracturing processes while showing the importance of fluid penetration into fractures as well as layering in determining fracture patterns.« less

Fracture-permeability behavior of shale

DOE PAGES

Carey, J. William; Lei, Zhou; Rougier, Esteban; ...

2015-05-08

The fracture-permeability behavior of Utica shale, an important play for shale gas and oil, was investigated using a triaxial coreflood device and X-ray tomography in combination with finite-discrete element modeling (FDEM). Fractures generated in both compression and in a direct-shear configuration allowed permeability to be measured across the faces of cylindrical core. Shale with bedding planes perpendicular to direct-shear loading developed complex fracture networks and peak permeability of 30 mD that fell to 5 mD under hydrostatic conditions. Shale with bedding planes parallel to shear loading developed simple fractures with peak permeability as high as 900 mD. In addition tomore » the large anisotropy in fracture permeability, the amount of deformation required to initiate fractures was greater for perpendicular layering (about 1% versus 0.4%), and in both cases activation of existing fractures are more likely sources of permeability in shale gas plays or damaged caprock in CO₂ sequestration because of the significant deformation required to form new fracture networks. FDEM numerical simulations were able to replicate the main features of the fracturing processes while showing the importance of fluid penetration into fractures as well as layering in determining fracture patterns.« less

Temporal changes in microbial ecology and geochemistry in produced water from hydraulically fractured Marcellus shale gas wells.

PubMed

Cluff, Maryam A; Hartsock, Angela; MacRae, Jean D; Carter, Kimberly; Mouser, Paula J

2014-06-03

Microorganisms play several important roles in unconventional gas recovery, from biodegradation of hydrocarbons to souring of wells and corrosion of equipment. During and after the hydraulic fracturing process, microorganisms are subjected to harsh physicochemical conditions within the kilometer-deep hydrocarbon-bearing shale, including high pressures, elevated temperatures, exposure to chemical additives and biocides, and brine-level salinities. A portion of the injected fluid returns to the surface and may be reused in other fracturing operations, a process that can enrich for certain taxa. This study tracked microbial community dynamics using pyrotag sequencing of 16S rRNA genes in water samples from three hydraulically fractured Marcellus shale wells in Pennsylvania, USA over a 328-day period. There was a reduction in microbial richness and diversity after fracturing, with the lowest diversity at 49 days. Thirty-one taxa dominated injected, flowback, and produced water communities, which took on distinct signatures as injected carbon and electron acceptors were attenuated within the shale. The majority (>90%) of the community in flowback and produced fluids was related to halotolerant bacteria associated with fermentation, hydrocarbon oxidation, and sulfur-cycling metabolisms, including heterotrophic genera Halolactibacillus, Vibrio, Marinobacter, Halanaerobium, and Halomonas, and autotrophs belonging to Arcobacter. Sequences related to halotolerant methanogenic genera Methanohalophilus and Methanolobus were detected at low abundance (<2%) in produced waters several months after hydraulic fracturing. Five taxa were strong indicators of later produced fluids. These results provide insight into the temporal trajectory of subsurface microbial communities after "fracking" and have important implications for the enrichment of microbes potentially detrimental to well infrastructure and natural gas fouling during this process.

Viscous Creep in Dry Unconsolidated Gulf of Mexico Shale

NASA Astrophysics Data System (ADS)

Chang, C.; Zoback, M. D.

2002-12-01

We conducted laboratory experiments to investigate creep characteristics of dry unconsolidated shale recovered from the pathfinder well, Gulf of Mexico (GOM). We subjected jacketed cylindrical specimens (25.4 mm diameter) to hydrostatic pressure that increased from 10 to 50 MPa in steps of 5 MPa. We kept the pressure constant in each step for at least 6 hours and measured axial and lateral strains (provided by LVDTs) and ultrasonic velocities (provided by seismic-wave transducers). The dry shale exhibited pronounced creep strain at all pressure levels, indicating that the dry frame of the shale possesses an intrinsic viscous property. Interestingly, the creep behavior of the shale is different above and below 30 MPa confining pressure. Above 30 MPa, the amount of creep strain in 6 hours is nearly constant with equal pressurization steps, indicating a linear viscous rheology. Below 30 MPa, the amount of creep increases linearly as pressure is raised in constant incremental steps, suggesting that the creep deformation accelerates as pressure increases within this pressure range. Thus, the general creep behavior of the GOM shale is characterized by a bilinear dependence on pressure magnitude. This creep characteristic is quite different from that observed in unconsolidated reservoir sands (Hagin and Zoback, 2002), which exhibited nearly constant amount of creep regardless of the pressure magnitude for equal increasing steps of pressure. The shale exhibits a lack of creep (and nearly negligible strain recovery) when unloaded, suggesting that the creep strain is irrecoverable and can be considered viscoplastic deformation. SEM observations show that the major mechanism of compaction of the dry shale appears to be packing of clay and a progressive collapse of pore (void) spaces. Creep compaction is considerably more significant than compaction that occurs instantaneously, indicating that the process of shale compaction is largely time-dependent.

Adequacy of Current State Setbacks for Directional High-Volume Hydraulic Fracturing in the Marcellus, Barnett, and Niobrara Shale Plays.

PubMed

Haley, Marsha; McCawley, Michael; Epstein, Anne C; Arrington, Bob; Bjerke, Elizabeth Ferrell

2016-09-01

There is an increasing awareness of the multiple potential pathways leading to human health risks from hydraulic fracturing. Setback distances are a legislative method to mitigate potential risks. We attempted to determine whether legal setback distances between well-pad sites and the public are adequate in three shale plays. We reviewed geography, current statutes and regulations, evacuations, thermal modeling, air pollution studies, and vapor cloud modeling within the Marcellus, Barnett, and Niobrara Shale Plays. The evidence suggests that presently utilized setbacks may leave the public vulnerable to explosions, radiant heat, toxic gas clouds, and air pollution from hydraulic fracturing activities. Our results suggest that setbacks may not be sufficient to reduce potential threats to human health in areas where hydraulic fracturing occurs. It is more likely that a combination of reasonable setbacks with controls for other sources of pollution associated with the process will be required. Haley M, McCawley M, Epstein AC, Arrington B, Bjerke EF. 2016. Adequacy of current state setbacks for directional high-volume hydraulic fracturing in the Marcellus, Barnett, and Niobrara Shale Plays. Environ Health Perspect 124:1323-1333; http://dx.doi.org/10.1289/ehp.1510547.

Dissolution of cemented fractures in gas bearing shales in the context of CO2 sequestration

NASA Astrophysics Data System (ADS)

Kwiatkowski, Kamil; Szymczak, Piotr

2016-04-01

Carbon dioxide has a stronger binding than methane to the organic matter contained in the matrix of shale rocks [1]. Thus, the injection of CO2 into shale formation may enhance the production rate and total amount of produced methane, and simultaneously permanently store pumped CO2. Carbon dioxide can be injected during the initial fracking stage as CO2 based hydraulic fracturing, and/or later, as a part of enhanced gas recovery (EGR) [2]. Economic and environmental benefits makes CO2 sequestration in shales potentially very for industrial-scale operation [3]. However, the effective process requires large area of fracture-matrix interface, where CO2 and CH4 can be exchanged. Usually natural fractures, existing in shale formation, are preferentially reactivated during hydraulic fracturing, thus they considerably contribute to the flow paths in the resulting fracture system [4]. Unfortunately, very often these natural fractures are sealed by calcite [5]. Consequently the layer of calcite coating surfaces impedes exchange of gases, both CO2 and CH4, between shale matrix and fracture. In this communication we address the question whether carbonic acid, formed when CO2 is mixed with brine, is able to effectively dissolve a calcite layer present in the natural fractures. We investigate numerically fluid flow and dissolution of calcite coating in natural shale fractures, with CO2-brine mixture as a reactive fluid. Moreover, we discuss the differences between slow dissolution (driven by carbonic acid) and fast dissolution (driven by stronger hydrochloric acid) of calcite layer. We compare an impact of the flow rate and geometry of the fracture on the parameters of practical importance: available surface area, morphology of dissolution front, time scale of the dissolution, and the penetration length. We investigate whether the dissolution is sufficiently non-uniform to retain the fracture permeability, even in the absence of the proppant. The sizes of analysed fractures varying from 0.2 x 0.2 m2 up to 4 x 4 m2, together with discussion of a further upscaling, make the study relevant to the industrial applications. While the results of this study should be applicable to different shale formations throughout the world, we discuss them in the context of preparation to gas-production from Pomeranian shale basin, located in the northern Poland. [1] Mosher, K., He, J., Liu, Y., Rupp, E., & Wilcox, J. Molecular simulation of methane adsorption in micro-and mesoporous carbons with applications to coal and gas shale systems. International Journal of Coal Geology, 109, 36-44 (2013) [2] Grieser, W. V., Wheaton, W. E., Magness, W. D., Blauch, M. E., & Loghry, R, "Surface Reactive Fluid's Effect on Shale." Proceedings of the Production and Operations Symposium, 31 March-3 April 2007, Oklahoma City (SPE-106815-MS) [3] Tao, Z. and Clarens, A., Estimating the carbon sequestration capacity of shale formations using methane production rates, Environmental Science and Technology, 47, 11318-11325 (2013). [4] Zhang, X., Jeffrey, R. G., & Thiercelin, M. (2009). Mechanics of fluid-driven fracture growth in naturally fractured reservoirs with simple network geometries. Journal of Geophysical Research: Solid Earth, 114, B12406 (2009) [5] Gale, J.F., Laubach, S.E., Olson, J.E., Eichhubl, P., Fall, A. Natural fractures in shale: A review and new observations. AAPG Bulletin 98(11):2165-2216 (2014)

Borehole petrophysical chemostratigraphy of Pennsylvanian black shales in the Kansas subsurface

USGS Publications Warehouse

Doveton, J.H.; Merriam, D.F.

2004-01-01

Pennsylvanian black shales in Kansas have been studied on outcrop for decades as the core unit of the classic Midcontinent cyclothem. These shales appear to be highstand condensed sections in the sequence stratigraphic paradigm. Nuclear log suites provide several petrophysical measurements of rock chemistry that are a useful data source for chemostratigraphic studies of Pennsylvanian black shales in the subsurface. Spectral gamma-ray logs partition natural radioactivity between contributions by U, Th, and K sources. Elevated U contents in black shales can be related to reducing depositional environments, whereas the K and Th contents are indicators of clay-mineral abundance and composition. The photoelectric factor log measurement is a direct function of aggregate atomic number and so is affected by clay-mineral volume, clay-mineral iron content, and other black shale compositional elements. Neutron porosity curves are primarily a response to hydrogen content. Although good quality logs are available for many black shales, borehole washout features invalidate readings from the nuclear contact devices, whereas black shales thinner than tool resolution will be averaged with adjacent beds. Statistical analysis of nuclear log data between black shales in successive cyclothems allows systematic patterns of their chemical and petrophysical properties to be discriminated in both space and time. ?? 2004 Elsevier B.V. All rights reserved.

Comparative study of microfacies variation in two samples from the Chittenango member, Marcellus shale subgroup, western New York state, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balulla, Shama, E-mail: shamamohammed77@outlook.com; Padmanabhan, E., E-mail: eswaran-padmanabhan@petronas.com.my; Over, Jeffrey, E-mail: over@geneseo.edu

This study demonstrates the significant lithologic variations that occur within the two shale samples from the Chittenango member of the Marcellus shale formation from western New York State in terms of mineralogical composition, type of lamination, pyrite occurrences and fossil content using thin section detailed description and field emission Scanning electron microscope (FESEM) with energy dispersive X-Ray Spectrum (EDX). This study is classified samples as laminated clayshale and fossiliferous carbonaceous shale. The most important detrital constituents of these shales are the clay mineral illite and chlorite, quartz, organic matter, carbonate mineral, and pyrite. The laminated clayshale has a lower amountmore » of quartz and carbonate minerals than fossiliferous carbonaceous shale while it has a higher amount of clay minerals (chlorite and illite) and organic matter. FESEM analysis confirms the presence of chlorite and illite. The fossil content in the laminated clayshale is much lower than the fossiliferous carbonaceous shale. This can provide greater insights about variations in the depositional and environmental factors that influenced its deposition. This result can be compiled with the sufficient data to be helpful for designing the horizontal wells and placement of hydraulic fracturing in shale gas exploration and production.« less

Subsurface stratigraphy of upper Devonian clastics in southern West Virginia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neal, D.W.; Patchen, D.G.

Studies of upper Devonian shales and siltstones in southern West Virginia have resulted in a refinement of the stratigraphic framework used in characterizing the gas-producing Devonian shales. Gamma-ray log correlation around the periphery of the Appalachian Basin has extended the usage of New York stratigraphic nomenclature for the interval between the base of the Dunkirk shale and the top of the Tully limestone to southern West Virginia. Equivalents of the Dunkirk shale and younger rocks of New York are recognized in southwestern West Virginia and are named according to Ohio usage. Gas production is primarily from the basal black shalemore » member of the Ohio shale. Gas shows from older black shale units (Rhinestreet and Marcellus shales) are recorded from wells east of the major producing trend. Provided suitable stimulation techniques can be developed, these older and deeper black shales may prove to be another potential gas resource.« less

The provenance of low-calcic black shales

NASA Astrophysics Data System (ADS)

Quinby-Hunt, M. S.; Wilde, P.

1991-04-01

The elemental concentration of sedimentary rocks depends on the varying reactivity of each element as it goes from the source through weathering, deposition, diagenesis, lithification, and even low rank metamorphism. However, non-reactive components of detrital particles ideally are characteristic of the original igneous source and thus are useful in provenance studies. To determine the source of detrital granitic and volcanic components of low-calcic (<1% CaCO3) marine black shales, the concentrations of apparently non-reactive (i.e. unaffected by diagenetic, redox and/or low-rank metamorphic processes) trace elements were examined using standard trace element discrimination diagrams developed for igneous rocks. The chemical data was obtained by neutron activation analyses of about 200 stratigraphically well-documented black shale samples from the Cambrian through the Jurassic. A La-Th-Sc ternary diagram distinguishes among contributions from the upper and bulk continental crust and the oceanic crust (Taylor and McLennan 1985). All the low-calcic black shales cluster within the region of the upper crust. Th-Hf-Co ternary diagrams also are commonly used to distinguish among the upper and bulk continental crust and the oceanic crust (Taylor and McLennan 1985). As Co is redox sensitive in black shale environments, it was necessary to substitute an immobile element (i.e. example Rb) in the diagram. With this substitution of black shales all cluster in the region of the upper continental crust. To determine the provenance of the granitic component (Pearce et al. 1984), plots of Ta vs Yb and Rb vs Yb + Ta shows a cluster at the junction of the boundaries separating the volcanic arc granite (VAG), syn-collision granite (syn-COLG), and within-plate granite (WPG) fields. The majority fall within the VAG field. There are no occurrences of ocean ridge granite (ORG). The minimal contribution of basalts to marine black shales is confirmed by the ternary Wood diagram Th-Hf/3-Ta (Wood et al. 1979). The black shales plot in a cluster in a high Th region outside the various basalt fields, which suggests contribution from the continental crust.

A Reactive Transport Model for Marcellus Shale Weathering

NASA Astrophysics Data System (ADS)

Li, L.; Heidari, P.; Jin, L.; Williams, J.; Brantley, S.

2017-12-01

Shale formations account for 25% of the land surface globally. One of the most productive shale-gas formations is the Marcellus, a black shale that is rich in organic matter and pyrite. As a first step toward understanding how Marcellus shale interacts with water, we developed a reactive transport model to simulate shale weathering under ambient temperature and pressure conditions, constrained by soil chemistry and water data. The simulation was carried out for 10,000 years, assuming bedrock weathering and soil genesis began right after the last glacial maximum. Results indicate weathering was initiated by pyrite dissolution for the first 1,000 years, leading to low pH and enhanced dissolution of chlorite and precipitation of iron hydroxides. After pyrite depletion, chlorite dissolved slowly, primarily facilitated by the presence of CO2 and organic acids, forming vermiculite as a secondary mineral. A sensitivity analysis indicated that the most important controls on weathering include the presence of reactive gases (CO2 and O2), specific surface area, and flow velocity of infiltrating meteoric water. The soil chemistry and mineralogy data could not be reproduced without including the reactive gases. For example, pyrite remained in the soil even after 10,000 years if O2 was not continuously present in the soil column; likewise, chlorite remained abundant and porosity remained small with the presence of soil CO2. The field observations were only simulated successfully when the specific surface areas of the reactive minerals were 1-3 orders of magnitude smaller than surface area values measured for powdered minerals, reflecting the lack of accessibility of fluids to mineral surfaces and potential surface coating. An increase in the water infiltration rate enhanced weathering by removing dissolution products and maintaining far-from-equilibrium conditions. We conclude that availability of reactive surface area and transport of H2O and gases are the most important factors affecting chemical weathering of the Marcellus shale in the shallow subsurface. This study documents the utility of reactive transport modeling for complex subsurface processes. Such modelling could be extended to understand interactions between injected fluids and Marcellus shale gas reservoirs at higher temperature and pressure.

Field and Lab-Based Microbiological Investigations of the Marcellus Shale

NASA Astrophysics Data System (ADS)

Wishart, J. R.; Neumann, K.; Edenborn, H. M.; Hakala, A.; Yang, J.; Torres, M. E.; Colwell, F. S.

2013-12-01

The recent exploration of shales for natural gas resources has provided the opportunity to study their subsurface geochemistry and microbiology. Evidence indicates that shale environments are marked by extreme conditions such as high temperature and pressure, low porosity, permeability and connectivity, and the presence of heavy metals and radionuclides. It has been postulated that many of these shales are naturally sterile due to the high pressure and temperature conditions under which they were formed. However, it has been shown in the Antrim and New Albany shales that microbial communities do exist in these environments. Here we review geochemical and microbiological evidence for the possible habitation of the Marcellus shale by microorganisms and compare these conditions to other shales in the U.S. Furthermore, we describe the development of sampling and analysis techniques used to evaluate microbial communities present in the Marcellus shale and associated hydraulic fracturing fluid. Sampling techniques thus far have consisted of collecting flowback fluids from wells and water impoundments and collecting core material from previous drilling expeditions. Furthermore, DNA extraction was performed on Marcellus shale sub-core with a MoBio PowerSoil kit to determine its efficiency. Assessment of the Marcellus shale indicates that it has low porosity and permeability that are not conducive to dense microbial populations; however, moderate temperatures and a natural fracture network may support a microbial community especially in zones where the Marcellus intersects more porous geologic formations. Also, hydraulic fracturing extends this fracture network providing more environments where microbial communities can exist. Previous research which collected flowback fluids has revealed a diverse microbial community that may be derived from hydrofrac fluid production or from the subsurface. DNA extraction from 10 g samples of Marcellus shale sub-core were unsuccessful even when samples were spiked with 8x108 cells/g of shale. This indicated that constituents of shale such as high levels of carbonates, humic acids and metals likely inhibited components of the PowerSoil kit. Future research is focused on refining sample collection and analyses to gain a full understanding of the microbiology of the Marcellus shale and associated flowback fluids. This includes the development of an in situ osmosampler, which will collect temporally relevant fluid and colonized substrate samples. The design of the osmosampler for hydraulic fracturing wells is being adapted from those used to sample marine environments. Furthermore, incubation experiments are underway to study interactions between microbial communities associated with hydraulic fracturing fluid and Marcellus shale samples. In conclusion, evidence suggests that the Marcellus shale is a possible component of the subsurface biosphere. Future studies will be valuable in determining the microbial community structure and function in relation to the geochemistry of the Marcellus shale and its future development as a natural gas resource.

Aircraft-Based Measurements of Point Source Methane Emissions in the Barnett Shale Basin.

PubMed

Lavoie, Tegan N; Shepson, Paul B; Cambaliza, Maria O L; Stirm, Brian H; Karion, Anna; Sweeney, Colm; Yacovitch, Tara I; Herndon, Scott C; Lan, Xin; Lyon, David

2015-07-07

We report measurements of methane (CH4) emission rates observed at eight different high-emitting point sources in the Barnett Shale, Texas, using aircraft-based methods performed as part of the Barnett Coordinated Campaign. We quantified CH4 emission rates from four gas processing plants, one compressor station, and three landfills during five flights conducted in October 2013. Results are compared to other aircraft- and surface-based measurements of the same facilities, and to estimates based on a national study of gathering and processing facilities emissions and 2013 annual average emissions reported to the U.S. EPA Greenhouse Gas Reporting Program (GHGRP). For the eight sources, CH4 emission measurements from the aircraft-based mass balance approach were a factor of 3.2-5.8 greater than the GHGRP-based estimates. Summed emissions totaled 7022 ± 2000 kg hr(-1), roughly 9% of the entire basin-wide CH4 emissions estimated from regional mass balance flights during the campaign. Emission measurements from five natural gas management facilities were 1.2-4.6 times larger than emissions based on the national study. Results from this study were used to represent "super-emitters" in a newly formulated Barnett Shale Inventory, demonstrating the importance of targeted sampling of "super-emitters" that may be missed by random sampling of a subset of the total.

Mason’s equation application for prediction of voltage of oil shale treeing breakdown

NASA Astrophysics Data System (ADS)

Martemyanov, S. M.

2017-05-01

The application of the formula, which is used to calculate the maximum field at the tip of the pin-plane electrode system was proposed to describe the process of electrical treeing and treeing breakdown in an oil shale. An analytical expression for the calculation of the treeing breakdown voltage in the oil shale, as a function of the inter-electrode distance, was taken. A high accuracy of the correspondence of the model to the experimental data in the range of inter-electrode distances from 0.03 to 0.5 m was taken.

GIS-based Geospatial Infrastructure of Water Resource Assessment for Supporting Oil Shale Development in Piceance Basin of Northwestern Colorado

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Wei; Minnick, Matthew D; Mattson, Earl D

Oil shale deposits of the Green River Formation (GRF) in Northwestern Colorado, Southwestern Wyoming, and Northeastern Utah may become one of the first oil shale deposits to be developed in the U.S. because of their richness, accessibility, and extensive prior characterization. Oil shale is an organic-rich fine-grained sedimentary rock that contains significant amounts of kerogen from which liquid hydrocarbons can be produced. Water is needed to retort or extract oil shale at an approximate rate of three volumes of water for every volume of oil produced. Concerns have been raised over the demand and availability of water to produce oilmore » shale, particularly in semiarid regions where water consumption must be limited and optimized to meet demands from other sectors. The economic benefit of oil shale development in this region may have tradeoffs within the local and regional environment. Due to these potential environmental impacts of oil shale development, water usage issues need to be further studied. A basin-wide baseline for oil shale and water resource data is the foundation of the study. This paper focuses on the design and construction of a centralized geospatial infrastructure for managing a large amount of oil shale and water resource related baseline data, and for setting up the frameworks for analytical and numerical models including but not limited to three-dimensional (3D) geologic, energy resource development systems, and surface water models. Such a centralized geospatial infrastructure made it possible to directly generate model inputs from the same database and to indirectly couple the different models through inputs/outputs. Thus ensures consistency of analyses conducted by researchers from different institutions, and help decision makers to balance water budget based on the spatial distribution of the oil shale and water resources, and the spatial variations of geologic, topographic, and hydrogeological Characterization of the basin. This endeavor encountered many technical challenging and hasn't been done in the past for any oil shale basin. The database built during this study remains valuable for any other future studies involving oil shale and water resource management in the Piceance Basin. The methodology applied in the development of the GIS based Geospatial Infrastructure can be readily adapted for other professionals to develop database structure for other similar basins.« less

Crack deflection in brittle media with heterogeneous interfaces and its application in shale fracking

NASA Astrophysics Data System (ADS)

Zeng, Xiaguang; Wei, Yujie

Driven by the rapid progress in exploiting unconventional energy resources such as shale gas, there is growing interest in hydraulic fracture of brittle yet heterogeneous shales. In particular, how hydraulic cracks interact with natural weak zones in sedimentary rocks to form permeable cracking networks is of significance in engineering practice. Such a process is typically influenced by crack deflection, material anisotropy, crack-surface friction, crustal stresses, and so on. In this work, we extend the He-Hutchinson theory (He and Hutchinson, 1989) to give the closed-form formulae of the strain energy release rate of a hydraulic crack with arbitrary angles with respect to the crustal stress. The critical conditions in which the hydraulic crack deflects into weak interfaces and exhibits a dependence on crack-surface friction and crustal stress anisotropy are given in explicit formulae. We reveal analytically that, with increasing pressure, hydraulic fracture in shales may sequentially undergo friction locking, mode II fracture, and mixed mode fracture. Mode II fracture dominates the hydraulic fracturing process and the impinging angle between the hydraulic crack and the weak interface is the determining factor that accounts for crack deflection; the lower friction coefficient between cracked planes and the greater crustal stress difference favor hydraulic fracturing. In addition to shale fracking, the analytical solution of crack deflection could be used in failure analysis of other brittle media.

Estimation of Potential Shale Gas Yield Amount and Land Degradation in China by Landcover Distribution regarding Water-Food-Energy and Forest

NASA Astrophysics Data System (ADS)

Kim, N.; Heo, S.; Lim, C. H.; Lee, W. K.

2017-12-01

Shale gas is gain attention due to the tremendous reserves beneath the earth. The two known high reservoirs are located in United States and China. According to U.S Energy Information Administration China have estimated 7,299 trillion cubic feet of recoverable shale gas and placed as world first reservoir. United States had 665 trillion cubic feet for the shale gas reservoir and placed fourth. Unlike the traditional fossil fuel, spatial distribution of shale gas is considered to be widely spread and the reserved amount and location make the resource as energy source for the next generation. United States dramatically increased the shale gas production. For instance, shale gas production composes more than 50% of total natural gas production whereas China and Canada shale gas produce very small amount of the shale gas. According to U.S Energy Information Administration's report, in 2014 United States produced shale gas almost 40 billion cubic feet per day but China only produced 0.25 billion cubic feet per day. Recently, China's policy had changed to decrease the coal powerplants to reduce the air pollution and the energy stress in China is keep increasing. Shale gas produce less air pollution while producing energy and considered to be clean energy source. Considering the situation of China and characteristics of shale gas, soon the demand of shale gas will increase in China. United States invested 71.7 billion dollars in 2013 but it Chinese government is only proceeding fundamental investment due to land degradation, limited water resources, geological location of the reservoirs.In this study, firstly we reviewed the current system and technology of shale gas extraction such as hydraulic Fracturing. Secondly, listed the possible environmental damages, land degradations, and resource demands for the shale gas extraction. Thirdly, invested the potential shale gas extraction amount in China based on the location of shale gas reservoirs and limited resources for the gas extraction. Fourthly, invested the potential land degradation on agricultural, surface water, and forest in developing shale gas extraction scenario. In conclusion, we suggested possible environmental damages and social impacts from shale gas extraction in China.

Water management practices used by Fayetteville shale gas producers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veil, J. A.

2011-06-03

Water issues continue to play an important role in producing natural gas from shale formations. This report examines water issues relating to shale gas production in the Fayetteville Shale. In particular, the report focuses on how gas producers obtain water supplies used for drilling and hydraulically fracturing wells, how that water is transported to the well sites and stored, and how the wastewater from the wells (flowback and produced water) is managed. Last year, Argonne National Laboratory made a similar evaluation of water issues in the Marcellus Shale (Veil 2010). Gas production in the Marcellus Shale involves at least threemore » states, many oil and gas operators, and multiple wastewater management options. Consequently, Veil (2010) provided extensive information on water. This current study is less complicated for several reasons: (1) gas production in the Fayetteville Shale is somewhat more mature and stable than production in the Marcellus Shale; (2) the Fayetteville Shale underlies a single state (Arkansas); (3) there are only a few gas producers that operate the large majority of the wells in the Fayetteville Shale; (4) much of the water management information relating to the Marcellus Shale also applies to the Fayetteville Shale, therefore, it can be referenced from Veil (2010) rather than being recreated here; and (5) the author has previously published a report on the Fayetteville Shale (Veil 2007) and has helped to develop an informational website on the Fayetteville Shale (Argonne and University of Arkansas 2008), both of these sources, which are relevant to the subject of this report, are cited as references.« less

Mass and heat transfer in crushed oil shale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carley, J.F.; Straub, J.S.; Ott, L.L.

1984-04-01

Heat and mass transfer between gases and oil-shale particles are both important for all proposed retorting processes. Past studies of transfer in packed beds, which have disagreed substantially in their results, have nearly all been done with beds of regular particles of uniform size, whereas oil-shale retorting involves particles of diverse shapes and widely ranging sizes. To resolve these questions, we have made 349 runs in which we measured mass-transfer rates from naphthalene particles of diverse shapes buried in packed beds through which air was passed at room temperature. This technique permits calculation of the mass-transfer coefficient for each activemore » particle in the bed rather than, as in most past studies, for the bed as a whole. The data were analyzed in two ways: (1) by the traditional correlation of Colburn j/sub D/ vs Reynolds number and (2) by multiple regression of the mass-transfer coefficient on air rate, traditional correlation of Colburn j/sub D/ vs Reynolds number and (3) by multiple regression of the mass-transfer coefficient on air rate, sizes of active and inert particles, void fraction, and temperature. Principal findings are: (1) local Reynolds number should be based on active particle size rather than average size for the bed; (2) no appreciable differences were seen between shallow beds and deep ones; (3) mass transfer was 26% faster for spheres and lozenges buried in shale than for all-sphere beds; (4) orientation of lozenges in shale beds has little effect on mass-transfer rate; (5) a useful summarizing equation for either mass or heat transfer in shale beds is log j.epsilon = -.0747 - .6344 log Re + .0592 log/sup 2/Re where j = either j/sub D/ or j/sub H/, the Chilton-Colburn j-factors for mass and heat transfer, Re = the Reynolds number defined for packed beds, and epsilon = the void fraction in the bed. 12 references, 15 figures.« less

An Integrated Environmental Assessment Model for Oil Shale Development

NASA Astrophysics Data System (ADS)

Pasqualini, D.; Witkowski, M. S.; Keating, G. N.; Ziock, H.; Wolfsberg, A. V.

2008-12-01

Due to the rising prices of conventional fuel, unconventional fossil fuels such as oil shale, tar sands, and coal to liquid have gained attention as an energy resource. The largest reserve of oil shale in the world is located in the western interior of North America, and includes parts of Colorado, Utah, and Wyoming. Development of oil shale in this area could reduce or eliminate the U.S. dependence on foreign fuel sources. However, oil shale production carries a number of potential environmental impacts. Fuel production associated with oil shale will create increasing competition for limited resources such as water, while potentially negatively impacting air quality, water quality, habitat, and wildlife. Water use, wastewater management, greenhouse gas emissions, air pollution, and land use are the main environmental issues that oil shale production involves. A proper analysis of the interrelationships between these factors and those of the new energy needs required for production is necessary to avoid serious negative impacts to the environment and the economies. We have developed a system dynamics integrated assessment model to evaluate potential fuel production capacity from oil shale within the limits of environmental quality, land use, and economics. Recognizing that the impacts of oil shale development are the outcomes of a complex process that involve water, energy, climate, social pressures, economics, regulations, technical advances, etc., and especially their couplings and feedbacks, we developed our model using the system dynamics (SD) modeling approach. Our SD model integrates all of these components and allows us to analyze the interdependencies among them. Our initial focus has been to address industry, regulator, and stakeholder concerns regarding the quantification and management of carbon and water resources impacts. The model focuses on oil shale production in the Piceance Basin in Colorado, but is inherently designed to be extendable to larger regions, levels of production, and different unconventional fuels.

Wastewater management and Marcellus Shale gas development: trends, drivers, and planning implications.

PubMed

Rahm, Brian G; Bates, Josephine T; Bertoia, Lara R; Galford, Amy E; Yoxtheimer, David A; Riha, Susan J

2013-05-15

Extraction of natural gas from tight shale formations has been made possible by recent technological advances, including hydraulic fracturing with horizontal drilling. Global shale gas development is seen as a potential energy and geopolitical "game-changer." However, widespread concern exists with respect to possible environmental consequences of this development, particularly impacts on water resources. In the United States, where the most shale gas extraction has occurred, the Marcellus Shale is now the largest natural gas producing play. To date, over 6,000,000 m(3) of wastewater has been generated in the process of extracting natural gas from this shale in the state of Pennsylvania (PA) alone. Here we examine wastewater management practices and trends for this shale play through analysis of industry-reported, publicly available data collected from the Pennsylvania Department of Environmental Protection Oil and Gas Reporting Website. We also analyze the tracking and transport of shale gas liquid waste streams originating in PA using a combination of web-based and GIS approaches. From 2008 to 2011 wastewater reuse increased, POTW use decreased, and data tracking became more complete, while the average distance traveled by wastewater decreased by over 30%. Likely factors influencing these trends include state regulations and policies, along with low natural gas prices. Regional differences in wastewater management are influenced by industrial treatment capacity, as well as proximity to injection disposal capacity. Using lessons from the Marcellus Shale, we suggest that nations, states, and regulatory agencies facing new unconventional shale development recognize that pace and scale of well drilling leads to commensurate wastewater management challenges. We also suggest they implement wastewater reporting and tracking systems, articulate a policy for adapting management to evolving data and development patterns, assess local and regional wastewater treatment infrastructure in terms of capacity and capability, promote well-regulated on-site treatment technologies, and review and update wastewater management regulations and policies. Copyright © 2013 Elsevier Ltd. All rights reserved.

Baseline groundwater chemistry characterization in an area of future Marcellus shale gas development

NASA Astrophysics Data System (ADS)

Eisenhauer, P.; Zegre, N.; Edwards, P. J.; Strager, M.

2012-12-01

The recent increase in development of the Marcellus shale formation for natural gas in the mid-Atlantic can be attributed to advances in unconventional extraction methods, namely hydraulic fracturing, a process that uses water to pressurize and fracture relatively impermeable shale layers to release natural gas. In West Virginia, the Department of Energy estimates 95 to 105 trillion cubic feet (TCF) of expected ultimately recovery (EUR) of natural gas for this formation. With increased development of the Marcellus shale formation comes concerns for the potential of contamination to groundwater resources that serve as primary potable water sources for many rural communities. However, the impacts of this practice on water resources are poorly understood because of the lack of controlled pre versus post-drilling experiments attributed to the rapid development of this resource. To address the knowledge gaps of the potential impacts of Marcellus shale development on groundwater resources, a pre versus post-drilling study has been initiated by the USFS Fernow Experimental Forest in the Monongahela National Forest. Drilling is expected to start at three locations within the next year. Pre-drilling water samples were collected and analyzed from two groundwater wells, a shallow spring, a nearby lake, and river to characterize background water chemistry and identify potential end-members. Geochemical analysis includes major ions, methane, δ13C-CH4, δ2H-CH4, 226Radium, and δ13C-DIC. In addition, a GIS-based conceptual ground water flow model was developed to identify possible interactions between shallow groundwater and natural gas wells given gas well construction failure. This model is used to guide management decisions regarding groundwater resources in an area of increasing shale gas development.

Characterization and growth mechanism of a peculiar nodular structure in shale: Comprehensive study over the Sitakund anticline, Bengal basin.

NASA Astrophysics Data System (ADS)

Gazi, M. Y.; Kabir, S. M. M.; Imam, M. B.

2017-12-01

Nodular shales commonly occur in comparatively older and silty shales near the axial (proximity to core) region of Sitakund Anticline (Study area), Sitapahar Anticline, Patharia Structure, Sylhet Anticline and Mirinja Anticline as observed. Stratigraphically, they are pronounced in the Surma group of Neogene succession. They are less abundant in limb portion. In many outcrop, they are found in the incompetent bed with the obliterated bedding bounded by well bedded competent beds. Their occurrence are sporadic rather than continuous along and across the strike of the bed. At some places huge number cluster of small and big nodular shales occur while in the other places, they occur as isolated mass in the highly disturbed or obliterated beds. The Surma group is the prime startigraphic unit in Bangladesh with major economic and academic importance. Yet there is a lack of comprehensive characterization of mudrocks of Surma group. This has prompted the present research to be undertaken. An initial field based study has been followed by detail textural, mineralogical, petrological and geochemical by using upscale laboratory techniques that include Thin Section Microscopy, Laser Particle Size Analyses, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and X-ray Florescence (XRF). From laser diffraction analysis, it is evident that nodular shales are silty in nature containing approximately 60% silt (Mainly quartz). XRD pattern shows that Nodular shale contains clay minerals, predominantly illite, Kaolinite, Chlorite and expandable mixed layer clay mineral. Detail geochemical analysis of some nodular shale samples shows that there are no significant variation from other samples in major and trace element concentration. Microcrack's within the quartz grains were observed in nodular shale. Projection of 15 nodular shale long axes in outcrop shows their orientation in NNW-SSE that is parallel to the fold axis. The study suggests a new name of conventionally called nodular shales. The proposed name is "Clay Cabbage". A new model naming as "Tectono-Diagenetic (TD) Model" is proposed in this study concerning the origin of nodular shale.

Time-dependent deformation of gas shales - role of rock framework versus reservoir fluids

NASA Astrophysics Data System (ADS)

Hol, Sander; Zoback, Mark

2013-04-01

Hydraulic fracturing operations are generally performed to achieve a fast, drastic increase of permeability and production rates. Although modeling of the underlying short-term mechanical response has proven successful via conventional geomechanical approaches, predicting long-term behavior is still challenging as the formation interacts physically and chemically with the fluids present in-situ. Recent experimental work has shown that shale samples subjected to a change in effective stress deform in a time-dependent manner ("creep"). Although the magnitude and nature of this behavior is strongly related to the composition and texture of the sample, also the choice of fluid used in the experiments affects the total strain response - strongly adsorbing fluids result in more, recoverable creep. The processes underlying time-dependent deformation of shales under in-situ stresses, and the long-term impact on reservoir performance, are at present poorly understood. In this contribution, we report triaxial mechanical tests, and theoretical/thermodynamic modeling work with the aim to identify and describe the main mechanisms that control time-dependent deformation of gas shales. In particular, we focus on the role of the shale solid framework versus the type and pressure of the present pore fluid. Our experiments were mainly performed on Eagle Ford Shale samples. The samples were subjected to cycles of loading and unloading, first in the dry state, and then again after equilibrating them with (adsorbing) CO2 and (non-adsorbing) He at fluid pressures of 4 MPa. Stresses were chosen close to those persisting under in-situ conditions. The results of our tests demonstrate that likely two main types of deformation mechanisms operate that relate to a) the presence of microfractures as a dominating feature in the solid framework of the shale, and b) the adsorbing potential of fluids present in the nanoscale voids of the shale. To explain the role of adsorption in the observed compaction creep, we postulate a serial coupling between 1) stress-driven desorption of the fluid species, 2) diffusion of the desorbed species out of the solid, and 3) consequent shrinkage. We propose a model in which the total shrinkage of the solid (Step 3) that is measured as bulk compaction, is driven by a change in stress state (Step 1), and evolves in time controlled by the diffusion characteristics of the system (Step 2). Our experimental and modeling study shows that both the nature of the solid framework of the shale, as well as the type and pressure of pore fluids affect the long-term in-situ mechanical behavior of gas shale reservoirs.

Shale gas development impacts on surface water quality in Pennsylvania.

PubMed

Olmstead, Sheila M; Muehlenbachs, Lucija A; Shih, Jhih-Shyang; Chu, Ziyan; Krupnick, Alan J

2013-03-26

Concern has been raised in the scientific literature about the environmental implications of extracting natural gas from deep shale formations, and published studies suggest that shale gas development may affect local groundwater quality. The potential for surface water quality degradation has been discussed in prior work, although no empirical analysis of this issue has been published. The potential for large-scale surface water quality degradation has affected regulatory approaches to shale gas development in some US states, despite the dearth of evidence. This paper conducts a large-scale examination of the extent to which shale gas development activities affect surface water quality. Focusing on the Marcellus Shale in Pennsylvania, we estimate the effect of shale gas wells and the release of treated shale gas waste by permitted treatment facilities on observed downstream concentrations of chloride (Cl(-)) and total suspended solids (TSS), controlling for other factors. Results suggest that (i) the treatment of shale gas waste by treatment plants in a watershed raises downstream Cl(-) concentrations but not TSS concentrations, and (ii) the presence of shale gas wells in a watershed raises downstream TSS concentrations but not Cl(-) concentrations. These results can inform future voluntary measures taken by shale gas operators and policy approaches taken by regulators to protect surface water quality as the scale of this economically important activity increases.

Sedimentary provenance of Maastrichtian oil shales, Central Eastern Desert, Egypt

NASA Astrophysics Data System (ADS)

Fathy, Douaa; Wagreich, Michael; Mohamed, Ramadan S.; Zaki, Rafat

2017-04-01

Maastrichtian oil shales are distributed within the Central Eastern Desert in Egypt. In this study elemental geochemical data have been applied to investigate the probable provenance of the sedimentary detrital material of the Maastrichtian oil shale beds within the Duwi and the Dakhla formations. The Maastrichtian oil shales are characterized by the enrichment in Ca, P, Mo, Ni, Zn, U, Cr and Sr versus post-Archean Australian shales (PAAS). The chondrite-normalized patterns of the Maastrichtian oil shale samples are showing LREE enrichment, HREE depletion, slightly negative Eu anomaly, no obvious Ce anomaly and typical shale-like PAAS-normalized patterns. The total REE well correlated with Si, Al, Fe, K and Ti, suggesting that the REE of the Maastrichtian oil shales are derived from terrigenous source. Chemical weathering indices such as Chemical Index of Alteration (CIA), Chemical Proxy of Alteration (CPA) and Plagioclase Index of Alteration (PIA) indicate moderate to strong chemical weathering. We suggest that the Maastrichtian oil shale is mainly derived from first cycle rocks especially intermediate rocks without any significant inputs from recycled or mature sources. The proposed data illustrated the impact of the parent material composition on evolution of oil shale chemistry. Furthermore, the paleo-tectonic setting of the detrital source rocks for the Maastrichtian oil shale is probably related to Proterozoic continental island arcs

43 CFR 3000.12 - What is the fee schedule for fixed fees?

Code of Federal Regulations, 2013 CFR

2013-10-01

... Processing and Filing Fee Table Document/action FY 2014 fee Oil & Gas (parts 3100, 3110, 3120, 3130, 3150... 325 Lease or lease interest transfer 65 Leasing of Solid Minerals Other Than Coal and Oil Shale (parts... claims) 1,495 (10 or fewer claims) Adverse claim 105 Protest 65 Oil Shale Management (parts 3900, 3910...

43 CFR 3000.12 - What is the fee schedule for fixed fees?

Code of Federal Regulations, 2014 CFR

2014-10-01

... Processing and Filing Fee Table Document/Action FY 2015 Fee Oil & Gas (parts 3100, 3110, 3120, 3130, 3150... Coal and Oil Shale (parts 3500, 3580) Applications other than those listed below 35. Prospecting permit... adjudication 3,035 (more than 10 claims). 1,520 (10 or fewer claims). Adverse claim 110. Protest 65. Oil Shale...

Fuel quality/processing study. Volume 2: Appendix. Task 1 literature survey

NASA Technical Reports Server (NTRS)

Ohara, J. B.; Bela, A.; Jentz, N. E.; Klumpe, H. W.; Kessler, H. E.; Kotzot, H. T.; Loran, B. L.

1981-01-01

The results of a literature survey of fuel processing and fuel quality are given. Liquid synfuels produced from coal and oil shale are discussed. Gas turbine fuel property specifications are discussed. On-site fuel pretreatment and emissions from stationary gas turbines are discussed. Numerous data tables and abstracts are given.

The Impact of a Potential Shale Gas Development in Germany and the United Kingdom on Local and Regional Air Quality

NASA Astrophysics Data System (ADS)

Weger, L.; Lupascu, A.; Cremonese, L.; Butler, T. M.

2017-12-01

Numerous countries in Europe that possess domestic shale gas reserves are considering exploiting this unconventional gas resource as part of their energy transition agenda. While natural gas generates less CO2 emissions upon combustion compared to coal or oil, making it attractive as a bridge in the transition from fossil fuels to renewables, production of shale gas leads to emissions of CH4 and air pollutants such as NOx, VOCs and PM. These gases in turn influence the climate as well as air quality. In this study, we investigate the impact of a potential shale gas development in Germany and the United Kingdom on local and regional air quality. This work builds on our previous study in which we constructed emissions scenarios based on shale gas utilization in these counties. In order to explore the influence of shale gas production on air quality, we investigate emissions predicted from our shale gas scenarios with the Weather Research and Forecasting model with chemistry (WRF-Chem) model. In order to do this, we first design a model set-up over Europe and evaluate its performance for the meteorological and chemical parameters. Subsequently we add shale gas emissions fluxes based on the scenarios over the area of the grid in which the shale gas activities are predicted to occur. Finally, we model these emissions and analyze the impact on air quality on both a local and regional scale. The aims of this work are to predict the range of adverse effects on air quality, highlight the importance of emissions control strategies in reducing air pollution, to promote further discussion, and to provide policy makers with information for decision making on a potential shale gas development in the two study countries.

Fractal Characteristics of Continental Shale Pores and its Significance to the Occurrence of Shale Oil in China: a Case Study of Biyang Depression

NASA Astrophysics Data System (ADS)

Li, Jijun; Liu, Zhao; Li, Junqian; Lu, Shuangfang; Zhang, Tongqian; Zhang, Xinwen; Yu, Zhiyuan; Huang, Kaizhan; Shen, Bojian; Ma, Yan; Liu, Jiewen

Samples from seven major exploration wells in Biyang Depression of Henan Oilfield were compared using low-temperature nitrogen adsorption and shale oil adsorption experiments. Comprehensive analysis of pore development, oiliness and shale oil flowability was conducted by combining fractal dimension. The results show that the fractal dimension of shale in Biyang Depression of Henan Oilfield was negatively correlated with the average pore size and positively correlated with the specific surface area. Compared with the large pore, the small pore has great fractal dimension, indicating the pore structure is more complicated. Using S1 and chloroform bitumen A to evaluate the relationship between shale oiliness and pore structure, it was found that the more heterogeneous the shale pore structure, the higher the complexity and the poorer the oiliness. Clay minerals are the main carriers involved in crude oil adsorption, affecting the mobility of shale oil. When the pore complexity of shale was high, the content of micro- and mesopores was high, and the high specific surface area could enhance the adsorption and reduce the mobility of shale oil.

Investigating Rare Earth Element Systematics in the Marcellus Shale

NASA Astrophysics Data System (ADS)

Yang, J.; Torres, M. E.; Kim, J. H.; Verba, C.

2014-12-01

The lanthanide series of elements (the 14 rare earth elements, REEs) have similar chemical properties and respond to different chemical and physical processes in the natural environment by developing unique patterns in their concentration distribution when normalized to an average shale REE content. The interpretation of the REE content in a gas-bearing black shale deposited in a marine environment must therefore take into account the paleoredox conditions of deposition as well as any diagenetic remobilization and authigenic mineral formation. We analyzed 15 samples from a core of the Marcellus Shale (Whipkey ST1, Greene Co., PA) for REEs, TOC, gas-producing potential, trace metal content, and carbon isotopes of organic matter in order to determine the REE systematics of a black shale currently undergoing shale gas development. We also conducted a series of sequential leaching experiments targeting the phosphatic fractions in order to evaluate the dominant host phase of REEs in a black shale. Knowledge of the REE system in the Marcellus black shale will allow us to evaluate potential REE release and behavior during hydraulic fracturing operations. Total REE content of the Whipkey ST1 core ranged from 65-185 μg/g and we observed three distinct REE shale-normalized patterns: middle-REE enrichment (MREE/MREE* ~2) with heavy-REE enrichment (HREE/LREE ~1.8-2), flat patterns, and a linear enrichment towards the heavy-REE (HREE/LREE ~1.5-2.5). The MREE enrichment occurred in the high carbonate samples of the Stafford Member overlying the Marcellus Formation. The HREE enrichment occurred in the Union Springs Member of the Marcellus Formation, corresponding to a high TOC peak (TOC ~4.6-6.2 wt%) and moderate carbonate levels (CaCO3 ~4-53 wt%). Results from the sequential leaching experiments suggest that the dominant host of the REEs is the organic fraction of the black shale and that the detrital and authigenic fractions have characteristic MREE enrichments. We present our conclusions on the impact of depositional setting and diagenetic remobilization and authigenic mineral formation on the REE system in the Marcellus Shale.

