Sample records for gas reservoir bluebell-altamont

  1. Coarse scale simulation of tight gas reservoirs 

    E-print Network

    El-Ahmady, Mohamed Hamed

    2004-09-30

    It is common for field models of tight gas reservoirs to include several wells with hydraulic fractures. These hydraulic fractures can be very long, extending for more than a thousand feet. A hydraulic fracture width is ...

  2. Underground natural gas storage reservoir management

    SciTech Connect

    Ortiz, I.; Anthony, R.

    1995-06-01

    The objective of this study is to research technologies and methodologies that will reduce the costs associated with the operation and maintenance of underground natural gas storage. This effort will include a survey of public information to determine the amount of natural gas lost from underground storage fields, determine the causes of this lost gas, and develop strategies and remedial designs to reduce or stop the gas loss from selected fields. Phase I includes a detailed survey of US natural gas storage reservoirs to determine the actual amount of natural gas annually lost from underground storage fields. These reservoirs will be ranked, the resultant will include the amount of gas and revenue annually lost. The results will be analyzed in conjunction with the type (geologic) of storage reservoirs to determine the significance and impact of the gas loss. A report of the work accomplished will be prepared. The report will include: (1) a summary list by geologic type of US gas storage reservoirs and their annual underground gas storage losses in ft{sup 3}; (2) a rank by geologic classifications as to the amount of gas lost and the resultant lost revenue; and (3) show the level of significance and impact of the losses by geologic type. Concurrently, the amount of storage activity has increased in conjunction with the net increase of natural gas imports as shown on Figure No. 3. Storage is playing an ever increasing importance in supplying the domestic energy requirements.

  3. Geomechanical Development of Fractured Reservoirs During Gas Production 

    E-print Network

    Huang, Jian

    2013-04-05

    Within fractured reservoirs, such as tight gas reservoir, coupled processes between matrix deformation and fluid flow are very important for predicting reservoir behavior, pore pressure evolution and fracture closure. To study the coupling between...

  4. Impes modeling of volumetric dry gas reservoirs with mobile water

    E-print Network

    Forghany, Saeed

    2004-09-30

    program specifically designed to model two-phase flow of gas and water in these reservoirs. Since fluid compression and viscous forces are the dominant parameters that control fluid movement in a dry gas reservoir, we used the Implicit Pressure...

  5. Tight gas reservoirs: A visual depiction

    SciTech Connect

    Not Available

    1993-12-01

    Future gas supplies in the US will depend on an increasing contribution from unconventional sources such as overpressured and tight gas reservoirs. Exploitation of these resources and their conversion to economically producible gas reserves represents a major challenge. Meeting this challenge will require not only the continuing development and application of new technologies, but also a detailed understanding of the complex nature of the reservoirs themselves. This report seeks to promote understanding of these reservoirs by providing examples. Examples of gas productive overpressured tight reservoirs in the Greater Green River Basin, Wyoming are presented. These examples show log data (raw and interpreted), well completion and stimulation information, and production decline curves. A sampling of wells from the Lewis and Mesaverde formations are included. Both poor and good wells have been chosen to illustrate the range of productivity that is observed. The second section of this document displays decline curves and completion details for 30 of the best wells in the Greater Green River Basin. These are included to illustrate the potential that is present when wells are fortuitously located with respect to local stratigraphy and natural fracturing, and are successfully hydraulically fractured.

  6. Seismic imaging of gas hydrate reservoir heterogeneities

    NASA Astrophysics Data System (ADS)

    Huang, Jun-Wei

    Natural gas hydrate, a type of inclusion compound or clathrate, are composed of gas molecules trapped within a cage of water molecules. The presence of gas hydrate has been confirmed by core samples recovered from boreholes. Interests in the distribution of natural gas hydrate stem from its potential as a future energy source, geohazard to drilling activities and their possible impact on climate change. However the current geophysical investigations of gas hydrate reservoirs are still too limited to fully resolve the location and the total amount of gas hydrate due to its complex nature of distribution. The goal of this thesis is twofold, i.e., to model (1) the heterogeneous gas hydrate reservoirs and (2) seismic wave propagation in the presence of heterogeneities in order to address the fundamental questions: where are the location and occurrence of gas hydrate and how much is stored in the sediments. Seismic scattering studies predict that certain heterogeneity scales and velocity contrasts will generate strong scattering and wave mode conversion. Vertical Seismic Profile (VSP) techniques can be used to calibrate seismic characterization of gas hydrate expressions on surface seismograms. To further explore the potential of VSP in detecting the heterogeneities, a wave equation based approach for P- and S-wave separation is developed. Tests on synthetic data as well as applications to field data suggest alternative acquisition geometries for VSP to enable wave mode separation. A new reservoir modeling technique based on random medium theory is developed to construct heterogeneous multi-variable models that mimic heterogeneities of hydrate-bearing sediments at the level of detail provided by borehole logging data. Using this new technique, I modeled the density, and P- and S-wave velocities in combination with a modified Biot-Gassmann theory and provided a first order estimate of the in situ volume of gas hydrate near the Mallik 5L-38 borehole. Our results suggest a range of 528 to 768x10 6 m3/km2 of natural gas trapped within hydrate, nearly an order of magnitude lower than earlier estimates which excluded effects of small-scale heterogeneities. Further, the petrophysical models are combined with a 3-D Finite Difference method to study seismic attenuation. Thus a framework is built to further tune the models of gas hydrate reservoirs with constraints from well logs other disciplinary data.

  7. Helium production in natural gas reservoirs

    Microsoft Academic Search

    E. B. Pereira; J. A. S. Adams

    1982-01-01

    About 11,000 published natural gas analyses of helium are used in the estimation of the average global scale accumulation and concentration of radiogenic helium in sediments. Simple lognormal statistics is employed to derive a net accumulation rate between 1†105 to 6.7†105 helium atoms per cubic meter of reservoir rock per second. This acccumulation rate permitted to infer an average helium

  8. Helium production in natural gas reservoirs

    Microsoft Academic Search

    E. B. Pereira; J. A. S. Adams

    1982-01-01

    About 11,000 published natural gas analyses of helium are used in the estimation of the average global scale accumulation and concentration of radiogenic helium in sediments. Simple lognormal statistics is employed to derive a net accumulation rate between 1dagger10⁵ to 6.7dagger10⁵ helium atoms per cubic meter of reservoir rock per second. This acccumulation rate permitted to infer an average helium

  9. Characterization and reservoir evaluation of a hydraulically fractured, shaly gas reservoir

    E-print Network

    Santiago Molina, Cesar Alfonso

    1991-01-01

    CHARACTERIZATION AND RESERVOIR EVALUATION OF A HYDRAULICALLY FRACTURED& SHALY GAS RESERVOIR A Thesis by CESAR ALFONSO SANTIAGO MOLINA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 1991 Major Subject: Petroleum Engineering CHARACTERIZATION AND RESERVOIR EVALUATION OF A HYDRAULICALLY FRACTURED, SHALY GAS RESERVOIR A Thesis by CESAR ALFONSO SANTIAGO MOLINA Approved...

  10. Analysis of gas production methods for methane gas hydrate reservoirs

    NASA Astrophysics Data System (ADS)

    Ivakhnenko, Aleksandr; Baluanov, Bakhytzhan; Shopenova, Aigerim; Gulnur, Asan; Agzomova, Bagdagul

    2015-04-01

    In methane gas hydrate reservoir (MH), pressure and temperature conditions are in the MH stability region in the initial stage. To dissociate MH and produce gas from a MH reservoir, pressure and temperature conditions should be moved to the dissociation region. Therefore, three methods of depressurization, thermal and inhibitor injection have been modeled and analyzed as a basic methods for different conditions that might occur in nature. Furthermore, several methods such as injection of gas other than methane and irradiation of ultrasonic wave were also investigated especially for the MH dissociation and possible gas production. The simulation results allowed to select optimal screening approach for the appropriate production method that can be employed in specific MH conditions.

  11. Evaluation of Devonian shale gas reservoirs

    SciTech Connect

    Vanorsdale, C.R.

    1987-05-01

    The evaluation of predominantly shale reservoirs presents a problem for engineers traditionally educated either to correct for or to ignore such lithologic zones. Currently accepted evaluation techniques and their applicability are discussed to determine the best way to forecast remaining recoverable gas reserves from the Devonian shales of the Appalachian basin. This study indicates that rate/time decline-curve analysis is the most reliable technique and presents typical decline curves based on production data gathered from 508 shale wells in a three-state study area. The resultant type curves illustrate a dual- (or multiple-) porosity mechanism that violates standard decline-curve analysis guidelines. The results, however, are typical not only for the Devonian shales but for all naturally fractured, multilayered, or similar shale reservoirs.

  12. Naturally fractured tight gas reservoir detection optimization

    SciTech Connect

    NONE

    1998-11-30

    The goal of the work this quarter has been to partition and high-grade the Greater Green River basin for exploration efforts in the Upper Cretaceous tight gas play and to initiate resource assessment of the basin. The work plan for the quarter of July 1-September 30, 1998 comprised three tasks: (1) Refining the exploration process for deep, naturally fractured gas reservoirs; (2) Partitioning of the basin based on structure and areas of overpressure; (3) Examination of the Kinney and Canyon Creek fields with respect to the Cretaceous tight gas play and initiation of the resource assessment of the Vermilion sub-basin partition (which contains these two fields); and (4) Initiation analysis of the Deep Green River Partition with respect to the Stratos well and assessment of the resource in the partition.

  13. Gross Greenhouse Gas Emissions from Brazilian Hydro Reservoirs

    Microsoft Academic Search

    Marco Santos; Bohdan Matvienko; Luiz Rosa; Elizabeth Sikar; Ednaldo Santos

    This paper presents the results of gross carbon dioxide and methane emission measurements in several Brazilian hydro reservoirs. The term ‘gross emissions’ means gas flux measurements from the reservoir surface without correcting for natural pre-impoundment emissions by natural bodies such as the river channel, seasonal flooding and terrestrial ecosystems. The net emissions result from estimating pre-existing emissions by the reservoir.

  14. [Greenhouse gas emission from reservoir and its influence factors].