Treatment of concentrated industrial wastewaters originating from oil shale and the like by electrolysis polyurethane foam interaction

DOEpatents

Tiernan, Joan E.

1990-01-01

Highly concentrated and toxic petroleum-based and synthetic fuels wastewaters such as oil shale retort water are treated in a unit treatment process by electrolysis in a reactor containing oleophilic, ionized, open-celled polyurethane foams and subjected to mixing and laminar flow conditions at an average detention time of six hours. Both the polyurethane foams and the foam regenerate solution are re-used. The treatment is a cost-effective process for waste-waters which are not treatable, or are not cost-effectively treatable, by conventional process series.

Fluidized-bed pyrolysis of oil shale: oil yield, composition, and kinetics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richardson, J H; Huss, E B; Ott, L L

1982-09-01

A quartz isothermal fluidized-bed reactor has been used to measure kinetics and oil properties relevant to surface processing of oil shale. The rate of oil formation has been described with two sequential first-order rate equations characterized by two rate constants, k/sub 1/ = 2.18 x 10/sup 10/ exp(-41.6 kcal/RT) s/sup -1/ and k/sub 2/ = 4.4 x 10/sup 6/ exp(-29.7 kcal/RT) s/sup -1/. These rate constants together with an expression for the appropriate weighting coefficients describe approximately 97/sup +/% of the total oil produced. A description is given of the results of different attempts to mathematically describe the data inmore » a manner suitable for modeling applications. Preliminary results are also presented for species-selective kinetics of methane, ethene, ethane and hydrogen, where the latter is clearly distinguished as the product of a distinct intermediate. Oil yields from Western oil shale are approximately 100% Fischer assay. Oil composition is as expected based on previous work and the higher heating rates (temperatures) inherent in fluidized-bed pyrolysis. Neither the oil yield, composition nor the kinetics varied with particle size between 0.2 and 2.0 mm within experimental error. The qualitatively expected change in oil composition due to cracking was observed over the temperature range studied (460 to 540/sup 0/C). Eastern shale exhibited significantly faster kinetics and higher oil yields than did Western shale.« less

Atmospheric emission characterization of Marcellus shale natural gas development sites.

PubMed

Goetz, J Douglas; Floerchinger, Cody; Fortner, Edward C; Wormhoudt, Joda; Massoli, Paola; Knighton, W Berk; Herndon, Scott C; Kolb, Charles E; Knipping, Eladio; Shaw, Stephanie L; DeCarlo, Peter F

2015-06-02

Limited direct measurements of criteria pollutants emissions and precursors, as well as natural gas constituents, from Marcellus shale gas development activities contribute to uncertainty about their atmospheric impact. Real-time measurements were made with the Aerodyne Research Inc. Mobile Laboratory to characterize emission rates of atmospheric pollutants. Sites investigated include production well pads, a well pad with a drill rig, a well completion, and compressor stations. Tracer release ratio methods were used to estimate emission rates. A first-order correction factor was developed to account for errors introduced by fenceline tracer release. In contrast to observations from other shale plays, elevated volatile organic compounds, other than CH4 and C2H6, were generally not observed at the investigated sites. Elevated submicrometer particle mass concentrations were also generally not observed. Emission rates from compressor stations ranged from 0.006 to 0.162 tons per day (tpd) for NOx, 0.029 to 0.426 tpd for CO, and 67.9 to 371 tpd for CO2. CH4 and C2H6 emission rates from compressor stations ranged from 0.411 to 4.936 tpd and 0.023 to 0.062 tpd, respectively. Although limited in sample size, this study provides emission rate estimates for some processes in a newly developed natural gas resource and contributes valuable comparisons to other shale gas studies.

Employment Creation of Shale Gas Investment in China

NASA Astrophysics Data System (ADS)

Wang, Xuecheng; Zhang, Baosheng; Wu, Meiling; Li, Xiang; Lin, Yuying

2018-01-01

An ambitious shale gas extraction plan has been proposed. The huge investment of shale gas may put an effect on the whole China’s economy, especially for employment. However, there is few study to date has quantified these effects. The aim of this paper is to quantify these effects especially employment creation and figures out whether shale gas investment in China is a good choice or not. Input-output analysis has been utilized in this study to estimate the employment creation in four different Chinese regions. Our findings show that shale gas investment will result in creating 660000, 370000, 140000 and 58000 equivalent jobs in Sichuan, Chongqing, Inner Mongolia and Guizhou, respectively. Considering the potential risks of environmental issues, we suggest that it may be a better strategy for the government, at least in the current situation, to slow down shale gas development investment.

Nanometer-Scale Pore Characteristics of Lacustrine Shale, Songliao Basin, NE China

PubMed Central

Wang, Min; Yang, Jinxiu; Wang, Zhiwei; Lu, Shuangfang

2015-01-01

In shale, liquid hydrocarbons are accumulated mainly in nanometer-scale pores or fractures, so the pore types and PSDs (pore size distributions) play a major role in the shale oil occurrence (free or absorbed state), amount of oil, and flow features. The pore types and PSDs of marine shale have been well studied; however, research on lacustrine shale is rare, especially for shale in the oil generation window, although lacustrine shale is deposited widely around the world. To investigate the relationship between nanometer-scale pores and oil occurrence in the lacustrine shale, 10 lacustrine shale core samples from Songliao Basin, NE China were analyzed. Analyses of these samples included geochemical measurements, SEM (scanning electron microscope) observations, low pressure CO2 and N2 adsorption, and high-pressure mercury injection experiments. Analysis results indicate that: (1) Pore types in the lacustrine shale include inter-matrix pores, intergranular pores, organic matter pores, and dissolution pores, and these pores are dominated by mesopores and micropores; (2) There is no apparent correlation between pore volumes and clay content, however, a weak negative correlation is present between total pore volume and carbonate content; (3) Pores in lacustrine shale are well developed when the organic matter maturity (Ro) is >1.0% and the pore volume is positively correlated with the TOC (total organic carbon) content. The statistical results suggest that oil in lacustrine shale mainly occurs in pores with diameters larger than 40 nm. However, more research is needed to determine whether this minimum pore diameter for oil occurrence in lacustrine shale is widely applicable. PMID:26285123

Nanometer-Scale Pore Characteristics of Lacustrine Shale, Songliao Basin, NE China.

PubMed

Wang, Min; Yang, Jinxiu; Wang, Zhiwei; Lu, Shuangfang

2015-01-01

In shale, liquid hydrocarbons are accumulated mainly in nanometer-scale pores or fractures, so the pore types and PSDs (pore size distributions) play a major role in the shale oil occurrence (free or absorbed state), amount of oil, and flow features. The pore types and PSDs of marine shale have been well studied; however, research on lacustrine shale is rare, especially for shale in the oil generation window, although lacustrine shale is deposited widely around the world. To investigate the relationship between nanometer-scale pores and oil occurrence in the lacustrine shale, 10 lacustrine shale core samples from Songliao Basin, NE China were analyzed. Analyses of these samples included geochemical measurements, SEM (scanning electron microscope) observations, low pressure CO2 and N2 adsorption, and high-pressure mercury injection experiments. Analysis results indicate that: (1) Pore types in the lacustrine shale include inter-matrix pores, intergranular pores, organic matter pores, and dissolution pores, and these pores are dominated by mesopores and micropores; (2) There is no apparent correlation between pore volumes and clay content, however, a weak negative correlation is present between total pore volume and carbonate content; (3) Pores in lacustrine shale are well developed when the organic matter maturity (Ro) is >1.0% and the pore volume is positively correlated with the TOC (total organic carbon) content. The statistical results suggest that oil in lacustrine shale mainly occurs in pores with diameters larger than 40 nm. However, more research is needed to determine whether this minimum pore diameter for oil occurrence in lacustrine shale is widely applicable.

[Application of wavelet transform and neural network in the near-infrared spectrum analysis of oil shale].

PubMed

Li, Su-Yi; Ji, Yan-Ju; Liu, Wei-Yu; Wang, Zhi-Hong

2013-04-01

In the present study, an innovative method is proposed, employing both wavelet transform and neural network, to analyze the near-infrared spectrum data in oil shale survey. The method entails using db8 wavelet at 3 levels decomposition to process raw data, using the transformed data as the input matrix, and creating the model through neural network. To verify the validity of the method, this study analyzes 30 synthesized oil shale samples, in which 20 samples are randomly selected for network training, the other 10 for model prediction, and uses the full spectrum and the wavelet transformed spectrum to carry out 10 network models, respectively. Results show that the mean speed of the full spectrum neural network modeling is 570.33 seconds, and the predicted residual sum of squares (PRESS) and correlation coefficient of prediction are 0.006 012 and 0.843 75, respectively. In contrast, the mean speed of the wavelet network modeling method is 3.15 seconds, and the mean PRESS and correlation coefficient of prediction are 0.002 048 and 0.953 19, respectively. These results demonstrate that the wavelet neural network modeling method is significantly superior to the full spectrum neural network modeling method. This study not only provides a new method for more efficient and accurate detection of the oil content of oil shale, but also indicates the potential for applying wavelet transform and neutral network in broad near-infrared spectrum analysis.

A Numerical Study of Factors Affecting Fracture-Fluid Cleanup and Produced Gas/Water in Marcellus Shale: Part II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seales, Maxian B.; Dilmore, Robert; Ertekin, Turgay

Horizontal wells combined with successful multi-stage hydraulic fracture treatments are currently the most established method for effectively stimulating and enabling economic development of gas bearing organic-rich shale formations. Fracture cleanup in the Stimulated Reservoir Volume (SRV) is critical to stimulation effectiveness and long-term well performance. However, fluid cleanup is often hampered by formation damage, and post-fracture well performance frequently falls below expectations. A systematic study of the factors that hinder fracture fluid cleanup in shale formations can help optimize fracture treatments and better quantify long term volumes of produced water and gas. Fracture fluid cleanup is a complex process influencedmore » by multi-phase flow through porous media (relative permeability hysteresis, capillary pressure etc.), reservoir rock and fluid properties, fracture fluid properties, proppant placement, fracture treatment parameters, and subsequent flowback and field operations. Changing SRV and fracture conductivity as production progresses further adds to the complexity of this problem. Numerical simulation is the best, and most practical approach to investigate such a complicated blend of mechanisms, parameters, their interactions, and subsequent impact on fracture fluid cleanup and well deliverability. In this paper, a 3-dimensional, 2-phase, dual-porosity model was used to investigate the impact of multiphase flow, proppant crushing, proppant diagenesis, shut-in time, reservoir rock compaction, gas slippage, and gas desorption on fracture fluid cleanup, and well performance in Marcellus shale. The research findings have shed light on the factors that substantially constrains efficient fracture fluid cleanup in gas shales, and provided guidelines for improved fracture treatment designs and water management.« less

Identifying different types of catalysts for CO 2 reduction by ethane through dry reforming and oxidative dehydrogenation

DOE PAGES

Marc D. Porosoff; Chen, Jingguang G.; Myint, Myat Noe Zin; ...

2015-11-10

In this study, the recent shale gas boom combined with the requirement to reduce atmospheric CO 2 have created an opportunity for using both raw materials (shale gas and CO 2) in a single process. Shale gas is primarily made up of methane, but ethane comprises about 10 % and reserves are underutilized. Two routes have been investigated by combining ethane decomposition with CO 2 reduction to produce products of higher value. The first reaction is ethane dry reforming which produces synthesis gas (CO+H 2). The second route is oxidative dehydrogenation which produces ethylene using CO 2 as a softmore » oxidant. The results of this study indicate that the Pt/CeO 2 catalyst shows promise for the production of synthesis gas, while Mo 2C-based materials preserve the C—C bond of ethane to produce ethylene. These findings are supported by density functional theory (DFT) calculations and X-ray absorption near-edge spectroscopy (XANES) characterization of the catalysts under in situ reaction conditions.« less

Effect of thermal maturity on remobilization of molybdenum in black shales

NASA Astrophysics Data System (ADS)

Ardakani, Omid H.; Chappaz, Anthony; Sanei, Hamed; Mayer, Bernhard

2016-09-01

Molybdenum (Mo) concentrations in sedimentary records have been widely used as a method to assess paleo-redox conditions prevailing in the ancient oceans. However, the potential effects of post-depositional processes, such as thermal maturity and burial diagenesis, on Mo concentrations in organic-rich shales have not been addressed, compromising its use as a redox proxy. This study investigates the distribution and speciation of Mo at various thermal maturities in the Upper Ordovician Utica Shale from southern Quebec, Canada. Samples display maturities ranging from the peak oil window (VRo ∼ 1%) to the dry gas zone (VRo ∼ 2%). While our data show a significant correlation between total organic carbon (TOC) and Mo (R2 = 0.40, n = 28, P < 0.0003) at lower thermal maturity, this correlation gradually deteriorates with increasing thermal maturity. Intervals within the thermally overmature section of the Utica Shale that contain elevated Mo levels (20-81 ppm) show petrographic and sulfur isotopic evidence of thermochemical sulfate reduction (TSR) along with formation of recrystallized pyrite. X-ray Absorption Fine Structure spectroscopy (XAFS) was used to determine Mo speciation in samples from intervals with elevated Mo contents (>30 ppm). Our results show the presence of two Mo species: molybdenite Mo(IV)S2 (39 ± 5%) and Mo(VI)-Organic Matter (61 ± 5%). This new evidence suggests that at higher thermal maturities, TSR causes sulfate reduction coupled with oxidation of organic matter (OM). This process is associated with H2S generation and pyrite formation and recrystallization. This in turn leads to the remobilization of Mo and co-precipitation of molybdenite with TSR-derived carbonates in the porous intervals. This could lead to alteration of the initial sedimentary signature of Mo in the affected intervals, hence challenging its use as a paleo-redox proxy in overmature black shales.

Numerical simulation and fracture identification of dual laterolog in organic shale

NASA Astrophysics Data System (ADS)

Maojin, Tan; Peng, Wang; Qiong, Liu

2012-09-01

Fracture is one of important spaces in shale oil and shale gas reservoirs, and fractures identification and evaluation are an important part in organic shale interpretation. According to the fractured shale gas reservoir, a physical model is set up to study the dual laterolog logging responses. First, based on the principle of dual laterolog, three-dimensional finite element method (FEM) is used to simulate the dual laterolog responses in various formation models with different fractures widths, different fracture numbers, different fractures inclination angle. All the results are extremely important for the fracture identification and evaluation in shale reservoirs. Appointing to different base rock resistivity models, the fracture models are constructed respectively through a number of numerical simulation, and the fracture porosity can be calculated by solving the corresponding formulas. A case study about organic shale formation is analyst and discussed, and the fracture porosity is calculated from dual laterolog. The fracture evaluation results are also be validated right by Full borehole Micro-resistivity Imaging (FMI). So, in case of the absence of borehole resistivity imaging log, the dual laterolog resistivity can be used to estimate the fracture development.

Comparative dermal carcinogenesis of shale and petroleum-derived distillates.

PubMed

Clark, C R; Walter, M K; Ferguson, P W; Katchen, M

1988-03-01

Ten test materials derived from petroleum or hydrotreated shale oils were applied 3 times/week for up to 105 weeks to the shaved skin of 25 male and 25 female C3H/HeN mice per group. Mineral oil and benzo(a) pyrene (0.15%) were control materials. Clinical observations were recorded during the study. At death, histopathologic examination was conducted on skin, internal organs and any gross lesions. Exposures to some materials were ended midway in the study due to severe irritation. Chronic toxicity of all materials was limited to inflammatory and degenerative skin changes. Significant increases over control incidence of skin tumors (squamous cell carcinoma and fibrosarcoma) occurred with both petroleum and shale-derived naphtha (21%, 50%), Jet A (26%, 28%), JP-4 (26%, 50%), and crude oils (84%, 54%). Severely hydrotreated shale oil and petroleum and shale-derived diesel distillates were not considered tumorigenic. Results indicate that toxicity of comparable petroleum and shale-derived fractions was qualitatively similar and confirm earlier findings that hydrotreating reduces or eliminates carcinogenicity of raw shale oil.

Western Greece unconventional hydrocarbon potential from oil shale and shale gas reservoirs

NASA Astrophysics Data System (ADS)

Karakitsios, Vasileios; Agiadi, Konstantina

2013-04-01

It is clear that we are gradually running out of new sedimentary basins to explore for conventional oil and gas and that the reserves of conventional oil, which can be produced cheaply, are limited. This is the reason why several major oil companies invest in what are often called unconventional hydrocarbons: mainly oil shales, heavy oil, tar sand and shale gas. In western Greece exist important oil and gas shale reservoirs which must be added to its hydrocarbon potential1,2. Regarding oil shales, Western Greece presents significant underground immature, or close to the early maturation stage, source rocks with black shale composition. These source rock oils may be produced by applying an in-situ conversion process (ICP). A modern technology, yet unproven at a commercial scale, is the thermally conductive in-situ conversion technology, developed by Shell3. Since most of western Greece source rocks are black shales with high organic content, those, which are immature or close to the maturity limit have sufficient thickness and are located below 1500 meters depth, may be converted artificially by in situ pyrolysis. In western Greece, there are several extensive areas with these characteristics, which may be subject of exploitation in the future2. Shale gas reservoirs in Western Greece are quite possibly present in all areas where shales occur below the ground-water level, with significant extent and organic matter content greater than 1%, and during their geological history, were found under conditions corresponding to the gas window (generally at depths over 5,000 to 6,000m). Western Greece contains argillaceous source rocks, found within the gas window, from which shale gas may be produced and consequently these rocks represent exploitable shale gas reservoirs. Considering the inevitable increase in crude oil prices, it is expected that at some point soon Western Greece shales will most probably be targeted. Exploration for conventional petroleum reservoirs, through the interpretation of seismic profiles and the surface geological data, will simultaneously provide the subsurface geometry of the unconventional reservoirs. Their exploitation should follow that of conventional hydrocarbons, in order to benefit from the anticipated technological advances, eliminating environmental repercussions. As a realistic approach, the environmental consequences of the oil shale and shale gas exploitation to the natural environment of western Greece, which holds other very significant natural resources, should be delved into as early as possible. References 1Karakitsios V. & Rigakis N. 2007. Evolution and Petroleum Potential of Western Greece. J.Petroleum Geology, v. 30, no. 3, p. 197-218. 2Karakitsios V. 2013. Western Greece and Ionian Sea petroleum systems. AAPG Bulletin, in press. 3Bartis J.T., Latourrette T., Dixon L., Peterson D.J., Cecchine G. 2005. Oil Shale Development in the United States: Prospect and Policy Issues. Prepared for the National Energy Tech. Lab. of the U.S. Dept Energy. RAND Corporation, 65 p.

Morbidity survey of US oil shale workers employed during 1948-1969

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rom, W.N.; Krueger, G.; Zone, J.

The health status of 325 oil shale workers employed at the Anvil Points, Colorado, demonstration facility from 1948 to 1969 was evaluated. As a comparison population, 323 Utah coal miners frequency matched for age were studied. The prevalence of respiratory symptoms among oil shale workers who smoked were similar to the coal miners who smoked, although nonsmoking oil shale workers had fewer symptoms compared to nonsmoking coal workers. Four cases of skin cancers were found on the oil shale workers and eight cases in the controls. Similar numbers of nevi, telangiectasiae, possible pitch warts, pigment changes (solar/senile lentigo), and papillomatamore » (seborrheic keratoses and skin tags) were seen in both groups, while actinic keratoses were more frequent in the oil shale workers. The prevalence of actinic keratoses was significantly associated with oil shale work after allowing for age, sun exposure, and other exposures. The prevalence of pulmonary cytology metaplasia was associated with years of production work in oil shale among both smokers and ex-smokers. More of the oil shale workers had atypical cells in the urine, but the excess mostly found among ex-smokers. Although these workers had short-term and limited oil shale exposure work exposure, the authors recommend that medical surveillance of oil shale workers consider the skin, respiratory, and urinary systems for special observation.« less

Shale gas development impacts on surface water quality in Pennsylvania

PubMed Central

Olmstead, Sheila M.; Muehlenbachs, Lucija A.; Shih, Jhih-Shyang; Chu, Ziyan; Krupnick, Alan J.

2013-01-01

Concern has been raised in the scientific literature about the environmental implications of extracting natural gas from deep shale formations, and published studies suggest that shale gas development may affect local groundwater quality. The potential for surface water quality degradation has been discussed in prior work, although no empirical analysis of this issue has been published. The potential for large-scale surface water quality degradation has affected regulatory approaches to shale gas development in some US states, despite the dearth of evidence. This paper conducts a large-scale examination of the extent to which shale gas development activities affect surface water quality. Focusing on the Marcellus Shale in Pennsylvania, we estimate the effect of shale gas wells and the release of treated shale gas waste by permitted treatment facilities on observed downstream concentrations of chloride (Cl−) and total suspended solids (TSS), controlling for other factors. Results suggest that (i) the treatment of shale gas waste by treatment plants in a watershed raises downstream Cl− concentrations but not TSS concentrations, and (ii) the presence of shale gas wells in a watershed raises downstream TSS concentrations but not Cl− concentrations. These results can inform future voluntary measures taken by shale gas operators and policy approaches taken by regulators to protect surface water quality as the scale of this economically important activity increases. PMID:23479604

Evaluation of Used Fuel Disposition in Clay-Bearing Rock

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jové Colón, Carlos F.; Weck, Philippe F.; Sassani, David H.

2014-08-01

Radioactive waste disposal in shale/argillite rock formations has been widely considered given its desirable isolation properties (low permeability), geochemically reduced conditions, anomalous groundwater pressures, and widespread geologic occurrence. Clay/shale rock formations are characterized by their high content of clay minerals such as smectites and illites where diffusive transport and chemisorption phenomena predominate. These, in addition to low permeability, are key attributes of shale to impede radionuclide mobility. Shale host-media has been comprehensively studied in international nuclear waste repository programs as part of underground research laboratories (URLs) programs in Switzerland, France, Belgium, and Japan. These investigations, in some cases a decademore » or more long, have produced a large but fundamental body of information spanning from site characterization data (geological, hydrogeological, geochemical, geomechanical) to controlled experiments on the engineered barrier system (EBS) (barrier clay and seals materials). Evaluation of nuclear waste disposal in shale formations in the USA was conducted in the late 70’s and mid 80’s. Most of these studies evaluated the potential for shale to host a nuclear waste repository but not at the programmatic level of URLs in international repository programs. This report covers various R&D work and capabilities relevant to disposal of heat-generating nuclear waste in shale/argillite media. Integration and cross-fertilization of these capabilities will be utilized in the development and implementation of the shale/argillite reference case planned for FY15. Disposal R&D activities under the UFDC in the past few years have produced state-of-the-art modeling capabilities for coupled Thermal-Hydrological-Mechanical-Chemical (THMC), used fuel degradation (source term), and thermodynamic modeling and database development to evaluate generic disposal concepts. The THMC models have been developed for shale repository leveraging in large part on the information garnered in URLs and laboratory data to test and demonstrate model prediction capability and to accurately represent behavior of the EBS and the natural (barrier) system (NS). In addition, experimental work to improve our understanding of clay barrier interactions and TM couplings at high temperatures are key to evaluate thermal effects as a result of relatively high heat loads from waste and the extent of sacrificial zones in the EBS. To assess the latter, experiments and modeling approaches have provided important information on the stability and fate of barrier materials under high heat loads. This information is central to the assessment of thermal limits and the implementation of the reference case when constraining EBS properties and the repository layout (e.g., waste package and drift spacing). This report is comprised of various parts, each one describing various R&D activities applicable to shale/argillite media. For example, progress made on modeling and experimental approaches to analyze physical and chemical interactions affecting clay in the EBS, NS, and used nuclear fuel (source term) in support of R&D objectives. It also describes the development of a reference case for shale/argillite media. The accomplishments of these activities are summarized as follows: Development of a reference case for shale/argillite; Investigation of Reactive Transport and Coupled THM Processes in EBS: FY14; Update on Experimental Activities on Buffer/Backfill Interactions at elevated Pressure and Temperature; and Thermodynamic Database Development: Evaluation Strategy, Modeling Tools, First-Principles Modeling of Clay, and Sorption Database Assessment;ANL Mixed Potential Model For Used Fuel Degradation: Application to Argillite and Crystalline Rock Environments.« less

Stratigraphic architecture and depositional history of lower Miocene, Planulina Zone, Southern Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gates, B.C.; Galloway, W.E.

1988-01-01

The Planulina zone is a wedge of clastic sediment positioned between the Anahuac shale below and the Oakville sandstone interval above. Planulna sediments were deposited on an erosional surface, during a general rise in the sea level, and formed a retrogradational wedge. Within the study area, the Planulina zone consists of two large depositional complexes: the Mud Lake complex in west Cameron Parish, Louisiana, and the East Cameron complex in east Cameron Parish. The lowermost depositional sequence in the East Cameron complex is preserved in a network of submarine canyons that were eroded into the upper slope. Framework sands weremore » deposited in channel systems confined to the axis of the canyons, and the sands are encased in marine shale containing benthonic foraminifera indicative of an upper to middle slope paleoenvironment. Two younger depositional sequences overlie the submarine canyon facies and were deposited by deltaic systems that prograded basinward. A zone of expansion extends east to west through the Planulina interval and is named the ''Planulina flexure.'' The flexure is a large fault located at the relict shelf edge and soles out downdip inn the Anahuac shale. Several thousand feet of sediment downthrown on the flexure is equivalent to several hundred feet upthrown, and the flexure represented the boundary dividing updip deltaic processes from downdip slope processes during the beginning of Planulina deposition. The Planulina depositional history and stratigraphic architecture are directly related to the displacement along the flexure and the structural deformation of the underlying Anahuac shale.« less

Water mist injection in oil shale retorting

DOEpatents

Galloway, T.R.; Lyczkowski, R.W.; Burnham, A.K.

1980-07-30

Water mist is utilized to control the maximum temperature in an oil shale retort during processing. A mist of water droplets is generated and entrained in the combustion supporting gas flowing into the retort in order to distribute the liquid water droplets throughout the retort. The water droplets are vaporized in the retort in order to provide an efficient coolant for temperature control.

The Shear Mechanisms of Natural Fractures during the Hydraulic Stimulation of Shale Gas Reservoirs.

PubMed

Zhang, Zhaobin; Li, Xiao

2016-08-23

The shearing of natural fractures is important in the permeability enhancement of shale gas reservoirs during hydraulic fracturing treatment. In this work, the shearing mechanisms of natural fractures are analyzed using a newly proposed numerical model based on the displacement discontinuities method. The fluid-rock coupling system of the model is carefully designed to calculate the shearing of fractures. Both a single fracture and a complex fracture network are used to investigate the shear mechanisms. The investigation based on a single fracture shows that the non-ignorable shearing length of a natural fracture could be formed before the natural fracture is filled by pressurized fluid. Therefore, for the hydraulic fracturing treatment of the naturally fractured shale gas reservoirs, the shear strength of shale is generally more important than the tensile strength. The fluid-rock coupling propagation processes of a complex fracture network are simulated under different crustal stress conditions and the results agree well with those of the single fracture. The propagation processes of complex fracture network show that a smaller crustal stress difference is unfavorable to the shearing of natural fractures, but is favorable to the formation of complex fracture network.

Is shale gas drilling an energy solution or public health crisis?

PubMed

Rafferty, Margaret A; Limonik, Elena

2013-01-01

High-volume horizontal hydraulic fracturing, a controversial new mining technique used to drill for shale gas, is being implemented worldwide. Chemicals used in the process are known neurotoxins, carcinogens, and endocrine disruptors. People who live near shale gas drilling sites report symptoms that they attribute to contaminated air and water. When they seek help from clinicians, a diagnosis is often elusive because the chemicals to which the patients have been exposed are a closely guarded trade secret. Many nurses have voiced grave concern about shale gas drilling safety. Full disclosure of the chemicals used in the process is necessary in order for nurses and other health professionals to effectively care for patients. The economic exuberance surrounding natural gas has resulted in insufficient scrutiny into the health implications. Nursing research aimed at determining what effect unconventional drilling has on human health could help fill that gap. Public health nurses using the precautionary principle should advocate for a more concerted transition from fossil fuels to sustainable energy. Any initiation or further expansion of unconventional gas drilling must be preceded by a comprehensive Health Impact Assessment (HIA). © 2013 Wiley Periodicals, Inc.

A Thermoplasticity Model for Oil Shale

DOE PAGES

White, Joshua A.; Burnham, Alan K.; Camp, David W.

2016-03-31

Several regions of the world have abundant oil shale resources, but accessing this energy supply poses a number of challenges. One particular difficulty is the thermomechanical behavior of the material. When heated to sufficient temperatures, thermal conversion of kerogen to oil, gas, and other products takes place. This alteration of microstructure leads to a complex geomechanical response. In this work, we develop a thermoplasticity model for oil shale. The model is based on critical state plasticity, a framework often used for modeling clays and soft rocks. The model described here allows for both hardening due to mechanical deformation and softeningmore » due to thermal processes. In particular, the preconsolidation pressure—defining the onset of plastic volumetric compaction—is controlled by a state variable representing the kerogen content of the material. As kerogen is converted to other phases, the material weakens and plastic compaction begins. We calibrate and compare the proposed model to a suite of high-temperature uniaxial and triaxial experiments on core samples from a pilot in situ processing operation in the Green River Formation. In conclusion, we also describe avenues for future work to improve understanding and prediction of the geomechanical behavior of oil shale operations.« less

The Shear Mechanisms of Natural Fractures during the Hydraulic Stimulation of Shale Gas Reservoirs

PubMed Central

Zhang, Zhaobin; Li, Xiao

2016-01-01

The shearing of natural fractures is important in the permeability enhancement of shale gas reservoirs during hydraulic fracturing treatment. In this work, the shearing mechanisms of natural fractures are analyzed using a newly proposed numerical model based on the displacement discontinuities method. The fluid-rock coupling system of the model is carefully designed to calculate the shearing of fractures. Both a single fracture and a complex fracture network are used to investigate the shear mechanisms. The investigation based on a single fracture shows that the non-ignorable shearing length of a natural fracture could be formed before the natural fracture is filled by pressurized fluid. Therefore, for the hydraulic fracturing treatment of the naturally fractured shale gas reservoirs, the shear strength of shale is generally more important than the tensile strength. The fluid-rock coupling propagation processes of a complex fracture network are simulated under different crustal stress conditions and the results agree well with those of the single fracture. The propagation processes of complex fracture network show that a smaller crustal stress difference is unfavorable to the shearing of natural fractures, but is favorable to the formation of complex fracture network. PMID:28773834

Properties of Silurian shales from the Barrandian Basin, Czech Republic

NASA Astrophysics Data System (ADS)

Weishauptová, Zuzana; Přibyl, Oldřich; Sýkorová, Ivana

2017-04-01

Although shale gas-bearing deposits have a markedly lower gas content than coal deposits, great attention has recently been paid to shale gas as a new potential source of fossil energy. Shale gas extraction is considered to be quite economical, despite the lower sorption capacity of shales, which is only about 10% of coal sorption capacities The selection of a suitable locality for extracting shale gas requires the sorption capacity of the shale to be determined. The sorption capacity is determined in the laboratory by measuring the amount of methane absorbed in a shale specimen at a pressure and a temperature corresponding to in situ conditions, using high pressure sorption. According to the principles of reversibility of adsorption/desorption, this amount should be roughly related to the amount of gas released by forced degassing. High pressure methane sorption isotherms were measured on seven representative samples of Silurian shales from the Barrandian Basin, Czech Republic. Excess sorption measurements were performed at a temperature of 45oC and at pressures up to 15 MPa on dry samples, using a manometric method. Experimental methane high-pressure isotherms were fitted to a modified Langmuir equation. The maximum measured excess sorption parameter and the Langmuir sorption capacity parameter were used to study the effect of TOC content, organic maturity, inorganic components and porosity on the methane sorption capacity. The studied shale samples with random reflectance of graptolite 0.56 to 1.76% had a very low TOC content and dominant mineral fractions. Illite was the prevailing clay mineral. The sample porosity ranged from 4.6 to 18.8%. In most samples, the micropore volumes were markedly lower than the meso- and macropore volumes. In the Silurian black shales, the occurrence of fractures parallel with the original sedimentary bending was highly significant. A greater proportion of fragments of carbonaceous particles of graptolites and bitumens in the Barrandian Silurian shales had a smooth surface without pores. No relation has been proven between TOC-normalized excess sorption capacities or the TOC-normalized Langmuir sorption capacities and thermal maturation of the shales. The methane sorption capacities of shale samples show a positive correlation with TOC and a positive correlation with the clay content. The highest sorption capacity was observed in shale samples with the highest percentage of micropores, indicating that the micropore volume in the organic matter and clay minerals is a principal factor affecting the sorption capacity of the shale samples.

A Model To Estimate Carbon Dioxide Injectivity and Storage Capacity for Geological Sequestration in Shale Gas Wells.

PubMed

Edwards, Ryan W J; Celia, Michael A; Bandilla, Karl W; Doster, Florian; Kanno, Cynthia M

2015-08-04

Recent studies suggest the possibility of CO2 sequestration in depleted shale gas formations, motivated by large storage capacity estimates in these formations. Questions remain regarding the dynamic response and practicality of injection of large amounts of CO2 into shale gas wells. A two-component (CO2 and CH4) model of gas flow in a shale gas formation including adsorption effects provides the basis to investigate the dynamics of CO2 injection. History-matching of gas production data allows for formation parameter estimation. Application to three shale gas-producing regions shows that CO2 can only be injected at low rates into individual wells and that individual well capacity is relatively small, despite significant capacity variation between shale plays. The estimated total capacity of an average Marcellus Shale well in Pennsylvania is 0.5 million metric tonnes (Mt) of CO2, compared with 0.15 Mt in an average Barnett Shale well. Applying the individual well estimates to the total number of existing and permitted planned wells (as of March, 2015) in each play yields a current estimated capacity of 7200-9600 Mt in the Marcellus Shale in Pennsylvania and 2100-3100 Mt in the Barnett Shale.

Organic geochemistry: Effects of organic components of shales on adsorption: Progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, P.C.

1988-11-01

The Sedimentary Rock Program at the Oak Ridge National Laboratory is investigating shale to determine its potential suitability as a host rock for the disposal of high-level radioactive wastes (HLW). The selected shales are Upper Dowelltown, Pierre, Green River Formation, and two Conasauga (Nolichucky and Pumpkin Valley) Shales, which represent mineralogical and compositional extremes of shales in the United States. According to mineralogical studies, the first three shales contain 5 to 13 wt % of organic matter, and the two Conasauga Shales only contain trace amounts (2 wt %) of organic matter. Soxhlet extraction with chloroform and a mixture ofmore » chloroform and methanol can remove 0.07 to 5.9 wt % of the total organic matter from these shales. Preliminary analysis if these organic extracts reveals the existence of organic carboxylic acids and hydrocarbons in these samples. Adsorption of elements such as Cs(I), Sr(II) and Tc(VII) on the organic-extracted Upper Dowelltown, Pierre, green River Formation and Pumpkin Valley Shales in synthetic groundwaters (simulating groundwaters in the Conasauga Shales) and in 0.03-M NaHCO/sub 3/ solution indicates interaction between each of the three elements and the organic-extractable bitumen. 28 refs., 8 figs., 10 tabs.« less

Contaminants from Cretaceous Black Shale Part 1: Natural weathering processes controlling contaminant cycling in Mancos Shale, southwestern United States, with emphasis on salinity and selenium

USGS Publications Warehouse

Tuttle, Michele L.W.; Fahy, Juli W.; Elliott, John G.; Grauch, Richard I.; Stillings, Lisa L.

2013-01-01

Soils derived from black shale can accumulate high concentrations of elements of environmental concern, especially in regions with semiarid to arid climates. One such region is the Colorado River basin in the southwestern United States where contaminants pose a threat to agriculture, municipal water supplies, endangered aquatic species, and water-quality commitments to Mexico. Exposures of Cretaceous Mancos Shale (MS) in the upper basin are a major contributor of salinity and selenium in the Colorado River. Here, we examine the roles of geology, climate, and alluviation on contaminant cycling (emphasis on salinity and Se) during weathering of MS in a Colorado River tributary watershed. Stage I (incipient weathering) began perhaps as long ago as 20 ka when lowering of groundwater resulted in oxidation of pyrite and organic matter. This process formed gypsum and soluble organic matter that persist in the unsaturated, weathered shale today. Enrichment of Se observed in laterally persistent ferric oxide layers likely is due to selenite adsorption onto the oxides that formed during fluctuating redox conditions at the water table. Stage II weathering (pedogenesis) is marked by a significant decrease in bulk density and increase in porosity as shale disaggregates to soil. Rainfall dissolves calcite and thenardite (Na2SO4) at the surface, infiltrates to about 1 m, and precipitates gypsum during evaporation. Gypsum formation (estimated 390 kg m−2) enriches soil moisture in Na and residual SO4. Transpiration of this moisture to the surface or exposure of subsurface soil (slumping) produces more thenardite. Most Se remains in the soil as selenite adsorbed to ferric oxides, however, some oxidizes to selenate and, during wetter conditions is transported with soil moisture to depths below 3 m. Coupled with little rainfall, relatively insoluble gypsum, and the translocation of soluble Se downward, MS landscapes will be a significant nonpoint source of salinity and Se to the Colorado River well into the future. Other trace elements weathering from MS that are often of environmental concern include U and Mo, which mimic Se in their behavior; As, Co, Cr, Cu, Ni, and Pb, which show little redistribution; and Cd, Sb, V, and Zn, which accumulate in Stage I shale, but are lost to varying degrees from upper soil intervals. None of these trace elements have been reported previously as contaminants in the study area.

Trace Metal Geochemistry and Mobility in the Marcellus Shale

EPA Pesticide Factsheets

Drilling and “fracing” of the Marcellus shale causes fluid‐rock interactions that has the potential to mobilize metals naturally enriched in the shale. While these metal concentrations are low, their mobilization from the solid, is cause for further study

Studies investigate effects of hydraulic fracturing

NASA Astrophysics Data System (ADS)

Balcerak, Ernie

2012-11-01

The use of hydraulic fracturing, also known as fracking, to enhance the retrieval of natural gas from shale has been increasing dramatically—the number of natural gas wells rose about 50% since 2000. Shale gas has been hailed as a relatively low-cost, abundant energy source that is cleaner than coal. However, fracking involves injecting large volumes of water, sand, and chemicals into deep shale gas reservoirs under high pressure to open fractures through which the gas can travel, and the process has generated much controversy. The popular press, advocacy organizations, and the documentary film Gasland by Josh Fox have helped bring this issue to a broad audience. Many have suggested that fracking has resulted in contaminated drinking water supplies, enhanced seismic activity, demands for large quantities of water that compete with other uses, and challenges in managing large volumes of resulting wastewater. As demand for expanded domestic energy production intensifies, there is potential for substantially increased use of fracking together with other recovery techniques for "unconventional gas resources," like extended horizontal drilling.

Unconventional shale-gas systems: The Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment

USGS Publications Warehouse

Jarvie, D.M.; Hill, R.J.; Ruble, T.E.; Pollastro, R.M.

2007-01-01

Shale-gas resource plays can be distinguished by gas type and system characteristics. The Newark East gas field, located in the Fort Worth Basin, Texas, is defined by thermogenic gas production from low-porosity and low-permeability Barnett Shale. The Barnett Shale gas system, a self-contained source-reservoir system, has generated large amounts of gas in the key productive areas because of various characteristics and processes, including (1) excellent original organic richness and generation potential; (2) primary and secondary cracking of kerogen and retained oil, respectively; (3) retention of oil for cracking to gas by adsorption; (4) porosity resulting from organic matter decomposition; and (5) brittle mineralogical composition. The calculated total gas in place (GIP) based on estimated ultimate recovery that is based on production profiles and operator estimates is about 204 bcf/section (5.78 ?? 109 m3/1.73 ?? 104 m3). We estimate that the Barnett Shale has a total generation potential of about 609 bbl of oil equivalent/ac-ft or the equivalent of 3657 mcf/ac-ft (84.0 m3/m3). Assuming a thickness of 350 ft (107 m) and only sufficient hydrogen for partial cracking of retained oil to gas, a total generation potential of 820 bcf/section is estimated. Of this potential, approximately 60% was expelled, and the balance was retained for secondary cracking of oil to gas, if sufficient thermal maturity was reached. Gas storage capacity of the Barnett Shale at typical reservoir pressure, volume, and temperature conditions and 6% porosity shows a maximum storage capacity of 540 mcf/ac-ft or 159 scf/ton. Copyright ?? 2007. The American Association of Petroleum Geologists. All rights reserved.

Microporoelastic Modeling of Organic-Rich Shales

NASA Astrophysics Data System (ADS)

Khosh Sokhan Monfared, S.; Abedi, S.; Ulm, F. J.

2014-12-01

Organic-rich shale is an extremely complex, naturally occurring geo-composite. The heterogeneous nature of organic-rich shale and its anisotropic behavior pose grand challenges for characterization, modeling and engineering design The intricacy of organic-rich shale, in the context of its mechanical and poromechanical properties, originates in the presence of organic/inorganic constituents and their interfaces as well as the occurrence of porosity and elastic anisotropy, at multiple length scales. To capture the contributing mechanisms, of 1st order, responsible for organic-rich shale complex behavior, we introduce an original approach for micromechanical modeling of organic-rich shales which accounts for the effect of maturity of organics on the overall elasticity through morphology considerations. This morphology contribution is captured by means of an effective media theory that bridges the gap between immature and mature systems through the choice of system's microtexture; namely a matrix-inclusion morphology (Mori-Tanaka) for immature systems and a polycrystal/granular morphology for mature systems. Also, we show that interfaces play a role on the effective elasticity of mature, organic-rich shales. The models are calibrated by means of ultrasonic pulse velocity measurements of elastic properties and validated by means of nanoindentation results. Sensitivity analyses using Spearman's Partial Rank Correlation Coefficient shows the importance of porosity and Total Organic Carbon (TOC) as key input parameters for accurate model predictions. These modeling developments pave the way to reach a "unique" set of clay properties and highlight the importance of depositional environment, burial and diagenetic processes on overall mechanical and poromechanical behavior of organic-rich shale. These developments also emphasize the importance of understanding and modeling clay elasticity and organic maturity on the overall rock behavior which is of critical importance for a practical rock physics model that accounts for time dependent phenomena which can be employed for seismic inversion.

Permeability Evolution of Slowly Slipping Faults in Shale Reservoirs

NASA Astrophysics Data System (ADS)

Wu, Wei; Reece, Julia S.; Gensterblum, Yves; Zoback, Mark D.

2017-11-01

Slow slip on preexisting faults during hydraulic fracturing is a process that significantly influences shale gas production in extremely low permeability "shale" (unconventional) reservoirs. We experimentally examined the impacts of mineralogy, surface roughness, and effective stress on permeability evolution of slowly slipping faults in Eagle Ford shale samples. Our results show that fault permeability decreases with slip at higher effective stress but increases with slip at lower effective stress. The permeabilities of saw cut faults fully recover after cycling effective stress from 2.5 to 17.5 to 2.5 MPa and increase with slip at constant effective stress due to asperity damage and dilation associated with slip. However, the permeabilities of natural faults only partially recover after cycling effective stress returns to 2.5 MPa and decrease with slip due to produced gouge blocking fluid flow pathways. Our results suggest that slowly slipping faults have the potential to enhance reservoir stimulation in extremely low permeability reservoirs.

Oil shale retort apparatus

DOEpatents

Reeves, Adam A.; Mast, Earl L.; Greaves, Melvin J.

1990-01-01

A retorting apparatus including a vertical kiln and a plurality of tubes for delivering rock to the top of the kiln and removal of processed rock from the bottom of the kiln so that the rock descends through the kiln as a moving bed. Distributors are provided for delivering gas to the kiln to effect heating of the rock and to disturb the rock particles during their descent. The distributors are constructed and disposed to deliver gas uniformly to the kiln and to withstand and overcome adverse conditions resulting from heat and from the descending rock. The rock delivery tubes are geometrically sized, spaced and positioned so as to deliver the shale uniformly into the kiln and form symmetrically disposed generally vertical paths, or "rock chimneys", through the descending shale which offer least resistance to upward flow of gas. When retorting oil shale, a delineated collection chamber near the top of the kiln collects gas and entrained oil mist rising through the kiln.

Effects of organic wastes on water quality from processing of oil shale from the Green River Formation, Colorado, Utah, and Wyoming

USGS Publications Warehouse

Leenheer, J.A.; Noyes, T.I.

1986-01-01

A series of investigations were conducted during a 6-year research project to determine the nature and effects of organic wastes from processing of Green River Formation oil shale on water quality. Fifty percent of the organic compounds in two retort wastewaters were identified as various aromatic amines, mono- and dicarboxylic acids phenols, amides, alcohols, ketones, nitriles, and hydroxypyridines. Spent shales with carbonaceous coatings were found to have good sorbent properties for organic constituents of retort wastewaters. However, soils sampled adjacent to an in situ retort had only fair sorbent properties for organic constituents or retort wastewater, and application of retort wastewater caused disruption of soil structure characteristics and extracted soil organic matter constituents. Microbiological degradation of organic solutes in retort wastewaters was found to occur preferentially in hydrocarbons and fatty acid groups of compounds. Aromatic amines did not degrade and they inhibited bacterial growth where their concentrations were significant. Ammonia, aromatic amines, and thiocyanate persisted in groundwater contaminated by in situ oil shale retorting, but thiosulfate was quantitatively degraded one year after the burn. Thiocyanate was found to be the best conservative tracer for retort water discharged into groundwater. Natural organic solutes, isolated from groundwater in contact with Green River Formation oil shale and from the White River near Rangely, Colorado, were readily distinguished from organic constituents in retort wastewaters by molecular weight and chemical characteristic differences. (USGS)

Iridium contents in the Late Cretaceous-Early Tertiary clays in relation to the K/T boundary, North Jordan

NASA Astrophysics Data System (ADS)

Abboud, Iyad Ahmed

2016-06-01

The mineralogy, lithology, and geochemistry of five discrete laminations across the K/T boundary of clayey shale at the Yarmouk River area, Jordan, were examined. There were no marked changes in the mineralogy of the clayey shale within the K/T boundary. This outcrop consists of more than 100 m of Maastrichtian oil shale overlying about 20 m limestone. Marly limestone included many clay laminations from organic and volcanic origins, which are considered an evidence of the K/T boundary through detected iridium anomalies. Any of these particular lamellae range from 2 mm to 5 mm in thickness. Smectite was the predominant clay mineral in smectitic shale laminations. It was located at eight meters above the K/T boundary and includes some anomalous concentrations of iridium and traces of other elements. The analysis of geochemical platinum group at the K/T boundary clays showed anomalous enrichments of iridium, compared with other carbonate rocks as a result of weathering processes of oil shale, or through concentration from weathering of basalt flows, but not pointing to an impact process. The clays in late Maastrichtian have Ir-Sc prevailed anomalies and synchronize with increasing of terrigenous and volcanogenic traced elements. Kaolin, smectite, and volkonskoite were the dominant clay minerals at the K/T boundary with high concentrations of iridium. The concentration levels of iridium in some laminations of the Yarmouk sediments ranged between 1.6 and 7.8 ppb.