    PubMed

    Zhao, Xiao-jie; Zhao, Tong-qian; Zheng, Hua; Duan, Xiao-nan; Chen, Fa-lin; Ouyang, Zhi-yun; Wang, Xiao-ke

    2008-08-01

    Reservoirs are significant sources of emissions of the greenhouse gases. Discussing greenhouse gas emission from the reservoirs and its influence factors are propitious to evaluate emission of the greenhouse gas accurately, reduce gas emission under hydraulic engineering and hydropower development. This paper expatiates the mechanism of the greenhouse gas production, sums three approaches of the greenhouse gas emission, which are emissions from nature emission of the reservoirs, turbines and spillways and downstream of the dam, respectively. Effects of greenhouse gas emission were discussed from character of the reservoirs, climate, pH of the water, vegetation growing in the reservoirs and so on. Finally, it has analyzed the heterogeneity of the greenhouse gas emission as well as the root of the uncertainty and carried on the forecast with emphasis to the next research. PMID:18839604

  15. Naturally fractured tight gas reservoir detection optimization

    SciTech Connect

    NONE

    1998-09-30

    During this quarter, work began on the regional structural and geologic analysis of the greater Green River basin (GGRB) in southwestern Wyoming, northwestern Colorado and northeastern Utah. The ultimate objective of the regional analysis is to apply the techniques developed and demonstrated during earlier phases of the project to sweet-spot delineation in a relatively new and underexplored play: tight gas from continuous-type Upper Cretaceous reservoirs of the GGRB. The primary goal of this work is to partition and high-grade the greater Green River basin for exploration efforts in the Cretaceous tight gas play. The work plan for the quarter of January 1, 1998--March 31, 1998 consisted of three tasks: (1) Acquire necessary data and develop base map of study area; (2) Process data for analysis; and (3) Initiate structural study. The first task and second tasks were completed during this reporting period. The third task was initiated and work continues.

  16. Modeling well performance in compartmentalized gas reservoirs 

    E-print Network

    Yusuf, Nurudeen

    2008-10-10

    to conventional consolidated reservoirs (with constant formation compressibility) but also to unconsolidated reservoirs (with variable formation compressibility) by including geomechanics, permeability deterioration and compartmentalization to estimate the OGIP...

  17. Modeling well performance in compartmentalized gas reservoirs 

    E-print Network

    Yusuf, Nurudeen

    2009-05-15

    to conventional consolidated reservoirs (with constant formation compressibility) but also to unconsolidated reservoirs (with variable formation compressibility) by including geomechanics, permeability deterioration and compartmentalization to estimate the OGIP...

  18. Mantle Reservoirs From a Noble Gas Perspective

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, S.

    2007-12-01

    The noble gases provide unique insight into mantle structure and the origin of the different mantle reservoirs. Many OIBs, such as Hawaii and Iceland, have 3He/4He ratios that are a factor of 4 to 6 higher than the canonical MORB value of 8±1 RA. The high 3He/4He ratios in OIBs are conventionally viewed as evidence for the existence of a primitive mantle reservoir. Such a view, however, is frequently challenged on the grounds that noble gas abundances in OIBs are an order of magnitude lower than in MORBs, an observation that traditional models of magmatic degassing cannot explain. The apparent concentration paradox has been resolved by incorporating kinetic fractionation of the noble gases during magmatic degassing of the erupting magma and it can be shown that higher CO2 and H2O content of OIBs, compared to MORBs, leads to more extensive degassing of He in OIB magmas (Gonnermann and Mukhopadhyay, 2007). In contrast to Hawaii and Iceland, some ocean islands, such as the Cook-Austral Islands and Canary Islands (HIMU ocean islands) have 3He/4He ratios of 4-7 RA, lower than the MORB range. The low 3He/4He ratios are attributed to the addition of radiogenic 4He from recycled slabs. Surprisingly, recent high-precision neon isotopic measurements made at Harvard in olivine phenocrysts from the Cook-Austral Islands indicate that HIMU neon is less nucleogenic than the MORB source. The He and Ne systematics from the Cook-Austral's demonstrate that the noble gas signature of HIMU basalts cannot arise either from simple diffusive equilibration of a recycled slab with a MORB source, or result from mixing of melts that are derived from recycled slabs and the MORB mantle. The He-Ne systematics, however, can be quantitatively modeled as a mixture of recycled slab and a primitive mantle reservoir. The scenario is consistent with He-Os and He- Nd correlations seen in the Cook-Austral basalts. Thus, both low and high 3He/4He OIBs incorporate the same primitive mantle reservoir, although in varying proportions. The notion of a reservoir that is primitive in its volatile content and sampled at ocean islands is very much alive. In spite of whole mantle convection, it appears that part of the Earth's mantle has remained largely undegassed. While significant progress has been made with respect to understanding the geochemical implications of He and Ne isotopic composition measured in MORBs and OIBs, our knowledge of Xenon in the mantle remains poor. Since 129Xe and 136Xe have been produced by the now extinct nuclides, 129I and 244Pu respectively, Xe isotopic composition of the mantle can be used to test models of atmosphere formation and provide unique clues to the volatile history of the Earth's mantle. Some of the outstanding issues that still need to be resolved are whether the Earth's mantle has solar or chondritic heavy noble gases, whether OIBs and MORB have the same Xe isotopic composition, and what fraction of the 136Xe is from 244Pu vs. 238U fission. Addressing these issues will require not only high precision measurements but also innovative experimental techniques to reduce air contamination that is ubiquitous in mantle-derived samples. High precision Xe isotopic measurements made at Harvard indicates that Samoa (a high 3He/4He ocean island) and MORBs have exactly the same proportion of radiogenic 129Xe to 136Xe. Although this result needs to be verified from other OIBs, it suggests that a single mantle reservoir supplies the excess 129Xe and 136Xe to both the MORB and OIB mantle source. The primitive mantle reservoir is the most likely carrier of the xenon isotopic anomaly.

  19. Effects of reservoir geometry and permeability anisotropy on ultimate gas recovery in Devonian Shale reservoirs 

    E-print Network

    Starnes, Lee McKennon

    1989-01-01

    reservoir pressure of 600 psi 3. Dry gas with a specific gravity of 0. 65 4. Gas produced from a single well at a constant bottornhole pressure of 100 psi 5. Well life of 50 years 6. Well spacings of 20, 40, 80, and 160 acres 7. Formation depth of 2000...EFFECTS OF RESERVOIR GEOMETRY AND PERMEABILITY ANISOTROPY ON ULTIMATE GAS RECOVERY IN DEVONIAN SHALE RESERVOIRS A Thesis by LEE McKENNON STARNES Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment...

  20. Using multi-layer models to forecast gas flow rates in tight gas reservoirs 

    E-print Network

    Jerez Vera, Sergio Armando

    2007-04-25

    -layer analyses techniques provide incorrect estimates of permeability, fracture conductivity, drainage area, and fracture half-length. These erroneous values of reservoir properties also provide the reservoir engineer with misleading values of forecasted gas...

  1. Numerical Modeling of Fractured Shale-Gas and Tight-Gas Reservoirs Using Unstructured Grids 

    E-print Network

    Olorode, Olufemi Morounfopefoluwa

    2012-02-14

    -ideal fracture geometries and coupled primary-secondary fracture interactions on reservoir performance in these unconventional gas reservoirs. This thesis provides a grid construction tool to generate high-resolution unstructured meshes using Voronoi grids...

  2. Gross Greenhouse Gas Emissions from Brazilian Hydro Reservoirs

    Microsoft Academic Search

    Marco Aurelio Santos; Bohdan Matvienko; Luiz Pinguelli Rosa; Elizabeth Sikar; Ednaldo Oliveira Santos

    \\u000a This paper presents the results of gross carbon dioxide and methane emission measurements in several Brazilian hydro reservoirs.\\u000a The term ‘gross emissions’ means gas flux measurements from the reservoir surface without correcting for natural pre-impoundment\\u000a emissions by natural bodies such as the river channel, seasonal flooding and terrestrial ecosystems. The net emissions result\\u000a from estimating pre-existing emissions by the reservoir.

  3. Estimation of Carbon Dioxide Storage Capacity for Depleted Gas Reservoirs

    NASA Astrophysics Data System (ADS)

    Lai, Yen Ting; Shen, Chien-Hao; Tseng, Chi-Chung; Fan, Chen-Hui; Hsieh, Bieng-Zih

    2015-04-01

    A depleted gas reservoir is one of the best options for CO2 storage for many reasons. First of all, the storage safety or the caprock integrity has been proven because the natural gas was trapped in the formation for a very long period of time. Also the formation properties and fluid flow characteristics for the reservoir have been well studied since the discovery of the gas reservoir. Finally the surface constructions and facilities are very useful and relatively easy to convert for the use of CO2 storage. The purpose of this study was to apply an analytical approach to estimate CO2 storage capacity in a depleted gas reservoir. The analytical method we used is the material balance equation (MBE), which have been widely used in natural gas storage. We proposed a modified MBE for CO2 storage in a depleted gas reservoir by introducing the z-factors of gas, CO2 and the mixture of the two. The MBE can be derived to a linear relationship between the ratio of pressure to gas z-factor (p/z) and the cumulative term (Gp-Ginj, where Gp is the cumulative gas production and Ginj is the cumulative CO2 injection). The CO2 storage capacity can be calculated when constraints of reservoir recovery pressure are adopted. The numerical simulation was also used for the validation of the theoretical estimation of CO2 storage capacity from the MBE. We found that the quantity of CO2 stored is more than that of gas produced when the reservoir pressure is recovered from the abandon pressure to the initial pressure. This result was basically from the fact that the gas- CO2 mixture z-factors are lower than the natural gas z-factors in reservoir conditions. We also established a useful p/z plot to easily observe the pressure behavior of CO2 storage and efficiently calculate the CO2 storage capacity. The application of the MBE we proposed was demonstrated by a case study of a depleted gas reservoir in northwestern Taiwan. The estimated CO2 storage capacities from conducting reservoir simulation and using analytical equation were very consistent. The validation results showed that the modified MBE we proposed in this study can be efficiently used for the estimation of CO2 storage capacity in a depleted gas reservoir.

  4. General inflow performance relationship for solution-gas reservoir wells

    SciTech Connect

    Dias-Couto, L.E.; Golan, M.

    1982-02-01

    Two equations are developed to describe the inflow performance relationship (IPR) of wells producing from solution-gas drive reservoirs. These are general equations (extensions of the currently available IPR's) that apply to wells with any drainage-area shape at any state of completion flow efficiency and any stage of reservoir depletion. 7 refs.

  5. Stress-dependent permeability on tight gas reservoirs 

    E-print Network

    Rodriguez, Cesar Alexander

    2005-02-17

    People in the oil and gas industry sometimes do not consider pressure-dependent permeability in reservoir performance calculations. It basically happens due to lack of lab data to determine level of dependency. This thesis ...

  6. Some modern notions on oil and gas reservoir production regulation

    SciTech Connect

    Lohrenz, J.; Monash, E.A.

    1980-05-21

    The historic rhetoric of oil and gas reservoir production regulations has been burdened with misconceptions. One was that most reservoirs are rate insensitive. Another was that a reservoir's decline is primarily a function of reservoir mechaism rather than a choice unconstrained by the laws of physics. Relieved of old notions like these, we introduce some modern notions, the most basic being that production regulation should have the purpose of obtaining the highest value from production per irreversible diminution of thermodynamically available energy. The laws of thermodynamics determine the available energy. What then is value. Value may include contributions other than production per se and purely monetary economic outcomes.