Public and stakeholder participation for managing and reducing the risks of shale gas development.

PubMed

North, D Warner; Stern, Paul C; Webler, Thomas; Field, Patrick

2014-01-01

Emerging technologies pose particularly strong challenges for risk governance when they have multidimensional and inequitable impacts, when there is scientific uncertainty about the technology and its risks, when there are strong value conflicts over the perceived benefits and risks, when decisions must be made urgently, and when the decision making environment is rife with mistrust. Shale gas development is one such emerging technology. Drawing on previous U.S. National Research Council committee reports that examined risk decision making for complex issues like these, we point to the benefits and challenges of applying the analytic-deliberative process recommended in those reports for stakeholder and public engagement in risk decision making about shale gas development in the United States. We discuss the different phases of such a process and conclude by noting the dangers of allowing controversy to ossify and the benefits of sound dialogue and learning among publics, stakeholders, industry, and regulatory decision makers.

Heterogeneity of shales in different scales and its implications to laboratory analyses - examples from sedimentology and organic geochemistry study of the Lower Paleozoic shales from shale gas exploration well located in the Baltic Basin, Poland.

NASA Astrophysics Data System (ADS)

Roszkowska-Remin, Joanna; Janas, Marcin

2017-04-01

We present the litho-sedimentological, organic geochemical results and organic porosity estimation of the Ordovician and Silurian shales in the SeqWell (shale gas exploration well located in the Pomerania region, Poland). The most perspective black and bituminous shales of the Upper Ordovician and the Lower Silurian may seem to be homogeneous. However, our results reveal that these shales show heterogeneity at different scales (m to mm). For example, in most cases the decrease of TOC content in the m scale is related to pyroclastic rock intercalations and "dark bioturbations" with no color difference when compared with surrounding sediments. While in cm scale heterogeneity is related to bioturbations, density of organic-rich laminas, or abundance of carbonates and pyrite. Without a detailed sedimentological study of polished core surfaces and Rock-Eval analyses those observations are rather invisible. The correct interpretation of results requires the understanding of rock's heterogeneity in different scales. It has a critical importance for laboratory tests applied on few cm long samples, especially if the results are to be extrapolated to wider intervals. Therefore in ShaleSeq project, a detailed sedimentological core logging and analysis of geochemical parameters of perspective formations in m to mm scale was performed for the first time. The results show good correlation between bioturbation index (BI) and organic geochemical indicators like organic carbon content (TOC) or oxic deposition conditions indicator (oxygen index - OI) leading to the assumption that environmental conditions may have played a crucial role in organic carbon preservation. The geochemical analyses of 12 samples showed that even within the few cm long sections shale can be really diversified. Eight out of twelve analyzed samples were considered geochemically mostly homogeneous, whilst four of them showed evident heterogeneity. Concluding, the sampling should be preceded by detailed sedimentological study, as it allows to control if the chosen samples are representative for wider intervals and give opportunity to place the laboratory results in the wider context. An attempt to estimate organic porosity using Rock-Eval data was based on Marathon Oil company study of the Polish Lower Paleozoic shales. The results of this study and suggested equations were used to calculate hypothetical organic porosity of the most perspective shales in the SeqWell. Calculated organic porosities in % bulk volume of rock suggested that organic porosity for Upper Ordovician and Lower Silurian shales in SeqWell may be at the level of 0,1-2,9% in bulk volume of rock. These results would suggest that organic porosity doesn't play a major role in total porosity system in these shales at the certain thermal maturity level. The hypothetical organic porosity values were not validated by the microscopic study though. Our study are part of the ShaleSeq Project co-funded by Norway Grants of the Polish-Norwegian Research Programme operated by the National Centre for Research and Development.

Analysis of river pollution data from low-flow period by means of multivariate techniques: a case study from the oil-shale industry region, northeastern Estonia.

PubMed

Truu, Jaak; Heinaru, Eeva; Talpsep, Ene; Heinaru, Ain

2002-01-01

The oil-shale industry has created serious pollution problems in northeastern Estonia. Untreated, phenol-rich leachate from semi-coke mounds formed as a by-product of oil-shale processing is discharged into the Baltic Sea via channels and rivers. An exploratory analysis of water chemical and microbiological data sets from the low-flow period was carried out using different multivariate analysis techniques. Principal component analysis allowed us to distinguish different locations in the river system. The riverine microbial community response to water chemical parameters was assessed by co-inertia analysis. Water pH, COD and total nitrogen were negatively related to the number of biodegradative bacteria, while oxygen concentration promoted the abundance of these bacteria. The results demonstrate the utility of multivariate statistical techniques as tools for estimating the magnitude and extent of pollution based on river water chemical and microbiological parameters. An evaluation of river chemical and microbiological data suggests that the ambient natural attenuation mechanisms only partly eliminate pollutants from river water, and that a sufficient reduction of more recalcitrant compounds could be achieved through the reduction of wastewater discharge from the oil-shale chemical industry into the rivers.

Adequacy of Current State Setbacks for Directional High-Volume Hydraulic Fracturing in the Marcellus, Barnett, and Niobrara Shale Plays

PubMed Central

Haley, Marsha; McCawley, Michael; Epstein, Anne C.; Arrington, Bob; Bjerke, Elizabeth Ferrell

2016-01-01

Background: There is an increasing awareness of the multiple potential pathways leading to human health risks from hydraulic fracturing. Setback distances are a legislative method to mitigate potential risks. Objectives: We attempted to determine whether legal setback distances between well-pad sites and the public are adequate in three shale plays. Methods: We reviewed geography, current statutes and regulations, evacuations, thermal modeling, air pollution studies, and vapor cloud modeling within the Marcellus, Barnett, and Niobrara Shale Plays. Discussion: The evidence suggests that presently utilized setbacks may leave the public vulnerable to explosions, radiant heat, toxic gas clouds, and air pollution from hydraulic fracturing activities. Conclusions: Our results suggest that setbacks may not be sufficient to reduce potential threats to human health in areas where hydraulic fracturing occurs. It is more likely that a combination of reasonable setbacks with controls for other sources of pollution associated with the process will be required. Citation: Haley M, McCawley M, Epstein AC, Arrington B, Bjerke EF. 2016. Adequacy of current state setbacks for directional high-volume hydraulic fracturing in the Marcellus, Barnett, and Niobrara Shale Plays. Environ Health Perspect 124:1323–1333; http://dx.doi.org/10.1289/ehp.1510547 PMID:26895553

Energy and Environment Division, annual report FY 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osowitt, M.

1981-07-01

This report covers research in: energy analysis; energy efficiency studies; solar energy; chemical process; energy-efficient buildings; environmental pollutant studies; combustion research; laser spectroscopy and trace elements; and oil shale and coal research. An energy and environment personnel listing is appended. Separate projects are indexed individually for the database. (PSB)

Sharing Water Data to Encourage Sustainable Choices in Areas of the Marcellus Shale

NASA Astrophysics Data System (ADS)

Brantley, S. L.; Abad, J. D.; Vastine, J.; Yoxtheimer, D.; Wilderman, C.; Vidic, R.; Hooper, R. P.; Brasier, K.

2012-12-01

Natural gas sourced from shales but stored in more permeable formations has long been exploited as an energy resource. Now, however, gas is exploited directly from the low-porosity and low-permeability shale reservoirs through the use of hydrofracturing. Hydrofracturing is not a new technique: it has long been utilized in the energy industry to promote flow of oil and gas from traditional reservoirs. To exploit gas in reservoirs such as the Marcellus shale in PA, hydrofracturing is paired with directional drilling. Such hydrofracturing utilizes large volumes of water to increase porosity in the shale formations at depth. Small concentrations of chemicals are added to the water to improve the formation and maintenance of the fractures. Significant public controversy has developed in response to the use of hydrofracturing especially in the northeastern states underlain by the Marcellus shale where some citizens and scientists question whether shale gas recovery will contaminate local surface and ground waters. Researchers, government agencies, and citizen scientists in Pennsylvania are teaming up to run the ShaleNetwork (www.shalenetwork.org), an NSF-funded research collaboration network that is currently finding, collating, sharing, publishing, and exploring data related to water quality and quantity in areas that are exploiting shale gas. The effort, focussed initially on Pennsylvania, is now developing the ShaleNetwork database that can be accessed through HydroDesktop in the CUAHSI Hydrologic Information System. In the first year since inception, the ShaleNetwork ran a workshop and reached eight conclusions, largely focussed on issues related to the sources, entry, and use of data. First, the group discovered that extensive water data is available in areas of shale gas. Second, participants agreed that the Shale Network team should partner with state agencies and industry to move datasets online. Third, participants discovered that the database allows participants to assess data gaps. Fourth, the team was encouraged to search for data that plug gaps. Fifth, the database should be easily sustained by others long-term if the Shale Network team simplifies the process of uploading data and finds ways to create community buy-in or incentives for data uploads. Sixth, the database itself and the workshops for the database should drive future agreement about analytical protocols. Seventh, the database is already encouraging other groups to publish data online. Finally, a user interface is needed that is easier and more accessible for citizens to use. Overall, it is clear that sharing data is one way to build bridges among decision makers, scientists, and citizens to understand issues related to sustainable development of energy resources in the face of issues related to water quality and quantity.

Fractures system within Qusaiba shale outcrop and its relationship to the lithological properties, Qasim area, Central Saudi Arabia

NASA Astrophysics Data System (ADS)

Ibrahim, Mohamed I. M.; Hariri, Mustafa M.; Abdullatif, Osman M.; Makkawi, Mohammad H.; Elzain, Hussam

2017-09-01

The basal Qusaiba hot shale member of Qalibah Formation is considered to be an important source rock in the Paleozoic petroleum system of Saudi Arabia and an exploration target for tight shale as one of the Unconventional resources of petroleum. This work has been carried out to understand the fractures network of Qusaiba shale member in outcrops located to the west of Qusayba' village in Al-Qasim area, Central Saudi Arabia. The main objective of this study is to understand the distribution of natural fractures over different lithological units. Description data sheets were used for the detailed lithological description of Qusaiba shale member on two outcrops. Spot-7 and Landsat ETM+ satellite images were used for lineament mapping and analyses on a regional scale in a GIS environment. Fractures characterization in outcrop-scale was conducted by using linear scanline method. Qusaiba shale member in the study area consists of 5 main lithofacies, divided based on their sedimentary structures and petrographical properties, from base to top in the outcrops, the lithofacies are; fissile shale, very fine-grained micaceous siltstone, bioturbated mudstone, very fine to fine-grained hummocky cross-stratified sandstone, and fine to medium-grained low/high angle cross-stratified sandstone lithofacies. Lineaments interpretation of the Spot-7 and Landsat ETM+ satellite images showed two major directions in the study area; 320° that could be related to Najd fault system and 20° that could be related to the extensional activities which took place after Amar collision. Fractures are much denser in the fissile shale and mudstone lithofacies than sandstones lithofacies, and average spacing is smaller in the fissile shale and mudstone lithofacies than sandstones lithofacies. Lineaments and large-scale fractures are Non-Stratabound fractures and they deal with the area as one big mechanical unit, but small-scale fractures are Stratabound fractures that propose different mechanical units within Qusaiba shale member in the study area. The fractures network in the study area has a wide range of properties related to fractures density, length, spacing, height, and termination degree. The conceptual multi-scale model divides the fractures in the study area into 4 orders depending on the available data that have been observed from satellite images and field. The multi-scale fractures model that was generated in this study could help to understand the distribution of stratigraphically controlled fractures when integrated with flow simulation models. Overall, this work could have a significant contribution to tight shale exploration plans in the subsurface by providing some knowledge about the fractures mechanical behavior of the lower part of Qusaiba shale member of Qalibah Formation.

Effects of Salinity and Confining Pressure on Hydration-Induced Fracture Propagation and Permeability of Mancos Shale

NASA Astrophysics Data System (ADS)

Zhang, Shifeng; Sheng, James J.

2017-11-01

Low-salinity water imbibition was considered an enhanced recovery method in shale oil/gas reservoirs due to the resulting hydration-induced fractures, as observed at ambient conditions. To study the effect of confining pressure and salinity on hydration-induced fractures, time-elapsed computerized tomography (CT) was used to obtain cross-sectional images of shale cores. Based on the CT data of these cross-sectional images, cut faces parallel to the core axial in the middle of the core and 3D fracture images were also reconstructed. To study the effects of confining pressure and salinity on shale pore fluid flowing, shale permeability was measured with Nitrogen (N2), distilled water, 4% KCl solution, and 8% KCl solution. With confining pressures increased to 2 MPa or more, either in distilled water or in KCl solutions of different salinities, fractures were observed to close instead to propagate at the end of the tests. The intrinsic permeabilities of #1 and #2 Mancos shale cores were 60.0 and 7000 nD, respectively. When tested with distilled water, the permeability of #1 shale sample with 20.0 MPa confining pressure loaded, and #2 shale sample with 2.5 MPa confining pressure loaded, decreased to 0.45 and 15 nD, respectively. Using KCl can partly mitigate shale permeability degradation. Compared to 4% KCl, 8% KCl can decrease more permeability damage. From this point of view, high salinity KCl solution should be required for the water-based fracturing fluid.

Experimental investigation on the fracture behaviour of black shale by acoustic emission monitoring and CT image analysis during uniaxial compression

NASA Astrophysics Data System (ADS)

Wang, Y.; Li, C. H.; Hu, Y. Z.

2018-04-01

Plenty of mechanical experiments have been done to investigate the deformation and failure characteristics of shale; however, the anisotropic failure mechanism has not been well studied. Here, laboratory Uniaxial Compressive Strength tests on cylindrical shale samples obtained by drilling at different inclinations to bedding plane were performed. The failure behaviours of the shale samples were studied by real-time acoustic emission (AE) monitoring and post-test X-ray computer tomography (CT) analysis. The experimental results suggest that the pronounced bedding planes of shale have a great influence on the mechanical properties and AE patterns. The AE counts and AE cumulative energy release curves clearly demonstrate different morphology, and the `U'-shaped curve relationship between the AE counts, AE cumulative energy release and bedding inclination was first documented. The post-test CT image analysis shows the crack patterns via 2-D image reconstructions, an index of stimulated fracture density is defined to represent the anisotropic failure mode of shale. What is more, the most striking finding is that the AE monitoring results are in good agreement with the CT analysis. The structural difference in the shale sample is the controlling factor resulting in the anisotropy of AE patterns. The pronounced bedding structure in the shale formation results in an anisotropy of elasticity, strength and AE information from which the changes in strength dominate the entire failure pattern of the shale samples.

On the possibility of magnetic nano-markers use for hydraulic fracturing in shale gas mining

NASA Astrophysics Data System (ADS)

Zawadzki, Jaroslaw; Bogacki, Jan

2016-04-01

Recently shale gas production became essential for the global economy, thanks to fast advances in shale fracturing technology. Shale gas extraction can be achieved by drilling techniques coupled with hydraulic fracturing. Further increasing of shale gas production is possible by improving the efficiency of hydraulic fracturing and assessing the spatial distribution of fractures in shale deposits. The latter can be achieved by adding magnetic markers to fracturing fluid or directly to proppant, which keeps the fracture pathways open. After that, the range of hydraulic fracturing can be assessed by measurement of vertical and horizontal component of earth's magnetic field before and after fracturing. The difference in these components caused by the presence of magnetic marker particles may allow to delineate spatial distribution of fractures. Due to the fact, that subterranean geological formations may contain minerals with significant magnetic properties, it is important to provide to the markers excellent magnetic properties which should be also, independent of harsh chemical and geological conditions. On the other hand it is of great significance to produce magnetic markers at an affordable price because of the large quantities of fracturing fluids or proppants used during shale fracturing. Examining the properties of nano-materials, it was found, that they possess clearly superior magnetic properties, as compared to the same structure but having a larger particle size. It should be then possible, to use lower amount of magnetic marker, to obtain the same effect. Although a research on properties of new magnetic nano-materials is very intensive, cheap magnetic nano-materials are not yet produced on a scale appropriate for shale gas mining. In this work we overview, in detail, geological, technological and economic aspects of using magnetic nano-markers in shale gas mining. Acknowledgment This work was supported by the NCBiR under Grant "Electromagnetic method to estimate penetration of proppant in the fracturing process".

Geochemical and mineralogical sampling of the Devonian shales in the Broadtop synclinorium, Appalachian basin, in Virginia, West Virginia, Maryland, and Pennsylvania

USGS Publications Warehouse

Enomoto, Catherine B.; Coleman, James L.; Swezey, Christopher S.; Niemeyer, Patrick W.; Dulong, Frank T.

2015-01-01

The presence of conventional anticlinal gas fields in the study area that are productive from the underlying Lower Devonian Oriskany Sandstone suggests that an unconventional (or continuous) shale gas system may be in place within the Marcellus Shale in the study area. Results of this study indicate that the Marcellus Shale in the Broadtop synclinorium generally is similar in organic geochemical nature throughout its extent, and based on the sample analyses, there are no clearly identifiable high potential areas (or “sweet spots”) in the study area. This report contains analyses of 132 outcrop and well drill-cuttings samples.

New Advances in Re-Os Geochronology of Organic-rich Sedimentary Rocks.

NASA Astrophysics Data System (ADS)

Creaser, R. A.; Selby, D.; Kendall, B. S.

2003-12-01

Geochronology using 187Re-187Os is applicable to limited rock and mineral matrices, but one valuable application is the determination of depositional ages for organic-rich clastic sedimentary rocks like black shales. Clastic sedimentary rocks, in most cases, do not yield depositional ages using other radioactive isotope methods, but host much of Earth's fossil record upon which the relative geological timescale is based. As such, Re-Os dating of black shales has potentially wide application in timescale calibration studies and basin analysis, if sufficiently high precision and accuracy could be achieved. This goal requires detailed, systematic studies and evaluation of factors like standard compound stoichiometry, geologic effects, and the 187Re decay constant. Ongoing studies have resulted in an improved understanding of the abilities, limitations and systematics of the Re-Os geochronometer in black shales. First-order knowledge of the effects of processes like hydrocarbon maturation and low-grade metamorphism is now established. Hydrocarbon maturation does not impact the ability of the Re-Os geochronometer to determine depositional ages from black shales. The Re-Os age determined for the Exshaw Fm of western Canada is accurate within 2σ analytical uncertainty of the known age of the unit (U-Pb monazite from ash, conodont biostratigraphy). This suggests that the large improvement in precision attained for Re-Os dating of black shales by Cohen et al (ESPL 1999) over the pioneering work of Ravizza & Turekian (GCA 1989), relates to advances in analytical methodologies and sampling strategies, rather than a lack of disturbance by hydrocarbon maturation. We have found that a significant reduction in isochron scatter can be achieved by using an alternate dissolution medium, which preferentially attacks organic matter in which Re and Os are largely concentrated. This likely results from a more limited release of detrital Os and Re held in silicate materials during dissolution, compared with the inverse aqua regia medium used for Carius tube analysis. Using these "organic-selective" dissolution techniques, precise depositional ages have now been obtained from samples with very low TOC contents ( ˜0.5%), meaning that a greater range of clastic sedimentary rocks is amenable for Re-Os age dating. Well-fitted Re-Os isochrons of plausible geological age have also been determined from low-TOC shales subjected to chlorite-grade regional metamorphism. These results further illustrate the wide, but currently underutilized, potential of the Re-Os geochronometer in shales. The precision of age data attainable by the Re-Os system directly from black shales can be better than +/- 1% uncertainty (2σ , derived from isochron regression analysis), and the derived ages are demonstrably accurate.

Formation resistivity as an indicator of oil generation in black shales

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hester, T.C.; Schmoker, J.W.

1987-08-01

Black, organic-rich shales of Late Devonian-Early Mississippi age are present in many basins of the North American craton and, where mature, have significant economic importance as hydrocarbon source rocks. Examples drawn from the upper and lower shale members of the Bakken Formation, Williston basin, North Dakota, and the Woodford Shale, Anadarko basin, Oklahoma, demonstrate the utility of formation resistivity as a direct in-situ indicator of oil generation in black shales. With the onset of oil generation, nonconductive hydrocarbons begin to replace conductive pore water, and the resistivity of a given black-shale interval increases from low levels associated with thermal immaturitymore » to values approaching infinity. Crossplots of a thermal-maturity index (R/sub 0/ or TTI) versus formation resistivity define two populations representing immature shales and shales that have generated oil. A resistivity of 35 ohm-m marks the boundary between immature and mature source rocks for each of the three shales studied. Thermal maturity-resistivity crossplots make possible a straightforward determination of thermal maturity at the onset of oil generation, and are sufficiently precise to detect subtle differences in source-rock properties. For example, the threshold of oil generation in the upper Bakken shale occurs at R/sub 0/ = 0.43-0.45% (TTI = 10-12). The threshold increases to R/sub 0/ = 0.48-0.51% (TTI = 20-26) in the lower Bakken shale, and to R/sub 0/ = 0.56-0.57% (TTI = 33-48) in the most resistive Woodford interval.« less

Shale Gas Geomechanics for Development and Performance of Unconventional Reservoirs

NASA Astrophysics Data System (ADS)

Domonik, Andrzej; Łukaszewski, Paweł; Wilczyński, Przemysław; Dziedzic, Artur; Łukasiak, Dominik; Bobrowska, Alicja

2017-04-01

Mechanical properties of individual shale formations are predominantly determined by their lithology, which reflects sedimentary facies distribution, and subsequent diagenetic and tectonic alterations. Shale rocks may exhibit complex elasto-viscoplastic deformation mechanisms depending on the rate of deformation and the amount of clay minerals, also bearing implications for subcritical crack growth and heterogeneous fracture network development. Thus, geomechanics for unconventional resources differs from conventional reservoirs due to inelastic matrix behavior, stress sensitivity, rock anisotropy and low matrix permeability. Effective horizontal drilling and hydraulic fracturing technologies are required to obtain and maintain high performance. Success of these techniques strongly depends on the geomechanical investigations of shales. An inelastic behavior of shales draws increasing attention of investigators [1], due to its role in stress relaxation between fracturing phases. A strong mechanical anisotropy in the vertical plane and a lower and more variable one in the horizontal plane are characteristic for shale rocks. The horizontal anisotropy plays an important role in determining the direction and effectiveness of propagation of technological hydraulic fractures. Non-standard rock mechanics laboratory experiments are being applied in order to obtain the mechanical properties of shales that have not been previously studied in Poland. Novel laboratory investigations were carried out to assess the creep parameters and to determine time-dependent viscoplastic deformation of shale samples, which can provide a limiting factor to tectonic stresses and control stress change caused by hydraulic fracturing. The study was supported by grant no.: 13-03-00-501-90-472946 "An integrated geomechanical investigation to enhance gas extraction from the Pomeranian shale formations", funded by the National Centre for Research and Development (NCBiR). References: Ch. Chang M. D. Zoback. 2009. Viscous creep in room-dried unconsolidated Gulf of Mexico shale (I): Experimental results. Journal of Petroleum Science and Engineering 69: 239-246.

Extraction of hydrocarbons from high-maturity Marcellus Shale using supercritical carbon dioxide

USGS Publications Warehouse

Jarboe, Palma B.; Philip A. Candela,; Wenlu Zhu,; Alan J. Kaufman,

2015-01-01

Shale is now commonly exploited as a hydrocarbon resource. Due to the high degree of geochemical and petrophysical heterogeneity both between shale reservoirs and within a single reservoir, there is a growing need to find more efficient methods of extracting petroleum compounds (crude oil, natural gas, bitumen) from potential source rocks. In this study, supercritical carbon dioxide (CO2) was used to extract n-aliphatic hydrocarbons from ground samples of Marcellus shale. Samples were collected from vertically drilled wells in central and western Pennsylvania, USA, with total organic carbon (TOC) content ranging from 1.5 to 6.2 wt %. Extraction temperature and pressure conditions (80 °C and 21.7 MPa, respectively) were chosen to represent approximate in situ reservoir conditions at sample depth (1920−2280 m). Hydrocarbon yield was evaluated as a function of sample matrix particle size (sieve size) over the following size ranges: 1000−500 μm, 250−125 μm, and 63−25 μm. Several methods of shale characterization including Rock-Eval II pyrolysis, organic petrography, Brunauer−Emmett−Teller surface area, and X-ray diffraction analyses were also performed to better understand potential controls on extraction yields. Despite high sample thermal maturity, results show that supercritical CO2 can liberate diesel-range (n-C11 through n-C21) n-aliphatic hydrocarbons. The total quantity of extracted, resolvable n-aliphatic hydrocarbons ranges from approximately 0.3 to 12 mg of hydrocarbon per gram of TOC. Sieve size does have an effect on extraction yield, with highest recovery from the 250−125 μm size fraction. However, the significance of this effect is limited, likely due to the low size ranges of the extracted shale particles. Additional trends in hydrocarbon yield are observed among all samples, regardless of sieve size: 1) yield increases as a function of specific surface area (r2 = 0.78); and 2) both yield and surface area increase with increasing TOC content (r2 = 0.97 and 0.86, respectively). Given that supercritical CO2 is able to mobilize residual organic matter present in overmature shales, this study contributes to a better understanding of the extent and potential factors affecting the extraction process.

Effect of organic matter properties, clay mineral type and thermal maturity on gas adsorption in organic-rich shale systems

USGS Publications Warehouse

Zhang, Tongwei; Ellis, Geoffrey S.; Ruppel, Stephen C.; Milliken, Kitty; Lewan, Mike; Sun, Xun; Baez, Luis; Beeney, Ken; Sonnenberg, Steve

2013-01-01

A series of CH4 adsorption experiments on natural organic-rich shales, isolated kerogen, clay-rich rocks, and artificially matured Woodford Shale samples were conducted under dry conditions. Our results indicate that physisorption is a dominant process for CH4 sorption, both on organic-rich shales and clay minerals. The Brunauer–Emmett–Teller (BET) surface area of the investigated samples is linearly correlated with the CH4 sorption capacity in both organic-rich shales and clay-rich rocks. The presence of organic matter is a primary control on gas adsorption in shale-gas systems, and the gas-sorption capacity is determined by total organic carbon (TOC) content, organic-matter type, and thermal maturity. A large number of nanopores, in the 2–50 nm size range, were created during organic-matter thermal decomposition, and they significantly contributed to the surface area. Consequently, methane-sorption capacity increases with increasing thermal maturity due to the presence of nanopores produced during organic-matter decomposition. Furthermore, CH4 sorption on clay minerals is mainly controlled by the type of clay mineral present. In terms of relative CH4 sorption capacity: montmorillonite ≫ illite – smectite mixed layer > kaolinite > chlorite > illite. The effect of rock properties (organic matter content, type, maturity, and clay minerals) on CH4 adsorption can be quantified with the heat of adsorption and the standard entropy, which are determined from adsorption isotherms at different temperatures. For clay-mineral rich rocks, the heat of adsorption (q) ranges from 9.4 to 16.6 kJ/mol. These values are considerably smaller than those for CH4 adsorption on kerogen (21.9–28 kJ/mol) and organic-rich shales (15.1–18.4 kJ/mol). The standard entropy (Δs°) ranges from -64.8 to -79.5 J/mol/K for clay minerals, -68.1 to -111.3 J/mol/K for kerogen, and -76.0 to -84.6 J/mol/K for organic-rich shales. The affinity of CH4 molecules for sorption on organic matter is stronger than for most common clay minerals. Thus, it is expected that CH4 molecules may preferentially occupy surface sites on organic matter. However, active sites on clay mineral surfaces are easily blocked by water. As a consequence, organic-rich shales possess a larger CH4-sorption capacity than clay-rich rocks lacking organic matter. The thermodynamic parameters obtained in this study can be incorporated into model predictions of the maximum Langmuir pressure and CH4- sorption capacity of shales under reservoir temperature and pressure conditions.

Statistical evaluation of the impact of shale gas activities on ozone pollution in North Texas.

PubMed

Ahmadi, Mahdi; John, Kuruvilla

2015-12-01

Over the past decade, substantial growth in shale gas exploration and production across the US has changed the country's energy outlook. Beyond its economic benefits, the negative impacts of shale gas development on air and water are less well known. In this study the relationship between shale gas activities and ground-level ozone pollution was statistically evaluated. The Dallas-Fort Worth (DFW) area in north-central Texas was selected as the study region. The Barnett Shale, which is one the most productive and fastest growing shale gas fields in the US, is located in the western half of DFW. Hourly meteorological and ozone data were acquired for fourteen years from monitoring stations established and operated by the Texas Commission on Environmental Quality (TCEQ). The area was divided into two regions, the shale gas region (SGR) and the non-shale gas (NSGR) region, according to the number of gas wells in close proximity to each monitoring site. The study period was also divided into 2000-2006 and 2007-2013 because the western half of DFW has experienced significant growth in shale gas activities since 2007. An evaluation of the raw ozone data showed that, while the overall trend in the ozone concentration was down over the entire region, the monitoring sites in the NSGR showed an additional reduction of 4% in the annual number of ozone exceedance days than those in the SGR. Directional analysis of ozone showed that the winds blowing from areas with high shale gas activities contributed to higher ozone downwind. KZ-filtering method and linear regression techniques were used to remove the effects of meteorological variations on ozone and to construct long-term and short-term meteorologically adjusted (M.A.) ozone time series. The mean value of all M.A. ozone components was 8% higher in the sites located within the SGR than in the NSGR. These findings may be useful for understanding the overall impact of shale gas activities on the local and regional ozone pollution. Copyright © 2015 Elsevier B.V. All rights reserved.

Hydraulic Fracture Extending into Network in Shale: Reviewing Influence Factors and Their Mechanism

PubMed Central

Ren, Lan; Zhao, Jinzhou; Hu, Yongquan

2014-01-01

Hydraulic fracture in shale reservoir presents complex network propagation, which has essential difference with traditional plane biwing fracture at forming mechanism. Based on the research results of experiments, field fracturing practice, theory analysis, and numerical simulation, the influence factors and their mechanism of hydraulic fracture extending into network in shale have been systematically analyzed and discussed. Research results show that the fracture propagation in shale reservoir is influenced by the geological and the engineering factors, which includes rock mineral composition, rock mechanical properties, horizontal stress field, natural fractures, treating net pressure, fracturing fluid viscosity, and fracturing scale. This study has important theoretical value and practical significance to understand fracture network propagation mechanism in shale reservoir and contributes to improving the science and efficiency of shale reservoir fracturing design. PMID:25032240

Speciation and weathering of selenium in upper cretaceous chalk and shale from South Dakota and Wyoming, USA

NASA Astrophysics Data System (ADS)

Kulp, Thomas R.; Pratt, Lisa M.

2004-09-01

In geologic materials, petroleum, and the environment, selenium occurs in various oxidation states (VI, IV, 0, -II), mineralized forms, and organo-Se complexes. Each of these forms is characterized by specific chemical and biochemical properties that control the element's solubility, toxicity, and environmental behavior. The organic rich chalks and shales of the Upper Cretaceous Niobrara Formation and the Pierre Shale in South Dakota and Wyoming are bentoniferous stratigraphic intervals characterized by anomalously high concentrations of naturally occurring Se. Numerous environmental problems have been associated with Se derived from these geological units, including the development of seleniferous soils and vegetation that are toxic to livestock and the contamination of drinking water supplies by Se mobilized in groundwater. This study describes a sequential extraction protocol followed by speciation treatments and quantitative analysis by Hydride Generation-Atomic Absorption Spectroscopy. This protocol was utilized to investigate the geochemical forms and the oxidation states in which Se occurs in these geologic units. Organic Se and di-selenide minerals are the predominant forms of Se present in the chalks, shales, and bentonites, but distinctive variations in these forms were observed between different sample types. Chalks contain significantly greater proportions of Se in the form of di-selenide minerals (including Se associated with pyrite) than the shales where base-soluble, humic, organo-Se complexes are more prevalent. A comparison between unweathered samples collected from lithologic drill cores and weathered samples collected from outcrop suggest that the humic, organic-Se compounds in shale are formed during oxidative weathering and that Se oxidized by weathering is more likely to be retained by shale than by chalk. Selenium enrichment in bentonites is inferred to result from secondary processes including the adsorption of Se mobilized by groundwater from surrounding organic rich sediments to clay mineral and iron hydroxide surfaces, as well as microbial reduction of Se within the bentonitic intervals. Distinct differences are inferred for the biogeochemical pathways that affected sedimentary Se sequestration during periods of chalk accumulation compared to shale deposition in the Cretaceous seaway. Mineralogy of sediment and the nature of the organic matter associated with each of these rock types have important implications for the environmental chemistry and release of Se to the environment during weathering.

Experimental investigations of the wettability of clays and shales

NASA Astrophysics Data System (ADS)

Borysenko, Artem; Clennell, Ben; Sedev, Rossen; Burgar, Iko; Ralston, John; Raven, Mark; Dewhurst, David; Liu, Keyu

2009-07-01

Wettability in argillaceous materials is poorly understood, yet it is critical to hydrocarbon recovery in clay-rich reservoirs and capillary seal capacity in both caprocks and fault gouges. The hydrophobic or hydrophilic nature of clay-bearing soils and sediments also controls to a large degree the movement of spilled nonaqueous phase liquids in the subsurface and the options available for remediation of these pollutants. In this paper the wettability of hydrocarbons contacting shales in their natural state and the tendencies for wettability alteration were examined. Water-wet, oil-wet, and mixed-wet shales from wells in Australia were investigated and were compared with simplified model shales (single and mixed minerals) artificially treated in crude oil. The intact natural shale samples (preserved with their original water content) were characterized petrophysically by dielectric spectroscopy and nuclear magnetic resonance, plus scanning electron, optical and fluorescence microscopy. Wettability alteration was studied using spontaneous imbibition, pigment extraction, and the sessile drop method for contact angle measurement. The mineralogy and chemical compositions of the shales were determined by standard methods. By studying pure minerals and natural shales in parallel, a correlation between the petrophysical properties, and wetting behavior was observed. These correlations may potentially be used to assess wettability in downhole measurements.

Organic / inorganic carbon content and isotope analysis of 3.1Ga Cleaverville Formation in Pilbara, Australia: Result of DXCL project

NASA Astrophysics Data System (ADS)

Miki, T.; Kiyokawa, S.; Ito, T.; Yamaguchi, K. E.; Ikehara, M.

2014-12-01

DXCL project was targeted for 3.2-3.1 Ga hydrothermal chert-black shale (Dixon Island Formation) and black shale-banded iron formation (Cleaverville Formation). CL3 core (200m long) was drilled from 1) upper part of Black Shale Member (35m thick) to 2) lower part of BIF Member (165m thick) of the Cleaverville Formation. Here, the BIF Member can be divided into three submembers; Greenish shale-siderite (50m thick), Magnetite-siderite (55m thick) and Black shale-siderite (60m) submembers. In this study, we used bulk samples and samples treated by hot hydrochloric acid in order to extract organic carbon. 　The Black shale Member consists of black carbonaceous　matter and fine grain quartz (< 100μm). Organic carbon content (Corg) of black shale is 1.2% in average and organic carbon isotope ratio (δ13Corg) is -31.4 to -28.7‰. On the other hand, inorganic carbon isotope ratio of siderite (δ13Ccarb) was -5.2 to +12.6‰. 　In the BIF Member, the Greenish shale-siderite submember is composed of well laminated greenish sideritic shale and white chert (<7mm thick), which is gradually increase from black shale of the Black shale Member through about 10m. Magnetite-siderite submember contains very fine magnetite lamination with inter-bedded greenish sideritic shale and siderite lamination. Hematite is identified near fractured part. The Black shale-siderite submember is composed of black shale, siderite and chert bands. 　1) Siderite layers of these three submembers showedδ13Ccarb value of -14.6 to -3.8‰. Corg and δ13Corg content are 0.2% and -18.3 to -0.3‰. 2) Siderite grains within greenish sideritic shales showedδ13Ccarb value of -12.9 to +15.0‰. 3) Black shale of Corg and δ13Corg content in the BIF Member are 0.1% and -36.3 to -17.1‰ respectively. 　We found great difference in values of δ13Ccarb of siderite. One is Corg-rich shale (up to +15.0‰) and the other is Corg-poor siderite layers (up to -3.8‰). The lighter value of siderite layers may be originated from precursor organic carbon which is strongly affected by biological activity.

Attenuation of Chemical Reactivity of Shale Matrixes following Scale Precipitation

NASA Astrophysics Data System (ADS)

Li, Q.; Jew, A. D.; Kohli, A. H.; Alalli, G.; Kiss, A. M.; Kovscek, A. R.; Zoback, M. D.; Brown, G. E.; Maher, K.; Bargar, J.

2017-12-01

Introduction of fracture fluids into shales initiates a myriad of fluid-rock reactions that can strongly influence migration of fluid and hydrocarbon through shale/fracture interfaces. Due to the extremely low permeability of shale matrixes, studies on chemical reactivity of shales have mostly focused on shale surfaces. Shale-fluid interactions inside within shale matrixes have not been examined, yet the matrix is the primary conduit through which hydrocarbons and potential contaminants are transmitted. To characterize changes in matrix mineralogy, porosity, diffusivity, and permeability during hydraulic stimulation, we reacted Marcellus (high clay and low carbonate) and Eagle Ford (low clay and high carbonate) shale cores with fracture fluids for 3 weeks at elevated pressure and temperature (80 oC, and 77 bars). In the carbonate-poor Marcellus system, fluid pH increased from 2 to 4, and secondary Fe(OH)3 precipitates were observed in the fluid. Sulfur X-ray fluorescence maps show that fluids had saturated and reacted with the entire 1-cm-diameter core. In the carbonate-rich Eagle Ford system, pH increased from 2 to 6 due to calcite dissolution. When additional Ba2+ and SO42- were present (log10(Q/K)=1.3), extensive barite precipitation was observed in the matrix of the Eagle Ford core (and on the surface). Barite precipitation was also observed on the surface of the Marcellus core, although to a lesser extent. In the Marcellus system, the presence of barite scale attenuated diffusivity in the matrix, as demonstrated by sharply reduced Fe leaching and much less sulfide oxidation. Systematic studies in homogeneous solution show that barite scale precipitation rates are highly sensitive to pH, salinity, and the presence of organic compounds. These findings imply that chemical reactions are not confined to shale/fluid interfaces but can penetrate into shale matrices, and that barite scale formation can clog diffusion pathways for both fluid and hydrocarbon.

Study on the microwave catalytic pyrolysis characteristics and energy consumption analysis of oil shale

NASA Astrophysics Data System (ADS)

Chen, Chunxiang; Cheng, Zheng; Xu, Qing; Qin, Songheng

2018-04-01

In order to explore the high-efficient utilization of oil shale, the effects of different microwave powers and different kinds of catalysts (metal oxides and metal salts) on the temperature characteristics and product yield towards the oil shale are investigated by microwave catalytic pyrolysis. The results show that the effect of microwave power on the heating and pyrolysis rates of oil shale is significant, and the maximum output of shale oil is 5.1% when the microwave power is 1500W; CaO has a certain effect on the temperature rise of oil shale, and MgO and CuO have a certain degree of inhibition, but the addition of three kinds of metal oxidation is beneficial to increase the shale oil production; From the perspective of unit power consumption and gas production, the catalytic effect order of three kinds of metal oxides is MgO> CaO> CuO; The addition of three kinds of metal salts is favorable for the increase of pyrolysis temperature of oil shale, after adding 5% ZnCl2, the unit power consumption of shale oil and pyrolysis gas increases by 62.60% and 81.96% respectively. After adding 5% NaH2PO3, the unit power consumption of shale oil increases by 64.64%, and reduces by 9.56% by adding 5% MgCl2.

Water use for Shale-gas production in Texas, U.S.

PubMed

Nicot, Jean-Philippe; Scanlon, Bridget R

2012-03-20

Shale-gas production using hydraulic fracturing of mostly horizontal wells has led to considerable controversy over water-resource and environmental impacts. The study objective was to quantify net water use for shale-gas production using data from Texas, which is the dominant producer of shale gas in the U.S. with a focus on three major plays: the Barnett Shale (~15,000 wells, mid-2011), Texas-Haynesville Shale (390 wells), and Eagle Ford Shale (1040 wells). Past water use was estimated from well-completion data, and future water use was extrapolated from past water use constrained by shale-gas resources. Cumulative water use in the Barnett totaled 145 Mm(3) (2000-mid-2011). Annual water use represents ~9% of water use in Dallas (population 1.3 million). Water use in younger (2008-mid-2011) plays, although less (6.5 Mm(3) Texas-Haynesville, 18 Mm(3) Eagle Ford), is increasing rapidly. Water use for shale gas is <1% of statewide water withdrawals; however, local impacts vary with water availability and competing demands. Projections of cumulative net water use during the next 50 years in all shale plays total ~4350 Mm(3), peaking at 145 Mm(3) in the mid-2020s and decreasing to 23 Mm(3) in 2060. Current freshwater use may shift to brackish water to reduce competition with other users.

The organic geochemical characterization: An indication of type of kerogen and maturity of early - Mid Jurassic shale in the Blue Nile formation

NASA Astrophysics Data System (ADS)

Shoieba, Monera Adam; Sum, Chow Weng; Abidin, Nor Syazwani Zainal; Bhattachary, Swapan Kumar

2018-06-01

The heterogeneity and complexity of shale gas has become clear as the development of unconventional resources have improved. The Blue Nile Basin, is one of the many Mesozoic rift basins in Sudan associated with the Central African Rift System (CARS). It is located in the eastern part of the Republic of Sudan and has been the major focus for shale gas exploration due to the hydrocarbon found in the basin. But so far no success of discovery has been achieved because the shale gas potentiality of the study area is still unknown. The objective of this study is to assess the type of kerogen and maturity of the shale samples from the Blue Nile Formation within the Blue Nile Basin. This was done by employing organic geochemical methods such as pyrolysis gas chromatography (Py-GC) and petrographic analysis such as vitrinite reflectance (Ro%). Ten representative shale samples from TW-1 well in the Blue Nile Formation have been used to assess the quality of the source rock. Pyrolysis GC analysis indicate that all the selected shale samples contain Type II kerogen that produces oil and gas. The Blue Nile Formation possesses vitrinite reflectance (Ro%) of 0.60-0.65%, indicating that the shale samples are mature in the oil window.

Feasibility Assessment of CO2 Sequestration and Enhanced Recovery in Gas Shale Reservoirs

NASA Astrophysics Data System (ADS)

Vermylen, J. P.; Hagin, P. N.; Zoback, M. D.

2008-12-01

CO2 sequestration and enhanced methane recovery may be feasible in unconventional, organic-rich, gas shale reservoirs in which the methane is stored as an adsorbed phase. Previous studies have shown that organic-rich, Appalachian Devonian shales adsorb approximately five times more carbon dioxide than methane at reservoir conditions. However, the enhanced recovery and sequestration concept has not yet been tested for gas shale reservoirs under realistic flow and production conditions. Using the lessons learned from previous studies on enhanced coalbed methane (ECBM) as a starting point, we are conducting laboratory experiments, reservoir modeling, and fluid flow simulations to test the feasibility of sequestration and enhanced recovery in gas shales. Our laboratory work investigates both adsorption and mechanical properties of shale samples to use as inputs for fluid flow simulation. Static and dynamic mechanical properties of shale samples are measured using a triaxial press under realistic reservoir conditions with varying gas saturations and compositions. Adsorption is simultaneously measured using standard, static, volumetric techniques. Permeability is measured using pulse decay methods calibrated to standard Darcy flow measurements. Fluid flow simulations are conducted using the reservoir simulator GEM that has successfully modeled enhanced recovery in coal. The results of the flow simulation are combined with the laboratory results to determine if enhanced recovery and CO2 sequestration is feasible in gas shale reservoirs.

A Tale of Two Regions: Landscape Ecological Planning for Shale Gas Energy Futures

NASA Astrophysics Data System (ADS)

Murtha, T., Jr.; Schroth, O.; Orland, B.; Goldberg, L.; Mazurczyk, T.

2015-12-01

As we increasingly embrace deep shale gas deposits to meet global energy demands new and dispersed local and regional policy and planning challenges emerge. Even in regions with long histories of energy extraction, such as coal, shale gas and the infrastructure needed to produce the gas and transport it to market offers uniquely complex transformations in land use and landcover not previously experienced. These transformations are fast paced, dispersed and can overwhelm local and regional planning and regulatory processes. Coupled to these transformations is a structural confounding factor. While extraction and testing are carried out locally, regulation and decision-making is multilayered, often influenced by national and international factors. Using a geodesign framework, this paper applies a set of geospatial landscape ecological planning tools in two shale gas settings. First, we describe and detail a series of ongoing studies and tools that we have developed for communities in the Marcellus Shale region of the eastern United States, specifically the northern tier of Pennsylvania. Second, we apply a subset of these tools to potential gas development areas of the Fylde region in Lancashire, United Kingdom. For the past five years we have tested, applied and refined a set of place based and data driven geospatial models for forecasting, envisioning, analyzing and evaluating shale gas activities in northern Pennsylvania. These models are continuously compared to important landscape ecological planning challenges and priorities in the region, e.g. visual and cultural resource preservation. Adapting and applying these tools to a different landscape allow us to not only isolate and define important regulatory and policy exigencies in each specific setting, but also to develop and refine these models for broader application. As we continue to explore increasingly complex energy solutions globally, we need an equally complex comparative set of landscape ecological planning tools to inform policy, design and regional planning. Adapting tools and techniques developed in Pennsylvania where shale gas extraction is ongoing to Lancashire, where industry is still in the exploratory phase offers a key opportunity to test and refine more generalizable models.

Lidar-based fracture characterization: An outcrop-scale study of the Woodford Shale, McAlister Shale Pit, Oklahoma

NASA Astrophysics Data System (ADS)

Hanzel, Jason

The use of lidar (light detection and ranging), a remote sensing tool based on principles of laser optometry, in mapping complex, multi-scale fracture networks had not been rigorously tested prior to this study despite its foreseeable utility in interpreting rock fabric with imprints of complex tectonic evolution. This thesis demonstrates lidar-based characterization of the Woodford Shale where intense fracturing could be due to both tectonism and mineralogy. The study area is the McAlister Shale Pit in south-central Oklahoma where both the upper and middle sections of the Woodford Shale are exposed and can be lidar-mapped. Lidar results are validated using hand-measured strike and dips of fracture planes, thin sections and mineral chemistry of selected samples using X-ray diffraction (XRD). Complexity of the fracture patterns as well as inaccessibility of multiple locations within the shale pit makes hand-measurement prone to errors and biases; lidar provides an opportunity for less biased and more efficient field mapping. Fracture mapping with lidar is a multi-step process. The lidar data are converted from point clouds into a mesh through triangulation. User-defined parameters such as size and orientation of the individual triangular elements are then used to group similar elements into surfaces. The strike and dip attribute of the simulated surfaces are visualized in an equal area lower hemisphere projection stereonet. Three fracture sets were identified in the upper and middle sections with common orientation but substantially different spatial density. Measured surface attributes and spatial density relations from lidar were validated using their hand-measured counterparts. Thin section analysis suggests that high fracture density in the upper Woodford measured by both the lidar and the hand-measured data could be due to high quartz. A significant finding of this study is the reciprocal relation between lidar intensity and gamma-ray (GR), which is generally used to infer outcrop mineralogy. XRD analysis of representative samples along the common profiles show that both GR and lidar intensity were influenced by the same minerals in essentially opposite ways. Results strongly suggest that the lidar cannot only remotely map the geomorphology, but also the relative mineralogical variations to the first order of approximation.