  7. Analyzing aquifers associated with gas reservoirs using aquifer influence functions

    E-print Network

    Targac, Gary Wayne

    1988-01-01

    ANALYZING AQUIFERS ASSOCIATED WITH GAS RESERVOIRS USING AQUIFER INFLUENCE FUNCTIONS A Thesis by GARY WAYNE TARGAC Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE V z May 1988 z V z z I- Major Subject: Petroleum Engineering ANALYZING AQUIFERS ASSOCIATED WITH GAS RESERVOIRS USING AQUIFER INFLUENCE FUNCTIONS A Thesis by GARY WAYNE TARGAC Approved as to style and content by: (Chair of Committ R...

  8. Gas reservoir identification by seismic AVO attributes on fluid substitution

    NASA Astrophysics Data System (ADS)

    Li, Jing-Ye

    2012-06-01

    Traditionally, fluid substitutions are often conducted on log data for calculating reservoir elastic properties with different pore fluids. Their corresponding seismic responses are computed by seismic forward modeling for direct gas reservoir identification. The workflow provides us with the information about reservoir and seismic but just at the well. For real reservoirs, the reservoir parameters such as porosity, clay content, and thickness vary with location. So the information from traditional fluid substitution just at the well is limited. By assuming a rock physics model linking the elastic properties to porosity and mineralogy, we conducted seismic forward modeling and AVO attributes computation on a three-layer earth model with varying porosity, clay content, and formation thickness. Then we analyzed the relations between AVO attributes at wet reservoirs and those at the same but gas reservoirs. We arrived at their linear relations within the assumption framework used in the forward modeling. Their linear relations make it possible to directly conduct fluid substitution on seismic AVO attributes. Finally, we applied these linear relations for fluid substitution on seismic data and identified gas reservoirs by the cross-plot between the AVO attributes from seismic data and those from seismic data after direct fluid substitution.

  9. Naturally fractured tight gas reservoir detection optimization

    SciTech Connect

    NONE

    1998-11-30

    The work plan for October 1, 1997 to September 30, 1998 consisted of investigation of a number of topical areas. These topical areas were reported in four quarterly status reports, which were submitted to DOE earlier. These topical areas are reviewed in this volume. The topical areas covered during the year were: (1) Development of preliminary tests of a production method for determining areas of natural fracturing. Advanced Resources has demonstrated that such a relationship exists in the southern Piceance basin tight gas play. Natural fracture clusters are genetically related to stress concentrations (also called stress perturbations) associated with local deformation such a faulting. The mechanical explanation of this phenomenon is that deformation generally initiates at regions where the local stress field is elevated beyond the regional. (2) Regional structural and geologic analysis of the Greater Green River Basin (GGRB). Application of techniques developed and demonstrated during earlier phases of the project for sweet-spot delineation were demonstrated in a relatively new and underexplored play: tight gas from continuous-typeUpper Cretaceous reservoirs of the Greater Green River Basin (GGRB). The effort included data acquisition/processing, base map generation, geophysical and remote sensing analysis and the integration of these data and analyses. (3) Examination of the Table Rock field area in the northern Washakie Basin of the Greater Green River Basin. This effort was performed in support of Union Pacific Resources- and DOE-planned horizontal drilling efforts. The effort comprised acquisition of necessary seismic data and depth-conversion, mapping of major fault geometry, and analysis of displacement vectors, and the development of the natural fracture prediction. (4) Greater Green River Basin Partitioning. Building on fundamental fracture characterization work and prior work performed under this contract, namely structural analysis using satellite and potential field data, the GGRB was divided into partitions that will be used to analyze the resource potential of the Frontier and Mesaverde Upper Cretaceous tight gas play. A total of 20 partitions were developed, which will be instrumental for examining the Upper Cretaceous play potential. (5) Partition Analysis. Resource assessment associated with individual partitions was initiated starting with the Vermilion Sub-basin and the Green River Deep (which include the Stratos well) partitions (see Chapter 5). (6) Technology Transfer. Tech transfer was achieved by documenting our research and presenting it at various conferences.

  10. Gas content of Gladys McCall reservoir brine

    SciTech Connect

    Hayden, C.G.; Randolph, P.L.

    1987-05-29

    On October 8, 1983, after the first full day of production from Sand No.8 in the Gladys McCall well, samples of separator gas and separator brine were collected for laboratory P-V-T (pressure, volume, temperature) studies. Recombination of amounts of these samples based upon measured rates at the time of sample collection, and at reservoir temperature (290 F), revealed a bubble point pressure of 9200 psia. This is substantially below the reported reservoir pressure of 12,783 psia. The gas content of the recombined fluids was 30.19 SCF of dry gas/STB of brine. In contrast, laboratory studies indicate that 35.84 SCF of pure methane would dissolve in each STB of 95,000 mg/L sodium chloride brine. These results indicate that the reservoir brine was not saturated with natural gas. By early April, 1987, production of roughly 25 million barrels of brine had reduced calculated flowing bottomhole pressure to about 6600 psia at a brine rate of 22,000 STB/D. If the skin factor(s) were as high as 20, flowing pressure drop across the skin would still be only about 500 psi. Thus, some portion of the reservoir volume was believed to have been drawn down to below the bubble point deduced from the laboratory recombination of separator samples. When the pressure in a geopressured geothermal reservoir is reduced to below the bubble point pressure for solution gas, gas is exsolved from the brine flowing through the pores in the reservoir rock. This exsolved gas is trapped in the reservoir until the fractional gas saturation of pore volume becomes large enough for gas flow to commence through a continuous gas-filled channel. At the same time, the gas/brine ratio becomes smaller and the chemistry of the remaining solution gas changes for the brine from which gas is exsolved. A careful search was made for the changes in gas/brine ratio or solution gas chemistry that would accompany pressure dropping below the bubble point pressure. Changes of about the same magnitude as the scatter in the data appear to have occurred in mid-1985 when calculated flowing bottomhole pressure was in the range of 9400 to 9700 psi. After the amount of brine flowing through the rock near to the wellbore has exsolved enough gas for onset of gas mobility through a continuous gas-filled channel, another test for whether the reservoir is below its bubble point becomes possible. This ''bubble test'' consists of suddenly increasing flow rate so that bottomhole pressure drops. Gas expansion then results in a small portion of the free gas from near the wellbore being produced in a short period of time. The resulting ''bubble'' of gas has a higher natural gas liquids content than gas produced before and after the transient. ''Bubble tests'' were performed in February 1986 and April 1987. Neither test liberated enough additional gas to provide a detectable change in produced gas/brine ratio. However, observed small transients in Ethane/Methane and Propane/Methane ratios indicate that some free gas was produced from the near wellbore region. These results suggest that the bubble point pressure must have been in the vicinity of the calculated 9500 psi flowing bottomhole pressure during the second of 1985. They conclude that: (1) Sand No.8 in the Gladys McCall well was not saturated with natural gas at the reported initial reservoir pressure of 12,873 psia; (2) flowing bottomhole pressure became less than the bubble point pressure during 1985; and (3) bubble point pressure was in the range of 9200 to 10,000 psi.

  11. Microbial Life in an Underground Gas Storage Reservoir

    NASA Astrophysics Data System (ADS)

    Bombach, Petra; van Almsick, Tobias; Richnow, Hans H.; Zenner, Matthias; Krüger, Martin

    2015-04-01

    While underground gas storage is technically well established for decades, the presence and activity of microorganisms in underground gas reservoirs have still hardly been explored today. Microbial life in underground gas reservoirs is controlled by moderate to high temperatures, elevated pressures, the availability of essential inorganic nutrients, and the availability of appropriate chemical energy sources. Microbial activity may affect the geochemical conditions and the gas composition in an underground reservoir by selective removal of anorganic and organic components from the stored gas and the formation water as well as by generation of metabolic products. From an economic point of view, microbial activities can lead to a loss of stored gas accompanied by a pressure decline in the reservoir, damage of technical equipment by biocorrosion, clogging processes through precipitates and biomass accumulation, and reservoir souring due to a deterioration of the gas quality. We present here results from molecular and cultivation-based methods to characterize microbial communities inhabiting a porous rock gas storage reservoir located in Southern Germany. Four reservoir water samples were obtained from three different geological horizons characterized by an ambient reservoir temperature of about 45 °C and an ambient reservoir pressure of about 92 bar at the time of sampling. A complementary water sample was taken at a water production well completed in a respective horizon but located outside the gas storage reservoir. Microbial community analysis by Illumina Sequencing of bacterial and archaeal 16S rRNA genes indicated the presence of phylogenetically diverse microbial communities of high compositional heterogeneity. In three out of four samples originating from the reservoir, the majority of bacterial sequences affiliated with members of the genera Eubacterium, Acetobacterium and Sporobacterium within Clostridiales, known for their fermenting capabilities. In contrast, bacteria belonging to Enterobacteriaceae were the most frequently encountered species in the sample from the water production well. Furthermore, bacterial sequences belonging to thermophiles within the family Thermotogaceae were found in all samples investigated. Archaeal community analysis revealed the dominance of methanogens clustering with members of Methanosarcinaceae, Methanomicrobiaceae and Methanobacteriaceae in three reservoir samples and the sample from the water production well. Cultivations of water samples under an atmosphere of storage gas blended by hydrogen as electron source at in situ-like conditions (45°C, 92 bar, p(H2) = 6 bar) revealed that hydrogen was quickly consumed in all laboratory microcosms with reservoir samples. Quantitative PCR analysis of the gene encoding for methyl-coenzyme M reductase (mcrA) along with reaction educt and product analyses suggested that methanogenesis was primarily responsible for hydrogen consumption during the experiments. While it is currently in question whether or not the laboratory data can be upscaled to actual reservoir conditions, they may allude to fermenting and thermophilic bacteria playing an important role for the investigated reservoir microbiology and also indicate potential stimulation of hydrogenotrophic methanogens if hydrogen would be introduced into the reservoir.

  12. Geological controls on coalbed methane reservoir capacity and gas content

    Microsoft Academic Search

    R. M Bustin; C. R Clarkson

    1998-01-01

    The influence of coal composition and rank on coalbed methane reservoir capacity, gas content and gas saturation have been investigated for a series of Australian, Canadian and United States coals. Globally there is no or little correlation between coal rank and methane adsorption capacity (as commonly assumed), although in particular basins there are general trends with rank and composition. Micropore1Micropores

  13. Efficient computation of the compositional model for gas condensate reservoirs

    NASA Astrophysics Data System (ADS)

    Zhou, Jifu; Li, Jiachun; Ye, Jigen

    2000-12-01

    In this paper, a direct method, unsymmetric-pattern multifrontal factorization, for a large sparse system of linear equations is applied in the compositional reservoir model. The good performances of this approach are shown by solving the Poisson equation. And then the numerical module is embedded in the compositional model for simulating X1/5 (3) gas condensate reservoir in KeKeYa gas field, Northwest China. The results of oil/gas reserves, variations of stratum pressure and oil/gas production, etc. are compared with the observation. Good agreement comparable to COMP4 model is achieved, suggesting that the present model is both efficient and powerful in compositional reservoir simulations.