The shale gas boom and the need for rational policy.

PubMed

Finkel, Madelon; Hays, Jake; Law, Adam

2013-07-01

High-volume, slick water hydraulic fracturing of shale relies on pumping millions of gallons of surface water laced with toxic chemicals and sand under high pressure to create fractures to release the flow of gas. The process, however, has the potential to cause serious and irreparable damage to the environment and the potential for harm to human and animal health. At issue is how society should form appropriate policy in the absence of well-designed epidemiological studies and health impact assessments. The issue is fraught with environmental, economic, and health implications, and federal and state governments must establish detailed safeguards and ensure regulatory oversight, both of which are presently lacking in states where hydraulic fracturing is allowed.

Synchrotron-based transmission x-ray microscopy for improved extraction in shale during hydraulic fracturing

NASA Astrophysics Data System (ADS)

Kiss, Andrew M.; Jew, Adam D.; Joe-Wong, Claresta; Maher, Kate M.; Liu, Yijin; Brown, Gordon E.; Bargar, John

2015-09-01

Engineering topics which span a range of length and time scales present a unique challenge to researchers. Hydraulic fracturing (fracking) of oil shales is one of these challenges and provides an opportunity to use multiple research tools to thoroughly investigate a topic. Currently, the extraction efficiency from the shale is low but can be improved by carefully studying the processes at the micro- and nano-scale. Fracking fluid induces chemical changes in the shale which can have significant effects on the microstructure morphology, permeability, and chemical composition. These phenomena occur at different length and time scales which require different instrumentation to properly study. Using synchrotron-based techniques such as fluorescence tomography provide high sensitivity elemental mapping and an in situ micro-tomography system records morphological changes with time. In addition, the transmission X-ray microscope (TXM) at the Stanford Synchrotron Radiation Lightsource (SSRL) beamline 6-2 is utilized to collect a nano-scale three-dimensional representation of the sample morphology with elemental and chemical sensitivity. We present the study of a simplified model system, in which pyrite and quartz particles are mixed and exposed to oxidizing solution, to establish the basic understanding of the more complex geology-relevant oxidation reaction. The spatial distribution of the production of the oxidation reaction, ferrihydrite, is retrieved via full-field XANES tomography showing the reaction pathway. Further correlation between the high resolution TXM data and the high sensitivity micro-probe data provides insight into potential morphology changes which can decrease permeability and limit hydrocarbon recovery.

Cytotoxic and mutagenic properties of shale oil byproducts. II. Comparison of mutagenic effects at five genetic markers induced by retort process water plus near ultraviolet light in Chinese hamster ovary cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, D.J.C.; Strniste, G.F.

1982-01-01

A Chinese hamster ovary (CHO) cell line heterozygous at the adenine phosphoribosyl transferase (APRT) locus was used for selection of induced mutants resistant to 8-azaadenine (8AA), 6-thioguanine (6TG), ouabain (OUA), emetine (EMT) and diphtheria toxin (DIP). The expression times necessary for optimizing the number of mutants recovered at the different loci have been determined using the known direct acting mutagen, far ultraviolet light (FUV), and a complex aqueous organic mixture (shale oil process water) activated with near ultraviolet light (NUV). The results indicate that optimal expression times following treatment with either mutagen was between 2 and 8 days. For CHOmore » cells treated with shale oil process water and subsequently exposed to NUV a linear dose response for mutant induction was observed for all five genetic loci. At 10% surviving fraction of cells, between 35- and 130-fold increases above backgound mutation frequencies were observed for the various markers examined.« less

Shale characterization in mass transport complex as a potential source rock: An example from onshore West Java Basin, Indonesia

NASA Astrophysics Data System (ADS)

Nugraha, A. M. S.; Widiarti, R.; Kusumah, E. P.

2017-12-01

This study describes a deep-water slump facies shale of the Early Miocene Jatiluhur/Cibulakan Formation to understand its potential as a source rock in an active tectonic region, the onshore West Java. The formation is equivalent with the Gumai Formation, which has been well-known as another prolific source rock besides the Oligocene Talang Akar Formation in North West Java Basin, Indonesia. The equivalent shale formation is expected to have same potential source rock towards the onshore of Central Java. The shale samples were taken onshore, 150 km away from the basin. The shale must be rich of organic matter, have good quality of kerogen, and thermally matured to be categorized as a potential source rock. Investigations from petrography, X-Ray diffractions (XRD), and backscattered electron show heterogeneous mineralogy in the shales. The mineralogy consists of clay minerals, minor quartz, muscovite, calcite, chlorite, clinopyroxene, and other weathered minerals. This composition makes the shale more brittle. Scanning Electron Microscope (SEM) analysis indicate secondary porosities and microstructures. Total Organic Carbon (TOC) shows 0.8-1.1 wt%, compared to the basinal shale 1.5-8 wt%. The shale properties from this outcropped formation indicate a good potential source rock that can be found in the subsurface area with better quality and maturity.

Influences of Eagle Ford Shale Development on Superintendent Leadership Experiences: A Phenomenological Narrative

ERIC Educational Resources Information Center

Moczygemba, Jeanette Winn

2017-01-01

This phenomenological narrative study examined the effects of the Eagle Ford Shale development upon public school superintendent leadership experiences during the boom phase of the energy industry expansion. The four research questions investigated the shale development's influence on experiences in the areas of instruction, finance and…

Mechanical Properties of Gas Shale During Drilling Operations

NASA Astrophysics Data System (ADS)

Yan, Chuanliang; Deng, Jingen; Cheng, Yuanfang; Li, Menglai; Feng, Yongcun; Li, Xiaorong

2017-07-01

The mechanical properties of gas shale significantly affect the designs of drilling, completion, and hydraulic fracturing treatments. In this paper, the microstructure characteristics of gas shale from southern China containing up to 45.1% clay were analyzed using a scanning electron microscope. The gas shale samples feature strongly anisotropic characteristics and well-developed bedding planes. Their strength is controlled by the strength of both the matrix and the bedding planes. Conventional triaxial tests and direct shear tests are further used to study the chemical effects of drilling fluids on the strength of shale matrix and bedding planes, respectively. The results show that the drilling fluid has a much larger impact on the strength of the bedding plane than that of the shale matrix. The impact of water-based mud (WBM) is much larger compared with oil-based mud. Furthermore, the borehole collapse pressure of shale gas wells considering the effects of drilling fluids are analyzed. The results show that the collapse pressure increases gradually with the increase of drilling time, especially for WBM.

Degradation of hydraulic fracturing additive 2-butoxyethanol using heat activated persulfate in the presence of shale rock.

PubMed

Manz, Katherine E; Carter, Kimberly E

2018-09-01

Changes in fluid composition during hydraulic fracturing (HF) for natural gas production can impact well productivity and the water quality of the fluids returning to the surface during productivity. Shale formation conditions can influence the extent of fluid transformation. Oxidizers, such as sodium persulfate, likely play a strong role in fluid transformation. This study investigates the oxidation of 2-butoxyethanol (2-BE), a surfactant used in HF, by sodium persulfate in the presence of heat, pH changes, Fe(II), and shale rock. Increasing temperature and Fe(II) concentrations sped up 2-BE oxidation, while pH played little to no role in 2-BE degradation. The presence of shale rock impeded 2-BE oxidation with increasing shale concentrations causing decreasing pseudo-first-order reaction rate constant to be observed. Over the course of reactions containing shales, dissolved solids were tracked to better understand how reactions with minerals in the shale impact water quality. Copyright © 2018 Elsevier Ltd. All rights reserved.

Deliberating the perceived risks, benefits, and societal implications of shale gas and oil extraction by hydraulic fracturing in the US and UK

NASA Astrophysics Data System (ADS)

Thomas, Merryn; Partridge, Tristan; Harthorn, Barbara Herr; Pidgeon, Nick

2017-04-01

Shale gas and oil production in the US has increased rapidly in the past decade, while interest in prospective development has also arisen in the UK. In both countries, shale resources and the method of their extraction (hydraulic fracturing, or 'fracking') have been met with opposition amid concerns about impacts on water, greenhouse gas emissions, and health effects. Here we report the findings of a qualitative, cross-national deliberation study of public perceptions of shale development in UK and US locations not yet subject to extensive shale development. When presented with a carefully calibrated range of risks and benefits, participants' discourse focused on risks or doubts about benefits, and potential impacts were viewed as inequitably distributed. Participants drew on direct, place-based experiences as well as national contexts in deliberating shale development. These findings suggest that shale gas development already evokes a similar 'signature' of risk across the US and UK.

Primary emissions and secondary formation of volatile organic compounds from natural gas production in five major U.S. shale plays

NASA Astrophysics Data System (ADS)

Gilman, J.; Lerner, B. M.; Warneke, C.; Graus, M.; Lui, R.; Koss, A.; Yuan, B.; Murphy, S. M.; Alvarez, S. L.; Lefer, B. L.; Min, K. E.; Brown, S. S.; Roberts, J. M.; Osthoff, H. D.; Hatch, C. D.; Peischl, J.; Ryerson, T. B.; De Gouw, J. A.

2014-12-01

According to the U.S. Energy and Information Administration (EIA), domestic production of natural gas from shale formations is currently at the highest levels in U.S. history. Shale gas production may also result in the production of natural gas plant liquids (NGPLs) such as ethane and propane as well as natural gas condensate composed of a complex mixture of non-methane hydrocarbons containing more than ~5 carbon atoms (e.g., hexane, cyclohexane, and benzene). The amounts of natural gas liquids and condensate produced depends on the particular reservoir. The source signature of primary emissions of hydrocarbons to the atmosphere within each shale play will therefore depend on the composition of the raw natural gas as well as the industrial processes and equipment used to extract, separate, store, and transport the raw materials. Characterizing the primary emissions of VOCs from natural gas production is critical to assessing the local and regional atmospheric impacts such as the photochemical formation of ozone and secondary formation of organic aerosol. This study utilizes ground-based measurements of a full suite of volatile organic compounds (VOCs) in two western U.S. basins, the Uintah (2012-2014 winter measurements only) and Denver-Julesburg (winter 2011 and summer 2012), and airborne measurements over the Haynesville, Fayetteville, and Marcellus shale basins (summer 2013). By comparing the observed VOC to propane enhancement ratios, we show that each basin has a unique VOC source signature associated with oil and natural gas operations. Of the shale basins studied, the Uintah basin had the largest overall VOC to propane enhancement ratios while the Marcellus had the lowest. For the western basins, we will compare the composition of oxygenated VOCs produced from photochemical oxidation of VOC precursors and contrast the oxygenated VOC mixture to a "typical" summertime urban VOC mixture. The relative roles of alkanes, alkenes, aromatics, and cycloalkanes as precursors for C2-C6 aldehydes and ketones, and C3-C4 alkyl nitrates will be investigated.

Preliminary source rock evaluation and hydrocarbon generation potential of the early Cretaceous subsurface shales from Shabwah sub-basin in the Sabatayn Basin, Western Yemen

NASA Astrophysics Data System (ADS)

Al-Matary, Adel M.; Hakimi, Mohammed Hail; Al Sofi, Sadam; Al-Nehmi, Yousif A.; Al-haj, Mohammed Ail; Al-Hmdani, Yousif A.; Al-Sarhi, Ahmed A.

2018-06-01

A conventional organic geochemical study has been performed on the shale samples collected from the early Cretaceous Saar Formation from the Shabwah oilfields in the Sabatayn Basin, Western Yemen. The results of this study were used to preliminary evaluate the potential source-rock of the shales in the Saar Formation. Organic matter richness, type, and petroleum generation potential of the analysed shales were assessed. Total organic carbon content and Rock- Eval pyrolysis results indicate that the shale intervals within the early Cretaceous Saar Formation have a wide variation in source rock generative potential and quality. The analysed shale samples have TOC content in the range of 0.50 and 5.12 wt% and generally can be considered as fair to good source rocks. The geochemical results of this study also indicate that the analysed shales in the Saar Formation are both oil- and gas-prone source rocks, containing Type II kerogen and mixed Types II-III gradient to Type III kerogen. This is consistent with Hydrogen Index (HI) values between 66 and 552 mg HC/g TOC. The temperature-sensitive parameters such as vitrinite reflectance (%VRo), Rock-Eval pyrolysis Tmax and PI reveal that the analysed shale samples are generally immature to early-mature for oil-window. Therefore, the organic matter has not been altered by thermal maturity thus petroleum has not yet generated. Therefore, exploration strategies should focus on the known deeper location of the Saar Formation in the Shabwah-sub-basin for predicting the kitchen area.

Geochemical and multi-isotopic ( 87Sr/ 86Sr, 143Nd/ 144Nd, 238U/ 235U) perspectives of sediment sources, depositional conditions, and diagenesis of the Marcellus Shale, Appalachian Basin, USA

DOE PAGES

Phan, Thai T.; Gardiner, James B.; Capo, Rosemary C.; ...

2017-10-25

Here, we investigate sediment sources, depositional conditions and diagenetic processes affecting the Middle Devonian Marcellus Shale in the Appalachian Basin, eastern USA, a major target of natural gas exploration. Multiple proxies, including trace metal contents, rare earth elements (REE), the Sm-Nd and Rb-Sr isotope systems, and U isotopes were applied to whole rock digestions and sequentially extracted fractions of the Marcellus shale and adjacent units from two locations in the Appalachian Basin. The narrow range of εNd values (from –7.8 to –6.4 at 390 Ma) is consistent with derivation of the clastic sedimentary component of the Marcellus Shale from amore » well-mixed source of fluvial and eolian material of the Grenville orogenic belt, and indicate minimal post-depositional alteration of the Sm-Nd system. While silicate minerals host >80% of the REE in the shale, data from sequentially extracted fractions reflect post-depositional modifications at the mineralogical scale, which is not observed in whole rock REE patterns.« less

Geochemical and multi-isotopic ( 87Sr/ 86Sr, 143Nd/ 144Nd, 238U/ 235U) perspectives of sediment sources, depositional conditions, and diagenesis of the Marcellus Shale, Appalachian Basin, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phan, Thai T.; Gardiner, James B.; Capo, Rosemary C.

Here, we investigate sediment sources, depositional conditions and diagenetic processes affecting the Middle Devonian Marcellus Shale in the Appalachian Basin, eastern USA, a major target of natural gas exploration. Multiple proxies, including trace metal contents, rare earth elements (REE), the Sm-Nd and Rb-Sr isotope systems, and U isotopes were applied to whole rock digestions and sequentially extracted fractions of the Marcellus shale and adjacent units from two locations in the Appalachian Basin. The narrow range of εNd values (from –7.8 to –6.4 at 390 Ma) is consistent with derivation of the clastic sedimentary component of the Marcellus Shale from amore » well-mixed source of fluvial and eolian material of the Grenville orogenic belt, and indicate minimal post-depositional alteration of the Sm-Nd system. While silicate minerals host >80% of the REE in the shale, data from sequentially extracted fractions reflect post-depositional modifications at the mineralogical scale, which is not observed in whole rock REE patterns.« less

Research on Utilization of Geo-Energy

NASA Astrophysics Data System (ADS)

Bock, Michaela; Scheck-Wenderoth, Magdalena; GeoEn Working Group

2013-04-01

The world's energy demand will increase year by year and we have to search for alternative energy resources. New concepts concerning the energy production from geo-resources have to be provided and developed. The joint project GeoEn combines research on the four core themes geothermal energy, shale gas, CO2 capture and CO2 storage. Sustainable energy production from deep geothermal energy resources is addressed including all processes related to geothermal technologies, from reservoir exploitation to energy conversion in the power plant. The research on the unconventional natural gas resource, shale gas, is focussed on the sedimentological, diagenetic and compositional characteristics of gas shales. Technologies and solutions for the prevention of the greenhouse gas carbon dioxide are developed in the research fields CO2 capture technologies, utilization, transport, and CO2 storage. Those four core themes are studied with an integrated approach using the synergy of cross-cutting methodologies. New exploration and reservoir technologies and innovative monitoring methods, e.g. CSMT (controlled-source magnetotellurics) are examined and developed. All disciplines are complemented by numerical simulations of the relevant processes. A particular strength of the project is the availability of large experimental infrastructures where the respective technologies are tested and monitored. These include the power plant Schwarze Pumpe, where the Oxyfuel process is improved, the pilot storage site for CO2 in Ketzin and the geothermal research platform Groß Schönebeck, with two deep wells and an experimental plant overground for research on corrosion. In addition to fundamental research, the acceptance of new technologies, especially in the field of CCS is examined. Another focus addressed is the impact of shale gas production on the environment. A further important goal is the education of young scientists in the new field "geo-energy" to fight skills shortage in this field of growing economic and ecologic relevance.

Fracture patterns and their origin in the upper Devonian Antrim Shale gas reservoir of the Michigan basin; a review

USGS Publications Warehouse

Ryder, Robert T.

1996-01-01

INTRODUCTION: Black shale members of the Upper Devonian Antrim Shale are both the source and reservoir for a regional gas accumulation that presently extends across parts of six counties in the northern part of the Michigan basin (fig. 1). Natural fractures are considered by most petroleum geologists and oil and gas operators who work the Michigan basin to be a necessary condition for commercial gas production in the Antrim Shale. Fractures provide the conduits for free gas and associated water to flow to the borehole through the black shale which, otherwise, has a low matrix permeability. Moreover, the fractures assist in the release of gas adsorbed on mineral and(or) organic matter in the shale (Curtis, 1992). Depths to the gas-producing intervals (Norwood and Lachine Members) generally range from 1,200 to 1,800 ft (Oil and Gas Journal, 1994). Locally, wells that produce gas from the accumulation are as deep as 2,200 (Oil and Gas Journal, 1994). Even though natural fractures are an important control on Antrim Shale gas production, most wells require stimulation by hydraulic fracturing to attain commercial production rates (Kelly, 1992). In the U.S. Geological Survey's National Assessment of United States oil and gas, Dolton (1995) estimates that, at a mean value, 4.45 trillion cubic feet (TCF) of gas are recoverable as additions to already discovered quantities from the Antrim Shale in the productive area of the northern Michigan trend. Dolton (1995) also suggests that undiscovered Antrim Shale gas accumulations exist in other parts of the Michigan basin. The character, distribution, and origin of natural fractures in the Antrim Shale gas accumulation have been studied recently by academia and industry. The intent of these investigations is to: 1) predict 'sweet spots', prior to drilling, in the existing gas-producing trend, 2) improve production practices in the existing trend, 3) predict analogous fracture-controlled gas accumulations in other parts of the Michigan basin, and 4) improve estimates of the recoverable gas in the Antrim Shale gas plays (Dolton, 1995). This review of published literature on the characteristics of Antrim Shale fractures, their origin, and their controls on gas production will help to define objectives and goals in future U.S. Geological Survey studies of Antrim Shale gas resources.

Anisotropic Failure Strength of Shale with Increasing Confinement: Behaviors, Factors and Mechanism.

PubMed

Cheng, Cheng; Li, Xiao; Qian, Haitao

2017-11-15

Some studies reported that the anisotropic failure strength of shale will be weakened by increasing confinement. In this paper, it is found that there are various types of anisotropic strength behaviors. Four types of anisotropic strength ratio ( S A 1 ) behaviors and three types of anisotropic strength difference ( S A 2 ) behaviors have been classified based on laboratory experiments on nine groups of different shale samples. The cohesion c w and friction angle ϕ w of the weak planes are proven to be two dominant factors according to a series of bonded-particle discrete element modelling analyses. It is observed that shale is more prone to a slight increase of S A 1 and significant increase of S A 2 with increasing confinement for higher cohesion c w and lower to medium friction angle ϕ w . This study also investigated the mechanism of the anisotropic strength behaviors with increasing confinement. Owing to different contributions of c w and ϕ w under different confinements, different combinations of c w and ϕ w may have various types of influences on the minimum failure strength with the increasing confinement; therefore, different types of anisotropic behaviors occur for different shale specimens as the confinement increases. These findings are very important to understand the stability of wellbore and underground tunneling in the shale rock mass, and should be helpful for further studies on hydraulic fracture propagations in the shale reservoir.

Anisotropic Failure Strength of Shale with Increasing Confinement: Behaviors, Factors and Mechanism

PubMed Central

Cheng, Cheng; Li, Xiao; Qian, Haitao

2017-01-01

Some studies reported that the anisotropic failure strength of shale will be weakened by increasing confinement. In this paper, it is found that there are various types of anisotropic strength behaviors. Four types of anisotropic strength ratio (SA1) behaviors and three types of anisotropic strength difference (SA2) behaviors have been classified based on laboratory experiments on nine groups of different shale samples. The cohesion cw and friction angle ϕw of the weak planes are proven to be two dominant factors according to a series of bonded-particle discrete element modelling analyses. It is observed that shale is more prone to a slight increase of SA1 and significant increase of SA2 with increasing confinement for higher cohesion cw and lower to medium friction angle ϕw. This study also investigated the mechanism of the anisotropic strength behaviors with increasing confinement. Owing to different contributions of cw and ϕw under different confinements, different combinations of cw and ϕw may have various types of influences on the minimum failure strength with the increasing confinement; therefore, different types of anisotropic behaviors occur for different shale specimens as the confinement increases. These findings are very important to understand the stability of wellbore and underground tunneling in the shale rock mass, and should be helpful for further studies on hydraulic fracture propagations in the shale reservoir. PMID:29140292

Developing a shale heterogeneity index to predict fracture response in the Mancos Shale

NASA Astrophysics Data System (ADS)

DeReuil, Aubry; Birgenheier, Lauren; McLennan, John

2017-04-01

The interplay between sedimentary heterogeneity and fracture propagation in mudstone is crucial to assess the potential of low permeability rocks as unconventional reservoirs. Previous experimental research has demonstrated a relationship between heterogeneity and fracture of brittle rocks, as discontinuities in a rock mass influence micromechanical processes such as microcracking and strain localization, which evolve into macroscopic fractures. Though numerous studies have observed heterogeneity influencing fracture development, fundamental understanding of the entire fracture process and the physical controls on this process is still lacking. This is partly due to difficulties in quantifying heterogeneity in fine-grained rocks. Our study tests the hypothesis that there is a correlation between sedimentary heterogeneity and the manner in which mudstone is fractured. An extensive range of heterogeneity related to complex sedimentology is represented by various samples from cored intervals of the Mancos Shale. Samples were categorized via facies analysis consisting of: visual core description, XRF and XRD analysis, SEM and thin section microscopy, and reservoir quality analysis that tested porosity, permeability, water saturation, and TOC. Systematic indirect tensile testing on a broad variety of facies has been performed, and uniaxial and triaxial compression testing is underway. A novel tool based on analytically derived and statistically proven relationships between sedimentary geologic and geomechanical heterogeneity is the ultimate result, referred to as the shale heterogeneity index. Preliminary conclusions from development of the shale heterogeneity index reveal that samples with compositionally distinct bedding withstand loading at higher stress values, while texturally and compositionally homogeneous, bedded samples fail at lower stress values. The highest tensile strength results from cemented Ca-enriched samples, medial to high strength samples have approximately equivalent proportions of Al-Ca-Si compositions, while Al-rich samples have consistently low strength. Moisture preserved samples fail on average at approximately 5 MPa lower than dry samples of similar facies. Additionally, moisture preserved samples fail in a step-like pattern when tested perpendicular to bedding. Tensile fractures are halted at heterogeneities and propagate parallel to bedding planes before developing a through-going failure plane, as opposed to the discrete, continuous fractures that crosscut dry samples. This result suggests that sedimentary heterogeneity plays a greater role in fracture propagation in moisture preserved samples, which are more indicative of in-situ reservoir conditions. Stress-strain curves will be further analyzed, including estimation of an energy released term based on post-failure response, and an estimation of volume of cracking measure on the physical fracture surface.

Preliminary stratigraphic cross section showing radioactive zones in the Devonian dark shales in the eastern part of the Appalachian Basin

USGS Publications Warehouse

West, Mareta N.

1978-01-01

The U.S. Geological Survey (USGS), in a cooperative agreement with the U.S. Department of Energy (DOE), is participating in the Eastern Gas Shales Project. The purpose of the DOE project is to increase the production of natural gas from eastern United States shales in petroliferous basins through improved exploration and extraction techniques. The USGS participation includes stratigraphic studies which will contribute to the characterization and appraisal of the natural gas resources of Devonian shale in the Appalachian basin.This cross section differs from others in this series partly because many of the shales in the eastern part of the basin are less radioactive than those farther west and because in this area shales that may be gas-productive are not necessarily highly radioactive and black.

Validation Results for Core-Scale Oil Shale Pyrolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Staten, Josh; Tiwari, Pankaj

2015-03-01

This report summarizes a study of oil shale pyrolysis at various scales and the subsequent development a model for in situ production of oil from oil shale. Oil shale from the Mahogany zone of the Green River formation was used in all experiments. Pyrolysis experiments were conducted at four scales, powdered samples (100 mesh) and core samples of 0.75”, 1” and 2.5” diameters. The batch, semibatch and continuous flow pyrolysis experiments were designed to study the effect of temperature (300°C to 500°C), heating rate (1°C/min to 10°C/min), pressure (ambient and 500 psig) and size of the sample on product formation.more » Comprehensive analyses were performed on reactants and products - liquid, gas and spent shale. These experimental studies were designed to understand the relevant coupled phenomena (reaction kinetics, heat transfer, mass transfer, thermodynamics) at multiple scales. A model for oil shale pyrolysis was developed in the COMSOL multiphysics platform. A general kinetic model was integrated with important physical and chemical phenomena that occur during pyrolysis. The secondary reactions of coking and cracking in the product phase were addressed. The multiscale experimental data generated and the models developed provide an understanding of the simultaneous effects of chemical kinetics, and heat and mass transfer on oil quality and yield. The comprehensive data collected in this study will help advance the move to large-scale in situ oil production from the pyrolysis of oil shale.« less

Pressurized fluidized-bed hydroretorting of Eastern oil shales -- Sulfur control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, M.J.; Abbasian, J.; Akin, C.

1992-05-01

This topical report on Sulfur Control'' presents the results of work conducted by the Institute of Gas Technology (IGT), the Illinois Institute of Technology (IIT), and the Ohio State University (OSU) to develop three novel approaches for desulfurization that have shown good potential with coal and could be cost-effective for oil shales. These are (1) In-Bed Sulfur Capture using different sorbents (IGT), (2) Electrostatic Desulfurization (IIT), and (3) Microbial Desulfurization and Denitrification (OSU and IGT). The objective of the task on In-Bed Sulfur Capture was to determine the effectiveness of different sorbents (that is, limestone, calcined limestone, dolomite, and siderite)more » for capturing sulfur (as H{sub 2}S) in the reactor during hydroretorting. The objective of the task on Electrostatic Desulfurization was to determine the operating conditions necessary to achieve a high degree of sulfur removal and kerogen recovery in IIT's electrostatic separator. The objectives of the task on Microbial Desulfurization and Denitrification were to (1) isolate microbial cultures and evaluate their ability to desulfurize and denitrify shale, (2) conduct laboratory-scale batch and continuous tests to improve and enhance microbial removal of these components, and (3) determine the effects of processing parameters, such as shale slurry concentration, solids settling characteristics, agitation rate, and pH on the process.« less

Estimating Hydraulic Conductivities in a Fractured Shale Formation from Pressure Pulse Testing and 3d Modeling

NASA Astrophysics Data System (ADS)

Courbet, C.; DICK, P.; Lefevre, M.; Wittebroodt, C.; Matray, J.; Barnichon, J.

2013-12-01

In the framework of its research on the deep disposal of radioactive waste in shale formations, the French Institute for Radiological Protection and Nuclear Safety (IRSN) has developed a large array of in situ programs concerning the confining properties of shales in their underground research laboratory at Tournemire (SW France). One of its aims is to evaluate the occurrence and processes controlling radionuclide migration through the host rock, from the disposal system to the biosphere. Past research programs carried out at Tournemire covered mechanical, hydro-mechanical and physico-chemical properties of the Tournemire shale as well as water chemistry and long-term behaviour of the host rock. Studies show that fluid circulations in the undisturbed matrix are very slow (hydraulic conductivity of 10-14 to 10-15 m.s-1). However, recent work related to the occurrence of small scale fractures and clay-rich fault gouges indicate that fluid circulations may have been significantly modified in the vicinity of such features. To assess the transport properties associated with such faults, IRSN designed a series of in situ and laboratory experiments to evaluate the contribution of both diffusive and advective process on water and solute flux through a clay-rich fault zone (fault core and damaged zone) and in an undisturbed shale formation. As part of these studies, Modular Mini-Packer System (MMPS) hydraulic testing was conducted in multiple boreholes to characterize hydraulic conductivities within the formation. Pressure data collected during the hydraulic tests were analyzed using the nSIGHTS (n-dimensional Statistical Inverse Graphical Hydraulic Test Simulator) code to estimate hydraulic conductivity and formation pressures of the tested intervals. Preliminary results indicate hydraulic conductivities of 5.10-12 m.s-1 in the fault core and damaged zone and 10-14 m.s-1 in the adjacent undisturbed shale. Furthermore, when compared with neutron porosity data from borehole logging, porosity varies by a factor of 2.5 whilst hydraulic conductivity varies by 2 to 3 orders of magnitude. In addition, a 3D numerical reconstruction of the internal structure of the fault zone inferred from borehole imagery has been built to estimate the permeability tensor variations. First results indicate that hydraulic conductivity values calculated for this structure are 2 to 3 orders of magnitude above those measured in situ. Such high values are due to the imaging method that only takes in to account open fractures of simple geometry (sine waves). Even though improvements are needed to handle more complex geometry, outcomes are promising as the fault damaged zone clearly appears as the highest permeability zone, where stress analysis show that the actual stress state may favor tensile reopening of fractures. Using shale samples cored from the different internal structures of the fault zone, we aim now to characterize the advection and diffusion using laboratory petrophysical tests combined with radial and through-diffusion experiments.

Environmental public health dimensions of shale and tight gas development.

PubMed

Shonkoff, Seth B C; Hays, Jake; Finkel, Madelon L

2014-08-01

The United States has experienced a boom in natural gas production due to recent technological innovations that have enabled this resource to be produced from shale formations. We reviewed the body of evidence related to exposure pathways in order to evaluate the potential environmental public health impacts of shale gas development. We highlight what is currently known and identify data gaps and research limitations by addressing matters of toxicity, exposure pathways, air quality, and water quality. There is evidence of potential environmental public health risks associated with shale gas development. Several studies suggest that shale gas development contributes to ambient air concentrations of pollutants known to be associated with increased risk of morbidity and mortality. Similarly, an increasing body of studies suggest that water contamination risks exist through a variety of environmental pathways, most notably during wastewater transport and disposal, and via poor zonal isolation of gases and fluids due to structural integrity impairment of cement in gas wells. Despite a growing body of evidence, data gaps persist. Most important, there is a need for more epidemiological studies to assess associations between risk factors, such as air and water pollution, and health outcomes among populations living in close proximity to shale gas operations.

Robust Library Building for Autonomous Classification of Downhole Geophysical Logs Using Gaussian Processes

NASA Astrophysics Data System (ADS)

Silversides, Katherine L.; Melkumyan, Arman

2017-03-01

Machine learning techniques such as Gaussian Processes can be used to identify stratigraphically important features in geophysical logs. The marker shales in the banded iron formation hosted iron ore deposits of the Hamersley Ranges, Western Australia, form distinctive signatures in the natural gamma logs. The identification of these marker shales is important for stratigraphic identification of unit boundaries for the geological modelling of the deposit. Machine learning techniques each have different unique properties that will impact the results. For Gaussian Processes (GPs), the output values are inclined towards the mean value, particularly when there is not sufficient information in the library. The impact that these inclinations have on the classification can vary depending on the parameter values selected by the user. Therefore, when applying machine learning techniques, care must be taken to fit the technique to the problem correctly. This study focuses on optimising the settings and choices for training a GPs system to identify a specific marker shale. We show that the final results converge even when different, but equally valid starting libraries are used for the training. To analyse the impact on feature identification, GP models were trained so that the output was inclined towards a positive, neutral or negative output. For this type of classification, the best results were when the pull was towards a negative output. We also show that the GP output can be adjusted by using a standard deviation coefficient that changes the balance between certainty and accuracy in the results.

Geology of the Devonian Marcellus Shale--Valley and Ridge province, Virginia and West Virginia--a field trip guidebook for the American Association of Petroleum Geologists Eastern Section Meeting, September 28-29, 2011

USGS Publications Warehouse

Enomoto, Catherine B.; Coleman, James L.; Haynes, John T.; Whitmeyer, Steven J.; McDowell, Ronald R.; Lewis, J. Eric; Spear, Tyler P.; Swezey, Christopher S.

2012-01-01

Detailed and reconnaissance field mapping and the results of geochemical and mineralogical analyses of outcrop samples indicate that the Devonian shales of the Broadtop Synclinorium from central Virginia to southern Pennsylvania have an organic content sufficiently high and a thermal maturity sufficiently moderate to be considered for a shale gas play. The organically rich Middle Devonian Marcellus Shale is present throughout most of the synclinorium, being absent only where it has been eroded from the crests of anticlines. Geochemical analyses of outcrop and well samples indicate that hydrocarbons have been generated and expelled from the kerogen originally in place in the shale. The mineralogical characteristics of the Marcellus Shale samples from the Broadtop Synclinorium are slightly different from the averages of samples from New York, Pennsylvania, northeast Ohio, and northern West Virginia. The Middle Devonian shale interval is moderately to heavily fractured in all areas, but in some areas substantial fault shearing has removed a regular "cleat" system of fractures. Conventional anticlinal gas fields in the study area that are productive from the Lower Devonian Oriskany Sandstone suggest that a continuous shale gas system may be in place within the Marcellus Shale interval at least in a portion of the synclinorium. Third-order intraformational deformation is evident within the Marcellus shale exposures. Correlations between outcrops and geophysical logs from exploration wells nearby will be examined by field trip attendees.

Detailed facies analysis of the Upper Cretaceous Tununk Shale Member, Henry Mountains Region, Utah: Implications for mudstone depositional models in epicontinental seas

NASA Astrophysics Data System (ADS)

Li, Zhiyang; Schieber, Juergen

2018-02-01

Lower-Middle Turonian strata of the Tununk Shale Member of the greater Mancos Shale were deposited along the western margin of the Cretaceous Western Interior Seaway during the Greenhorn second-order sea level cycle. In order to examine depositional controls on facies development in this mudstone-rich succession, this study delineates temporal and spatial relationships in a process-sedimentologic-based approach. The 3-dimensional expression of mudstone facies associations and their stratal architecture is assessed through a fully integrative physical and biologic characterization as exposed in outcrops in south-central Utah. Sedimentologic characteristics from the millimeter- to kilometer-scale are documented in order to fully address the complex nature of sediment transport mechanisms observed in this shelf muddy environment. The resulting facies model developed from this characterization consists of a stack of four lithofacies packages including: 1) carbonate-bearing, silty and sandy mudstone (CSSM), 2) silt-bearing, calcareous mudstone (SCM), 3) carbonate-bearing, silty mudstone to muddy siltstone (CMS), and 4) non-calcareous, silty and sandy mudstone (SSM). Spatial and temporal variations in lithofacies type and sedimentary facies characteristics indicate that the depositional environments of the Tununk Shale shifted in response to the 2nd-order Greenhorn transgressive-regressive sea-level cycle. During this eustatic event, the Tununk shows a characteristic vertical shift from distal middle shelf to outer shelf (CSSM to SCM facies), then from outer shelf to inner shelf environment (SCM to CMS, and to SSM facies). Shifting depositional environments, as well as changes in dominant paleocurrent direction throughout this succession, indicate multiple source areas and transport mechanisms (i.e. longshore currents, offshore-directed underflows, storm reworking). This study provides a rare documentation of the Greenhorn cycle as exposed across the entire shelf setting. High-resolution mapping of genetically-related packages facilitate the development of process-based depositional models that can be utilized for lateral correlations into the equivalent foredeep strata of the Cretaceous Interior.

Hydraulic fracturing offers view of microbial life in the deep terrestrial subsurface.

PubMed

Mouser, Paula J; Borton, Mikayla; Darrah, Thomas H; Hartsock, Angela; Wrighton, Kelly C

2016-11-01

Horizontal drilling and hydraulic fracturing are increasingly used for recovering energy resources in black shales across the globe. Although newly drilled wells are providing access to rocks and fluids from kilometer depths to study the deep biosphere, we have much to learn about microbial ecology of shales before and after 'fracking'. Recent studies provide a framework for considering how engineering activities alter this rock-hosted ecosystem. We first provide data on the geochemical environment and microbial habitability in pristine shales. Next, we summarize data showing the same pattern across fractured shales: diverse assemblages of microbes are introduced into the subsurface, eventually converging to a low diversity, halotolerant, bacterial and archaeal community. Data we synthesized show that the shale microbial community predictably shifts in response to temporal changes in geochemistry, favoring conservation of key microorganisms regardless of inputs, shale location or operators. We identified factors that constrain diversity in the shale and inhibit biodegradation at the surface, including salinity, biocides, substrates and redox. Continued research in this engineered ecosystem is required to assess additive biodegradability, quantify infrastructure biocorrosion, treat wastewaters that return to the surface and potentially enhance energy production through in situ methanogenesis. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

An Overview of Current and Projected Shale and Tight Gas Water Use in Texas: Implications for Local Water Resources, March 29-30, 2011

EPA Pesticide Factsheets

The objective of the study was to determine the amount of water used for different purposes (well drilling, completion, and secondary and tertiary recovery processes of conventional resources) across the state.

Comparison of Pore Fractal Characteristics Between Marine and Continental Shales

NASA Astrophysics Data System (ADS)

Liu, Jun; Yao, Yanbin; Liu, Dameng; Cai, Yidong; Cai, Jianchao

Fractal characterization offers a quantitative evaluation on the heterogeneity of pore structure which greatly affects gas adsorption and transportation in shales. To compare the fractal characteristics between marine and continental shales, nine samples from the Lower Silurian Longmaxi formation in the Sichuan basin and nine from the Middle Jurassic Dameigou formation in the Qaidam basin were collected. Reservoir properties and fractal dimensions were characterized for all the collected samples. In this study, fractal dimensions were originated from the Frenkel-Halsey-Hill (FHH) model with N2 adsorption data. Compared to continental shale, marine shale has greater values of quartz content, porosity, specific surface area and total pore volume but lower level of clay minerals content, permeability, average pore diameter and methane adsorption capacity. The quartz in marine shale is mostly associated with biogenic origin, while that in continental shale is mainly due to terrigenous debris. The N2 adsorption-desorption isotherms exhibit that marine shale has fewer inkbottle-shaped pores but more plate-like and slit-shaped pores than continental shale. Two fractal dimensions (D1 and D2) were obtained at P/Po of 0-0.5 and 0.5-1. The dimension D2 is commonly greater than D1, suggesting that larger pores (diameter >˜ 4nm) have more complex structures than small pores (diameter <˜ 4nm). The fractal dimensions (both D1 and D2) positively correlate to clay minerals content, specific surface area and methane adsorption capacity, but have negative relationships with porosity, permeability and average pore diameter. The fractal dimensions increase proportionally with the increasing quartz content in marine shale but have no obvious correlation with that in continental shale. The dimension D1 is correlative to the TOC content and permeability of marine shale at a similar degree with dimension D2, while the dimension D1 is more sensitive to those of continental shale than dimension D2. Compared with dimension D2, for two shales, dimension D1 is better associated with the content of clay minerals but has worse correlations with the specific surface area and average pore diameter.

Economic Impacts Analysis of Shale Gas Investment in China

NASA Astrophysics Data System (ADS)

Han, Shangfeng; Zhang, Baosheng; Wang, Xuecheng

2018-01-01

Chinese government has announced an ambitious shale gas extraction plan, which requires significant investment. This has the potential to draw investment from other areas and may affect the whole China’s economy. There is few study to date has quantified these shale gas investment’s effects on Chinese economy. The aim of this paper is to quantify the economic effect and figures out whether shale gas investment in China is a good choice or not. Input-output analysis has been utilized in this study to estimate the economic impacts in four different Chinese regions. Our findings show that shale gas investment will result in approximately 868, 427, 115 and 42 Billion RMB economic impacts in Sichuan, Chongqing, Inner Mongolia and Guizhou, respectively. The total economic impact is only around 1453 Billion RMB, which is not significant compared to the economic impact of coalbed methane investment. Considering the potential risks of environmental issues, we suggest that it may be a better strategy for the government, at least in the current situation, to slow down shale gas development investment.

Shale gas activity and increased rates of sexually transmitted infections in Ohio, 2000-2016.

PubMed

Deziel, Nicole C; Humeau, Zoe; Elliott, Elise G; Warren, Joshua L; Niccolai, Linda M

2018-01-01

The growing shale gas ("fracking") industry depends on a mobile workforce, whose influx could have social impacts on host communities. Sexually transmitted infections (STIs) can increase through sexual mixing patterns associated with labor migration. No prior studies have quantified the relationship between shale gas activity and rates of three reportable STIs: chlamydia, gonorrhea, and syphilis. We conducted a longitudinal, ecologic study from 2000-2016 in Ohio, situated in a prolific shale gas region in the United States (US). Data on reported cases of chlamydia, gonorrhea, and syphilis by county and year were obtained from the Ohio Department of Health. All 88 counties were classified as none, low, and high shale gas activity in each year, using data from the Ohio Department of Natural Resources. Annual rate ratios (RR) and 95% confidence intervals (95% CIs) were calculated from mixed-effects Poisson regression models evaluating the relationship between shale gas activity and reported annual STI rates while adjusting for secular trends and potential confounders obtained from the US Census. Compared to counties with no shale gas activity, counties with high activity had 21% (RR = 1.21; 95%CI = 1.08-1.36) increased rates of chlamydia and 19% (RR = 1.27; 95%CI 0.98-1.44) increased rates of gonorrhea, respectively. No association was observed for syphilis. This first report of a link between shale gas activity and increased rates of both chlamydia and gonorrhea may inform local policies and community health efforts.

Microbial metabolisms in a 2.5-km-deep ecosystem created by hydraulic fracturing in shales

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daly, Rebecca A.; Borton, Mikayla A.; Wilkins, Michael J.

Hydraulic fracturing is the industry standard for extracting hydrocarbons from shale formations. Attention has been paid to the economic benefits and environmental impacts of this process, yet the biogeochemical changes induced in the deep subsurface are poorly understood. Recent single-gene investigations revealed that halotolerant microbial communities were enriched after hydraulic fracturing. Here the reconstruction of 31 unique genomes coupled to metabolite data from the Marcellus and Utica shales revealed that methylamine cycling supports methanogenesis in the deep biosphere. Fermentation of injected chemical additives also sustains long-term microbial persistence, while sulfide generation from thiosulfate represents a poorly recognized corrosion mechanism inmore » shales. Extensive links between viruses and microbial hosts demonstrate active viral predation, which may contribute to the release of labile cellular constituents into the extracellular environment. Our analyses show that hydraulic fracturing provides the organismal and chemical inputs for colonization and persistence in the deep terrestrial subsurface.« less

Method for rubblizing an oil shale deposit for in situ retorting

DOEpatents

Lewis, Arthur E.

1977-01-01

A method for rubblizing an oil shale deposit that has been formed in alternate horizontal layers of rich and lean shale, including the steps of driving a horizontal tunnel along the lower edge of a rich shale layer of the deposit, sublevel caving by fan drilling and blasting of both rich and lean overlying shale layers at the distal end of the tunnel to rubblize the layers, removing a substantial amount of the accessible rubblized rich shale to permit the overlying rubblized lean shale to drop to tunnel floor level to form a column of lean shale, performing additional sublevel caving of rich and lean shale towards the proximate end of the tunnel, removal of a substantial amount of the additionally rubblized rich shale to allow the overlying rubblized lean shale to drop to tunnel floor level to form another column of rubblized lean shale, similarly performing additional steps of sublevel caving and removal of rich rubble to form additional columns of lean shale rubble in the rich shale rubble in the tunnel, and driving additional horizontal tunnels in the deposit and similarly rubblizing the overlying layers of rich and lean shale and forming columns of rubblized lean shale in the rich, thereby forming an in situ oil shale retort having zones of lean shale that remain permeable to hot retorting fluids in the presence of high rubble pile pressures and high retorting temperatures.

Do scaly clays control seismicity on faulted shale rocks?

NASA Astrophysics Data System (ADS)

Orellana, Luis Felipe; Scuderi, Marco M.; Collettini, Cristiano; Violay, Marie

2018-04-01

One of the major challenges regarding the disposal of radioactive waste in geological formations is to ensure isolation of radioactive contamination from the environment and the population. Shales are suitable candidates as geological barriers. However, the presence of tectonic faults within clay formations put the long-term safety of geological repositories into question. In this study, we carry out frictional experiments on intact samples of Opalinus Clay, i.e. the host rock for nuclear waste storage in Switzerland. We report experimental evidence suggesting that scaly clays form at low normal stress (≤20 MPa), at sub-seismic velocities (≤300 μm/s) and is related to pre-existing bedding planes with an ongoing process where frictional sliding is the controlling deformation mechanism. We have found that scaly clays show a velocity-weakening and -strengthening behaviour, low frictional strength, and poor re-strengthening over time, conditions required to allow the potential nucleation and propagation of earthquakes within the scaly clays portion of the formation. The strong similarities between the microstructures of natural and experimental scaly clays suggest important implications for the slip behaviour of shallow faults in shales. If natural and anthropogenic perturbations modify the stress conditions of the fault zone, earthquakes might have the potential to nucleate within zones of scaly clays controlling the seismicity of the clay-rich tectonic system, thus, potentially compromising the long-term safeness of geological repositories situated in shales.

Waste oil shale ash as a novel source of calcium for precipitated calcium carbonate: carbonation mechanism, modeling, and product characterization.

PubMed

Velts, O; Uibu, M; Kallas, J; Kuusik, R

2011-11-15

In this paper, a method for converting lime-containing oil shale waste ash into precipitated calcium carbonate (PCC), a valuable commodity is elucidated. The mechanism of ash leachates carbonation was experimentally investigated in a stirred semi-batch barboter-type reactor by varying the CO(2) partial pressure, gas flow rate, and agitation intensity. A consistent set of model equations and physical-chemical parameters is proposed to describe the CaCO(3) precipitation process from oil shale ash leachates of complex composition. The model enables the simulation of reactive species (Ca(2+), CaCO(3), SO(4)(2-), CaSO(4), OH(-), CO(2), HCO(3)(-), H(+), CO(3)(2-)) concentration profiles in the liquid, gas, and solid phases as well as prediction of the PCC formation rate. The presence of CaSO(4) in the product may also be evaluated and used to assess the purity of the PCC product. A detailed characterization of the PCC precipitates crystallized from oil shale ash leachates is also provided. High brightness PCC (containing up to ∼ 96% CaCO(3)) with mean particle sizes ranging from 4 to 10 μm and controllable morphology (such as rhombohedral calcite or coexisting calcite and spherical vaterite phases) was obtained under the conditions studied. Copyright © 2011 Elsevier B.V. All rights reserved.