  14. Altering Wettability in Gas Condensate Sandstone Reservoirs for Gas Mobillity Improvement

    E-print Network

    Fernandez Martinez, Ruth Gabriela

    2012-07-16

    In gas-condensate reservoirs, production rate starts to decrease when retrograde condensation occurs. As the bottomhole pressure drops below the dewpoint, gascondensate and water buildup impede flow of gas to the surface. To stop the impairment...

  15. Geotechnology for low-permeability gas reservoirs, 1995

    SciTech Connect

    Brown, S.; Harstad, H.; Lorenz, J.; Warpinski, N.; Boneau, T.; Holcomb, D.; Teufel, L.; Young, C. [Sandia National Labs., Albuquerque, NM (United States). Geomechanics Dept.

    1995-06-01

    The permeability, and thus the economics, of tight reservoirs are largely dependent on natural fractures, and on the in situ stresses that both originated fractures and control subsequent fracture permeability. Natural fracture permeability ultimately determines the gas (or oil) producibility from the rock matrix. Therefore, it is desirable to be able to predict, both prior to drilling and during reservoir production, (1) the natural fracture characteristics, (2) the mechanical and transport properties of fractures and the surrounding rock matrix, and (3) the present in situ stress magnitudes and orientations. The combination of activities described in this report extends the earlier work to other Rocky Mountain gas reservoirs. Additionally, it extends the fracture characterizations to attempts of crosswell geophysical fracture detection using shear wave birefringence and to obtaining detailed quantitative models of natural fracture systems for use in improved numerical reservoir simulations. Finally, the project continues collaborative efforts to evaluate and advance cost-effective methods for in situ stress measurements on core.

  16. Characterization of oil and gas reservoir heterogeneity

    SciTech Connect

    Tyler, N.; Barton, M.D.; Bebout, D.G.; Fisher, R.S.; Grigsby, J.D.; Guevara, E.; Holtz, M.; Kerans, C.; Nance, H.S.; Levey, R.A.

    1992-10-01

    Research described In this report addresses the internal architecture of two specific reservoir types: restricted-platform carbonates and fluvial-deltaic sandstones. Together, these two reservoir types contain more than two-thirds of the unrecovered mobile oil remaining ill Texas. The approach followed in this study was to develop a strong understanding of the styles of heterogeneity of these reservoir types based on a detailed outcrop description and a translation of these findings into optimized recovery strategies in select subsurface analogs. Research targeted Grayburg Formation restricted-platform carbonate outcrops along the Algerita Escarpment and In Stone Canyon In southeastern New Mexico and Ferron deltaic sandstones in central Utah as analogs for the North Foster (Grayburg) and Lake Creek (Wilcox) units, respectively. In both settings, sequence-stratigraphic style profoundly influenced between-well architectural fabric and permeability structure. It is concluded that reservoirs of different depositional origins can therefore be categorized Into a heterogeneity matrix'' based on varying intensity of vertical and lateral heterogeneity. The utility of the matrix is that it allows prediction of the nature and location of remaining mobile oil. Highly stratified reservoirs such as the Grayburg, for example, will contain a large proportion of vertically bypassed oil; thus, an appropriate recovery strategy will be waterflood optimization and profile modification. Laterally heterogeneous reservoirs such as deltaic distributary systems would benefit from targeted infill drilling (possibly with horizontal wells) and improved areal sweep efficiency. Potential for advanced recovery of remaining mobile oil through heterogeneity-based advanced secondary recovery strategies In Texas is projected to be an Incremental 16 Bbbl. In the Lower 48 States this target may be as much as 45 Bbbl at low to moderate oil prices over the near- to mid-term.

  17. Analysis of condensate banking dynamics in a gas condensate reservoir under different injection schemes 

    E-print Network

    Sandoval Rodriguez, Angelica Patricia

    2002-01-01

    If the reservoir pressure falls below the dewpoint pressure when producing a gas condensate reservoir, liquid dropout takes place in the reservoir. Liquid builds up in the near wellbore area causing what is known as a ...

  18. Horizontal wells enhance development of thin offshore gas reservoirs

    SciTech Connect

    Gidman, B. [Chevron USA, Lafayette, LA (United States); Hammons, L.R.B.; Paulk, M.D. [Baker Hughes INTEQ, Lafayette, LA (United States)

    1995-03-01

    Horizontal wells in clastic rocks can reduce water coning problems and increase production rates as much as six-fold. They are now practical to drill for developing Gulf of Mexico gas reservoirs that may be less than 10 ft thick. In 1991, Chevron USA began exploring the feasibility of developing thin gas reservoirs in western Gulf of Mexico (GOM) fields. A critical element that needed to be addressed was the minimum target thickness that is geologically and operationally practical to drill with current horizontal well technology. Chevron`s first GOM horizontal well spudded in February 1992. The target was 31 ft of net effective gas on water in a massive Pleistocene sand at 1,700 ft TVD. Chevron spudded a second horizontal well in the same field during June 1993. This well was geosteered into a 19-ft gas sand with no immediate water contact at 1,650 ft TVD. The entire 1,000-ft horizontal section was interpreted as gas from the MWD tool response. A spinner survey was not run in this hole. At 19 MMcfd of gas, this well also proved to be a major economic success because of its low cost. After the second completion, Chevron`s next proposed well targeted a gas reservoir with a maximum thickness of only 7 ft.