The Eagle Ford Shale, Texas: an initial insight into Late Cretaceous organic-rich mudrock palaeoenvironments

NASA Astrophysics Data System (ADS)

Forshaw, Joline; Jarvis, Ian; Trabucho-Alexandre, João; Tocher, Bruce; Pearce, Martin

2014-05-01

The hypothesised reduction of oxygen within the oceans during the Cretaceous is believed to have led to extended intervals of regional anoxia in bottom waters, resulting in increased preservation of organic matter and the deposition of black shales. Episodes of more widespread anoxia, and even euxinia, in both bottom and surface waters are associated with widespread black shale deposition during Ocean Anoxic Events (OAEs). The most extensive Late Cretaceous OAE, which occurred ~ 94 Ma during Cenomanian-Turonian boundary times, and was particularly well developed in the proto-North Atlantic and Tethyan regions, lasted for around 500 kyr (OAE2). Although the causes of this and other events are still hotly debated, research is taking place internationally to produce a global picture of the causes and consequences of Cretaceous OAEs. Understanding OAEs will enable a better interpretation of the climate fluctuations that ensued, and their association with the widespread deposition of black shales, rising temperatures, increased pCO2, enhanced weathering, and increased nutrient fluxes. The Eagle Ford Formation, of Cenomanian - Turonian age, is a major shale gas play in SW and NE Texas, extending over an area of more than 45,000 km2. The formation, which consists predominantly of black shales (organic-rich calcareous mudstones), was deposited during an extended period of relative tectonic quiescence in the northern Gulf Coast of the Mexico Basin, bordered by reefs along the continental shelf. The area offers an opportunity to study the effects of OAE2 in an organic-rich shelf setting. The high degree of organic matter preservation in the formation has produced excellent oil and gas source rocks. Vast areas of petroleum-rich shales are now being exploited in the Southern States of the US for shale gas, and the Eagle Ford Shale is fast becoming one of the countries largest producers of gas, oil and condensate. The Eagle Ford Shale stratigraphy is complex and heterogeneous, making further study essential before these resources can be fully developed. Therefore, a thorough understanding of the subsurface sediments within a coherent stratigraphic framework is required before exploitation can be optimimised. Here, we present initial palynological data (dinoflagellate cyst abundance), in conjunction with geochemistry, from material obtained from the Maverick Basin in the southwestern area of Eagle Ford Shale deposition. Results are presented as part of a wider study of the Eagle Ford Shale, utilising both core and outcrop material, that is using dinoflagellate cysts and chemostratigraphy to develop an improved stratigraphic framework and to reconstruct depositional palaeoenvironments in the basin.

Toxicity of Water Accommodated Fractions of Estonian Shale Fuel Oils to Aquatic Organisms.

PubMed

Blinova, Irina; Kanarbik, Liina; Sihtmäe, Mariliis; Kahru, Anne

2016-02-01

Estonia is the worldwide leading producer of the fuel oils from the oil shale. We evaluated the ecotoxicity of water accommodated fraction (WAF) of two Estonian shale fuel oils ("VKG D" and "VKG sweet") to aquatic species belonging to different trophic levels (marine bacteria, freshwater crustaceans and aquatic plants). Artificial fresh water and natural lake water were used to prepare WAFs. "VKG sweet" (lower density) proved more toxic to aquatic species than "VKG D" (higher density). Our data indicate that though shale oils were very toxic to crustaceans, the short-term exposure of Daphnia magna to sub-lethal concentrations of shale fuel oils WAFs may increase the reproductive potential of survived organisms. The weak correlation between measured chemical parameters (C10-C40 hydrocarbons and sum of 16 PAHs) and WAF's toxicity to studied species indicates that such integrated chemical parameters are not very informative for prediction of shale fuel oils ecotoxicity.

Specific mineral associations of hydrothermal shale (South Kamchatka)

NASA Astrophysics Data System (ADS)

Rychagov, S. N.; Sergeeva, A. V.; Chernov, M. S.

2017-11-01

The sequence of hydrothermal shale from the East Pauzhet thermal field within the Pauzhet hydrothermal system (South Kamchatka) was studied in detail. It was established that the formation of shale resulted from argillization of an andesitic lava flow under the influence of an acidic sulfate vapor condensate. The horizons with radically different compositions and physical properties compared to those of the overlying homogeneous plastic shale were distinguished at the base of the sequence. These horizons are characterized by high (up to two orders of magnitude in comparison with average values in hydrothermal shale) concentrations of F, P, Na, Mg, K, Ca, Sc, Ti, V, Cr, Cu, and Zn. We suggested a geological-geochemical model, according to which a deep metal-bearing chloride-hydrocarbonate solution infiltrated into the permeable zone formed at the root of the andesitic lava flow beneath plastic shale at a certain stage of evolution of the hydrothermal system.

Occurrence of shale soils along the Calabar-Itu highway, Southeastern Nigeria and their implication for the subgrade construction.

PubMed

Ilori, Abidemi Olujide

2016-01-01

This study concerned a stretch of 17 km of a 94-km highway alignment in Southeastern Nigeria that has a high incidence of pavement failure arising from subgrade failure. The subgrade of this section of the roadway is composed of Ekenkpon shale, New Netim marl, and Nkporo shale. Under the Unified Soil Classification System, the shales classify as OH (organic clay) and the marl classifies as MH (inorganic silt). Under the American Association of State and Transportation Officials (AASHTO) M 145 soil classification, all these soils classify as A-7-5 soil. Using the AASHTO M 145 group index, none of these soils was considered suitable as subgrade in its native form. Therefore, cement was investigated as a stabilizing agent. Testing demonstrated that 7, 3 and 12 % by weight were the optimum cement contents to reinforce the Ekenkpon shale, New Netim marl, and Nkporo shale, respectively.

Prediction of shale prospectivity from seismically-derived reservoir and completion qualities: Application to a shale-gas field, Horn River Basin, Canada

NASA Astrophysics Data System (ADS)

Mo, Cheol Hoon; Lee, Gwang H.; Jeoung, Taek Ju; Ko, Kyung Nam; Kim, Ki Soo; Park, Kyung-sick; Shin, Chang Hoon

2018-04-01

Prospective shale plays require a combination of good reservoir and completion qualities. Total organic carbon (TOC) is an important reservoir quality and brittleness is the most critical condition for completion quality. We analyzed seismically-derived brittleness and TOC to investigate the prospectivity of the Horn River Group shale (the Muskwa, Otter Park, Evie shales) of a shale-gas field in the western Horn River Basin, British Columbia, Canada. We used the λρ-μρ brittleness template, constructed from the mineralogy-based brittleness index (MBI) and elastic logs from two wells, to convert the λρ and μρ volumes from prestack seismic inversion to the volume for the brittleness petrotypes (most brittle, intermediate, and least brittle). The probability maps of the most brittle petrotype for the three shales were generated from Bayesian classification, based on the λρ-μρ template. The relationship between TOC and P-wave and S-wave velocity ratio (VP/VS) at the wells allowed the conversion of the VP/VS volume from prestack inversion to the TOC volume, which in turn was used to construct the TOC maps for the three shales. Increased TOC is correlated with high brittleness, contrasting with the commonly-held understanding. Therefore, the prospectivity of the shales in the study area can be represented by high brittleness and increased TOC. We propose a shale prospectivity index (SPI), computed by the arithmetic average of the normalized probability of the most brittle petrotype and the normalized TOC. The higher SPI corresponds to higher production rates in the Muskwa and Evie shales. The areas of the highest SPI have not been fully tested. The future drilling should be focused on these areas to increase the economic viability of the field.

Microbial methane from in situ biodegradation of coal and shale: A review and reevaluation of hydrogen and carbon isotope signatures

USGS Publications Warehouse

Vinson, David S.; Blair, Neal E.; Martini, Anna M.; Larter, Steve; Orem, William H.; McIntosh, Jennifer C.

2017-01-01

Stable carbon and hydrogen isotope signatures of methane, water, and inorganic carbon are widely utilized in natural gas systems for distinguishing microbial and thermogenic methane and for delineating methanogenic pathways (acetoclastic, hydrogenotrophic, and/or methylotrophic methanogenesis). Recent studies of coal and shale gas systems have characterized in situ microbial communities and provided stable isotope data (δD-CH4, δD-H2O, δ13C-CH4, and δ13C-CO2) from a wider range of environments than available previously. Here we review the principal biogenic methane-yielding pathways in coal beds and shales and the isotope effects imparted on methane, document the uncertainties and inconsistencies in established isotopic fingerprinting techniques, and identify the knowledge gaps in understanding the subsurface processes that govern H and C isotope signatures of biogenic methane. We also compare established isotopic interpretations with recent microbial community characterization techniques, which reveal additional inconsistencies in the interpretation of microbial metabolic pathways in coal beds and shales. Collectively, the re-assessed data show that widely-utilized isotopic fingerprinting techniques neglect important complications in coal beds and shales.Isotopic fingerprinting techniques that combine δ13C-CH4 with δD-CH4 and/or δ13C-CO2have significant limitations: (1) The consistent ~ 160‰ offset between δD-H2O and δD-CH4 could imply that hydrogenotrophic methanogenesis is the dominant metabolic pathway in microbial gas systems. However, hydrogen isotopes can equilibrate between methane precursors and coexisting water, yielding a similar apparent H isotope signal as hydrogenotrophic methanogenesis, regardless of the actual methane formation pathway. (2) Non-methanogenic processes such as sulfate reduction, Fe oxide reduction, inputs of thermogenic methane, anaerobic methane oxidation, and/or formation water interaction can cause the apparent carbon isotope fractionation between δ13C-CH4 and δ13C-CO2(α13CCO2-CH4) to differ from the true methanogenic fractionation, complicating interpretation of methanogenic pathways. (3) Where little-fractionating non-methanogenic bacterial processes compete with highly-fractionating methanogenesis, the mass balance between CH4 and CO2 is affected. This has implications for δ13C values and provides an alternative interpretation for net C isotope signatures than solely the pathways used by active methanogens. (4) While most of the reviewed values of δD-H2O - δD-CH4 and α13CCO2-CH4 are apparently consistent with hydrogenotrophic methanogenesis as the dominant pathway in coal beds and shales, recent microbial community characterization techniques suggest a possible role for acetoclastic or methylotrophic methanogenesis in some basins.

Geochemical and multi-isotopic (87Sr/86Sr, 143Nd/144Nd, 238U/235U) perspectives of sediment sources, depositional conditions, and diagenesis of the Marcellus Shale, Appalachian Basin, USA

NASA Astrophysics Data System (ADS)

Phan, Thai T.; Gardiner, James B.; Capo, Rosemary C.; Stewart, Brian W.

2018-02-01

We investigate sediment sources, depositional conditions and diagenetic processes affecting the Middle Devonian Marcellus Shale in the Appalachian Basin, eastern USA, a major target of natural gas exploration. Multiple proxies, including trace metal contents, rare earth elements (REE), the Sm-Nd and Rb-Sr isotope systems, and U isotopes were applied to whole rock digestions and sequentially extracted fractions of the Marcellus shale and adjacent units from two locations in the Appalachian Basin. The narrow range of εNd values (from -7.8 to -6.4 at 390 Ma) is consistent with derivation of the clastic sedimentary component of the Marcellus Shale from a well-mixed source of fluvial and eolian material of the Grenville orogenic belt, and indicate minimal post-depositional alteration of the Sm-Nd system. While silicate minerals host >80% of the REE in the shale, data from sequentially extracted fractions reflect post-depositional modifications at the mineralogical scale, which is not observed in whole rock REE patterns. Limestone units thought to have formed under open ocean (oxic) conditions have δ238U values and REE patterns consistent with modern seawater. The δ238U values in whole rock shale and authigenic phases are greater than those of modern seawater and the upper crust. The δ238U values of reduced phases (the oxidizable fraction consisting of organics and sulfide minerals) are ∼0.6‰ greater than that of modern seawater. Bulk shale and carbonate cement extracted from the shale have similar δ238U values, and are greater than δ238U values of adjacent limestone units. We suggest these trends are due to the accumulation of chemically and, more likely, biologically reduced U from anoxic to euxinic bottom water as well as the influence of diagenetic reactions between pore fluids and surrounding sediment and organic matter during diagenesis and catagenesis.

Deposition of sedimentary organic matter in black shale facies indicated by the geochemistry and petrography of high-resolution samples, blake nose, western North Atlantic

USGS Publications Warehouse

Barker, C.E.; Pawlewicz, M.; Cobabe, E.A.

2001-01-01

A transect of three holes drilled across the Blake Nose, western North Atlantic Ocean, retrieved cores of black shale facies related to the Albian Oceanic Anoxic Events (OAE) lb and ld. Sedimentary organic matter (SOM) recovered from Ocean Drilling Program Hole 1049A from the eastern end of the transect showed that before black shale facies deposition organic matter preservation was a Type III-IV SOM. Petrography reveals that this SOM is composed mostly of degraded algal debris, amorphous SOM and a minor component of Type III-IV terrestrial SOM, mostly detroinertinite. When black shale facies deposition commenced, the geochemical character of the SOM changed from a relatively oxygen-rich Type III-IV to relatively hydrogen-rich Type II. Petrography, biomarker and organic carbon isotopic data indicate marine and terrestrial SOM sources that do not appear to change during the transition from light-grey calcareous ooze to the black shale facies. Black shale subfacies layers alternate from laminated to homogeneous. Some of the laminated and the poorly laminated to homogeneous layers are organic carbon and hydrogen rich as well, suggesting that at least two SOM depositional processes are influencing the black shale facies. The laminated beds reflect deposition in a low sedimentation rate (6m Ma-1) environment with SOM derived mostly from gravity settling from the overlying water into sometimes dysoxic bottom water. The source of this high hydrogen content SOM is problematic because before black shale deposition, the marine SOM supplied to the site is geochemically a Type III-IV. A clue to the source of the H-rich SOM may be the interlayering of relatively homogeneous ooze layers that have a widely variable SOM content and quality. These relatively thick, sometimes subtly graded, sediment layers are thought to be deposited from a Type II SOM-enriched sediment suspension generated by turbidities or direct turbidite deposition.

Multivariate analysis relating oil shale geochemical properties to NMR relaxometry

USGS Publications Warehouse

Birdwell, Justin E.; Washburn, Kathryn E.

2015-01-01

Low-field nuclear magnetic resonance (NMR) relaxometry has been used to provide insight into shale composition by separating relaxation responses from the various hydrogen-bearing phases present in shales in a noninvasive way. Previous low-field NMR work using solid-echo methods provided qualitative information on organic constituents associated with raw and pyrolyzed oil shale samples, but uncertainty in the interpretation of longitudinal-transverse (T1–T2) relaxometry correlation results indicated further study was required. Qualitative confirmation of peaks attributed to kerogen in oil shale was achieved by comparing T1–T2 correlation measurements made on oil shale samples to measurements made on kerogen isolated from those shales. Quantitative relationships between T1–T2 correlation data and organic geochemical properties of raw and pyrolyzed oil shales were determined using partial least-squares regression (PLSR). Relaxometry results were also compared to infrared spectra, and the results not only provided further confidence in the organic matter peak interpretations but also confirmed attribution of T1–T2 peaks to clay hydroxyls. In addition, PLSR analysis was applied to correlate relaxometry data to trace element concentrations with good success. The results of this work show that NMR relaxometry measurements using the solid-echo approach produce T1–T2 peak distributions that correlate well with geochemical properties of raw and pyrolyzed oil shales.

Ammonia stripping, activated carbon adsorption and anaerobic biological oxidation as process combination for the treatment of oil shale wastewater.

PubMed

Alexandre, Verônica M F; do Nascimento, Felipe V; Cammarota, Magali C

2016-10-01

Anaerobic biodegradability of oil shale wastewater was investigated after the following pretreatment sequence: ammonia stripping and activated carbon adsorption. Anaerobic biological treatment of oil shale wastewater is technically feasible after stripping at pH 11 for reducing the N-NH3 concentration, adsorption with 5 g/L of activated carbon in order to reduce recalcitrance and pH adjustment with CO2 so that the sulphate concentration in the medium remains low. After this pretreatment sequence, it was possible to submit the wastewater without dilution to an anaerobic treatment with 62.7% soluble chemical oxygen demand removal and specific methane production of 233.2 mL CH4STP/g CODremoved.

Production of valuable hydrocarbons by flash pyrolysis of oil shale

DOEpatents

Steinberg, M.; Fallon, P.T.

1985-04-01

A process for the production of gas and liquid hydrocarbons from particulated oil shale by reaction with a pyrolysis gas at a temperature of from about 700/sup 0/C to about 1100/sup 0/C, at a pressure of from about 400 psi to about 600 psi, for a period of about 0.2 second to about 20 seconds. Such a pyrolysis gas includes methane, helium, or hydrogen. 3 figs., 3 tabs.

Refining of Military Jet Fuels from Shale Oil. Part II. Volume III. Above Ground Shale Oil Process Data.

DTIC Science & Technology

1982-03-01

system. Regenerator flue gas composi- tion, spent catalyst carbon content and regenerated cata- lyst content are monitored for material balance purposes...and good material balance closures obtained. During each run pro- duct gas samples, regenerator flue gas samples, spent and -85- regenerated...TEMPERATURE DEPENDENCE OF DENITROGENATION AT 2 LHSV ON CO/MO ......................... 26 111-2 TEMPERATURE DEPENDENCE OF DESULFURIZATION AT 2 LHSV ON

Identifying Different Types of Catalysts for CO2 Reduction by Ethane through Dry Reforming and Oxidative Dehydrogenation.

PubMed

Porosoff, Marc D; Myint, Myat Noe Zin; Kattel, Shyam; Xie, Zhenhua; Gomez, Elaine; Liu, Ping; Chen, Jingguang G

2015-12-14

The recent shale gas boom combined with the requirement to reduce atmospheric CO2 have created an opportunity for using both raw materials (shale gas and CO2 ) in a single process. Shale gas is primarily made up of methane, but ethane comprises about 10 % and reserves are underutilized. Two routes have been investigated by combining ethane decomposition with CO2 reduction to produce products of higher value. The first reaction is ethane dry reforming which produces synthesis gas (CO+H2 ). The second route is oxidative dehydrogenation which produces ethylene using CO2 as a soft oxidant. The results of this study indicate that the Pt/CeO2 catalyst shows promise for the production of synthesis gas, while Mo2 C-based materials preserve the CC bond of ethane to produce ethylene. These findings are supported by density functional theory (DFT) calculations and X-ray absorption near-edge spectroscopy (XANES) characterization of the catalysts under in situ reaction conditions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cost Effective Recovery of Low-TDS Frac Flowback Water for Re-use

DOE Office of Scientific and Technical Information (OSTI.GOV)

Claire Henderson; Harish Acharya; Hope Matis

2011-03-31

The project goal was to develop a cost-effective water recovery process to reduce the costs and envi-ronmental impact of shale gas production. This effort sought to develop both a flowback water pre-treatment process and a membrane-based partial demineralization process for the treatment of the low-Total Dissolved Solids (TDS) portion of the flowback water produced during hydrofracturing operations. The TDS cutoff for consideration in this project is < 35,000 {approx} 45,000 ppm, which is the typical limit for economic water recovery employing reverse osmosis (RO) type membrane desalination processes. The ultimate objective is the production of clean, reclaimed water suitable formore » re-use in hydrofracturing operations. The team successfully compiled data on flowback composition and other attributes across multiple shale plays, identified the likely applicability of membrane treatment processes in those shales, and expanded the proposed product portfolio to include four options suitable for various reuse or discharge applications. Pretreatment technologies were evaluated at the lab scale and down-selected based upon their efficacy in removing key contaminants. The chosen technologies were further validated by performing membrane fouling studies with treated flowback water to demonstrate the technical feasibility of flowback treatment with RO membranes. Process flow schemes were constructed for each of the four product options based on experimental performance data from actual flowback water treatment studies. For the products requiring membrane treatment, membrane system model-ing software was used to create designs for enhanced water recovery beyond the typical seawater desalination benchmark. System costs based upon vendor and internal cost information for all process flow schemes were generated and are below target and in line with customer expectations. Finally, to account for temporal and geographic variability in flowback characteristics as well as local disposal costs and regulations, a parametric value assessment tool was created to assess the economic attractiveness of a given flowback recovery process relative to conventional disposal for any combination of anticipated flowback TDS and local disposal cost. It is concluded that membrane systems in combination with appropriate pretreatment technologies can provide cost-effective recovery of low-TDS flow-back water for either beneficial reuse or safe surface discharge.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Potter, P.E.; Maynard, J.B.; Pryor, W.A.

Studies of shales in the Appalachian area are reported (mainly in the form of abstracts of reports or manuscripts). They discuss the geology, lithology, stratigraphy, radioactivity, organic matter, the isotopic abundance of carbon and sulfur isotopes, etc. of shales in this area with maps. One report discusses Devonian paliocurrents in the central and northern Appalachian basin. Another discusses sedimentology of the Brallier Formation. The stratigraphy of upper Devonian shales along the southern shore of Lake Erie was also studied. (LTN)

Environmental Public Health Dimensions of Shale and Tight Gas Development

PubMed Central

Hays, Jake; Finkel, Madelon L.

2014-01-01

Background: The United States has experienced a boom in natural gas production due to recent technological innovations that have enabled this resource to be produced from shale formations. Objectives: We reviewed the body of evidence related to exposure pathways in order to evaluate the potential environmental public health impacts of shale gas development. We highlight what is currently known and identify data gaps and research limitations by addressing matters of toxicity, exposure pathways, air quality, and water quality. Discussion: There is evidence of potential environmental public health risks associated with shale gas development. Several studies suggest that shale gas development contributes to ambient air concentrations of pollutants known to be associated with increased risk of morbidity and mortality. Similarly, an increasing body of studies suggest that water contamination risks exist through a variety of environmental pathways, most notably during wastewater transport and disposal, and via poor zonal isolation of gases and fluids due to structural integrity impairment of cement in gas wells. Conclusion: Despite a growing body of evidence, data gaps persist. Most important, there is a need for more epidemiological studies to assess associations between risk factors, such as air and water pollution, and health outcomes among populations living in close proximity to shale gas operations. Citation: Shonkoff SB, Hays J, Finkel ML. 2014. Environmental public health dimensions of shale and tight gas development. Environ Health Perspect 122:787–795; http://dx.doi.org/10.1289/ehp.1307866 PMID:24736097

Understanding public perception of hydraulic fracturing: a case study in Spain.

PubMed

Costa, D; Pereira, V; Góis, J; Danko, A; Fiúza, A

2017-12-15

Public acceptance is crucial for the implementation of energy technologies. Hydraulic fracturing is a technology widely used in the USA for natural gas production from shale formations, but currently finds strong public opposition worldwide, especially in Europe. Shale gas exploitation and exploration have the potential to significantly reduce import dependency in several countries, including Spain. To better understand public opinion on this issue, this article reports a survey targeting both the entire Spanish population and the inhabitants of the province of Burgos, the location where shale gas exploration permits have already been issued. Results demonstrate that half of the Spanish population opposes shale gas, and this opposition increases in autonomous communities that are closer to possible exploration sites. The results also show that socio-demographic aspects are not strong predictors of opposition. In addition, Burgos' population show different behaviours toward shale gas that demonstrates that proximity and prospect of shale gas development affects opinion. Finally, there is still a great level of unfamiliarity with high volume hydraulic fracturing and shale gas in both populations sampled. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of shales on tidal response of water level to large earthquakes

NASA Astrophysics Data System (ADS)

Zhang, Y.; Wang, C. Y.; Fu, L. Y.

2017-12-01

Tidal response of water level in wells has been widely used to study properties of aquifers and, in particular, the response of groundwater to earthquakes. The affect of lithology on such response has not received deserved attention. Using data from selected wells in the intermediate and far fields of the 2008 Mw 7.9 Wenchuan and the 2011 Mw 9.1 Tohoku earthquakes, we examine how the presence of shales affects the tidal response of water level. Three categories of responses are recognized: horizontal flow, vertical flow and combined horizontal and vertical flow, with most wells with shales in the last category. We found that wells with shales are significantly influenced by fractures, leading semi-confined condition and vertical drainage, poorer well bore storage and decreased or unchanged co-seismic phase shifts. We also found a strong correlation between the shale content in the aquifer and the amplitude of tidal response, with higher shale content correlated with lower amplitude response, which we attribute to the compact structure (low porosity/low permeability) of shales.

The pore structure and fractal characteristics of shales with low thermal maturity from the Yuqia Coalfield, northern Qaidam Basin, northwestern China

NASA Astrophysics Data System (ADS)

Hou, Haihai; Shao, Longyi; Li, Yonghong; Li, Zhen; Zhang, Wenlong; Wen, Huaijun

2018-03-01

The continental shales from the Middle Jurassic Shimengou Formation of the northern Qaidam Basin, northwestern China, have been investigated in recent years because of their shale gas potential. In this study, a total of twenty-two shale samples were collected from the YQ-1 borehole in the Yuqia Coalfield, northern Qaidam Basin. The total organic carbon (TOC) contents, pore structure parameters, and fractal characteristics of the samples were investigated using TOC analysis, low-temperature nitrogen adsorption experiments, and fractal analysis. The results show that the average pore size of the Shimengou shales varied from 8.149 nm to 20.635 nm with a mean value of 10.74 nm, which is considered mesopore-sized. The pores of the shales are mainly inkbottle- and slit-shaped. The sedimentary environment plays an essential role in controlling the TOC contents of the low maturity shales, with the TOC values of shales from deep to semi-deep lake facies (mean: 5.23%) being notably higher than those of the shore-shallow lake facies (mean: 0.65%). The fractal dimensions range from 2.4639 to 2.6857 with a mean of 2.6122, higher than those of marine shales, which indicates that the pore surface was rougher and the pore structure more complex in these continental shales. The fractal dimensions increase with increasing total pore volume and total specific surface area, and with decreasing average pore size. With increasing TOC contents in shales, the fractal dimensions increase first and then decrease, with the highest value occurring at 2% of TOC content, which is in accordance with the trends between the TOC and both total specific surface area and total pore volume. The pore structure complexity and pore surface roughness of these low-maturity shales would be controlled by the combined effects of both sedimentary environments and the TOC contents.

Remedial processing of oil shale fly ash (OSFA) and its value-added conversion into glass-ceramics.

PubMed

Zhang, Zhikun; Zhang, Lei; Li, Aimin

2015-12-01

Recently, various solid wastes such as sewage sludge, coal fly ash and slag have been recycled into various products such as sintered bricks, ceramics and cement concrete. Application of these recycling approaches is much better and greener than conventional landfills since it can solve the problems of storage of industrial wastes and reduce exploration of natural resources for construction materials to protect the environment. Therefore, in this study, an attempt was made to recycle oil shale fly ash (OSFA), a by-product obtained from the extracting of shale oil in the oil shale industry, into a value-added glass-ceramic material via melting and sintering method. The influence of basicity (CaO/SiO2 ratio) by adding calcium oxide on the performance of glass-ceramics was studied in terms of phase transformation, mechanical properties, chemical resistances and heavy metals leaching tests. Crystallization kinetics results showed that the increase of basicity reduced the activation energies of crystallization but did not change the crystallization mechanism. When increasing the basicity from 0.2 to 0.5, the densification of sintering body was enhanced due to the promotion of viscous flow of glass powders, and therefore the compression strength and bending strength of glass-ceramics were increased. Heavy metals leaching results indicated that the produced OSFA-based glass-ceramics could be taken as non-hazardous materials. The maximum mechanical properties of compression strength of 186 ± 3 MPa, bending strength of 78 ± 6 MPa, good chemical resistances and low heavy metals leaching concentrations showed that it could be used as a substitute material for construction applications. The proposed approach will be one of the potential sustainable solutions in reducing the storage of oil shale fly ash as well as converting it into a value-added product. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Column Experiment To Determine Black Shale Degradation And Colonization By Means of δ13C and 14C Analysis Of Phospholipid Fatty Acids And DNA Extraction

NASA Astrophysics Data System (ADS)

Seifert, A.; Gleixner, G.

2008-12-01

We investigated the degradation of black shale organic matter by microbial communities. We inoculated two columns respectively, with the fungi Schizophyllum commune, the gram-positive bacterium Pseudomonas putida and the gram-negative bacteria Streptomyces griseus and Streptomyces chartreusis. These microorganisms are known to degrade a wide variety of organic macromolecules. Additionally, we had two sets of control columns. To one set the same nutrient solution was added as to the inoculated columns and to the other set only sterile deionised water was supplied. All columns contained 1.5 kg of freshly crushed not autoclaved black shale material with a particle size of 0.63-2 mm. The columns were incubated at 28° C and 60% humidity in the dark. The aim was to investigate, which microorganisms live on black shales and if these microorganisms are able to degrade ancient organic matter. We used compound specific stable isotope measurement techniques and compound specific 14C-dating methods. After 183 days PLFAs were extracted from the columns to investigate the microbial community, furthermore we extracted on one hand total-DNA of column material and on the other hand DNA from pure cultures isolates which grew on Kinks-agar B, Starch-casein-nitrate-agar (SCN) and on complete-yeast-medium-agar (CYM). According to the PLFA analysis bacteria dominated in the columns, whereas in pure cultures more fungi were isolated. A principal component analysis revealed differences between the columns in accordance with the inoculation, but it seems that the inoculated microorganisms were replaced by the natural population. For AMS measurements palmitic acid (C 16:0) was re-isolated from total-PLFA-extract with a preparative fraction collector (PFC). Preliminary results of the study revealed that microorganisms are able to degrade black shale material and that PLFA analysis are useful methods to be combined with analysis of stable isotope and 14C measurements to study microbial degradation processes.

Cracking mechanism of shale cracks during fracturing

NASA Astrophysics Data System (ADS)

Zhao, X. J.; Zhan, Q.; Fan, H.; Zhao, H. B.; An, F. J.

2018-06-01

In this paper, we set up a model for calculating the shale fracture pressure on the basis of Huang’s model by the theory of elastic-plastic mechanics, rock mechanics and the application of the maximum tensile stress criterion, which takes into account such factors as the crustal stress field, chemical field, temperature field, tectonic stress field, the porosity of shale and seepage of drilling fluid and so on. Combined with the experimental data of field fracturing and the experimental results of three axis compression of shale core with different water contents, the results show that the error between the present study and the measured value is 3.85%, so the present study can provide technical support for drilling engineering.

Petroleum source rock evaluation of the Alum and Dictyonema Shales (Upper Cambrian-Lower Ordovician) in the Baltic Basin and Podlasie Depression (eastern Poland)

NASA Astrophysics Data System (ADS)

Kosakowski, Paweł; Kotarba, Maciej J.; Piestrzyński, Adam; Shogenova, Alla; Więcław, Dariusz

2017-03-01

We present geochemical characteristics of the Lower Palaeozoic shales deposited in the Baltic Basin and Podlasie Depression. In the study area, this strata are represented by the Upper Cambrian-Lower Ordovician Alum Shale recognized in southern Scandinavia and Polish offshore and a equivalent the Lower Tremadocian Dictyonema Shale from the northern Estonia and the Podlasie Depression in Poland. Geochemical analyses reveal that the Alum Shale and Dictyonema Shale present high contents of organic carbon. These deposits have the best source quality among the Lower Palaeozoic strata, and they are the best source rocks in the Baltic region. The bituminous shales complex has TOC contents up to ca. 22 wt%. The analysed rocks contain low-sulphur, oil-prone Type-II kerogen deposited in anoxic or sub-oxic conditions. The maturity of the Alum and Dictyonema Shales changes gradually, from the east and north-east to the west and south-west, i.e. in the direction of the Tornquist-Teisseyre Zone. Samples, located in the seashore of Estonia and in the Podlasie region, are immature and in the initial phase of "oil window". The mature shales were found in the central offshore part of the Polish Baltic Basin, and the late mature and overmature are located in the western part of the Baltic Basin. The Alum and Dictyonema Shales are characterized by a high grade of radioactive elements, especially uranium. The enrichment has a syngenetic or early diagenetic origin. The measured content of uranium reached up to 750 ppm and thorium up to 37 ppm.

Impact of Shale Gas Development on Water Resource in Fuling, China

NASA Astrophysics Data System (ADS)

Yang, Hong; Huang, Xianjin; Yang, Qinyuan; Tu, Jianjun

2015-04-01

As a low-carbon energy, shale gas rapidly developed in U.S. in last years due to the innovation of the technique of hydraulic fracture, or fracking. Shale gas boom produces more gas with low price and reduced the reliance on fuel import. To follow the American shale gas success, China made an ambitious plan of shale gas extraction, 6.5 billion m3 by 2015. To extract shale gas, huge amount water is needed to inject into each gas well. This will intensify the competition of water use between industry, agricultural and domestic sectors. It may finally exacerbate the water scarcity in China. After the extraction, some water was returned to the ground. Without adequate treatment, the flowback water can introduce heavy metal, acids, pesticides, and other toxic material into water and land. This may inevitably worsen the water and land contamination. This study analysed the potential water consumption and wastewater generation in shale gas development in Fuling, Southwest China. The survey found the average water consumption is 30,000 cubic meter for one well, higher than shale well in U.S. Some 2%-20% water flowed back to the ground. The water quality monitoring showed the Total Suspended Solid (TSS) and Chemical Oxygen Demand (COD) were the main factors above those specified by China's water regulation. Shale gas is a lower-carbon energy, but it is important to recognize the water consuming and environmental pollution during the fracking. Strict monitoring and good coordination during the shale gas exploitation is urgently needed for the balance of economic development, energy demand and environmental protection.

The Shale Gas Boom and the Need for Rational Policy

PubMed Central

Finkel, Madelon; Law, Adam

2013-01-01

High-volume, slick water hydraulic fracturing of shale relies on pumping millions of gallons of surface water laced with toxic chemicals and sand under high pressure to create fractures to release the flow of gas. The process, however, has the potential to cause serious and irreparable damage to the environment and the potential for harm to human and animal health. At issue is how society should form appropriate policy in the absence of well-designed epidemiological studies and health impact assessments. The issue is fraught with environmental, economic, and health implications, and federal and state governments must establish detailed safeguards and ensure regulatory oversight, both of which are presently lacking in states where hydraulic fracturing is allowed. PMID:23678928

Using Neutrons to Study Fluid-Rock Interactions in Shales

NASA Astrophysics Data System (ADS)

DiStefano, V. H.; McFarlane, J.; Anovitz, L. M.; Gordon, A.; Hale, R. E.; Hunt, R. D.; Lewis, S. A., Sr.; Littrell, K. C.; Stack, A. G.; Chipera, S.; Perfect, E.; Bilheux, H.; Kolbus, L. M.; Bingham, P. R.

2015-12-01

Recovery of hydrocarbons by hydraulic fracturing depends on complex fluid-rock interactions that we are beginning to understand using neutron imaging and scattering techniques. Organic matter is often thought to comprise the majority of porosity in a shale. In this study, correlations between the type of organic matter embedded in a shale and porosity were investigated experimentally. Selected shale cores from the Eagle Ford and Marcellus formations were subjected to pyrolysis-gas chromatography, Differential Thermal Analysis/Thermogravimetric analysis, and organic solvent extraction with the resulting affluent analyzed by gas chromatography-mass spectrometry. The pore size distribution of the microporosity (~1 nm to 2 µm) in the Eagle Ford shales was measured before and after solvent extraction using small angle neutron scattering. Organics representing mass fractions of between 0.1 to 1 wt.% were removed from the shales and porosity generally increased across the examined microporosity range, particularly at larger pore sizes, approximately 50 nm to 2 μm. This range reflects extraction of accessible organic material, including remaining gas molecules, bitumen, and kerogen derivatives, indicating where the larger amount of organic matter in shale is stored. An increase in porosity at smaller pore sizes, ~1-3 nm, was also present and could be indicative of extraction of organic material stored in the inter-particle spaces of clays. Additionally, a decrease in porosity after extraction for a sample was attributed to swelling of pores with solvent uptake. This occurred in a shale with high clay content and low thermal maturity. The extracted hydrocarbons were primarily paraffinic, although some breakdown of larger aromatic compounds was observed in toluene extractions. The amount of hydrocarbon extracted and an overall increase in porosity appeared to be primarily correlated with the clay percentage in the shale. This study complements fluid transport neutron imaging studies, to explain the physics and chemistry of fluid-rock behavior. Research supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division and the Bredesen Center at the University of Tennessee.

Dual pore-connectivity and flow-paths affect shale hydrocarbon production

NASA Astrophysics Data System (ADS)

Hayman, N. W.; Daigle, H.; Kelly, E. D.; Milliken, K. L.; Jiang, H.

2016-12-01

Aided with integrated characterization approaches of droplet contact angle measurement, mercury intrusion capillary pressure, low-pressure gas physisorption, scanning electron microscopy, and small angle neutron scattering, we have systematically studied how pore connectivity and wettability are associated with mineral and organic matter phases of shales (Barnett, Bakken, Eagle Ford), as well as their influence on macroscopic fluid flow and hydrocarbon movement, from the following complementary tests: vacuum saturation with vacuum-pulling on dry shale followed with tracer introduction and high-pressure intrusion, tracer diffusion into fluid-saturated shale, fluid and tracer imbibition into partially-saturated shale, and Wood's metal intrusion followed with imaging and elemental mapping. The first three tests use tracer-bearing fluids (hydrophilic API brine and hydrophobic n-decane) fluids with a suite of wettability tracers of different sizes and reactivities developed in our laboratory. These innovative and integrated approaches indicate a Dalmatian wettability behavior at a scale of microns, limited connectivity (<500 microns from shale sample edge) shale pores, and disparity of well-connected hydrophobic pore network ( 10 nm) and sparsely connected hydrophilic pore systems (>50-100 nm), which is linked to the steep initial decline and low overall recovery because of the limited connection of hydrocarbon molecules in the shale matrix to the stimulated fracture network.

Shale characterization on Barito field, Southeast Kalimantan for shale hydrocarbon exploration

NASA Astrophysics Data System (ADS)

Sumotarto, T. A.; Haris, A.; Riyanto, A.; Usman, A.

2017-07-01

Exploration and exploitation in Indonesia now are still focused on conventional hydrocarbon energy than unconventional hydrocarbon energy such as shale gas. Tanjung Formation is a source rock of Barito Basin located in South Kalimantan that potentially as shale hydrocarbon. In this research, integrated methods using geochemical analysis, mineralogy, petrophysical analysis and seismic interpretation has been applied to explore the shale hydrocarbon potential in Barito Field for Tanjung formation. The first step is conducting geochemical and mineralogy analysis to the shale rock sample. Our analysis shows that the organic richness is ranging from 1.26-5.98 wt.% (good to excellent) with the depth of early mature window of 2170 m. The brittleness index is in an average of 0.44-0.56 (less Brittle) and Kerogen type is classified into II/III type that potentially produces oil and gas. The second step is continued by performing petrophysical analysis, which includes Total Organic Carbon (TOC) calculation and brittleness index continuously. The result has been validated with a laboratory measurement that obtained a good correlation. In addition, seismic interpretation based on inverted acoustic impedance is applied to map the distributions of shale hydrocarbon potential. Our interpretation shows that shale hydrocarbon potential is localized in the eastern and southeastern part of the study area.

Dual pore-connectivity and flow-paths affect shale hydrocarbon production

NASA Astrophysics Data System (ADS)

Hu, Q.; Barber, T.; Zhang, Y.; Md Golam, K.

2017-12-01

Aided with integrated characterization approaches of droplet contact angle measurement, mercury intrusion capillary pressure, low-pressure gas physisorption, scanning electron microscopy, and small angle neutron scattering, we have systematically studied how pore connectivity and wettability are associated with mineral and organic matter phases of shales (Barnett, Bakken, Eagle Ford), as well as their influence on macroscopic fluid flow and hydrocarbon movement, from the following complementary tests: vacuum saturation with vacuum-pulling on dry shale followed with tracer introduction and high-pressure intrusion, tracer diffusion into fluid-saturated shale, fluid and tracer imbibition into partially-saturated shale, and Wood's metal intrusion followed with imaging and elemental mapping. The first three tests use tracer-bearing fluids (hydrophilic API brine and hydrophobic n-decane) fluids with a suite of wettability tracers of different sizes and reactivities developed in our laboratory. These innovative and integrated approaches indicate a Dalmatian wettability behavior at a scale of microns, limited connectivity (<500 microns from shale sample edge) shale pores, and disparity of well-connected hydrophobic pore network ( 10 nm) and sparsely connected hydrophilic pore systems (>50-100 nm), which is linked to the steep initial decline and low overall recovery because of the limited connection of hydrocarbon molecules in the shale matrix to the stimulated fracture network.

Oil/source rock correlations in the Polish Flysch Carpathians and Mesozoic basement and organic facies of the Oligocene Menilite Shales: Insights from hydrous pyrolysis experiments

USGS Publications Warehouse

Curtis, John B.; Kotarba, M.J.; Lewan, M.D.; Wieclaw, D.

2004-01-01

The Oligocene Menilite Shales in the study area in the Polish Flysch Carpathians are organic-rich and contain varying mixtures of Type-II, Type-IIS and Type-III kerogen. The kerogens are thermally immature to marginally mature based on atomic H/C ratios and Rock-Eval data. This study defined three organic facies, i.e., sedimentary strata with differing hydrocarbon-generation potentials due to varying types and concentrations of organic matter. These facies correspond to the Silesian Unit and the eastern and western portions of the Skole Unit. Analysis of oils generated by hydrous pyrolysis of outcrop samples of Menilite Shales demonstrates that natural crude oils reservoired in the flysch sediments appear to have been generated from the Menilite Shales. Natural oils reservoired in the Mesozoic basement of the Carpathian Foredeep appear to be predominantly derived and migrated from Menilite Shales, with a minor contribution from at least one other source rock most probably within Middle Jurassic strata. Definition of organic facies may have been influenced by the heterogeneous distribution of suitable Menilite Shales outcrops and producing wells, and subsequent sample selection during the analytical phases of the study. ?? 2004 Elsevier Ltd. All rights reserved.

Practical measures for reducing the risk of environmental contamination in shale energy production.

PubMed

Ziemkiewicz, Paul; Quaranta, John D; McCawley, Michael

2014-07-01

Gas recovery from shale formations has been made possible by advances in horizontal drilling and hydraulic fracturing technology. Rapid adoption of these methods has created a surge in natural gas production in the United States and increased public concern about its environmental and human health effects. We surveyed the environmental literature relevant to shale gas development and studied over fifteen well sites and impoundments in West Virginia to evaluate pollution caused by air emissions, light and noise during drilling. Our study also characterized liquid and solid waste streams generated by drilling and hydraulic fracturing and evaluated the integrity of impoundments used to store fluids produced by hydraulic fracturing. While most shale gas wells are completed with little or no environmental contamination, we found that many of the problems associated with shale gas development resulted from inattention to accepted engineering practices such as impoundment construction, improper liner installation and a lack of institutional controls. Recommendations are provided based on the literature and our field studies. They will address not all but a great many of the deficiencies that result in environmental release of contaminants from shale gas development. We also identified areas where new technologies are needed to fully address contaminant releases to air and water.

A reactive transport model for Marcellus shale weathering

NASA Astrophysics Data System (ADS)

Heidari, Peyman; Li, Li; Jin, Lixin; Williams, Jennifer Z.; Brantley, Susan L.

2017-11-01

Shale formations account for 25% of the land surface globally and contribute a large proportion of the natural gas used in the United States. One of the most productive shale-gas formations is the Marcellus, a black shale that is rich in organic matter and pyrite. As a first step toward understanding how Marcellus shale interacts with water in the surface or deep subsurface, we developed a reactive transport model to simulate shale weathering under ambient temperature and pressure conditions, constrained by soil and water chemistry data. The simulation was carried out for 10,000 years since deglaciation, assuming bedrock weathering and soil genesis began after the last glacial maximum. Results indicate weathering was initiated by pyrite dissolution for the first 1000 years, leading to low pH and enhanced dissolution of chlorite and precipitation of iron hydroxides. After pyrite depletion, chlorite dissolved slowly, primarily facilitated by the presence of CO2 and organic acids, forming vermiculite as a secondary mineral. A sensitivity analysis indicated that the most important controls on weathering include the presence of reactive gases (CO2 and O2), specific surface area, and flow velocity of infiltrating meteoric water. The soil chemistry and mineralogy data could not be reproduced without including the reactive gases. For example, pyrite remained in the soil even after 10,000 years if O2 was not continuously present in the soil column; likewise, chlorite remained abundant and porosity remained small if CO2 was not present in the soil gas. The field observations were only simulated successfully when the modeled specific surface areas of the reactive minerals were 1-3 orders of magnitude smaller than surface area values measured for powdered minerals. Small surface areas could be consistent with the lack of accessibility of some fluids to mineral surfaces due to surface coatings. In addition, some mineral surface is likely interacting only with equilibrated pore fluids. An increase in the water infiltration rate enhanced weathering by removing dissolution products and maintaining far-from-equilibrium conditions. We conclude from these observations that availability of reactive surface area and transport of H2O and gases are the most important factors affecting rates of Marcellus shale weathering of the in the shallow subsurface. This weathering study documents the utility of reactive transport modeling for complex subsurface processes. Such modelling could be extended to understand interactions between injected fluids and Marcellus shale gas reservoirs at higher temperature, pressure, and salinity conditions.

Shale gas activity and increased rates of sexually transmitted infections in Ohio, 2000–2016

PubMed Central

Humeau, Zoe; Elliott, Elise G.; Warren, Joshua L.; Niccolai, Linda M.

2018-01-01

Background The growing shale gas (“fracking”) industry depends on a mobile workforce, whose influx could have social impacts on host communities. Sexually transmitted infections (STIs) can increase through sexual mixing patterns associated with labor migration. No prior studies have quantified the relationship between shale gas activity and rates of three reportable STIs: chlamydia, gonorrhea, and syphilis. Methods We conducted a longitudinal, ecologic study from 2000–2016 in Ohio, situated in a prolific shale gas region in the United States (US). Data on reported cases of chlamydia, gonorrhea, and syphilis by county and year were obtained from the Ohio Department of Health. All 88 counties were classified as none, low, and high shale gas activity in each year, using data from the Ohio Department of Natural Resources. Annual rate ratios (RR) and 95% confidence intervals (95% CIs) were calculated from mixed-effects Poisson regression models evaluating the relationship between shale gas activity and reported annual STI rates while adjusting for secular trends and potential confounders obtained from the US Census. Results Compared to counties with no shale gas activity, counties with high activity had 21% (RR = 1.21; 95%CI = 1.08–1.36) increased rates of chlamydia and 19% (RR = 1.27; 95%CI 0.98–1.44) increased rates of gonorrhea, respectively. No association was observed for syphilis. Conclusion This first report of a link between shale gas activity and increased rates of both chlamydia and gonorrhea may inform local policies and community health efforts. PMID:29570712

Modeling of Gas Production from Shale Reservoirs Considering Multiple Transport Mechanisms.

PubMed

Guo, Chaohua; Wei, Mingzhen; Liu, Hong

2015-01-01

Gas transport in unconventional shale strata is a multi-mechanism-coupling process that is different from the process observed in conventional reservoirs. In micro fractures which are inborn or induced by hydraulic stimulation, viscous flow dominates. And gas surface diffusion and gas desorption should be further considered in organic nano pores. Also, the Klinkenberg effect should be considered when dealing with the gas transport problem. In addition, following two factors can play significant roles under certain circumstances but have not received enough attention in previous models. During pressure depletion, gas viscosity will change with Knudsen number; and pore radius will increase when the adsorption gas desorbs from the pore wall. In this paper, a comprehensive mathematical model that incorporates all known mechanisms for simulating gas flow in shale strata is presented. The objective of this study was to provide a more accurate reservoir model for simulation based on the flow mechanisms in the pore scale and formation geometry. Complex mechanisms, including viscous flow, Knudsen diffusion, slip flow, and desorption, are optionally integrated into different continua in the model. Sensitivity analysis was conducted to evaluate the effect of different mechanisms on the gas production. The results showed that adsorption and gas viscosity change will have a great impact on gas production. Ignoring one of following scenarios, such as adsorption, gas permeability change, gas viscosity change, or pore radius change, will underestimate gas production.

Modeling of Gas Production from Shale Reservoirs Considering Multiple Transport Mechanisms

PubMed Central

Guo, Chaohua; Wei, Mingzhen; Liu, Hong

2015-01-01

Gas transport in unconventional shale strata is a multi-mechanism-coupling process that is different from the process observed in conventional reservoirs. In micro fractures which are inborn or induced by hydraulic stimulation, viscous flow dominates. And gas surface diffusion and gas desorption should be further considered in organic nano pores. Also, the Klinkenberg effect should be considered when dealing with the gas transport problem. In addition, following two factors can play significant roles under certain circumstances but have not received enough attention in previous models. During pressure depletion, gas viscosity will change with Knudsen number; and pore radius will increase when the adsorption gas desorbs from the pore wall. In this paper, a comprehensive mathematical model that incorporates all known mechanisms for simulating gas flow in shale strata is presented. The objective of this study was to provide a more accurate reservoir model for simulation based on the flow mechanisms in the pore scale and formation geometry. Complex mechanisms, including viscous flow, Knudsen diffusion, slip flow, and desorption, are optionally integrated into different continua in the model. Sensitivity analysis was conducted to evaluate the effect of different mechanisms on the gas production. The results showed that adsorption and gas viscosity change will have a great impact on gas production. Ignoring one of following scenarios, such as adsorption, gas permeability change, gas viscosity change, or pore radius change, will underestimate gas production. PMID:26657698

High-resolution seismic reflection to delineate shallow gas in Eastern Kansas

USGS Publications Warehouse

Miller, R.D.; Watney, W.L.; Begay, D.K.; Xia, J.

2000-01-01

Unique amplitude characteristics of shallow gas sands within Pennsylvanian clastic-carbonate dominated sequences are discernible on high-resolution seismic reflection data in eastern Kansas. Upward grading sequences of sand into shale represent a potential gas reservoir with a low-impedence acoustic contrast at the base of the encasing layer. The gas sand and encasing shale, which define the gas reservoir studied here, are part of an erosional incised valley where about 30 m of carbonates and shale have been replaced by sandstone and shale confined to the incised valley. These consolidated geologic settings would normally possess high impedence gas sand reservoirs as defined by abrupt contacts between the gas sand and encasing shale. Based orr core and borehole logs, the gas sand studied here grades from sand into shale in a fashion analogous to that observed in classic low-impedance environments. Amplitude and phase characteristics of high-resolution seismic data across this approximately 400-m wide gas sand are indicative of a low-impedance reservoir. Shot gathers possess classic amplitude with offsett-dependent characteristics which are manifeted on the stacked section as "bright spots." Dominant Frequencies of around 120 Hz allow detection of several reflectors within the 30+ meters of sand/shale that make up this localized gas-rich incised valley fill. The gradational nature of the trapping mechanism observed in this gas reservoir would make detection with conventional seismic reflection methods unlikely.

Effects of retorting factors on combustion properties of shale char. 3. Distribution of residual organic matters.

PubMed

Han, Xiangxin; Jiang, Xiumin; Cui, Zhigang; Liu, Jianguo; Yan, Junwei

2010-03-15

Shale char, formed in retort furnaces of oil shale, is classified as a dangerous waste containing several toxic compounds. In order to retort oil shale to produce shale oil as well as treat shale char efficiently and in an environmentally friendly way, a novel kind of comprehensive utilization system was developed to use oil shale for shale oil production, electricity generation (shale char fired) and the extensive application of oil shale ash. For exploring the combustion properties of shale char further, in this paper organic matters within shale chars obtained under different retorting conditions were extracted and identified using a gas chromatography-mass spectrometry (GC-MS) method. Subsequently, the effects of retorting factors, including retorting temperature, residence time, particle size and heating rate, were analyzed in detail. As a result, a retorting condition with a retorting temperature of 460-490 degrees C, residence time of <40 min and a middle particle size was recommended for both keeping nitrogenous organic matters and aromatic hydrocarbons in shale char and improving the yield and quality of shale oil. In addition, shale char obtained under such retorting condition can also be treated efficiently using a circulating fluidized bed technology with fractional combustion. (c) 2009 Elsevier B.V. All rights reserved.

Assessment of freshwater withdrawals and availability for Marcellus shale natural gas development: a case study in Pennsylvania

Treesearch

Patrick C. Eisenhauer; Nicolas P. Zegre; Samuel J. Lamont

2013-01-01

To evaluate surface water withdrawals used for Marcellus shale natural gas development and to assess potential impacts on water yield, a regional water balance model was developed for the Pine Creek watershed, located primarily in Lycoming County, Pennsylvania. Marcellus shale development has increased rapidly in Lycoming County since 2007. We used precipitation,...

The origin, type and hydrocarbon generation potential of organic matter in a marine-continental transitional facies shale succession (Qaidam Basin, China).

PubMed

Wang, Guo-Cang; Sun, Min-Zhuo; Gao, Shu-Fang; Tang, Li

2018-04-26

This organic-rich shale was analyzed to determine the type, origin, maturity and depositional environment of the organic matter and to evaluate the hydrocarbon generation potential of the shale. This study is based on geochemical (total carbon content, Rock-Eval pyrolysis and the molecular composition of hydrocarbons) and whole-rock petrographic (maceral composition) analyses. The petrographic analyses show that the shale penetrated by the Chaiye 2 well contains large amounts of vitrinite and sapropelinite and that the organic matter within these rocks is type III and highly mature. The geochemical analyses show that these rocks are characterized by high total organic carbon contents and that the organic matter is derived from a mix of terrestrial and marine sources and highly mature. These geochemical characteristics are consistent with the results of the petrographic analyses. The large amounts of organic matter in the Carboniferous shale succession penetrated by the Chaiye 2 well may be due to good preservation under hypersaline lacustrine and anoxic marine conditions. Consequently, the studied shale possesses very good hydrocarbon generation potential because of the presence of large amounts of highly mature type III organic matter.

Integrated Experimental and Computational Study of Hydraulic Fracturing and the Use of Alternative Fracking Fluids

NASA Astrophysics Data System (ADS)

Viswanathan, H.; Carey, J. W.; Karra, S.; Porter, M. L.; Rougier, E.; Zhang, D.; Makedonska, N.; Middleton, R. S.; Currier, R.; Gupta, R.; Lei, Z.; Kang, Q.; O'Malley, D.; Hyman, J.

2014-12-01

Shale gas is an unconventional fossil energy resource that is already having a profound impact on US energy independence and is projected to last for at least 100 years. Production of methane and other hydrocarbons from low permeability shale involves hydrofracturing of rock, establishing fracture connectivity, and multiphase fluid-flow and reaction processes all of which are poorly understood. The result is inefficient extraction with many environmental concerns. A science-based capability is required to quantify the governing mesoscale fluid-solid interactions, including microstructural control of fracture patterns and the interaction of engineered fluids with hydrocarbon flow. These interactions depend on coupled thermo-hydro-mechanical-chemical (THMC) processes over scales from microns to tens of meters. Determining the key mechanisms in subsurface THMC systems has been impeded due to the lack of sophisticated experimental methods to measure fracture aperture and connectivity, multiphase permeability, and chemical exchange capacities at the high temperature, pressure, and stresses present in the subsurface. This project uses innovative high-pressure microfluidic and triaxial core flood experiments on shale to explore fracture-permeability relations and the extraction of hydrocarbon. These data are integrated with simulations including lattice Boltzmann modeling of pore-scale processes, finite-element/discrete element models of fracture development in the near-well environment, discrete-fracture modeling of the reservoir, and system-scale models to assess the economics of alternative fracturing fluids. The ultimate goal is to make the necessary measurements to develop models that can be used to determine the reservoir operating conditions necessary to gain a degree of control over fracture generation, fluid flow, and interfacial processes over a range of subsurface conditions.

Mixed biogenic and hydrothermal quartz in Permian lacustrine shale of Santanghu Basin, NW China: implications for penecontemporaneous transformation of silica minerals

NASA Astrophysics Data System (ADS)

Jiao, Xin; Liu, Yiqun; Yang, Wan; Zhou, Dingwu; Wang, Shuangshuang; Jin, Mengqi; Sun, Bin; Fan, Tingting

2018-01-01

The cycling of various isomorphs of authigenic silica minerals is a complex and long-term process. A special type of composite quartz (Qc) grains in tuffaceous shale of Permian Lucaogou Formation in the sediment-starved volcanically and hydrothermally active intracontinental lacustrine Santanghu rift basin (NW China) is studied in detail to demonstrate such processes. Samples from one well in the central basin were subject to petrographic, elemental chemical, and fluid inclusion analyses. About 200 Qc-bearing laminae are 0.1-2 mm and mainly 1 mm thick and intercalated within tuffaceous shale laminae. The Qc grains occur as framework grains and are dispersed in igneous feldspar-dominated matrix, suggesting episodic accumulation. The Qc grains are bedding-parallel, uniform in size (100 s µm), elongate, and radial in crystal pattern, suggesting a biogenic origin. Qc grains are composed of a core of anhedral microcrystalline quartz and an outer part of subhedral mega-quartz grains, whose edges are composed of small euhedral quartz crystals, indicating multiple episodic processes of recrystallization and overgrowth. Abundance of Al and Ti in quartz crystals and estimated temperature from fluid inclusions in Qc grains indicate that processes are related to hydrothermal fluids. Finally, the Qc grains are interpreted as original silica precipitation in microorganism (algae?) cysts, which were reworked by bottom currents and altered by hydrothermal fluids to recrystalize and overgrow during penecontemporaneous shallow burial. It is postulated that episodic volcanic and hydrothermal activities had changed lake water chemistry, temperature, and nutrient supply, resulting in variations in microorganic productivities and silica cycling. The transformation of authigenic silica from amorphous to well crystallized had occurred in a short time span during shallow burial.

Assessment of potential shale-oil and shale-gas resources in Silurian shales of Jordan, 2014

USGS Publications Warehouse

Schenk, Christopher J.; Pitman, Janet K.; Charpentier, Ronald R.; Klett, Timothy R.; Tennyson, Marilyn E.; Mercier, Tracey J.; Nelson, Philip H.; Brownfield, Michael E.; Pawlewicz, Mark J.; Wandrey, Craig J.

2014-01-01

Using a geology-based assessment methodology, the U.S. Geological Survey estimated means of 11 million barrels of potential shale-oil and 320 billion cubic feet of shale-gas resources in Silurian shales of Jordan.

Characterization of Early Stage Marcellus Shale Development Atmospheric Emissions and Regional Air Quality Impacts using Fast Mobile Measurements

NASA Astrophysics Data System (ADS)

Goetz, J. D.; Floerchinger, C. R.; Fortner, E.; Wormhoult, J.; Massoli, P.; Herndon, S. C.; Kolb, C. E., Jr.; Knighton, W. B.; Shaw, S. L.; Knipping, E. M.; DeCarlo, P. F.

2014-12-01

The Marcellus shale is the largest shale gas resource in the United States and is found in the Appalachian region. Rapid large-scale development, and the scarcity of direct air measurements make the impact of Marcellus shale development on local and regional air quality and the global climate highly uncertain. Air pollutant and greenhouse gas emission sources include transitory emission from well pad development as well as persistent sources including the processing and distribution of natural gas. In 2012, the Aerodyne Inc. Mobile Laboratory was equipped with a suite of real-time (~ 1 Hz) instrumentation to measure source emissions associated with Marcellus shale development and to characterize regional air quality in the Marcellus basin. The Aerodyne Inc. Mobile Laboratory was equipped to measure methane, ethane, N2O (tracer gas), C2H2 (tracer gas), CO2, CO, NOx, aerosols (number, mass, and composition), and VOC including light aromatic compounds and constituents of natural gas. Site-specific emissions from Marcellus shale development were quantified using tracer release ratio methods. Emissions of sub-micron aerosol mass and VOC were generally not observed at any tracer release site, although particle number concentrations were often enhanced. Compressor stations were found to have the largest emission rates of combustion products with NOx emissions ranging from 0.01 to 1.6 tons per day (tpd) and CO emissions ranging from 0.03 to 0.42 tpd. Transient sources, including a well site in the drill phase, were observed to be large emitters of natural gas. The largest methane emissions observed in the study were at a flowback well completion with a value of 7.7 tpd. Production well pads were observed to have the lowest emissions of natural gas and the emission of combustion products was only observed at one of three well pads investigated. Regional background measurements of all measured species were made while driving between tracer release sites and while stationary at night. Median background mixing ratios of methane in Pennsylvania were observed to be 19.7 ppmv in the Southwestern part of the state and 20.5 ppmv in Northeast. The atmospheric background measurements provide information about the temporal and spatial characteristics of the Marcellus basin during the early stages of shale gas development.

Radium release mechanisms during hydraulic fracturing of Marcellus Shale

NASA Astrophysics Data System (ADS)

Sharma, M.; Landis, J. D.; Renock, D. J.

2016-12-01

Wastewater co-produced with methane from Devonian Marcellus Shale is hypersaline and enriched in Ra. Recent studies find that water injected during hydraulic fracturing can leach out significant quantities of Na, Ca, Ba and Sr from solid phases in the shale over just hours to days. Here, we show with water-rock leaching experiments that the measured 226Ra/228Ra ratios of Marcellus wastewater could also derive from rapid leaching of mineral and organic phases of the shale. Radium isotopes 226Ra (t1/2 = 1600 a) and 228Ra (t1/2 = 5.8 a) are produced through radioactive decay of 238U (t1/2 = 4.5 Ga) and 232Th (t1/2 = 14 Ga), respectively. In the absence of processes that fractionate U, Th and Ra from one another, the decay rates of each parent-daughter pair become identical over 5 half-lives of the daughter radionuclide reaching a condition of secular equilibrium. Water-rock interaction may induce pronounced deviations from secular equilibrium in the water phase, however. Such is the case during hydraulic fracturing, where Ra is soluble and mobile, and is orphaned from insoluble U and Th parents. Once 226Ra and 228Ra are mobilized no fractionation between these isotopes is expected during their transport to the surface. Thus the 226Ra/228Ra ratio in wastewater provides a fingerprint of Ra source(s). Leaching Marcellus Shale with pure water under anoxic conditions releases mainly 228Ra from clays; extraction of 228Ra from radiation damaged sites is likely the dominant contributing mechanism. Using a novel isotope dilution technique we find that 90% of the Ra released in pure water partitions back onto rock (possibly clays). In comparison, leaching with high ionic strength solutions induces the release of 226Ra from mainly organics; the breakdown of organic matter in these solutions may be the driving mechanism controlling 226Ra release in solution. Radium released by high ionic strength solutions strongly partitions into water and results in the development of leachates with high 226Ra/228Ra ratios that are comparable to those of Marcellus wastewaters. Our results suggest that hydraulic fracturing using dilute HCl solution releases Ca and Na from the shale and effects rapid Ra release from the rock. Hypersaline and radioactive wastewater is thus a consequence of active leaching of shale during hydraulic fracturing.

Ultraviolet laser-induced voltage in anisotropic shale

NASA Astrophysics Data System (ADS)

Miao, Xinyang; Zhu, Jing; Li, Yizhang; Zhao, Kun; Zhan, Honglei; Yue, Wenzheng

2018-01-01

The anisotropy of shales plays a significant role in oil and gas exploration and engineering. Owing to various problems and limitations, anisotropic properties were seldom investigated by direct current resistivity methods. Here in this work, a 248 nm ultraviolet laser was employed to assess the anisotropic electrical response of a dielectric shale. Angular dependence of laser-induced voltages (V p) were obtained, with a data symmetry at the location of 180° and a ~62.2% V p anisotropy of the sample. The double-exponential functions have provided an explanation for the electrical field controlled carrier transportation process in horizontal and vertical directions. The results demonstrate that the combination of optics and electrical logging analysis (Opti-electrical Logging) is a promising technology for the investigation of unconventional reservoirs.

Hydrologic-information needs for oil-shale development, northwestern Colorado

USGS Publications Warehouse

Taylor, O.J.

1982-01-01

Hydrologic information is not adequate for proper development of the large oil-shale reserves of Piceance basin in northwestern Colorado. Exploratory drilling and aquifer testing are needed to define the hydrologic system, to provide wells for aquifer testing, to design mine-drainage techniques, and to explore for additional water supplies. Sampling networks are needed to supply hydrologic data on the quantity and quality of surface water, ground water, and springs. A detailed sampling network is proposed for the White River basin because of expected impacts related to water supplies and waste disposal. Emissions from oil-shale retorts to the atmosphere need additional study because of possible resulting corrosion problems and the destruction of fisheries. Studies of the leachate materials and the stability of disposed retorted shale piles are needed to insure that these materials will not cause problems. Hazards related to in-situ retorts, and the wastes related to oil-shale development in general also need further investigation. (USGS)

Discourse over a contested technology on Twitter: A case study of hydraulic fracturing.

PubMed

Hopke, Jill E; Simis, Molly

2015-10-04

High-volume hydraulic fracturing, a drilling simulation technique commonly referred to as "fracking," is a contested technology. In this article, we explore discourse over hydraulic fracturing and the shale industry on the social media platform Twitter during a period of heightened public contention regarding the application of the technology. We study the relative prominence of negative messaging about shale development in relation to pro-shale messaging on Twitter across five hashtags (#fracking, #globalfrackdown, #natgas, #shale, and #shalegas). We analyze the top actors tweeting using the #fracking hashtag and receiving @mentions with the hashtag. Results show statistically significant differences in the sentiment about hydraulic fracturing and shale development across the five hashtags. In addition, results show that the discourse on the main contested hashtag #fracking is dominated by activists, both individual activists and organizations. The highest proportion of tweeters, those posting messages using the hashtag #fracking, were individual activists, while the highest proportion of @mention references went to activist organizations. © The Author(s) 2015.

Water quality of groundwater and stream base flow in the Marcellus Shale Gas Field of the Monongahela River Basin, West Virginia, 2011-12

USGS Publications Warehouse

Chambers, Douglas B.; Kozar, Mark D.; Messinger, Terence; Mulder, Michon L.; Pelak, Adam J.; White , Jeremy S.

2015-01-01

This study provides a baseline of water-quality conditions in the Monongahela River Basin in West Virginia during the early phases of development of the Marcellus Shale gas field. Although not all inclusive, the results of this study provide a set of reliable water-quality data against which future data sets can be compared and the effects of shale-gas development may be determined.

Germanium and uranium in coalified wood bom upper Devonian black shale

USGS Publications Warehouse

Breger, I.A.; Schopf, J.M.

1955-01-01

Microscopic study of black, vitreous, carbonaceous material occurring in the Chattanooga shale in Tennessee and in the Cleveland member of the Ohio shale in Ohio has revealed coalified woody plant tissue. Some samples have shown sufficient detail to be identified with the genus Cauixylon. Similar material has been reported in the literature as "bituminous" or "asphaltic" stringers. Spectrographic analyses of the ash from the coalified wood have shown unusually high percentages of germanium, uranium, vanadium, and nickel. The inverse relationship between uranium and germanium in the ash and the ash content of various samples shows an association of these elements with the organic constituents of the coal. On the basis of geochemical considerations, it seems most probable that the wood or coalified wood was germanium-bearing at the time logs or woody fragmenta were floated into the basins of deposition of the Chattanooga shale and the Cleveland member of the Ohio shale. Once within the marine environment, the material probably absorbed uranium with the formation of organo-uranium compounds such as exist in coals. It is suggested that a more systematic search for germaniferous coals in the vicinity of the Chattanooga shale and the Cleveland member of the Ohio shale might be rewarding. ?? 1955.

Sustainability of UK shale gas in comparison with other electricity options: Current situation and future scenarios.

PubMed

Cooper, Jasmin; Stamford, Laurence; Azapagic, Adisa

2018-04-01

Many countries are considering exploitation of shale gas but its overall sustainability is currently unclear. Previous studies focused mainly on environmental aspects of shale gas, largely in the US, with scant information on socio-economic aspects. To address this knowledge gap, this paper integrates for the first time environmental, economic and social aspects of shale gas to evaluate its overall sustainability. The focus is on the UK which is on the cusp of developing a shale gas industry. Shale gas is compared to other electricity options for the current situation and future scenarios up to the year 2030 to investigate whether it can contribute towards a more sustainable electricity mix in the UK. The results obtained through multi-criteria decision analysis suggest that, when equal importance is assumed for each of the three sustainability aspects shale gas ranks seventh out of nine electricity options, with wind and solar PV being the best and coal the worst options. However, it outranks biomass and hydropower. Changing the importance of the sustainability aspects widely, the ranking of shale gas ranges between fourth and eighth. For shale gas to become the most sustainable option of those assessed, large improvements would be needed, including a 329-fold reduction in environmental impacts and 16 times higher employment, along with simultaneous large changes (up to 10,000 times) in the importance assigned to each criterion. Similar changes would be needed if it were to be comparable to conventional or liquefied natural gas, biomass, nuclear or hydropower. The results also suggest that a future electricity mix (2030) would be more sustainable with a lower rather than a higher share of shale gas. These results serve to inform UK policy makers, industry and non-governmental organisations. They will also be of interest to other countries considering exploitation of shale gas. Copyright © 2017 Elsevier B.V. All rights reserved.

Isopach and isoresource maps for oil shale deposits in the Eocene Green River Formation for the combined Uinta and Piceance Basins, Utah and Colorado

USGS Publications Warehouse

Mercier, Tracey J.; Johnson, Ronald C.

2012-01-01

The in-place oil shale resources in the Eocene Green River Formation of the Piceance Basin of western Colorado and the Uinta Basin of western Colorado and eastern Utah are estimated at 1.53 trillion barrels and 1.32 trillion barrels, respectively. The oil shale strata were deposited in a single large saline lake, Lake Uinta, that covered both basins and the intervening Douglas Creek arch, an area of comparatively low rates of subsidence throughout the history of Lake Uinta. Although the Green River Formation is largely eroded for about a 20-mile area along the crest of the arch, the oil shale interval is similar in both basins, and 17 out of 18 of the assessed oil shale zones are common to both basins. Assessment maps for these 17 zones are combined so that the overall distribution of oil shale over the entire extent of Lake Uinta can be studied. The combined maps show that throughout most of the history of Lake Uinta, the richest oil shale was deposited in the depocenter in the north-central part of the Piceance Basin and in the northeast corner of the Uinta Basin where it is closest to the Piceance Basin, which is the only area of the Uinta Basin where all of the rich and lean oil shale zones, originally defined in the Piceance Basin, can be identified. Both the oil shale and saline mineral depocenter in the Piceance Basin and the richest oil shale area in the Uinta Basin were in areas with comparatively low rates of subsidence during Lake Uinta time, but both areas had low rates of clastic influx. Limiting clastic influx rather than maximizing subsidence appears to have been the most important factor in producing rich oil shale.

Distribution and variation of the inorganic fraction of Devonian to Bashkirian black shales in the north-western part of the Dniepr-Donets Basin, Ukraine

NASA Astrophysics Data System (ADS)

Wegerer, Eva; Sachsenhofer, Reinhard; Misch, David; Aust, Nicolai

2016-04-01

Mineralogical data of 112 core samples from 12 wells are used to investigate lateral and vertical variations in the lithofacies of Devonian to Bashkirian black shales in the north-western part of the Dniepr-Donets-Basin. Sulphur and carbonate contents as well as organic geochemical parameters, including TOC and Hydrogen Index have been determined on the same sample set within the frame of an earlier study (Sachsenhofer et al. 2010). This allows the correlation of inorganic and organic composition of the black shales. Aims of the study are to distinguish between detrital and authigenic minerals, to relate the lithofacies of the black shales with the tectono-stratigraphic sequences of the Dniepr-Donets Basin, to contribute to the reconstruction of the depositional environment and to relate diagenetic processes with the thermal history of the basin. Mineral compositions were determined primarily using XRD-measurements applying several measurement procedures, e.g. chemical and temperature treatment, and specific standards. Major differences exist in the mineralogical composition of the black shales. For example, clay mineral contents range from less than 20 to more than 80 Vol%. Kaolinite contents are significantly higher in rocks with a Tournaisian or Early Visean age than in any other stratigraphic unit. This is also true for two Lower Visean coal samples from the shallow north-westernmost part of the basin. Chlorite contents reach maxima in uppermost Visean and overlying rocks. Quartz contents are often high in Upper Visean rocks and reach maxima in Bashkirian units. Feldspar-rich rocks are observed in Devonian sediments from the north-western part of the study area and may reflect the proximity to a sediment source. Carbonate contents are typically low, but reach very high values in some Tournaisian, Lower Visean and Serpukhovian samples. Pyrite contents reach maxima along the basin axis in Tournaisian and Visean rocks reflecting anoxic conditions. Mixed layer minerals are dominated by illite. Their presence in samples from depth exceeding 5 km reflects the low thermal overprint of Paleozoic rocks in the north-western Dniepr-Donets-Basin.

Reactivity of Dazomet, a Hydraulic Fracturing Additive: Hydrolysis and Interaction with Pyrite

NASA Astrophysics Data System (ADS)

Consolazio, N.; Lowry, G. V.; Karamalidis, A.; Hakala, A.

2015-12-01

The Marcellus Shale is currently the largest shale gas formation in play across the world. The low-permeability formation requires hydraulic fracturing to be produced. In this process, millions of gallons of water are blended with chemical additives and pumped into each well to fracture the reservoir rock. Although additives account for less than 2% of the fracking fluid mixture, they amount to hundreds of tons per frack job. The environmental properties of some of these additives have been studied, but their behavior under downhole conditions is not widely reported in the peer-reviewed literature. These compounds and their reaction products may return to the surface as produced or waste water. In the event of a spill or release, this water has the potential to contaminate surface soil and water. Of these additives, biocides may present a formidable challenge to water quality. Biocides are toxic compounds (by design), typically added to the Marcellus Shale to control bacteria in the well. An assessment of the most frequently used biocides indicated a need to study the chemical dazomet under reservoir conditions. The Marcellus Shale contains significant deposits of pyrite. This is a ubiquitous mineral within black shales that is known to react with organic compounds in both oxic and anoxic settings. Thus, the objective of our study was to determine the effect of pyrite on the hydrolysis of dazomet. Liquid chromatography-triple quadrupole mass spectrometry (LC-QQQ) was used to calculate the loss rate of aqueous dazomet. Gas chromatography-mass spectrometry (GC-MS) was used to identify the reaction products. Our experiments show that in water, dazomet rapidly hydrolyses in water to form organic and inorganic transformation products. This reaction rate was unaffected when performed under anoxic conditions. However, with pyrite we found an appreciable increase in the removal rate of dazomet. This was accompanied by a corresponding change in the distribution of observed reaction products. Our results indicate the need to determine specific mineral-additive interactions to evaluate the potential risks of chemical use in hydraulic fracturing.

Bacterial physiological diversity in the rhizosphere of range plants in response to retorted shale stress. [Agropyron smithii Rydb; Atriplex canescens (Pursh) Nutt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metzger, W.C.; Klein, D.A.; Redente, E.F.

1986-10-01

Bacterial populations were isolated from the soil-root interface and root-free regions of Agropyron smithii Rydb. and Atriplex canescens (Pursh) Nutt. grown in soil, retorted shale, or soil over shale. Bacteria isolated from retorted shale exhibited a wider range of tolerance to alkalinity and salinity and decreased growth on amino acid substrates compared with bacteria from soil and soil-over-shale environments. Exoenzyme production was only slightly affected by growth medium treatment. Viable bacterial populations were higher in the rhizosphere and rhizoplane of plants grown in retorted shale than in plants grown in soil or soil over shale. In addition, a greater numbermore » of physiological groups of rhizosphere bacteria was observed in retorted shale, compared with soil alone. Two patterns of community similarity were observed in comparisons of bacteria from soil over shale with those from soil and retorted-shale environments. Root-associated populations from soil over shale had a higher proportion of physiological groups in common with those from the soil control than those from the retorted-shale treatment. However, in non-rhizosphere populations, bacterial groups from soil over shale more closely resembled the physiological groups from retorted shale.« less

Experimental insights into geochemical changes in hydraulically fractured Marcellus Shale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marcon, Virginia; Joseph, Craig; Carter, Kimberly E.

Hydraulic fracturing applied to organic-rich shales has significantly increased the recoverable volume of methane available for U.S. energy consumption. Fluid-shale reactions in the reservoir may affect long-term reservoir productivity and waste management needs through changes to fracture mineral composition and produced fluid chemical composition. We performed laboratory experiments with Marcellus Shale and lab-generated hydraulic fracturing fluid at elevated pressures and temperatures to evaluate mineral reactions and the release of trace elements into solution. Results from the experiment containing fracturing chemicals show evidence for clay and carbonate dissolution, secondary clay and anhydrite precipitation, and early-stage (24-48 h) fluid enrichment of certainmore » elements followed by depletion in later stages (i.e. Al, Cd, Co, Cr, Cu, Ni, Sc, Zn). Other elements such as As, Fe, Mn, Sr, and Y increased in concentration and remained elevated throughout the duration of the experiment with fracturing fluid. Geochemical modeling of experimental fluid data indicates primary clay dissolution, and secondary formation of smectites and barite, after reaction with fracturing fluid. Changes in aqueous organic composition were observed, indicating organic additives may be chemically transformed or sequestered by the formation after hydraulic fracturing. The NaCl concentrations in our fluids are similar to measured concentrations in Marcellus Shale produced waters, showing that these experiments are representative of reservoir fluid chemistries and can provide insight on geochemical reactions that occur in the field. These results can be applied towards evaluating the evolution of hydraulically-fractured reservoirs, and towards understanding geochemical processes that control the composition of produced water from unconventional shales.« less

Experimental insights into geochemical changes in hydraulically fractured Marcellus Shale

DOE PAGES

Marcon, Virginia; Joseph, Craig; Carter, Kimberly E.; ...

2016-11-09

Hydraulic fracturing applied to organic-rich shales has significantly increased the recoverable volume of methane available for U.S. energy consumption. Fluid-shale reactions in the reservoir may affect long-term reservoir productivity and waste management needs through changes to fracture mineral composition and produced fluid chemical composition. We performed laboratory experiments with Marcellus Shale and lab-generated hydraulic fracturing fluid at elevated pressures and temperatures to evaluate mineral reactions and the release of trace elements into solution. Results from the experiment containing fracturing chemicals show evidence for clay and carbonate dissolution, secondary clay and anhydrite precipitation, and early-stage (24-48 h) fluid enrichment of certainmore » elements followed by depletion in later stages (i.e. Al, Cd, Co, Cr, Cu, Ni, Sc, Zn). Other elements such as As, Fe, Mn, Sr, and Y increased in concentration and remained elevated throughout the duration of the experiment with fracturing fluid. Geochemical modeling of experimental fluid data indicates primary clay dissolution, and secondary formation of smectites and barite, after reaction with fracturing fluid. Changes in aqueous organic composition were observed, indicating organic additives may be chemically transformed or sequestered by the formation after hydraulic fracturing. The NaCl concentrations in our fluids are similar to measured concentrations in Marcellus Shale produced waters, showing that these experiments are representative of reservoir fluid chemistries and can provide insight on geochemical reactions that occur in the field. These results can be applied towards evaluating the evolution of hydraulically-fractured reservoirs, and towards understanding geochemical processes that control the composition of produced water from unconventional shales.« less

Bacterial Paleontology and Studies of Carbonaceous Chondrites

NASA Technical Reports Server (NTRS)

Gerasimenko, L. M.; Hoover, Richard B.; Rozanov, Alexei Y.; Zhegallo, E. A.; Zhmur, S. I.

1999-01-01

The study of the fossilization processes of modern cyanobacteria provides insights needed to recognize bacterial microfossils. The fossilization of cyanobacteria is discussed and images of recent and fossil bacteria and cyanobacteria from the Early Proterozoic to Neogene carbonaceous rocks (kerites, shungites, and black shales) and phosphorites are provided. These are compared with biomorphic microstructures and possible microfossils encountered in-situ in carbonaceous meteorites.

Shale gas characterization based on geochemical and geophysical analysis: Case study of Brown shale, Pematang formation, Central Sumatra Basin

NASA Astrophysics Data System (ADS)

Haris, A.; Nastria, N.; Soebandrio, D.; Riyanto, A.

2017-07-01

Geochemical and geophysical analyses of shale gas have been carried out in Brown Shale, Middle Pematang Formation, Central Sumatra Basin. The paper is aimed at delineating the sweet spot distribution of potential shale gas reservoir, which is based on Total Organic Carbon (TOC), Maturity level data, and combined with TOC modeling that refers to Passey and Regression Multi Linear method. We used 4 well data, side wall core and 3D pre-stack seismic data. Our analysis of geochemical properties is based on well log and core data and its distribution are constrained by a framework of 3D seismic data, which is transformed into acoustic impedance. Further, the sweet spot of organic-rich shale is delineated by mapping TOC, which is extracted from inverted acoustic impedance. Our experiment analysis shows that organic materials contained in the formation of Middle Pematang Brown Shale members have TOC range from 0.15 to 2.71 wt.%, which is classified in the quality of poor to very good. In addition, the maturity level of organic material is ranging from 373°C to 432°C, which is indicated by vitrinite reflectance (Ro) of 0.58. In term of kerogen type, this Brown shale formation is categorized as kerogen type of II I III, which has the potential to generate a mixture of gasIoil on the environment.

Geochemical behavior of Cs, Sr, Tc, Np, and U in saline groundwaters: Sorption experiments on shales and their clay mineral components: Progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, R.E.; Arnold, W.D.; Ho, P.C.

1987-11-01

The Sedimentary Rock Program at the Oak Ridge National Laboratory is investigating shale to determine its potential suitability as a host rock for the disposal of high-level radioactive wastes (HLW). In support of this program, preliminary studies were carried out on sorption of cesium, strontium, technetium, neptunium, and uranium onto Chattanooga (Upper Dowelltown), Pierre, Green River Formation, Nolichucky, and Pumpkin Valley Shales under oxic conditions (air present). Three simulated groundwaters were used. One of the groundwaters was a synthetic brine made up to simulate highly saline groundwaters in the Pumpkin Valley Shale. The second was a 100/1 dilution of thismore » groundwater and the third was 0.03 M NaHCO/sub 3/. Moderate to significant sorption was observed under most conditions for all of the tested radionuclides except technetium. Moderate technetium sorption occurred on Upper Dowelltown Shale, and although technetium sorption was low on the other shales, it was higher than expected for Tc(VII), present as the anion TcO/sub 4//sup -/. Little sorption of strontium onto the shales was observed from the concentrated saline groundwater. These data can be used in a generic fashion to help assess the sorption characteristics of shales in support of a national survey. 10 refs., 4 figs., 23 tabs.« less

Residents’ Self-Reported Health Effects and Annoyance in Relation to Air Pollution Exposure in an Industrial Area in Eastern-Estonia

PubMed Central

Idavain, Jane; Pindus, Mihkel; Orru, Kati; Kesanurm, Kaisa; Lang, Aavo; Tomasova, Jelena

2018-01-01

Eastern Estonia has large oil shale mines and industrial facilities mainly focused on electricity generation from oil shale and shale oil extraction, which produce high air pollution emissions. The “Study of the health impact of the oil shale sector—SOHOS” was aimed at identifying the impacts on residents’ health and annoyance due to the industrial processing. First, a population-wide survey about health effects and annoyance was carried out. Second, the total and oil shale sectors’ emitted concentrations of benzene, phenol, and PM2.5 were modelled. Third, the differences between groups were tested and relationships between health effects and environmental pollution studied using multiple regression analysis. Compared to the control groups from non-industrial areas in Tartu or Lääne-Viru, residents of Ida-Viru more frequently (p < 0.05) reported wheezing, chest tightness, shortness of breath, asthma attacks, a long-term cough, hypertension, heart diseases, myocardial infarction, stroke, and diabetes. All health effects except asthma were reported more frequently among non-Estonians. People living in regions with higher levels of PM2.5, had significantly higher odds (p < 0.05) of experiencing chest tightness (OR = 1.13, 95% CI 1.02–1.26), shortness of breath (1.16, 1.03–1.31) or an asthma attack (1.22, 1.04–1.42) during the previous year. People living in regions with higher levels of benzene had higher odds of experiencing myocardial infarction (1.98, 1.11–3.53) and with higher levels of phenol chest tightness (1.44, 1.03–2.00), long-term cough (1.48, 1.06–2.07) and myocardial infarction (2.17, 1.23–3.83). The prevalence of adverse health effects was also higher among those who had been working in the oil shale sector. Next to direct health effects, up to a quarter of the residents of Ida-Viru County were highly annoyed about air pollution. Perceived health risk from air pollution increased the odds of being annoyed. Annoyed people in Ida-Viru had significantly higher odds of experiencing respiratory symptoms during the last 12 months, e.g., wheezing (2.30, 1.31–4.04), chest tightness (2.88, 1.91–4.33 or attack of coughing (1.99, 1.34–2.95). PMID:29393920

Residents' Self-Reported Health Effects and Annoyance in Relation to Air Pollution Exposure in an Industrial Area in Eastern-Estonia.

PubMed

Orru, Hans; Idavain, Jane; Pindus, Mihkel; Orru, Kati; Kesanurm, Kaisa; Lang, Aavo; Tomasova, Jelena

2018-02-02

Eastern Estonia has large oil shale mines and industrial facilities mainly focused on electricity generation from oil shale and shale oil extraction, which produce high air pollution emissions. The "Study of the health impact of the oil shale sector-SOHOS" was aimed at identifying the impacts on residents' health and annoyance due to the industrial processing. First, a population-wide survey about health effects and annoyance was carried out. Second, the total and oil shale sectors' emitted concentrations of benzene, phenol, and PM 2.5 were modelled. Third, the differences between groups were tested and relationships between health effects and environmental pollution studied using multiple regression analysis. Compared to the control groups from non-industrial areas in Tartu or Lääne-Viru, residents of Ida-Viru more frequently ( p < 0.05) reported wheezing, chest tightness, shortness of breath, asthma attacks, a long-term cough, hypertension, heart diseases, myocardial infarction, stroke, and diabetes. All health effects except asthma were reported more frequently among non-Estonians. People living in regions with higher levels of PM 2.5 , had significantly higher odds ( p < 0.05) of experiencing chest tightness (OR = 1.13, 95% CI 1.02-1.26), shortness of breath (1.16, 1.03-1.31) or an asthma attack (1.22, 1.04-1.42) during the previous year. People living in regions with higher levels of benzene had higher odds of experiencing myocardial infarction (1.98, 1.11-3.53) and with higher levels of phenol chest tightness (1.44, 1.03-2.00), long-term cough (1.48, 1.06-2.07) and myocardial infarction (2.17, 1.23-3.83). The prevalence of adverse health effects was also higher among those who had been working in the oil shale sector. Next to direct health effects, up to a quarter of the residents of Ida-Viru County were highly annoyed about air pollution. Perceived health risk from air pollution increased the odds of being annoyed. Annoyed people in Ida-Viru had significantly higher odds of experiencing respiratory symptoms during the last 12 months, e.g., wheezing (2.30, 1.31-4.04), chest tightness (2.88, 1.91-4.33 or attack of coughing (1.99, 1.34-2.95).

Seismically induced shale diapirism: the Mine d'Or section, Vilaine estuary, Southern Brittany

NASA Astrophysics Data System (ADS)

van Vliet-Lanoe, B.; Hibsch, C.; Csontos, L.; Jegouzo, S.; Hallégouët, B.; Laurent, M.; Maygari, A.; Mercier, D.; Voinchet, P.

2009-07-01

The Pénestin section (southern Brittany) presents large regular undulations, commonly interpreted as evidence of periglacial pingos. It is an upper Neogene palaeoestuary of the Vilaine River reactivated during the middle Quaternary (middle terrace). It is incised into a thick kaolinitic saprolite and deformed by saprolite diapirs. This paper presents the arguments leading to a mechanistic interpretation of the deformations at Pénestin. Neither recent transpressive tectonics nor diagnostic evidence of periglacial pingo have been found despite evidence for a late paleo-permafrost. The major deformational process is shale diapirism, initially triggered by co-seismic water supply, with further loading and lateral spreading on an already deformed and deeply weathered basement, which allowed the shale diapirism to develop. Deformations are favoured by the liquefaction of the saprolite and a seaward mass movement and recorded, rather distant, effects of an earthquake (c. 280 ka B.P.) resulting from the progressive subsidence of the southern Armorican margin. These deformations triggered by an earthquake are similar to those induced by classical shale diapirism. They are probably common in tectonically active continental environments with shallow water table.

Investigation of Controlling Factors Impacting Water Quality in Shale Gas Produced Brine

NASA Astrophysics Data System (ADS)

Fan, W.; Hayes, K. F.; Ellis, B. R.

2014-12-01

The recent boom in production of natural gas from unconventional reservoirs has generated a substantial increase in the volume of produced brine that must be properly managed to prevent contamination of fresh water resources. Produced brine, which includes both flowback and formation water, is often highly saline and may contain elevated concentrations of naturally occurring radioactive material and other toxic elements. These characteristics present many challenges with regard to designing effective treatment and disposal strategies for shale gas produced brine. We will present results from a series of batch experiments where crushed samples from two shale formations in the Michigan Basin, the Antrim and Utica-Collingwood shales, were brought into contact with synthetic hydraulic fracturing fluids under in situ temperature and pressure conditions. The Antrim has been an active shale gas play for over three decades, while the Utica-Collingwood formation (a grouped reservoir consisting of the Utica shale and Collingwood limestone) is an emerging shale gas play. The goal of this study is to investigate the influence of water-rock interactions in controlling produced water quality. We evaluate toxic element leaching from shale samples in contact with model hydraulic fracturing fluids under system conditions corresponding to reservoir depths up to 1.5 km. Experimental results have begun to elucidate the relative importance of shale mineralogy, system conditions, and chemical additives in driving changes in produced water quality. Initial results indicate that hydraulic fracturing chemical additives have a strong influence on the extent of leaching of toxic elements from the shale. In particular, pH was a key factor in the release of uranium (U) and divalent metals, highlighting the importance of the mineral buffering capacity of the shale. Low pH values persisted in the Antrim and Utica shale experiments and resulted in higher U extraction efficiencies than that observed in the presence of the carbonate-rich Collingwood limestone. In addition to assessing U leaching, we also measured the activity of 226Ra and 228Ra via high-resolution gamma ray spectroscopy. Laboratory results will be compared to observations from a complimentary field sampling campaign of Antrim produced brine.

Shale gas characteristics of the Lower Toarcian Posidonia Shale in Germany: from basin to nanometre scale

NASA Astrophysics Data System (ADS)

Schulz, Hans-Martin; Bernard, Sylvain; Horsfield, Brian; Krüger, Martin; Littke, Ralf; di primio, Rolando

2013-04-01

The Early Toarcian Posidonia Shale is a proven hydrocarbon source rock which was deposited in a shallow epicontinental basin. In southern Germany, Tethyan warm-water influences from the south led to carbonate sedimentation, whereas cold-water influxes from the north controlled siliciclastic sedimentation in the northwestern parts of Germany and the Netherlands. Restricted sea-floor circulation and organic matter preservation are considered to be the consequence of an oceanic anoxic event. In contrast, non-marine conditions led to sedimentation of coarser grained sediments under progressively terrestrial conditions in northeastern Germany The present-day distribution of Posidonia Shale in northern Germany is restricted to the centres of rift basins that formed in the Late Jurassic (e.g., Lower Saxony Basin and Dogger Troughs like the West and East Holstein Troughs) as a result of erosion on the basin margins and bounding highs. The source rock characteristics are in part dependent on grain size as the Posidonia Shale in eastern Germany is referred to as a mixed to non-source rock facies. In the study area, the TOC content and the organic matter quality vary vertically and laterally, likely as a consequence of a rising sea level during the Toarcian. Here we present and compare data of whole Posidonia Shale sections, investigating these variations and highlighting the variability of Posidonia Shale depositional system. During all phases of burial, gas was generated in the Posidonia Shale. Low sedimentation rates led to diffusion of early diagenetically formed biogenic methane. Isochronously formed diagenetic carbonates tightened the matrix and increased brittleness. Thermogenic gas generation occurred in wide areas of Lower Saxony as well as in Schleswig Holstein. Biogenic methane gas can still be formed today in Posidonia Shale at shallow depth in areas which were covered by Pleistocene glaciers. Submicrometric interparticle pores predominate in immature samples. At thermal maturities beyond the oil window, intra-mineral and intra-organic pores develop. In such overmature samples, nanopores occur within pyrobitumen masses. Important for gas storage and transport, they likely result from exsolution of gaseous hydrocarbon. References Bernard S., Wirth R., Schreiber A., Bowen L., Aplin A.C., Mathia E.J., Schulz H-M., & Horsfield B.: FIB-SEM and TEM investigations of an organic-rich shale maturation series (Lower Toarcian Posidonia Shale): Nanoscale pore system and fluid-rock interactions. AAPG Bulletin Special Issue "Electron Microscopy of Shale Hydrocarbon Reservoirs" (in press). Bernard, S., Horsfield, B., Schulz, H-M., Wirth, R., Schreiber, A., & Sherwood, N., 2012, Geochemical evolution of organic-rich shales with increasing maturity: A STXM and TEM study of the Posidonia Shale (Lower Toarcian, northern Germany): Marine and Petroleum Geology 31 (1) 70-89. Lott, G.K., Wong, T.E., Dusar, M., Andsbjerg, J., Mönnig, E., Feldman-Olszewska, A. & Verreussel, R.M.C.H., 2010. Jurassic. In: Doornenbal, J.C. and Stevenson, A.G. (editors): Petroleum Geological Atlas of the Southern Permian Basin Area. EAGE Publications b.v. (Houten): 175-193.

The Value of Water in Extraction of Natural Gas from the Marcellus Shale

NASA Astrophysics Data System (ADS)

Rimsaite, R.; Abdalla, C.; Collins, A.

2013-12-01

Hydraulic fracturing of shale has increased the demand for the essential input of water in natural gas production. Increased utilization of water by the shale gas industry, and the development of water transport and storage related infrastructure suggest that the value of water is increasing where hydraulic fracturing is occurring. Few studies on the value of water in industrial uses exist and, to our knowledge, no studies of water's value in extracting natural gas from shale have been published. Our research aims to fill this knowledge gap by exploring several key dimensions of the value of water used in shale gas development. Our primary focus was to document the costs associated with water acquisition for shale gas extraction in West Virginia and Pennsylvania, two states located in the gas-rich Marcellus shale formation with active drilling and extraction underway. This research involved a) gathering data on the sources of and costs associated with water acquisition for shale gas extraction b) comparing unit costs with prices and costs paid by the gas industry users of water; c) determining factors that potentially impact total and per unit costs of water acquisition for the shale gas industry; and d) identifying lessons learned for water managers and policy-makers. The population of interest was all private and public entities selling water to the shale gas industry in Pennsylvania and West Virginia. Primary data were collected from phone interviews with water sellers and secondary data were gathered from state regulatory agencies. Contact information was obtained for 40 water sellers in the two states. Considering both states, the average response rate was 49%. Relatively small amounts of water, approximately 11% in West Virginia and 29% in Pennsylvania, were purchased from public water suppliers by the shale gas industry. The price of water reveals information about the value of water. The average price charged to gas companies was 6.00/1000 gallons and 7.60/1000 gallons in West Virginia and Pennsylvania, respectively. The additional water sales uniformly increased revenues and the financial status of water suppliers in some cases by substantial amounts. However, due to the temporary and uncertain demand for water from gas companies, many suppliers were cautious about reliance on these revenues. It must be stressed that the price charged reflects only a minimum value, or willingness to pay, by the shale gas companies for water. The full value of water for Marcellus shale gas production would include the costs of transportation, storage, and other activities to bring the water to the well drilling sites. Transportation costs are estimated in this research. The results are interpreted in light of other components of water value for shale gas production and compared to the estimated values of water in other industrial uses and in selected water consuming sectors.

Application of fluid-rock reaction studies to in situ recovery from oil sand deposits, Alberta, Canada - I. Aqueous phase results for an experimental-statistical study of water-bitumen-shale reactions

NASA Astrophysics Data System (ADS)

Boon, J. A.; Hitchon, Brian

1983-02-01

In situ recovery operations in oil sand deposits effectively represent man-imposed low to intermediate temperature metamorphism of the sediments in the deposit. In order to evaluate some of the reactions which occur, a factorial experiment was earned out in which a shale from the Lower Cretaceous McMurray Formation in the Athabasca oil sand deposit of Alberta, in the presence or absence of bitumen, was subjected to hydrothermal treatment with aqueous fluids of varying pH and salinity, at two different temperatures, for periods up to 92 hours. The aqueous fluid was analyzed and the analytical data subjected to statistical factor analysis and analysis of variance, which enabled identification of the main processes, namely, cation exchange, the production of two types of colloidal material, and the dissolution of quartz There is also saturation of the aqueous phase by. as yet unidentified, "total organic carbon" and complete conversion and removal of all nitrogen in the shale to the aqueous phase. These reactions have implications with regards to the economics of the in situ recovery process, specifically with respect to the reuse and/or disposal of the produced water and the plugging of the pore space and hence of reduction of permeability between the injection and production wells. As a result of these experiments it is suggested that monitoring of the composition of the produced water from in situ recovery operations in oil sand deposits would be advisable.

Treatment of concentrated industrial wastewaters originating from oil shale and the like by electrolysis polyurethane foam interaction

DOEpatents

Tiernan, Joan E.

1991-01-01

Highly concentrated and toxic petroleum-based and synthetic fuels wastewaters such as oil shale retort water are treated in a unit treatment process by electrolysis in a reactor containing oleophilic, ionized, open-celled polyurethane foams and subjected to mixing and l BACKGROUND OF THE INVENTION The invention described herein arose in the course of, or under, Contract No. DE-AC03-76SF00098 between the U.S. Department of Energy and the University of California.

Impact of Shale Gas Development on Water Resources: A Case Study in Northern Poland

NASA Astrophysics Data System (ADS)

Vandecasteele, Ine; Marí Rivero, Inés; Sala, Serenella; Baranzelli, Claudia; Barranco, Ricardo; Batelaan, Okke; Lavalle, Carlo

2015-06-01

Shale gas is currently being explored in Europe as an alternative energy source to conventional oil and gas. There is, however, increasing concern about the potential environmental impacts of shale gas extraction by hydraulic fracturing (fracking). In this study, we focussed on the potential impacts on regional water resources within the Baltic Basin in Poland, both in terms of quantity and quality. The future development of the shale play was modeled for the time period 2015-2030 using the LUISA modeling framework. We formulated two scenarios which took into account the large range in technology and resource requirements, as well as two additional scenarios based on the current legislation and the potential restrictions which could be put in place. According to these scenarios, between 0.03 and 0.86 % of the total water withdrawals for all sectors could be attributed to shale gas exploitation within the study area. A screening-level assessment of the potential impact of the chemicals commonly used in fracking was carried out and showed that due to their wide range of physicochemical properties, these chemicals may pose additional pressure on freshwater ecosystems. The legislation put in place also influenced the resulting environmental impacts of shale gas extraction. Especially important are the protection of vulnerable ground and surface water resources and the promotion of more water-efficient technologies.

Impact of shale gas development on water resources: a case study in northern poland.

PubMed

Vandecasteele, Ine; Marí Rivero, Inés; Sala, Serenella; Baranzelli, Claudia; Barranco, Ricardo; Batelaan, Okke; Lavalle, Carlo

2015-06-01

Shale gas is currently being explored in Europe as an alternative energy source to conventional oil and gas. There is, however, increasing concern about the potential environmental impacts of shale gas extraction by hydraulic fracturing (fracking). In this study, we focussed on the potential impacts on regional water resources within the Baltic Basin in Poland, both in terms of quantity and quality. The future development of the shale play was modeled for the time period 2015-2030 using the LUISA modeling framework. We formulated two scenarios which took into account the large range in technology and resource requirements, as well as two additional scenarios based on the current legislation and the potential restrictions which could be put in place. According to these scenarios, between 0.03 and 0.86% of the total water withdrawals for all sectors could be attributed to shale gas exploitation within the study area. A screening-level assessment of the potential impact of the chemicals commonly used in fracking was carried out and showed that due to their wide range of physicochemical properties, these chemicals may pose additional pressure on freshwater ecosystems. The legislation put in place also influenced the resulting environmental impacts of shale gas extraction. Especially important are the protection of vulnerable ground and surface water resources and the promotion of more water-efficient technologies.

Local CO2-induced swelling of shales

NASA Astrophysics Data System (ADS)

Pluymakers, Anne; Dysthe, Dag Kristian

2017-04-01

In heterogeneous shale rocks, CO2 adsorbs more strongly to organic matter than to the other components. CO2-induced swelling of organic matter has been shown in coal, which is pure carbon. The heterogeneity of the shale matrix makes an interesting case study. Can local swelling through adsorption of CO2 to organic matter induce strain in the surrounding shale matrix? Can fractures close due to CO2-induced swelling of clays and organic matter? We have developed a new generation of microfluidic high pressure cells (up to 100 bar), which can be used to study flow and adsorption phenomena at the microscale in natural geo-materials. The devices contain one transparent side and a shale sample on the other side. The shale used is the Pomeranian shale, extracted from 4 km depth in Poland. This formation is a potential target of a combined CO2-storage and gas extraction project. To answer the first question, we place the pressure cell under a Veeco NT1100 Interferometer, operated in Vertical Scanning Interferometry mode and equipped with a Through Transmissive Media objective. This allows for observation of local swelling or organic matter with nanometer vertical resolution and micrometer lateral resolution. We expose the sample to CO2 atmospheres at different pressures. Comparison of the interferometry data and using SEM-EDS maps plus optical microscopy delivers local swelling maps where we can distinguish swelling of different mineralogies. Preliminary results indicate minor local swelling of organic matter, where the total amount is both time- and pressure-dependent.

The water footprint of hydraulic fracturing in Sichuan Basin, China.

PubMed

Zou, Caineng; Ni, Yunyan; Li, Jian; Kondash, Andrew; Coyte, Rachel; Lauer, Nancy; Cui, Huiying; Liao, Fengrong; Vengosh, Avner

2018-07-15

Shale gas is likely to play a major role in China's transition away from coal. In addition to technological and infrastructural constraints, the main challenges to China's sustainable shale gas development are sufficient shale gas production, water availability, and adequate wastewater management. Here we present, for the first time, actual data of shale gas production and its water footprint from the Weiyuan gas field, one of the major gas fields in Sichuan Basin. We show that shale gas production rates during the first 12 months (24 million m 3 per well) are similar to gas production rates in U.S. shale basins. The amount of water used for hydraulic fracturing (34,000 m 3 per well) and the volume of flowback and produced (FP) water in the first 12 months (19,800 m 3 per well) in Sichuan Basin are also similar to the current water footprints of hydraulic fracturing in U.S. basins. We present salinity data of the FP water (5000 to 40,000 mgCl/L) in Sichuan Basin and the treatment operations, which include sedimentation, dilution with fresh water, and recycling of the FP water for hydraulic fracturing. We utilize the water use data, empirical decline rates of shale gas and FP water productions in Sichuan Basin to generate two prediction models for water use for hydraulic fracturing and FP water production upon achieving China's goals to generate 100 billion m 3 of shale gas by 2030. The first model utilizes the current water use and FP production data, and the second assumes a yearly 5% intensification of the hydraulic fracturing process. The predicted water use for hydraulic fracturing in 2030 (50-65 million m 3 per year), FP water production (50-55 million m 3 per year), and fresh water dilution of FP water (25 million m 3 per year) constitute a water footprint that is much smaller than current water consumption and wastewater generation for coal mining, but higher than those of conventional gas production in China. Given estimates for water availability in Sichuan Basin, our predictions suggest that water might not be a limiting factor for future large-scale shale gas development in Sichuan Basin. Copyright © 2018 Elsevier B.V. All rights reserved.

Landslides: Geomorphology and Sea Cliff Hazard Potential, Santa Barbara - Isla Vista, California J.F. Klath and E.A. Keller

NASA Astrophysics Data System (ADS)

Klath, J. F.; Keller, E. A.

2015-12-01

Coastal areas are often characterized by high population densities in an ever changing, dynamic environment. The world's coasts are often dominated by steeply sloping sea cliffs, the morphology of which reflects rock type, wave erosion, and surface erosion, as well as human activities such changing vegetation, urban runoff, and construction of coastal defenses. The Santa Barbara and Goleta area, with over 17 km of sea cliffs and beaches, extends from Santa Barbara Point west to the hamlet of Isla Vista. A deeper understanding of the local geology and the physical processes generating slope failure and, thus, landward cliff retreat is important for general public safety, as well as future development and planning. Our research objective includes assessment of landslide hazard potential through investigation of previous landslides and how these events relate to various physical variables and characteristics within the surrounding bedrock. How does landslide frequency, volume, and type relate to varying local bedrock and structure? Two geologic formations dominate the sea cliffs of the Santa Barbara area: Monterey shale (upper, middle, and lower) and Monterey Sisquoc shale. Geology varies from hard cemented shale and diatomaceous, low specific gravity shale to compaction shale. Variations in landslide characteristics are linked closely to the geology of a specific site that affects how easily rock units are weathered and eroded by wave erosion, naturally occurring oil and water seeps, burnt shale events, and landslide type and frequency on steeply dipped bedding planes/daylighting beds. Naturally occurring features linked to human processes often weaken bedrock and, thus, increase the likelihood of landslides. We categorize landslide frequency, type, and triggers; location of beach access, drainage pipes, and water; and oil and tar seeps in order to develop suggestions to minimize landslide potential. Lastly, using previously published erosion cliff retreat rates and sea level rise estimates, a map displaying likely position of the coastline by 2100 will be created. This information will be useful to the county of Santa Barbara, California when considering future development and hazard mitigation plans.

Migration through soil of organic solutes in an oil-shale process water

USGS Publications Warehouse

Leenheer, J.A.; Stuber, H.A.

1981-01-01

The migration through soil of organic solutes in an oil-shale process water (retort water) was studied by using soil columns and analyzing leachates for various organic constituents. Retort water extracted significant quantities of organic anions leached from ammonium-saturated-soil organic matter, and a distilled-water rinse, which followed retort-water leaching, released additional organic acids from the soil. After being corrected for organic constitutents extracted from soil by retort water, dissolved-organic-carbon fractionation analyses of effluent fractions showed that the order of increasing affinity of six organic compound classes for the soil was as follows: hydrophilic neutrals nearly equal to hydrophilic acids, followed by the sequence of hydrophobic acids, hydrophilic bases, hydrophobic bases, and hydrophobic neutrals. Liquid-chromatographic analysis of the aromatic amines in the hydrophobic- and hydrophilic-base fractions showed that the relative order of the rates of migration through the soil column was the same as the order of migration on a reversed-phase, octadecylsilica liquid-chromatographic column.

Sulfur-, oxygen-, and carbon-isotope studies of Ag-Pb-Zn vein-breccia occurrences, sulfide-bearing concretions, and barite deposits in the north-central Brooks Range, with comparisons to shale-hosted stratiform massive sulfide deposits: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998

USGS Publications Warehouse

Kelley, Karen D.; Leach, David L.; Johnson, Craig A.

2000-01-01

Stratiform shale-hosted massive sulfide deposits, sulfidebearing concretions and vein breccias, and barite deposits are widespread in sedimentary rocks of Late Devonian to Permian age in the northern Brooks Range. All of the sulfide-bearing concretions and vein breccias are hosted in mixed continental-marine clastic rocks of the Upper Devonian to Lower Mississippian Endicott Group. The clastic rocks and associated sulfide occurrences underlie chert and shale of Mississippian-Pennsylvanian(?) age that contain large stratiform massive sulfide deposits like that at Red Dog. The relative stratigraphic position of the vein breccias, as well as previously published mineralogical, geochemical, and lead-isotope data, suggest that the vein breccias formed coevally with overlying shale-hosted massive sulfide deposits and that they may represent pathways of oreforming hydrothermal fluids. Barite deposits are hosted either in Mississippian chert and limestone (at essentially the same stratigraphic position as the shale-hosted massive sulfide deposits) or Permian chert and shale. Although most barite deposits have no associated base-metal mineralization, barite occurs with massive sulfide deposits at the Red Dog deposit.Galena and sphalerite from most vein breccias have δ34S values from –7.3 to –0.7‰ (per mil) and –5.1 to 3.6‰, respectively; sphalerite from sulfide-bearing concretions have δ34S values of 0.7 and 4.7‰. This overall range in δ34S values largely overlaps with the range previously determined for galena and sphalerite from shale-hosted massive sulfide deposits at Red Dog and Drenchwater. The Kady vein-breccia occurrence is unusual in having higher δ34S values for sphalerite (12.1 to 12.9‰) and pyrite (11.3‰), consistent with previously published values for the shale-hosted Lik deposit. The correspondence in sulfur isotopic compositions between the stratiform and vein-breccia deposits suggests that they share a common source of reduced sulfur, or derived reduced sulfur by similar geochemical processes. Most likely, the reduced sulfur was derived by biogenic sulfate reduction (BSR) or thermochemical sulfate reduction (TSR) of seawater sulfate during Devonian-Mississippian time.The δ18O values of quartz from the vein breccias are between 16.6 and 19.9‰. Using the sphalerite-galena sulfur isotopic temperature of 188°±25°C, the calulated hydrothermal fluids had δ18O values of 4.2 to 7.5‰. The calculated range of δ18O values of the fluids is similar to that of pore fluids in equilibrium with sedimentary rocks during diagenesis at 100°– 190°C.

Determinants of Clay and Shale Microfabric Signatures: Processes and Mechanisms

DTIC Science & Technology

1991-01-01

macroenvironments . The interplay of geological, chemical, and biological processes and mechanisms during transport, deposition, and burial of...and macroenviron - a function of processes and mechanisms, are antecedent to gain- ments. The interplay of geological, chemical, and biological pro

System for producing a uniform rubble bed for in situ processes

DOEpatents

Galloway, T.R.

1983-07-05

A method and a cutter are disclosed for producing a large cavity filled with a uniform bed of rubblized oil shale or other material, for in situ processing. A raise drill head has a hollow body with a generally circular base and sloping upper surface. A hollow shaft extends from the hollow body. Cutter teeth are mounted on the upper surface of the body and relatively small holes are formed in the body between the cutter teeth. Relatively large peripheral flutes around the body allow material to drop below the drill head. A pilot hole is drilled into the oil shale deposit. The pilot hole is reamed into a large diameter hole by means of a large diameter raise drill head or cutter to produce a cavity filled with rubble. A flushing fluid, such as air, is circulated through the pilot hole during the reaming operation to remove fines through the raise drill, thereby removing sufficient material to create sufficient void space, and allowing the larger particles to fill the cavity and provide a uniform bed of rubblized oil shale. 4 figs.

The geological and microbiological controls on the enrichment of Se and Te in sedimentary rocks

NASA Astrophysics Data System (ADS)

Bullock, Liam; Parnell, John; Armstrong, Joseph; Boyce, Adrian; Perez, Magali

2017-04-01

Selenium (Se) and tellurium (Te) have become elements of high interest, mainly due to their photovoltaic and photoconductive properties, and can contaminate local soils and groundwater systems during mobilisation. Due to their economic and environmental significance, it is important to understand the processes that lead to Se- and Te-enrichment in sediments. The distribution of Se and Te in sedimentary environments is primarily a function of redox conditions, and may be transported and concentrated by the movement of reduced fluids through oxidised strata. Se and Te concentrations have been measured in a suite of late Neoproterozoic Gwna Group black shales (UK) and uranium red bed (roll-front) samples (USA). Due to the chemical affinity of Se and sulphur (S), variations in the S isotopic composition of pyrite have also been measured in order to provide insights into their origin. Scanning electron microscopy of pyrite in the black shales shows abundant inclusions of the lead selenide mineral clausthalite. The data for the black shale samples show marked enrichment in Te and Se relative to crustal mean and several hundreds of other samples processed through our laboratory. While Se levels in sulphidic black shales are typically below 5 ppm, the measured values of up to 116 ppm are remarkable. The Se enrichment in roll-fronts (up to 168 ppm) is restricted to a narrow band of alteration at the interface between the barren oxidised core, and the highly mineralised reduced nose of the front. Te is depleted in roll-fronts with respect to the continental crust and other geological settings and deposits. S isotope compositions for pyrite in both the black shales and roll-fronts are very light and indicate precipitation by microbial sulphate reduction, suggesting that Se was microbially sequestered. Results show that Gwna Group black shales and U.S roll-front deposits contain marked elemental enrichments (particularly Se content). In Gwna Group black shales, Se and Te were sequestered out of seawater into pyritic shales at a higher rate than into crusts. Se enrichment in roll-fronts relates to the initial mobilisation of trace elements in oxidised conditions, and later precipitation downgradient in reduced conditions. Results highlight the potential for sedimentary types of Se- and Te-bearing deposits. The enrichment of elements of high value for future technologies in sedimentary rocks deserve careful assessment for potential future resources, and should be monitored during exploration and mobilisation due to the potential contamination effects. This work forms part of the NERC-funded 'Security of Supply of Mineral Resources' project, which aims to detail the science needed to sustain the security of supply of strategic minerals in a changing environment.

Quantifying the signature of the industrial revolution from Pb and Cd isotopes in the Susquehanna Shale Hills Critical Zone Observatory

NASA Astrophysics Data System (ADS)

Ma, L.; Herndon, E.; Jin, L.; Sanchez, D.; Brantley, S. L.

2013-12-01

Anthropogenic forcings have dominated metal cycling in many environments. During the period of the industrial revolution, mining and smelting of ores and combustion of fossil fuels released non-negligible amounts of potentially toxic metals such as Pb, Cd, Mn, and Zn into the environment. The extent and fate of these metal depositions in soils during that period however, have not been adequately evaluated. Here, we combine Pb isotopes with Cd isotopes to trace the sources of metal pollutants in a small temperate watershed (Shale Hills) in Pennsylvania. Previous work has shown that Mn additions to soils in central PA was caused by early iron production, as well as coal burning and steel making upwind. Comparison of the Pb and Cd concentrations in the bedrock and soils from this watershed show that Pb and Cd in soils at Shale Hills are best characterized by addition profiles, consistent with atmospheric additions. Three soil profiles at Shale Hills on the same hillslope have very similar anthropogenic Pb inventories. Pb isotope results further reveal that the extensive use of local coals during iron production in early 19th century in Pennsylvania is most likely the anthropogenic Pb source for the surface soils at Shale Hills. Pb concentrations and isotope ratios were used to calculate mass balance and diffusive transport models in soil profiles. The model results further reveal that during the 1850s to 1920s, coal burning in local iron blasting furnaces significantly increased the Pb deposition rates to 8-14 μg cm-2 yr-1, even more than modern Pb deposition rates derived from the use of leaded gasoline in the 1940s to 1980s. Furthermore, Cd has a low boiling point (~760 °C) and easily evaporates and condenses. The evaporation and condensation processes could generate systematic mass-dependent isotope fractionation between Cd in coal burning products and the naturally occurring Cd in the sulfide minerals of coals. This fractionation indicates that Cd isotopes can be used as a novel tracer of materials that have been affected by industrial high temperature processes, distinguishing them from natural Cd sources. Our ongoing Cd isotope measurements in the same soil profiles thus hold significant promise for tracing anthropogenic sources of this highly toxic metal in the environment. This will be the first time that Cd isotopes are characterized for polluted soils related to coal-burning activities. Such information will provide the first Cd isotope dataset to assess the environmental impacts due to the use of coals on a global scale. These new Pb and Cd isotope results, along with previous observations of Mn enrichment at Shale Hills, suggest that historical point sources from the industrial revolution could contribute significant amounts of metal contamination to top-soils. Our study highlights the importance of using multiple isotope systems to investigate Critical Zone processes in identical lithology and environmental settings.

Evaluation of 90-Day Inhalation Toxicity of Petroleum and Oil Shale Diesel Fuel Marine (DFM)

DTIC Science & Technology

1985-12-01

developed mineralization and papillary hyperplasia . These stexposure renal changes were generally less severe in qjje rats exposed to S0 T Shale DEN and...exposure incluled mild pulmonary inflammatory lesions in subjects assigned to tho Shale DFM study (Table 8). Mice exposed to Petroleum DFM did not...exhibit significant pulmonary inflammatory changes. Liver inflammatory changes consisting of multifocal accumulations of chronic inflammatory cells were

In-place oil shale resources of the Mahogany zone sorted by grade, overburden thickness and stripping ratio, Green River Formation, Piceance Basin, Colorado and Uinta Basin, Utah

USGS Publications Warehouse

Birdwell, Justin E.; Mercier, Tracey J.; Johnson, Ronald C.; Brownfield, Michael E.

2015-01-01

A range of geological parameters relevant to mining oil shale have been examined for the Mahogany zone of the Green River Formation in the Piceance Basin, Colorado, and Uinta Basin, Utah, using information available in the U.S. Geological Survey Oil Shale Assessment database. Basinwide discrete and cumulative distributions of resource in-place as a function of (1) oil shale grade, (2) Mahogany zone thickness, (3) overburden thickness, and (4) stripping ratio (overburden divided by zone thickness) were determined for both basins on a per-acre basis, and a resource map showing the areal distribution of these properties was generated. Estimates of how much of the Mahogany zone resource meets various combinations of these parameters were also determined. Of the 191.7 billion barrels of Mahogany zone oil in-place in the Piceance Basin, 32.3 percent (61.8 billion barrels) is associated with oil shale yielding at least 25 gallons of oil per ton (GPT) of rock processed, is covered by overburden 1,000 feet thick or less, and has a stripping ratio of less than 10. In the Uinta Basin, 14.0 percent (29.9 billion barrels) of the 214.5 billion barrels of Mahogany zone oil in-place meets the same overburden and stripping ratio criteria but only for the lower grade cutoff of 15 GPT.

Organic matter from the Bunte Breccia of the Ries Crater, southern Germany: investigating possible thermal effects of the impact

NASA Astrophysics Data System (ADS)

Hofmann, P.; Leythaeuser, D.; Schwark, L.

2001-07-01

In order to determine thermal effects of the Ries impact, southern Germany, on organic matter in its ejecta blanket, the maturity of organic matter of Posidonia Shale components from the Bunte Breccia at Harburg and Gundelsheim is compared with the maturity of organic matter of a reference section of Posidonia Shale outside the impact site at Hesselberg. Three black shale samples from the Bunte Breccia were identified as corresponding to the organic matter-rich Posidonia Shale based on the molecular composition of extractable organic matter. They show n-alkane patterns with a maximum of n-C 17, a predominance of odd over even n-alkanes in the range from n-C 26 to n-C 35, a dominance of unsaturated sterenes over steranes and monoaromatic over triaromatic steroids, and contain isorenieratene. The maturity of the organic matter from the Bunte Breccia samples corresponds to 0.32-0.35% random vitrinite reflectance ( Rr) and a spectral red/green quotient ( Q) of 0.32-0.34. The organic matter from the Bunte Breccia is more mature than the Posidonia Shale sample from the reference site Hesselberg (0.25% Rr; 0.21 for Q). The thermal overprint is presumed to be too high to be explained by differences in the burial history prior to the impact alone and is, therefore, attributed to processes related to the displacement of the Bunte Breccia.

A Theoretical Investigation of Radial Lateral Wells with Shockwave Completion in Shale Gas Reservoirs

NASA Astrophysics Data System (ADS)

Shan, Jia

As its role in satisfying the energy demand of the U.S. and as a clean fuel has become more significant than ever, the shale gas production in the U.S. has gained increasing momentum over recent years. Thus, effective and environmentally friendly methods to extract shale gas are critical. Hydraulic fracturing has been proven to be efficient in the production of shale gas. However, environmental issues such as underground water contamination and high usage of water make this technology controversial. A potential technology to eliminate the environmental issues concerning water usage and contamination is to use blast fracturing, which uses explosives to create fractures. It can be further aided by HEGF and multi-pulse pressure loading technology, which causes less crushing effect near the wellbore and induces longer fractures. Radial drilling is another relatively new technology that can bypass damage zones due to drilling and create a larger drainage area through drilling horizontal wellbores. Blast fracturing and radial drilling both have the advantage of cost saving. The successful combination of blast fracturing and radial drilling has a great potential for improving U.S. shale gas production. An analytical productivity model was built in this study, considering linear flow from the reservoir rock to the fracture face, to analyze factors affecting shale gas production from radial lateral wells with shockwave completion. Based on the model analyses, the number of fractures per lateral is concluded to be the most effective factor controlling the productivity index of blast-fractured radial lateral wells. This model can be used for feasibility studies of replacing hydraulic fracturing by blast fracturing in shale gas well completions. Prediction of fracture geometry is recommended for future studies.

Investigating the relationship between seismicity and fluid injection in the Barnett Shale, Texas using coupled poroelastic model and surface deformation data

NASA Astrophysics Data System (ADS)

Zhai, G.; Shirzaei, M.

2017-12-01

Across the Barnett Shale, Texas a noticeable increase in seismic activity was observed during 2007 and 2015, which was accompanied by high volume injection at several nearby disposal wells. Many studies focused on the positive correlation between injection rate at individual wells and the adjacent seismicity, suggesting that seismicity is triggered or induced due to increased pore fluid pressure associated with fluid injection in hydraulically connected geological units. However, investigating temporal evolution of total volume of injected fluid and concurrent earthquakes in a larger area indicates more complex patterns, requiring a more comprehensive analysis of the spatiotemporal evolution of coupled poroelastic stress and pore fluid pressure. In this study, we created a coupled poroelastic model to simulate large scale spatiotemporal evolution of pore pressure, poroelastic stresses, and Coulomb failure stress in the Barnett Shale using injection time series of 96 high-volume injection wells spanning from 2007 to 2015. We additionally account for a layered poroelastic medium, where its parameters are set up using geological maps and seismic tomographic data sets. Fault orientations and relevant frictional properties are also extracted from published literatures. We further integrate observation of surface deformation obtained from interferometric processing of 16 ALOS L-Band SAR images to optimize rock hydraulic diffusivity and constrain the extent to which fluid may migrate. The preliminary modeling result shows that poroelastic stress is only 10% of pore pressure. However, the superimposition of these two effects is spatially and temporally responsible for the occurrence of earthquakes in the Barnett Shale. Also, not all area with increased Coulomb failure stress experiences elevated seismicity, suggesting possible heterogeneous background tectonic stresses, lacking pre-existing faults, and/or heterogeneous fault orientations.

The influence of nitrate on selenium in irrigated agricultural groundwater systems.

PubMed

Bailey, Ryan T; Hunter, William J; Gates, Timothy K

2012-01-01

Selenium (Se) contamination of groundwater is an environmental concern especially in areas where aquifer systems are underlain by Se-bearing geologic formations such as marine shale. This study examined the influence of nitrate (NO₃) on Se species in irrigated soil and groundwater systems and presents results from field and laboratory studies that further clarify this influence. Inhibition of selenate (SeO₄) reduction in the presence of NO₃ and the oxidation of reduced Se from shale by autotrophic denitrification were investigated. Groundwater sampling from piezometers near an alluvium-shale interface suggests that SeO₄ present in the groundwater was due in part to autotrophic denitrification. Laboratory shale oxidation batch studies indicate that autotrophic denitrification is a major driver in the release of SeO₄ and sulfate. Similar findings occurred for a shale oxidation flow-through column study, with 70 and 31% more reduced Se and S mass, respectively, removed from the shale material in the presence of NO₃ than in its absence. A final laboratory flow-through column test was performed with shallow soil samples to assess the inhibition of SeO₄ reduction in the presence of NO₃, with results suggesting that a concentration of NO₃ of approximately 5 mg L or greater will diminish the reduction of SeO₄. The inclusion of the fate and transport of NO₃ and dissolved oxygen is imperative when studying or simulating the fate and transport of Se species in soil and groundwater systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

The geochemistry of naturally occurring methane and saline groundwater in an area of unconventional shale gas development

NASA Astrophysics Data System (ADS)

Harkness, Jennifer S.; Darrah, Thomas H.; Warner, Nathaniel R.; Whyte, Colin J.; Moore, Myles T.; Millot, Romain; Kloppmann, Wolfram; Jackson, Robert B.; Vengosh, Avner

2017-07-01

Since naturally occurring methane and saline groundwater are nearly ubiquitous in many sedimentary basins, delineating the effects of anthropogenic contamination sources is a major challenge for evaluating the impact of unconventional shale gas development on water quality. This study investigates the geochemical variations of groundwater and surface water before, during, and after hydraulic fracturing and in relation to various geospatial parameters in an area of shale gas development in northwestern West Virginia, United States. To our knowledge, we are the first to report a broadly integrated study of various geochemical techniques designed to distinguish natural from anthropogenic sources of natural gas and salt contaminants both before and after drilling. These measurements include inorganic geochemistry (major cations and anions), stable isotopes of select inorganic constituents including strontium (87Sr/86Sr), boron (δ11B), lithium (δ7Li), and carbon (δ13C-DIC), select hydrocarbon molecular (methane, ethane, propane, butane, and pentane) and isotopic tracers (δ13C-CH4, δ13C-C2H6), tritium (3H), and noble gas elemental and isotopic composition (helium, neon, argon) in 105 drinking-water wells, with repeat testing in 33 of the wells (total samples = 145). In a subset of wells (n = 20), we investigated the variations in water quality before and after the installation of nearby (<1 km) shale-gas wells. Methane occurred above 1 ccSTP/L in 37% of the groundwater samples and in 79% of the samples with elevated salinity (chloride > 50 mg/L). The integrated geochemical data indicate that the saline groundwater originated via naturally occurring processes, presumably from the migration of deeper methane-rich brines that have interacted extensively with coal lithologies. These observations were consistent with the lack of changes in water quality observed in drinking-water wells following the installation of nearby shale-gas wells. In contrast to groundwater samples that showed no evidence of anthropogenic contamination, the chemistry and isotope ratios of surface waters (n = 8) near known spills or leaks occurring at disposal sites mimicked the composition of Marcellus flowback fluids, and show direct evidence for impact on surface water by fluids accidentally released from nearby shale-gas well pads and oil and gas wastewater disposal sites. Overall this study presents a comprehensive geochemical framework that can be used as a template for assessing the sources of elevated hydrocarbons and salts to water resources in areas potentially impacted by oil and gas development.

The enrichment behavior of natural radionuclides in pulverized oil shale-fired power plants.

PubMed

Vaasma, Taavi; Kiisk, Madis; Meriste, Tõnis; Tkaczyk, Alan Henry

2014-12-01

The oil shale industry is the largest producer of NORM (Naturally Occurring Radioactive Material) waste in Estonia. Approximately 11-12 million tons of oil shale containing various amounts of natural radionuclides is burned annually in the Narva oil shale-fired power plants, which accounts for approximately 90% of Estonian electricity production. The radionuclide behavior characteristics change during the fuel combustion process, which redistributes the radionuclides between different ash fractions. Out of 24 operational boilers in the power plants, four use circulating fluidized bed (CFB) technology and twenty use pulverized fuel (PF) technology. Over the past decade, the PF boilers have been renovated, with the main objective to increase the efficiency of the filter systems. Between 2009 and 2012, electrostatic precipitators (ESP) in four PF energy blocks were replaced with novel integrated desulphurization technology (NID) for the efficient removal of fly ash and SO2 from flue gases. Using gamma spectrometry, activity concentrations and enrichment factors for the (238)U ((238)U, (226)Ra, (210)Pb) and (232)Th ((232)Th, (228)Ra) family radionuclides as well as (40)K were measured and analyzed in different PF boiler ash fractions. The radionuclide activity concentrations in the ash samples increased from the furnace toward the back end of the flue gas duct. The highest values in different PF boiler ash fractions were in the last field of the ESP and in the NID ash, where radionuclide enrichment factors were up to 4.2 and 3.3, respectively. The acquired and analyzed data on radionuclide activity concentrations in different PF boiler ashes (operating with an ESP and a NID system) compared to CFB boiler ashes provides an indication that changes in the fuel (oil shale) composition and boiler working parameters, as well as technological enhancements in Estonian oil shale fired power plants, have had a combined effect on the distribution patterns of natural radionuclides in the oil shale combustion products. Copyright © 2014 Elsevier Ltd. All rights reserved.

Inferences from Microfractures and Geochemistry in Dynamic Shale-CO2 Packed Bed Experiments

NASA Astrophysics Data System (ADS)

Radonjic, M.; Olabode, A.

2016-12-01

Subsurface storage of large volumes of carbondioxide (CO2) is expected to have long term rock-fluid interactions impact on reservoir and seal rocks properties. Caprocks, particularly sedimentary types, are the ultimate hydraulic barrier in carbon sequestration. The mineralogical components of sedimentary rocks are geochemically active under enormous earth stresses, which generate high pressure and temperature conditions. It has been postulated that in-situ mineralization can lead to flow impedance in natural fractures in the presence of favorable geochemical and thermodynamic conditions. This experimental modelling research investigated the impact of in-situ geochemical precipitation on conductivity of fractures. Geochemical analyses were performed on four different samples of shale rocks, effluent fluids and recovered precipitates both before and after CO2-brine flooding of crushed shale rocks at moderately high temperature and pressure conditions. The results showed that most significant diagenetic changes in shale rocks after flooding with CO2-brine, reflected in the effluent fluid with predominantly calcium based minerals dissolving and precipitating under experimental conditions. Major and trace elements in the effluent (using ICP-OES analysis) indicated that multiple geochemical reactions are occurring with almost all of the constituent minerals participating. The geochemical composition of precipitates recovered after the experiments showed diagenetic carbonates and opal as the main constituents. The bulk rock showed little changes in composition except for sharper and more refined peaks on XRD analysis, suggesting that a significant portion of the amorphous content of the rocks have been removed via dissolution by the slightly acid CO2-brine fluid that was injected. Micro-indentation results captured slight reduction in the hardness of the shale rocks and this reduction appeared dependent on diagenetic quartz content. It can be inferred that convective reactive transport of dissolved minerals are involved in nanoscale precipitation-dissolution processes in shale. This reactive transport of dissolved minerals can occlude micro-fracture flow paths, thereby improving shale caprock seal integrity with respect to leakage risk under CO2 sequestration conditions.

Beyond Consultation: First Nations and the Governance of Shale Gas in British Columbia

NASA Astrophysics Data System (ADS)

Garvie, Kathryn Henderson

As the province of British Columbia seeks to rapidly develop an extensive natural gas industry, it faces a number of challenges. One of these is that of ensuring that development does not disproportionately impact some of the province's most marginalized communities: the First Nations on whose land extraction will take place. This is particularly crucial given that environmental problems are often caused by unjust and inequitable social conditions that must be rectified before sustainable development can be advanced. This research investigates how the BC Oil and Gas Commission's consultation process addresses, and could be improved to better address Treaty 8 First Nations' concerns regarding shale gas development within their traditional territories. Interviews were conducted with four Treaty 8 First Nations, the Treaty 8 Tribal Association, and provincial government and industry staff. Additionally, participant observation was conducted with the Fort Nelson First Nation Lands and Resources Department. Findings indicate that like many other resource consultation processes in British Columbia, the oil and gas consultation process is unable to meaningfully address First Nations' concerns and values due to fundamental procedural problems, including the permit-by-permit approach and the exclusion of First Nations from the point of decision-making. Considering the government's failure to regulate the shale gas industry in a way that protects ecological, social and cultural resilience, we argue that new governance mechanisms are needed that reallocate authority to First Nations and incorporate proposals for early engagement, long-term planning and cumulative impact assessment and monitoring. Additionally, considering the exceptional power differential between government, industry and First Nations, we argue that challenging industry's social license to operate is an important strategy for First Nations working to gain greater influence over development within their territories, and to ensure a more sustainable shale gas industry.

Mechanistic Processes Controlling Gas Sorption in Shale Reservoirs

NASA Astrophysics Data System (ADS)

Schaef, T.; Loring, J.; Ilton, E. S.; Davidson, C. L.; Owen, T.; Hoyt, D.; Glezakou, V. A.; McGrail, B. P.; Thompson, C.

2014-12-01

Utilization of CO2 to stimulate natural gas production in previously fractured shale-dominated reservoirs where CO2 remains in place for long-term storage may be an attractive new strategy for reducing the cost of managing anthropogenic CO2. A preliminary analysis of capacities and potential revenues in US shale plays suggests nearly 390 tcf in additional gas recovery may be possible via CO2 driven enhanced gas recovery. However, reservoir transmissivity properties, optimum gas recovery rates, and ultimate fate of CO2 vary among reservoirs, potentially increasing operational costs and environmental risks. In this paper, we identify key mechanisms controlling the sorption of CH4 and CO2 onto phyllosilicates and processes occurring in mixed gas systems that have the potential of impacting fluid transfer and CO2 storage in shale dominated formations. Through a unique set of in situ experimental techniques coupled with molecular-level simulations, we identify structural transformations occurring to clay minerals, optimal CO2/CH4 gas exchange conditions, and distinguish between adsorbed and intercalated gases in a mixed gas system. For example, based on in situ measurements with magic angle spinning NMR, intercalation of CO2 within the montmorillonite structure occurs in CH4/CO2 gas mixtures containing low concentrations (<5 mol%) of CO2. A stable montmorillonite structure dominates during exposure to pure CH4 (90 bar), but expands upon titration of small fractions (1-3 mol%) of CO2. Density functional theory was used to quantify the difference in sorption behavior between CO2 and CH4 and indicates complex interactions occurring between hydrated cations, CH4, and CO2. The authors will discuss potential impacts of these experimental results on CO2-based hydrocarbon recovery processes.

Synthesis and analysis of jet fuels from shale oil and coal syncrudes

NASA Technical Reports Server (NTRS)

Antoine, A. C.; Gallagher, J. P.

1976-01-01

The technical problems involved in converting a significant portion of a barrel of either a shale oil or coal syncrude into a suitable aviation turbine fuel were studied. TOSCO shale oil, H-Coal and COED coal syncrudes were the starting materials. They were processed by distillation and hydrocracking to produce two levels of yield (20 and 40 weight percent) of material having a distillation range of approximately 422 to 561 K (300 F to 550 F). The full distillation range 311 to 616 K (100 F to 650 F) materials were hydrotreated to meet two sets of specifications (20 and 40 volume percent aromatics, 13.5 and 12.75 weight percent H, 0.2 and 0.5 weight percent S, and 0.1 and 0.2 weight percent N). The hydrotreated materials were distilled to meet given end point and volatility requirements. The syntheses were carried out in laboratory and pilot plant equipment scaled to produce thirty-two 0.0757 cu m (2-gal)samples of jet fuel of varying defined specifications. Detailed analyses for physical and chemical properties were made on the crude starting materials and on the products.

Guar Gum Stimulates Biogenic Sulfide Production at Elevated Pressures: Implications for Shale Gas Extraction

PubMed Central

Nixon, Sophie L.; Walker, Leanne; Streets, Matthew D. T.; Eden, Bob; Boothman, Christopher; Taylor, Kevin G.; Lloyd, Jonathan R.

2017-01-01

Biogenic sulfide production is a common problem in the oil industry, and can lead to costly hydrocarbon processing and corrosion of extraction infrastructure. The same phenomenon has recently been identified in shale gas extraction by hydraulic fracturing, and organic additives in fracturing fluid have been hypothesized to stimulate this process. Constraining the relative effects of the numerous organic additives on microbial metabolism in situ is, however, extremely challenging. Using a bespoke bioreactor system we sought to assess the potential for guar gum, the most commonly used gelling agent in fracturing fluids, to stimulate biogenic sulfide production by sulfate-reducing microorganisms at elevated pressure. Two pressurized bioreactors were fed with either sulfate-amended freshwater medium, or low-sulfate natural surface water, in addition to guar gum (0.05 w/v%) and an inoculum of sulfate-reducing bacteria for a period of 77 days. Sulfide production was observed in both bioreactors, even when the sulfate concentration was low. Analysis of 16S rRNA gene sequences indicate that heterotrophic bacteria closely associated with the genera Brevundimonas and Acinetobacter became enriched early in the bioreactor experiments, followed by an increase in relative abundance of 16S rRNA genes associated with sulfate-reducing bacteria (Desulfosporosinus and Desulfobacteraceae) at later time points. Results demonstrate that guar gum can stimulate acid- and sulfide-producing microorganisms at elevated pressure, and may have implications for the potential role in microbially induced corrosion during hydraulic fracturing operations. Key differences between experimental and in situ conditions are discussed, as well as additional sources of carbon and energy for biogenic sulfide production during shale gas extraction. Our laboratory approach can be tailored to better simulate deep subsurface conditions in order to probe the role of other fracturing fluid additives and downhole parameters on microbial metabolisms observed in these systems. Such baseline studies will prove essential for effective future development of shale gas worldwide. PMID:28469616

Guar Gum Stimulates Biogenic Sulfide Production at Elevated Pressures: Implications for Shale Gas Extraction.

PubMed

Nixon, Sophie L; Walker, Leanne; Streets, Matthew D T; Eden, Bob; Boothman, Christopher; Taylor, Kevin G; Lloyd, Jonathan R

2017-01-01

Biogenic sulfide production is a common problem in the oil industry, and can lead to costly hydrocarbon processing and corrosion of extraction infrastructure. The same phenomenon has recently been identified in shale gas extraction by hydraulic fracturing, and organic additives in fracturing fluid have been hypothesized to stimulate this process. Constraining the relative effects of the numerous organic additives on microbial metabolism in situ is, however, extremely challenging. Using a bespoke bioreactor system we sought to assess the potential for guar gum, the most commonly used gelling agent in fracturing fluids, to stimulate biogenic sulfide production by sulfate-reducing microorganisms at elevated pressure. Two pressurized bioreactors were fed with either sulfate-amended freshwater medium, or low-sulfate natural surface water, in addition to guar gum (0.05 w/v%) and an inoculum of sulfate-reducing bacteria for a period of 77 days. Sulfide production was observed in both bioreactors, even when the sulfate concentration was low. Analysis of 16S rRNA gene sequences indicate that heterotrophic bacteria closely associated with the genera Brevundimonas and Acinetobacter became enriched early in the bioreactor experiments, followed by an increase in relative abundance of 16S rRNA genes associated with sulfate-reducing bacteria ( Desulfosporosinus and Desulfobacteraceae) at later time points. Results demonstrate that guar gum can stimulate acid- and sulfide-producing microorganisms at elevated pressure, and may have implications for the potential role in microbially induced corrosion during hydraulic fracturing operations. Key differences between experimental and in situ conditions are discussed, as well as additional sources of carbon and energy for biogenic sulfide production during shale gas extraction. Our laboratory approach can be tailored to better simulate deep subsurface conditions in order to probe the role of other fracturing fluid additives and downhole parameters on microbial metabolisms observed in these systems. Such baseline studies will prove essential for effective future development of shale gas worldwide.

Germanium and uranium in coalified wood from Upper Devonian black shale

USGS Publications Warehouse

Breger, Irving A.; Schopf, James M.

1954-01-01

Microscopic study of black, vitreous, carbonaceous material occurring in the Chattanooga shale in Tennessee and in the Cleveland member of the Ohio shale in Ohio has revealed coalified woody plant tissue. Some samples have shown sufficient detail to be identified with the genus Callixylon. Similar material has been reported in the literature as "bituminous" or "asphaltic" stringers. Spectrographic analyses of the ash from the coalified wood have shown unusually high percentages of germanium, uranium, vanadium, and nickel. The inverse relationship between uranium and germanium in the ash and the ash content of various samples shows an association of these elements with the organic constituents of the coal. On the basis of geochemical considerations, it seems most probable that the wood or coalified wood was germanium-bearing at the time logs or woody fragments were floated into the basins of deposition of the Chattanooga shale and the Cleveland member of the Ohio shale. Once within the marine environment, the material probably absorbed uranium with the formation of organo-uranium compounds such as have been found to exist in coals. It is suggested that a more systematic search for germaniferous coals in the vicinity of the Chattanooga shale and the Cleveland member of the Ohio shale might be rewarding.

Imbibition of hydraulic fracturing fluids into partially saturated shale

NASA Astrophysics Data System (ADS)

Birdsell, Daniel T.; Rajaram, Harihar; Lackey, Greg

2015-08-01

Recent studies suggest that imbibition of hydraulic fracturing fluids into partially saturated shale is an important mechanism that restricts their migration, thus reducing the risk of groundwater contamination. We present computations of imbibition based on an exact semianalytical solution for spontaneous imbibition. These computations lead to quantitative estimates of an imbibition rate parameter (A) with units of LT-1/2 for shale, which is related to porous medium and fluid properties, and the initial water saturation. Our calculations suggest that significant fractions of injected fluid volumes (15-95%) can be imbibed in shale gas systems, whereas imbibition volumes in shale oil systems is much lower (3-27%). We present a nondimensionalization of A, which provides insights into the critical factors controlling imbibition, and facilitates the estimation of A based on readily measured porous medium and fluid properties. For a given set of medium and fluid properties, A varies by less than factors of ˜1.8 (gas nonwetting phase) and ˜3.4 (oil nonwetting phase) over the range of initial water saturations reported for the Marcellus shale (0.05-0.6). However, for higher initial water saturations, A decreases significantly. The intrinsic permeability of the shale and the viscosity of the fluids are the most important properties controlling the imbibition rate.

Potential water resource impacts of hydraulic fracturing from unconventional oil production in the Bakken shale.

PubMed

Shrestha, Namita; Chilkoor, Govinda; Wilder, Joseph; Gadhamshetty, Venkataramana; Stone, James J

2017-01-01

Modern drilling techniques, notably horizontal drilling and hydraulic fracturing, have enabled unconventional oil production (UOP) from the previously inaccessible Bakken Shale Formation located throughout Montana, North Dakota (ND) and the Canadian province of Saskatchewan. The majority of UOP from the Bakken shale occurs in ND, strengthening its oil industry and businesses, job market, and its gross domestic product. However, similar to UOP from other low-permeability shales, UOP from the Bakken shale can result in environmental and human health effects. For example, UOP from the ND Bakken shale generates a voluminous amount of saline wastewater including produced and flowback water that are characterized by unusual levels of total dissolved solids (350 g/L) and elevated levels of toxic and radioactive substances. Currently, 95% of the saline wastewater is piped or trucked onsite prior to disposal into Class II injection wells. Oil and gas wastewater (OGW) spills that occur during transport to injection sites can potentially result in drinking water resource contamination. This study presents a critical review of potential water resource impacts due to deterministic (freshwater withdrawals and produced water management) and probabilistic events (spills due to leaking pipelines and truck accidents) related to UOP from the Bakken shale in ND. Copyright © 2016 Elsevier Ltd. All rights reserved.

Multiparameter Analysis of Gas Transport Phenomena in Shale Gas Reservoirs: Apparent Permeability Characterization.

PubMed

Shen, Yinghao; Pang, Yu; Shen, Ziqi; Tian, Yuanyuan; Ge, Hongkui

2018-02-08

The large amount of nanoscale pores in shale results in the inability to apply Darcy's law. Moreover, the gas adsorption of shale increases the complexity of pore size characterization and thus decreases the accuracy of flow regime estimation. In this study, an apparent permeability model, which describes the adsorptive gas flow behavior in shale by considering the effects of gas adsorption, stress dependence, and non-Darcy flow, is proposed. The pore size distribution, methane adsorption capacity, pore compressibility, and matrix permeability of the Barnett and Eagle Ford shales are measured in the laboratory to determine the critical parameters of gas transport phenomena. The slip coefficients, tortuosity, and surface diffusivity are predicted via the regression analysis of the permeability data. The results indicate that the apparent permeability model, which considers second-order gas slippage, Knudsen diffusion, and surface diffusion, could describe the gas flow behavior in the transition flow regime for nanoporous shale. Second-order gas slippage and surface diffusion play key roles in the gas flow in nanopores for Knudsen numbers ranging from 0.18 to 0.5. Therefore, the gas adsorption and non-Darcy flow effects, which involve gas slippage, Knudsen diffusion, and surface diffusion, are indispensable parameters of the permeability model for shale.

[Effect of near infrared spectrum on the precision of PLS model for oil yield from oil shale].

PubMed

Wang, Zhi-Hong; Liu, Jie; Chen, Xiao-Chao; Sun, Yu-Yang; Yu, Yang; Lin, Jun

2012-10-01

It is impossible to use present measurement methods for the oil yield of oil shale to realize in-situ detection and these methods unable to meet the requirements of the oil shale resources exploration and exploitation. But in-situ oil yield analysis of oil shale can be achieved by the portable near infrared spectroscopy technique. There are different correlativities of NIR spectrum data formats and contents of sample components, and the different absorption specialities of sample components shows in different NIR spectral regions. So with the proportioning samples, the PLS modeling experiments were done by 3 formats (reflectance, absorbance and K-M function) and 4 regions of modeling spectrum, and the effect of NIR spectral format and region to the precision of PLS model for oil yield from oil shale was studied. The results show that the best data format is reflectance and the best modeling region is combination spectral range by PLS model method and proportioning samples. Therefore, the appropriate data format and the proper characteristic spectral region can increase the precision of PLS model for oil yield form oil shale.

Integrated geostatistics for modeling fluid contacts and shales in Prudhoe Bay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perez, G.; Chopra, A.K.; Severson, C.D.

1997-12-01

Geostatistics techniques are being used increasingly to model reservoir heterogeneity at a wide range of scales. A variety of techniques is now available with differing underlying assumptions, complexity, and applications. This paper introduces a novel method of geostatistics to model dynamic gas-oil contacts and shales in the Prudhoe Bay reservoir. The method integrates reservoir description and surveillance data within the same geostatistical framework. Surveillance logs and shale data are transformed to indicator variables. These variables are used to evaluate vertical and horizontal spatial correlation and cross-correlation of gas and shale at different times and to develop variogram models. Conditional simulationmore » techniques are used to generate multiple three-dimensional (3D) descriptions of gas and shales that provide a measure of uncertainty. These techniques capture the complex 3D distribution of gas-oil contacts through time. The authors compare results of the geostatistical method with conventional techniques as well as with infill wells drilled after the study. Predicted gas-oil contacts and shale distributions are in close agreement with gas-oil contacts observed at infill wells.« less

Experimental study on the influence of slickwater on shale permeability

NASA Astrophysics Data System (ADS)

Liu, Zhonghua; Bai, Baojun; Zhang, Zheyu; Tang, Jing; Zeng, Shunpeng; Li, Xiaogang

2018-02-01

There are two diametrically opposite views of the influence of slickwater on shale permeability among scholars at home and abroad. We used the shale outcrops rock samples from the Lower Silurian Longmaxi Formation in Sichuan Basin. The permeability of these dry samples before and after immersion in different solution systems were tested by pulse attenuation method. The experimental results show that the impregnation of different slickwater components and standard salt solution can promote the increase of the permeability of shale samples. The stress sensitivity of shale samples after liquid immersion is medium weak to weak. The sample stress sensitivity is weak after soaked by the synergist solution and Drag reducing agent solution, and the sensitivity of the sample stress is medium weak after immersed by the standard saline solution, defoamer solution and antiswelling solution; The Ki/K0 of the shale sample after liquid immersion on σi/σ0 is consistent with the exponential stress sensitive evaluation model. With the increase of soaking time, the increase of sample permeability increases first and then decreases.

Assessment and longitudinal analysis of health impacts and stressors perceived to result from unconventional shale gas development in the Marcellus Shale region.

PubMed

Ferrar, Kyle J; Kriesky, Jill; Christen, Charles L; Marshall, Lynne P; Malone, Samantha L; Sharma, Ravi K; Michanowicz, Drew R; Goldstein, Bernard D

2013-01-01

Concerns for health and social impacts have arisen as a result of Marcellus Shale unconventional natural gas development. Our goal was to document the self-reported health impacts and mental and physical health stressors perceived to result from Marcellus Shale development. Two sets of interviews were conducted with a convenience sample of community members living proximal to Marcellus Shale development, session 1 March-September 2010 (n = 33) and session 2 January-April 2012 (n = 20). Symptoms of health impacts and sources of psychological stress were coded. Symptom and stressor counts were quantified for each interview. The counts for each participant were compared longitudinally. Participants attributed 59 unique health impacts and 13 stressors to Marcellus Shale development. Stress was the most frequently-reported symptom. Over time, perceived health impacts increased (P = 0·042), while stressors remained constant (P = 0·855). Exposure-based epidemiological studies are needed to address identified health impacts and those that may develop as unconventional natural gas extraction continues. Many of the stressors can be addressed immediately.

Pressurized fluidized-bed hydroretorting of Eastern oil shales -- Sulfur control. Topical report for Subtask 3.1, In-bed sulfur capture tests; Subtask 3.2, Electrostatic desulfurization; Subtask 3.3, Microbial desulfurization and denitrification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, M.J.; Abbasian, J.; Akin, C.

1992-05-01

This topical report on ``Sulfur Control`` presents the results of work conducted by the Institute of Gas Technology (IGT), the Illinois Institute of Technology (IIT), and the Ohio State University (OSU) to develop three novel approaches for desulfurization that have shown good potential with coal and could be cost-effective for oil shales. These are (1) In-Bed Sulfur Capture using different sorbents (IGT), (2) Electrostatic Desulfurization (IIT), and (3) Microbial Desulfurization and Denitrification (OSU and IGT). The objective of the task on In-Bed Sulfur Capture was to determine the effectiveness of different sorbents (that is, limestone, calcined limestone, dolomite, and siderite)more » for capturing sulfur (as H{sub 2}S) in the reactor during hydroretorting. The objective of the task on Electrostatic Desulfurization was to determine the operating conditions necessary to achieve a high degree of sulfur removal and kerogen recovery in IIT`s electrostatic separator. The objectives of the task on Microbial Desulfurization and Denitrification were to (1) isolate microbial cultures and evaluate their ability to desulfurize and denitrify shale, (2) conduct laboratory-scale batch and continuous tests to improve and enhance microbial removal of these components, and (3) determine the effects of processing parameters, such as shale slurry concentration, solids settling characteristics, agitation rate, and pH on the process.« less

Transient pressure-pulse decay permeability measurements in the Barnett shale

NASA Astrophysics Data System (ADS)

Bhandari, A. R.; Reece, J.; Cronin, M. B.; Flemings, P. B.; Polito, P. J.

2012-12-01

We conducted transient pressure-pulse decay permeability measurements on core plugs of the Barnett shale using a hydrostatic pressure cell. Core plugs, 3.8 cm in diameter and less than 2.5 cm in length, were prepared from a core obtained at a depth of approximately 2330 m from the Mitchel Energy 2 T. P. Sims well in the Mississippian Barnett Formation (Loucks and Ruppel, 2007). We performed permeability measurements of the core plugs using argon at varying confining pressures in two different directions (perpendicular and parallel to bedding planes). We calculate gas permeability from changes in pressure with time using the analytical solution of the pressure diffusion equation with appropriate boundary conditions for our test setup (Dicker and Smits, 1988). Based on our limited results, we interpret 2 × 10-18 m2 for vertical permeability and 156 × 10-18 m2 for horizontal permeability. We demonstrate an extreme stress dependence of the horizontal flow permeability where permeability decreases from 156 × 10-18 m2 to 2.5 × 10-18 m2 as the confining stress is increased from 3.5 to 35 MPa. These permeability measurements are at the high side of other pulsed permeability measurements in the Barnett shale (Bustin et al. 2008; Vermylen, 2011). Permeabilities calculated from mercury injection capillary pressure curves, using theoretically derived permeability-capillary pressure models based on parallel tubes assumption, are orders of magnitude less than our transient pressure-pulse decay permeability measurements (for example, 3.7×10-21 m2 (this study), 10-21 -10-20 m2 (Sigal, 2007), 10-20 -10-17 m2 (Prince et al., 2010)). We interpret that the high measured permeabilities are due to microfractures in the sample. At this point, we do not know if the microfractures are due to sampling disturbance (stress-relief induced) or represent an in-situ fracture network. Our study illustrates the importance of characterization of microfractures at the core scale to understand better the transport behavior in shale matrix and sealing efficiency of cap rocks. References Bustin et al. (2008), Impact of shale properties on pore structure and storage characteristics, SPE 119892. Dicker and Smits (1988), A practical method for determining permeability from laboratory pressure-pulse decay measurements, SPE 17578. Loucks and Ruppel (2007), Mississippian Barnett Shale: Lithofacies and depositional setting of a deep-water shale gas succession in the Fort Worth Basin, Texas, AAPG 2007. Sigal (2007), Mercury capillary pressure measurements on Barnett core. (http://shale.ou.edu/Home/Publication) Prince et al. (2010), Shale diagenesis and permeability: examples from the Barnett shale and the Marcellus formation, AAPG 2010. Vermylen, J.P. (2011), Geomechanical studies of the Barnett Shale, Texas, USA, PhD thesis, Stanford University.

Assessment of undiscovered shale gas and shale oil resources in the Mississippian Barnett Shale, Bend Arch–Fort Worth Basin Province, North-Central Texas

USGS Publications Warehouse

Marra, Kristen R.; Charpentier, Ronald R.; Schenk, Christopher J.; Lewan, Michael D.; Leathers-Miller, Heidi M.; Klett, Timothy R.; Gaswirth, Stephanie B.; Le, Phuong A.; Mercier, Tracey J.; Pitman, Janet K.; Tennyson, Marilyn E.

2015-12-17

Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean volumes of 53 trillion cubic feet of shale gas, 172 million barrels of shale oil, and 176 million barrels of natural gas liquids in the Barnett Shale of the Bend Arch–Fort Worth Basin Province of Texas.

Influence of irrigation and weathering reactions on the composition of percolates from retorted oil shale in field lysimeters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garland, T. R.; Wildung, R. E.; Harbert, H. P.

1979-04-01

Major cations, anions, trace elements and dissolved organic C were measured in percolate from retorted oil shale collected from irrigated lysimeters in the field at Anvil Points, Colorado, over a two year period. The investigations indicated that chemical equilibrium was not established over the monitoring period and major changes occurred in percolate composition as a function of applied water volume and water residence time in the shale. Field and laboratory studies indicated that several factors contributed to changes in the chemistry of the shale on weathering, including recarbonization of the surface horizons with atmospheric CO/sub 2/ and the activities ofmore » microorganisms in surface and subsurface horizons. However, the principal mechanism responsible for the decreases in pH and salt concentrations appeared to be the conversion of major quantities of sulfide in the retorted shale to sulfate through a thiosulfate intermediate.« less

Vanadium Extraction from Shale via Sulfuric Acid Baking and Leaching

NASA Astrophysics Data System (ADS)

Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing

2018-01-01

Fluorides are widely used to improve vanadium extraction from shale in China. Sulfuric acid baking-leaching (SABL) was investigated as a means of recovering vanadium which does not require the use of fluorides and avoids the productions of harmful fluoride-containing wastewater. Various effective factors were systematically studied and the experimental results showed that 90.1% vanadium could be leached from the shale. On the basis of phase transformations and structural changes after baking the shale, a mechanism of vanadium extraction from shale via SABL was proposed. The mechanism can be described as: (1) sulfuric acid diffusion into particles; (2) the formation of concentrated sulfuric acid media in the particles after water evaporation; (3) hydroxyl groups in the muscovite were removed and transient state [SO4 2-] was generated; and (4) the metals in the muscovite were sulfated by active [SO4 2-] and the vanadium was released. Thermodynamics modeling confirmed this mechanism.

An improved evaluation method for measuring TOC of the Longmaxi Formation shale in the Sichuan Basin, south China

NASA Astrophysics Data System (ADS)

Zhang, Y.; Hu, C.; Wang, M.

2017-12-01

The evaluation of total organic carbon (TOC) in shale using logging data is one of the most crucial steps in shale gas exploration. However, it didn't achieve the ideal effect for the application of `ΔlogR' method in the Longmaxi Formation shale of Sichuan Basin.The reason may be the organic matter carbonization in Longmaxi Formation. An improved evaluation method, using the classification by lithology and sedimentary structure: 1) silty mudstone (wellsite logging data show silty); 2) calcareous mudstone (calcareous content > 25%); 3) laminated mudstone (laminations are recognized by core and imaging logging technology); 4) massive mudstone (massive textures are recognized by core and imaging logging technology, was proposed. This study compares two logging evaluation methods for measuring TOC in shale: the △logR method and the new proposed method. The results showed that the correlation coefficient between the calculated TOC and the tested TOC, based on the △logR method, was only 0.17. The correlation coefficient obtained according to the new method reached 0.80. The calculation results illustrated that, because of the good correlation between lithologies and sedimentary structure zones and TOC of different types of shale, the shale reservoirs could be graded according to four shale types. The new proposed method is more efficient, faster, and has higher vertical resolution than the △logR method. In addition, a new software had been completed. It was found to be especially effective under conditions of insufficient data during the early stages of shale gas exploration in the Silurian Longmaxi Formation, Muai Syncline Belt, south of the Sichuan Basin.

Pore-Scale Simulation and Sensitivity Analysis of Apparent Gas Permeability in Shale Matrix

PubMed Central

Zhang, Pengwei; Hu, Liming; Meegoda, Jay N.

2017-01-01

Extremely low permeability due to nano-scale pores is a distinctive feature of gas transport in a shale matrix. The permeability of shale depends on pore pressure, porosity, pore throat size and gas type. The pore network model is a practical way to explain the macro flow behavior of porous media from a microscopic point of view. In this research, gas flow in a shale matrix is simulated using a previously developed three-dimensional pore network model that includes typical bimodal pore size distribution, anisotropy and low connectivity of the pore structure in shale. The apparent gas permeability of shale matrix was calculated under different reservoir pressures corresponding to different gas exploitation stages. Results indicate that gas permeability is strongly related to reservoir gas pressure, and hence the apparent permeability is not a unique value during the shale gas exploitation, and simulations suggested that a constant permeability for continuum-scale simulation is not accurate. Hence, the reservoir pressures of different shale gas exploitations should be considered. In addition, a sensitivity analysis was also performed to determine the contributions to apparent permeability of a shale matrix from petro-physical properties of shale such as pore throat size and porosity. Finally, the impact of connectivity of nano-scale pores on shale gas flux was analyzed. These results would provide an insight into understanding nano/micro scale flows of shale gas in the shale matrix. PMID:28772465

Pore-Scale Simulation and Sensitivity Analysis of Apparent Gas Permeability in Shale Matrix.

PubMed

Zhang, Pengwei; Hu, Liming; Meegoda, Jay N

2017-01-25

Extremely low permeability due to nano-scale pores is a distinctive feature of gas transport in a shale matrix. The permeability of shale depends on pore pressure, porosity, pore throat size and gas type. The pore network model is a practical way to explain the macro flow behavior of porous media from a microscopic point of view. In this research, gas flow in a shale matrix is simulated using a previously developed three-dimensional pore network model that includes typical bimodal pore size distribution, anisotropy and low connectivity of the pore structure in shale. The apparent gas permeability of shale matrix was calculated under different reservoir pressures corresponding to different gas exploitation stages. Results indicate that gas permeability is strongly related to reservoir gas pressure, and hence the apparent permeability is not a unique value during the shale gas exploitation, and simulations suggested that a constant permeability for continuum-scale simulation is not accurate. Hence, the reservoir pressures of different shale gas exploitations should be considered. In addition, a sensitivity analysis was also performed to determine the contributions to apparent permeability of a shale matrix from petro-physical properties of shale such as pore throat size and porosity. Finally, the impact of connectivity of nano-scale pores on shale gas flux was analyzed. These results would provide an insight into understanding nano/micro scale flows of shale gas in the shale matrix.

Determination of factors responsible for the bioweathering of copper minerals from organic-rich copper-bearing Kupferschiefer black shale.

PubMed

Włodarczyk, Agnieszka; Szymańska, Agata; Skłodowska, Aleksandra; Matlakowska, Renata

2016-04-01

The aim of this study was to investigate the bioweathering of copper minerals present in the alkaline, copper-bearing and organic-rich Kupferschiefer black shale through the action of a consortium of indigenous lithobiontic, heterotrophic, neutrophilic bacteria isolated from this sedimentary rock. The involvement of microorganisms in the direct/enzymatic bioweathering of fossil organic matter of the rock was confirmed. As a result of bacterial activity, a spectrum of various organic compounds such as urea and phosphoric acid tributyl ester were released from the rock. These compounds indirectly act on the copper minerals occurring in the rock and cause them to weather. This process was reflected in the mobilization of copper, iron and sulfur and in changes in the appearance of copper minerals observed under reflected light. The potential role of identified enzymes in biodegradation of fossil organic matter and role of organic compounds released from black shale as a result of this process in copper minerals weathering was discussed. The presented results provide a new insight into the role of chemical compounds released by bacteria during fossil organic matter bioweathering potentially important in the cycling of copper and iron deposited in the sedimentary rock. The originality of the described phenomenon lies in the fact that the bioweathering of fossil organic matter and, consequently, of copper minerals occur simultaneously in the same environment, without any additional sources of energy, electrons and carbon. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparing Laser Desorption Ionization and Atmospheric Pressure Photoionization Coupled to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry To Characterize Shale Oils at the Molecular Level

USGS Publications Warehouse

Cho, Yunjo; Jin, Jang Mi; Witt, Matthias; Birdwell, Justin E.; Na, Jeong-Geol; Roh, Nam-Sun; Kim, Sunghwan

2013-01-01

Laser desorption ionization (LDI) coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to analyze shale oils. Previous work showed that LDI is a sensitive ionization technique for assessing aromatic nitrogen compounds, and oils generated from Green River Formation oil shales are well-documented as being rich in nitrogen. The data presented here demonstrate that LDI is effective in ionizing high-double-bond-equivalent (DBE) compounds and, therefore, is a suitable method for characterizing compounds with condensed structures. Additionally, LDI generates radical cations and protonated ions concurrently, the distribution of which depends upon the molecular structures and elemental compositions, and the basicity of compounds is closely related to the generation of protonated ions. This study demonstrates that LDI FT-ICR MS is an effective ionization technique for use in the study of shale oils at the molecular level. To the best of our knowledge, this is the first time that LDI FT-ICR MS has been applied to shale oils.

The first data on the porous space structure of the Domanik shales as a potential object for EOR applying

NASA Astrophysics Data System (ADS)

Kadyrov, R.; Statsenko, E.

2018-05-01

The resources of shale oil, contained in the organic matter of the wood deposits, can be considered as a source of profitable production of hydrocarbons, when modern EOR technologies are used. As a result of the primary studies of the pore space structure, it is revealed that two types of porous space are prevailing in the studied samples of the Domanik oil shales. The most prevailing is intrakerogen porosity with pore volumes of 5 × 10-8 1 × 10-6 mm3. The volumetric reconstruction of the structure of this pore space shows that the voids are confined directly to micro lenses of organic matter. The second type of the found void is represented by leaching cracks. It is characteristic of more carbonate varieties of the Dominik oil shale with spotted structure. It is the oil shale intervals with such cracks that are of greatest interest to the EOR, since they consist of a large area with smaller pores and through which pressurization and spread of various agents are possible to occur in order to increase the oil recovery.

Combuston method of oil shale retorting

DOEpatents

Jones, Jr., John B.; Reeves, Adam A.

1977-08-16

A gravity flow, vertical bed of crushed oil shale having a two level injection of air and a three level injection of non-oxygenous gas and an internal combustion of at least residual carbon on the retorted shale. The injection of air and gas is carefully controlled in relation to the mass flow rate of the shale to control the temperature of pyrolysis zone, producing a maximum conversion of the organic content of the shale to a liquid shale oil. The parameters of the operation provides an economical and highly efficient shale oil production.

The stable isotopes of site wide waters at an oil sands mine in northern Alberta, Canada

NASA Astrophysics Data System (ADS)

Baer, Thomas; Barbour, S. Lee; Gibson, John J.

2016-10-01

Oil sands mines have large disturbance footprints and contain a range of new landforms constructed from mine waste such as shale overburden and the byproducts of bitumen extraction such as sand and fluid fine tailings. Each of these landforms are a potential source of water and chemical release to adjacent surface and groundwater, and consequently, the development of methods to track water migration through these landforms is of importance. The stable isotopes of water (i.e. 2H and 18O) have been widely used in hydrology and hydrogeology to characterize surface water/groundwater interactions but have not been extensively applied in mining applications, or specifically to oil sands mining in northern Alberta. A prerequisite for applying these techniques is the establishment of a Local Meteoric Water Line (LMWL) to characterize precipitation at the mine sites as well as the development of a 'catalogue' of the stable water isotope signatures of various mine site waters. This study was undertaken at the Mildred Lake Mine Site, owned and operated by Syncrude Canada Ltd. The LMWL developed from 2 years (2009/2012) of sample collection is shown to be consistent with other LMWLs in western Canada. The results of the study highlight the unique stable water isotope signatures associated with hydraulically placed tailings (sand or fluid fine tailings) and overburden shale dumps relative to natural surface water and groundwater. The signature associated with the snow melt water on reclaimed landscapes was found to be similar to ground water recharge in the region. The isotopic composition of the shale overburden deposits are also distinct and consistent with observations made by other researchers in western Canada on undisturbed shales. The process water associated with the fine and coarse tailings streams has highly enriched 2H and 18O signatures. These signatures are developed through the non-equilibrium fractionation of imported fresh river water during evaporation from cooling towers used within the raw water process circuit. This highly fractionated surface water eventually becomes part of the recycled tailings water circuit, and as a consequence it undergoes further non-equilibrium fractionation as a result of surface evaporation, leading to additional enrichment along local evaporation lines.

Joint DoD/DoE Shale Oil Project. Volume 3. Testing of Refined Shale Oil Fuels.

DTIC Science & Technology

1983-12-01

inches displacement NO Nitric oxide CLR Cooperative Lubrication Research NOX Oxides of nitrogen CO Carbon monoxide CO2 Carbon dioxide cSt Centistokes... composition and properties, and evaluation of toxicity. This report summarizes the results of these test and evalua- tion studies. The Paraho/Sohio effort...TABLE 11-1. DOE ALTERNATIVE FUELS PROGRAM DIESEL ENGINE TESTS WITH SHALE FUELS ............................... 11-11 TABLE 11-2. COMPOSITION OF

Controls on selenium distribution and mobilization in an irrigated shallow groundwater system underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA

USGS Publications Warehouse

Mills, Taylor J.; Mast, M. Alisa; Thomas, Judith C.; Keith, Gabrielle L.

2016-01-01

Elevated selenium (Se) concentrations in surface water and groundwater have become a concern in areas of the Western United States due to the deleterious effects of Se on aquatic ecosystems. Elevated Se concentrations are most prevalent in irrigated alluvial valleys underlain by Se-bearing marine shales where Se can be leached from geologic materials into the shallow groundwater and surface water systems. This study presents groundwater chemistry and solid-phase geochemical data from the Uncompahgre River Basin in Western Colorado, an irrigated alluvial landscape underlain by Se-rich Cretaceous marine shale. We analyzed Se species, major and trace elements, and stable nitrogen and oxygen isotopes of nitrate in groundwater and aquifer sediments to examine processes governing selenium release and transport in the shallow groundwater system. Groundwater Se concentrations ranged from below detection limit (< 0.5 μg L− 1) to 4070 μg L− 1, and primarily are controlled by high groundwater nitrate concentrations that maintain oxidizing conditions in the aquifer despite low dissolved oxygen concentrations. High nitrate concentrations in non-irrigated soils and nitrate isotopes indicate nitrate is largely derived from natural sources in the Mancos Shale and alluvial material. Thus, in contrast to areas that receive substantial NO3 inputs through inorganic fertilizer application, Se mitigation efforts that involve limiting NO3 application might have little impact on groundwater Se concentrations in the study area. Soluble salts are the primary source of Se to the groundwater system in the study area at-present, but they constitute a small percentage of the total Se content of core material. Sequential extraction results indicate insoluble Se is likely composed of reduced Se in recalcitrant organic matter or discrete selenide phases. Oxidation of reduced Se species that constitute the majority of the Se pool in the study area could be a potential source of Se in the future as soluble salts are progressively depleted.

Controls on selenium distribution and mobilization in an irrigated shallow groundwater system underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA.

PubMed

Mills, Taylor J; Mast, M Alisa; Thomas, Judith; Keith, Gabrielle

2016-10-01

Elevated selenium (Se) concentrations in surface water and groundwater have become a concern in areas of the Western United States due to the deleterious effects of Se on aquatic ecosystems. Elevated Se concentrations are most prevalent in irrigated alluvial valleys underlain by Se-bearing marine shales where Se can be leached from geologic materials into the shallow groundwater and surface water systems. This study presents groundwater chemistry and solid-phase geochemical data from the Uncompahgre River Basin in Western Colorado, an irrigated alluvial landscape underlain by Se-rich Cretaceous marine shale. We analyzed Se species, major and trace elements, and stable nitrogen and oxygen isotopes of nitrate in groundwater and aquifer sediments to examine processes governing selenium release and transport in the shallow groundwater system. Groundwater Se concentrations ranged from below detection limit (<0.5μgL(-1)) to 4070μgL(-1), and primarily are controlled by high groundwater nitrate concentrations that maintain oxidizing conditions in the aquifer despite low dissolved oxygen concentrations. High nitrate concentrations in non-irrigated soils and nitrate isotopes indicate nitrate is largely derived from natural sources in the Mancos Shale and alluvial material. Thus, in contrast to areas that receive substantial NO3 inputs through inorganic fertilizer application, Se mitigation efforts that involve limiting NO3 application might have little impact on groundwater Se concentrations in the study area. Soluble salts are the primary source of Se to the groundwater system in the study area at-present, but they constitute a small percentage of the total Se content of core material. Sequential extraction results indicate insoluble Se is likely composed of reduced Se in recalcitrant organic matter or discrete selenide phases. Oxidation of reduced Se species that constitute the majority of the Se pool in the study area could be a potential source of Se in the future as soluble salts are progressively depleted. Published by Elsevier B.V.

Demographic response of Louisiana Waterthrush, a stream obligate songbird of conservation concern, to shale gas development

USGS Publications Warehouse

Frantz, Mack W.; Wood, Petra B.; Sheehan, James; George, Gregory

2018-01-01

Shale gas development continues to outpace the implementation of best management practices for wildlife affected by development. We examined demographic responses of the Louisiana Waterthrush (Parkesia motacilla) to shale gas development during 2009–2011 and 2013–2015 in a predominantly forested landscape in West Virginia, USA. Forest cover across the study area decreased from 95% in 2008 to 91% in 2015, while the area affected by shale gas development increased from 0.4% to 3.9%. We quantified nest survival and productivity, a source–sink threshold, riparian habitat quality, territory density, and territory length by monitoring 58.1 km of forested headwater streams (n = 14 streams). Across years, we saw annual variability in nest survival, with a general declining trend over time. Of 11 a priori models tested to explain nest survival (n = 280 nests), 4 models that included temporal, habitat, and shale gas covariates were supported, and 2 of these models accounted for most of the variation in daily nest survival rate. After accounting for temporal effects (rainfall, nest age, and time within season), shale gas development had negative effects on nest survival. Population-level nest productivity declined and individual productivity was lower in areas disturbed by shale gas development than in undisturbed areas, and a source–sink threshold suggested that disturbed areas were more at risk of being sink habitat. Riparian habitat quality scores, as measured by a U.S. Environmental Protection Agency index and a waterthrush-specific habitat suitability index, differed by year and were negatively related to the amount of each territory disturbed by shale gas development. Territory density was not related to the amount of shale gas disturbance, but decreased over time as territory lengths increased. Overall, our results suggest a decline in waterthrush site quality as shale gas development increases, despite relatively small site-wide forest loss.

Pretreatment of shale gas drilling flowback fluid (SGDF) by the microscale Fe0/persulfate/O3 process (mFe0/PS/O3).

PubMed

Zhang, Heng; Xiong, Zhaokun; Ji, Fangzhou; Lai, Bo; Yang, Ping

2017-06-01

Shale gas drilling flowback fluid (SGDF) generated during shale gas extraction is of great concern due to its high total dissolved solid, radioactive elements and organic matter. To remove the toxic and refractory pollutants in SGDF and improve its biodegradability, a microsacle Fe 0 /Persulfate/O 3 process (mFe 0 /PS/O 3 ) was developed to pretreat this wastewater obtained from a shale gas well in southwestern China. First, effects of mFe 0 dosage, O 3 flow rate, PS dosage, pH values on the treatment efficiency of mFe 0 /PS/O 3 process were investigated through single-factor experiments. Afterward, the optimal conditions (i.e., pH = 6.7, mFe 0 dosage = 6.74 g/L, PS = 16.89 mmol/L, O 3 flow rate = 0.73 L/min) were obtained by using response surface methodology (RSM). Under the optimal conditions, high COD removal (75.3%) and BOD 5 /COD ratio (0.49) were obtained after 120 min treatment. Moreover, compared with control experiments (i.e., mFe 0 , O 3 , PS, mFe 0 /O 3 , mFe 0 /PS, O 3 /PS), mFe 0 /PS/O 3 system exerted better performance for pollutants removal in SGDF due to strong synergistic effect between mFe 0 , PS and O 3 . In addition, the decomposition or transformation of the organic pollutants in SGDF was analyzed by using GC-MS. Finally, the reaction mechanism of the mFe 0 /PS/O 3 process was proposed according to the analysis results of SEM-EDS and XRD. It can be concluded that high-efficient mFe 0 /PS/O 3 process was mainly resulted from the combination effect of direct oxidation by ozone and persulfate, heterogeneous and homogeneous catalytic oxidation, Fenton-like reaction and adsorption. Therefore, mFe 0 /PS/O 3 process was proven to be an effective method for pretreatment of SGDF prior to biological treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbial diversity and methanogenic activity of Antrim Shale formation waters from recently fractured wells

PubMed Central

Wuchter, Cornelia; Banning, Erin; Mincer, Tracy J.; Drenzek, Nicholas J.; Coolen, Marco J. L.

2013-01-01

The Antrim Shale in the Michigan Basin is one of the most productive shale gas formations in the U.S., but optimal resource recovery strategies must rely on a thorough understanding of the complex biogeochemical, microbial, and physical interdependencies in this and similar systems. We used Illumina MiSeq 16S rDNA sequencing to analyze the diversity and relative abundance of prokaryotic communities present in Antrim shale formation water of three closely spaced recently fractured gas-producing wells. In addition, the well waters were incubated with a suite of fermentative and methanogenic substrates in an effort to stimulate microbial methane generation. The three wells exhibited substantial differences in their community structure that may arise from their different drilling and fracturing histories. Bacterial sequences greatly outnumbered those of archaea and shared highest similarity to previously described cultures of mesophiles and moderate halophiles within the Firmicutes, Bacteroidetes, and δ- and ε-Proteobacteria. The majority of archaeal sequences shared highest sequence similarity to uncultured euryarchaeotal environmental clones. Some sequences closely related to cultured methylotrophic and hydrogenotrophic methanogens were also present in the initial well water. Incubation with methanol and trimethylamine stimulated methylotrophic methanogens and resulted in the largest increase in methane production in the formation waters, while fermentation triggered by the addition of yeast extract and formate indirectly stimulated hydrogenotrophic methanogens. The addition of sterile powdered shale as a complex natural substrate stimulated the rate of methane production without affecting total methane yields. Depletion of methane indicative of anaerobic methane oxidation (AMO) was observed over the course of incubation with some substrates. This process could constitute a substantial loss of methane in the shale formation. PMID:24367357

Response of Velocity Anisotropy of Shale Under Isotropic and Anisotropic Stress Fields

NASA Astrophysics Data System (ADS)

Li, Xiaying; Lei, Xinglin; Li, Qi

2018-03-01

We investigated the responses of P-wave velocity and associated anisotropy in terms of Thomsen's parameters to isotropic and anisotropic stress fields on Longmaxi shales cored along different directions. An array of piezoelectric ceramic transducers allows us to measure P-wave velocities along numerous different propagation directions. Anisotropic parameters, including the P-wave velocity α along a symmetry axis, Thomsen's parameters ɛ and δ, and the orientation of the symmetry axis, could then be extracted by fitting Thomsen's weak anisotropy model to the experimental data. The results indicate that Longmaxi shale displays weakly intrinsic velocity anisotropy with Thomsen's parameters ɛ and δ being approximately 0.05 and 0.15, respectively. The isotropic stress field has only a slight effect on velocity and associated anisotropy in terms of Thomsen's parameters. In contrast, both the magnitude and orientation of the anisotropic stress field with respect to the shale fabric are important in controlling the evolution of velocity and associated anisotropy in a changing stress field. For shale with bedding-parallel loading, velocity anisotropy is enhanced because velocities with smaller angles relative to the maximum stress increase significantly during the entire loading process, whereas those with larger angles increase slightly before the yield stress and afterwards decrease with the increasing differential stress. For shale with bedding-normal loading, anisotropy reversal is observed, and the anisotropy is progressively modified by the applied differential stress. Before reaching the yield stress, velocities with smaller angles relative to the maximum stress increase more significantly and even exceed the level of those with larger angles. After reaching the yield stress, velocities with larger angles decrease more significantly. Microstructural features such as the closure and generation of microcracks can explain the modification of the velocity anisotropy due to the applied stress anisotropy.

The Multi-Porosity Multi-Permeability and Electrokinetic Natures of Shales and Their Effects in Hydraulic Fracturing of Unconventional Shale Reservoirs

NASA Astrophysics Data System (ADS)

Liu, C.; Hoang, S. K.; Tran, M. H.; Abousleiman, Y. N.

2013-12-01

Imaging studies of unconventional shale reservoir rocks have recently revealed the multi-porosity multi-permeability nature of these intricate formations. In particular, the porosity spectrum of shale reservoir rocks often comprises of the nano-porosity in the organic matters, the inter-particle micro-porosity, and the macroscopic porosity of the natural fracture network. Shale is also well-known for its chemically active behaviors, especially shrinking and swelling when exposed to aqueous solutions, as the results of pore fluid exchange with external environment due to the difference in electro-chemical potentials. In this work, the effects of natural fractures and electrokinetic nature of shale on the formation responses during hydraulic fracturing are examined using the dual-poro-chemo-electro-elasticity approach which is a generalization of the classical Biot's poroelastic formulation. The analyses show that the presence of natural fractures can substantially increase the leak-off rate of fracturing fluid into the formation and create a larger region of high pore pressure near the fracture face as shown in Fig.1a. Due to the additional fluid invasion, the naturally fractured shale swells up more and the fracture aperture closes faster compared to an intrinsically low permeability non-fractured shale formation as shown in Fig.1b. Since naturally fractured zones are commonly targeted as pay zones, it is important to account for the faster fracture closing rate in fractured shales in hydraulic fracturing design. Our results also show that the presence of negative fixed charges on the surface of clay minerals creates an osmotic pressure at the interface of the shale and the external fluid as shown in Fig.1c. This additional Donnan-induced pore pressure can result in significant tensile effective stresses and tensile damage in the shale as shown in Fig.1d. The induced tensile damage can exacerbate the problem of proppant embedment resulting in more fracture closure and reduction of fracture length and productivity. The results also suggest that a fracturing fluid with appropriately designed salinity can minimize the chemically induced tensile damage and, thus, maximize the productivity from the created hydraulic fractures.

The subsurface impact of hydraulic fracturing in shales- Perspectives from the well and reservoir

NASA Astrophysics Data System (ADS)

ter Heege, Jan; Coles, Rhys

2017-04-01

It has been identified that the main risks of subsurface shale gas operations in the U.S.A. and Canada are associated with (1) drilling and well integrity, (2) hydraulic fracturing, and (3) induced seismicity. Although it is unlikely that hydraulic fracturing operations result in direct pathways of enhanced migration between stimulated fracture disturbed rock volume and shallow aquifers, operations may jeopardize well integrity or induce seismicity. From the well perspective, it is often assumed that fluid injection leads to the initiation of tensile (mode I) fractures at different perforation intervals along the horizontal sections of shale gas wells if pore pressure exceeds the minimum principal stress. From the reservoir perspective, rise in pore pressure resulting from fluid injection may lead to initiation of tensile fractures, reactivation of shear (mode II) fractures if the criterion for failure in shear is exceeded, or combinations of different fracturing modes. In this study, we compare tensile fracturing simulations using conventional well-based models with shear fracturing simulations using a fractured shale model with characteristic fault populations. In the fractured shale model, stimulated permeability is described by an analytical model that incorporates populations of reactivated faults and that combines 3D permeability tensors for layered shale matrix, damage zone and fault core. Well-based models applied to wells crosscutting the Posidonia Shale Formation are compared to generic fractured shale models, and fractured shale models are compared to micro-seismic data from the Marcellus Shale. Focus is on comparing the spatial distribution of permeability, stimulated reservoir volume and seismicity, and on differences in fracture initiation pressure and fracture orientation for tensile and shear fracturing end-members. It is shown that incorporation of fault populations (for example resulting from analysis of 3D seismics or outcrops) in hydraulic fracturing models provides better constraints on well pressures, stimulated fracture disturbed volume and induced seismicity. Thereby, it helps assessing the subsurface impact of hydraulic fracturing in shales and mitigating risks associated with loss of loss of well integrity, loss of fracture containment, and induced seismicity.

Assessment of in-place oil shale resources of the Eocene Green River Formation, a foundation for calculating recoverable resources

USGS Publications Warehouse

Johnson, Ronald C.; Mercier, Tracy

2011-01-01

The recently completed assessment of in-place resources of the Eocene Green River Formation in the Piceance Basin, Colorado; the Uinta Basin, Utah and Colorado; and the Greater Green River Basin Wyoming, Colorado, and Utah and their accompanying ArcGIS projects will form the foundation for estimating technically-recoverable resources in those areas. Different estimates will be made for each of the various above-ground and in-situ recovery methodologies currently being developed. Information required for these estimates include but are not limited to (1) estimates of the amount of oil shale that exceeds various grades, (2) overburden calculations, (3) a better understanding of oil shale saline facies, and (4) a better understanding of the distribution of various oil shale mineral facies. Estimates for the first two are on-going, and some have been published. The present extent of the saline facies in all three basins is fairly well understood, however, their original extent prior to ground water leaching has not been studied in detail. These leached intervals, which have enhanced porosity and permeability due to vugs and fractures and contain significant ground water resources, are being studied from available core descriptions. A database of all available xray mineralogy data for the oil shale interval is being constructed to better determine the extents of the various mineral facies. Once these studies are finished, the amount of oil shale with various mineralogical and physical properties will be determined.

Review of Emerging Resources: U.S. Shale Gas and Shale Oil Plays

EIA Publications

2011-01-01

To gain a better understanding of the potential U.S. domestic shale gas and shale oil resources, the Energy Information Administration (EIA) commissioned INTEK, Inc. to develop an assessment of onshore lower 48 states technically recoverable shale gas and shale oil resources. This paper briefly describes the scope, methodology, and key results of the report and discusses the key assumptions that underlie the results.

Carbon sequestration in depleted oil shale deposits

DOEpatents

Burnham, Alan K; Carroll, Susan A

2014-12-02

A method and apparatus are described for sequestering carbon dioxide underground by mineralizing the carbon dioxide with coinjected fluids and minerals remaining from the extraction shale oil. In one embodiment, the oil shale of an illite-rich oil shale is heated to pyrolyze the shale underground, and carbon dioxide is provided to the remaining depleted oil shale while at an elevated temperature. Conditions are sufficient to mineralize the carbon dioxide.

New insights on the Karoo shale gas potential from borehole KZF-1 (Western Cape, South Africa)

NASA Astrophysics Data System (ADS)

Campbell, Stuart A.; Götz, Annette E.; Montenari, Michael

2016-04-01

A study on world shale reserves conducted by the Energy Information Agency (EIA) in 2013 concluded that there could be as much as 390 Tcf recoverable reserves of shale gas in the southern and south-western parts of the Karoo Basin. This would make it the 8th-largest shale gas resource in the world. However, the true extent and commercial viability is still unknown, due to the lack of exploration drilling and modern 3D seismic. Within the framework of the Karoo Research Initiative (KARIN), two deep boreholes were drilled in the Eastern and Western Cape provinces of South Africa. Here we report on new core material from borehole KZF-1 (Western Cape) which intersected the Permian black shales of the Ecca Group, the Whitehill Formation being the main target formation for future shale gas production. To determine the original source potential for shale gas we investigated the sedimentary environments in which the potential source rocks formed, addressing the research question of how much sedimentary organic matter the shales contained when they originally formed. Palynofacies indicates marginal marine conditions of a stratified basin setting with low marine phytoplankton percentages (acritarchs, prasinophytes), good AOM preservation, high terrestrial input, and a high spores:bisaccates ratio (kerogen type III). Stratigraphically, a deepening-upward trend is observed. Laterally, the basin configuration seems to be much more complex than previously assumed. Furthermore, palynological data confirms the correlation of marine black shales of the Prince Albert and Whitehill formations in the southern and south-western parts of the Karoo Basin with the terrestrial coals of the Vryheid Formation in the north-eastern part of the basin. TOC values (1-6%) classify the Karoo black shales as promising shale gas resources, especially with regard to the high thermal maturity (Ro >3). The recently drilled deep boreholes in the southern and south-western Karoo Basin, the first since the SOEKOR exploration programmes of the 1960's and 1970's, provide new core material to determine the likely current potential for retention of shale gas with regard to the structural and thermal history of the basin. Thus, the KARIN research program will produce a valuable data set for future unconventional gas exploration and production in South Africa.

Explosively produced fracture of oil shale

NASA Astrophysics Data System (ADS)

Morris, W. A.

1982-05-01

Rock fragmentation research in oil shale to develop the blasting technologies and designs required to prepare a rubble bed for a modified in situ retort is reported. Experimental work is outlined, proposed studies in explosive characterization are detailed and progress in numerical calculation techniques to predict fracture of the shale is described. A detailed geologic characterization of two Anvil Points experiment sites is related to previous work at Colony Mine. The second section focuses on computer modeling and theory. The latest generation of the stress wave code SHALE, its three dimensional potential, and the slide line package for it are described. A general stress rate equation that takes energy dependence into account is discussed.

Fossil fuel furnace reactor

DOEpatents

Parkinson, William J.

1987-01-01

A fossil fuel furnace reactor is provided for simulating a continuous processing plant with a batch reactor. An internal reaction vessel contains a batch of shale oil, with the vessel having a relatively thin wall thickness for a heat transfer rate effective to simulate a process temperature history in the selected continuous processing plant. A heater jacket is disposed about the reactor vessel and defines a number of independent controllable temperature zones axially spaced along the reaction vessel. Each temperature zone can be energized to simulate a time-temperature history of process material through the continuous plant. A pressure vessel contains both the heater jacket and the reaction vessel at an operating pressure functionally selected to simulate the continuous processing plant. The process yield from the oil shale may be used as feedback information to software simulating operation of the continuous plant to provide operating parameters, i.e., temperature profiles, ambient atmosphere, operating pressure, material feed rates, etc., for simulation in the batch reactor.

Petrophysical Properties of Cody, Mowry, Shell Creek, and Thermopolis Shales, Bighorn Basin, Wyoming

NASA Astrophysics Data System (ADS)

Nelson, P. H.

2013-12-01

The petrophysical properties of four shale formations are documented from well-log responses in 23 wells in the Bighorn Basin in Wyoming. Depths of the examined shales range from 4,771 to 20,594 ft. The four formations are the Thermopolis Shale (T), the Shell Creek Shale (SC), the Mowry Shale (M), and the lower part of the Cody Shale (C), all of Cretaceous age. These four shales lie within a 4,000-ft, moderately overpressured, gas-rich vertical interval in which the sonic velocity of most rocks is less than that of an interpolated trendline representing a normal increase of velocity with depth. Sonic velocity, resistivity, neutron, caliper, and gamma-ray values were determined from well logs at discrete intervals in each of the four shales in 23 wells. Sonic velocity in all four shales increases with depth to a present-day depth of about 10,000 ft; below this depth, sonic velocity remains relatively unchanged. Velocity (V), resistivity (R), neutron porosity (N), and hole diameter (D) in the four shales vary such that: VM > VC > VSC > VT, RM > RC > RSC > RT, NT > NSC ≈ NC > NM, and DT > DC ≈ DSC > DM. These orderings can be partially understood on the basis of rock compositions. The Mowry Shale is highly siliceous and by inference comparatively low in clay content, resulting in high sonic velocity, high resistivity, low neutron porosity, and minimal borehole enlargement. The Thermopolis Shale, by contrast, is a black fissile shale with very little silt--its high clay content causes low velocity, low resistivity, high neutron response, and results in the greatest borehole enlargement. The properties of the Shell Creek and lower Cody Shales are intermediate to the Mowry and Thermopolis Shales. The sonic velocities of all four shales are less than that of an interpolated trendline that is tied to velocities in shales above and below the interval of moderate overpressure. The reduction in velocity varies among the four shales, such that the amount of offset (O) from the trendline is OT > OSC > OC > OM, that is, the velocity in the Mowry Shale is reduced the least and the velocity in the Thermopolis Shale is reduced the most. Velocity reductions are attributed to increases in pore pressure during burial, caused by the generation and retention of gas, with lithology playing a key role in the amount of reduction. Sonic velocity in the four shale units remains low to the present day, after uplift and erosion of as much as 6,500 ft in the deeper part of the basin and consequent possible reduction from maximum pore pressures reached when strata were more deeply buried. A model combining burial history, the decrease of effective stress with increasing pore pressure, and Bower's model for the dependence of sonic velocity on effective stress is proposed to explain the persistence of low velocity in shale units. Interruptions to compaction gradients associated with gas occurrences and overpressure are observed in correlative strata in other basins in Wyoming, so the general results for shales in the Bighorn Basin established in this paper should be applicable elsewhere.