  19. Prediction of Gas Injection Performance for Heterogeneous Reservoirs

    SciTech Connect

    Blunt, Martin J.; Orr, Jr., Franklin M.

    1999-12-20

    This report describes research carried out in the Department of Petroleum Engineering at Stanford University from September 1998 - September 1998 under the third year of a three-year Department of Energy (DOE) grant on the ''Prediction of Gas Injection Performance for Heterogeneous Reservoirs''. The research effort is an integrated study of the factors affecting gas injection, from the pore scale to the field scale, and involves theoretical analysis, laboratory experiments and numerical simulation. The research is divided into four main areas: (1) Pore scale modeling of three-phase flow in porous media; (2) Laboratory experiments and analysis of factors influencing gas injection performance at the core scale with an emphasis on the fundamentals of three-phase flow; (3) Benchmark simulations of gas injection at the field scale; and (4) Development of streamline-based reservoir simulator.

  20. Insights Into Natural Gas Production From Low-Permeability Reservoirs

    Microsoft Academic Search

    D. A. Northrop

    1988-01-01

    Insights have been gained into natural gas production from low permeability sandstone reservoirs in the western United States as a result of the US Department of Energy's Multiwell Experiment (MWX). Three wells, between 110 and 215 ft (34-66 m) apart at depth have been drilled at a site southwest of Rifle, Colorado, in the Piceance Basin, where the Cretaceous-age Mesaverde

  1. Gas Hydrate Reservoir Characterization Using Converted Waves

    NASA Astrophysics Data System (ADS)

    Bünz, S.; Mienert, J.; Berndt, C.

    Geophysical evidence exists for gas hydrates along the northern sidewall of the Storegga Slide. A BSR reflects the base of the Gas Hydrate Stability Zone (GHSZ), and the free gas zone beneath it. Gas hydrates exist outside and inside the slide area of the Storegga Slide. Ocean Bottom Seismometer, Ocean Bottom Cable and geotechni- cal borehole data allow to assess the elastic properties of hydrated and gassy sediments in an integrated approach. The P-S data evaluation requires a special processing pro- cedure, which involves two different approaches to determine the Vp/Vs-ratio and the shear-wave velocity of the sediments. The compressional-wave velocity shows a distinctive increase just above the BSR and a low-velocity zone below the BSR. We in- terpret these zones to be caused by hydrated and gas-charged sediments, respectively. Another low-velocity zone occurs at about 250 m below the BSR, at the base of the Naust Formation. This is the upper termination of a polygonal fault system and the base of a fluid leakage system in the area. The magnitude of the velocity decrease, i.e. 200 U 300 m/s, is caused by free gas. The Vp/Vs-ratio decreases through the whole sediment column from 7 for the uppermost sediments to 5 at the depth of the BSR. It shows a positive deviation from its downward decreasing trend associated with the p-wave low-velocity zone just below the BSR. This indicates the occurrence of gas underneath the hydrates. Further downward, the Vp/Vs-ratio continues to decrease to values of about 3 at a depth of 600 m below seafloor. The second gas-charged layer at about 500 m depth is not detected by the shear waves. One of the premier applications in offshore industry of recording shear waves is to image through gas clouds. Whereas shear waves behave exemplary for the lower gas-charged layer in our case, they do not so for the gas that occurs beneath the BSR. It is therefore concluded that the decrease in shear-wave velocity is caused by overpressure of gas that is trapped underneath the hydrates. Such overpressure would reduce the effective stress and grain coupling leading to low shear modulus and low shear-wave velocity.

  2. Calculation of hydrocarbon-in-place in gas and gas-condensate reservoirs - Carbon dioxide sequestration

    USGS Publications Warehouse

    Verma, Mahendra K.

    2012-01-01

    The Energy Independence and Security Act of 2007 (Public Law 110-140) authorized the U.S. Geological Survey (USGS) to conduct a national assessment of geologic storage resources for carbon dioxide (CO2), requiring estimation of hydrocarbon-in-place volumes and formation volume factors for all the oil, gas, and gas-condensate reservoirs within the U.S. sedimentary basins. The procedures to calculate in-place volumes for oil and gas reservoirs have already been presented by Verma and Bird (2005) to help with the USGS assessment of the undiscovered resources in the National Petroleum Reserve, Alaska, but there is no straightforward procedure available for calculating in-place volumes for gas-condensate reservoirs for the carbon sequestration project. The objective of the present study is to propose a simple procedure for calculating the hydrocarbon-in-place volume of a condensate reservoir to help estimate the hydrocarbon pore volume for potential CO2 sequestration.

  3. Predicting horizontal well performance in solution-gas drive reservoirs 

    E-print Network

    Plahn, Sheldon Von

    1986-01-01

    . Capillary pres ure is ignored 15 7. The reservoir mechanisms are solution-gas drive and gravity drainage. 8. The reservoir pressure is initially at the bubble-point. Assumption 2 is illustrated in Figure 6. t D t The input data that was used...! production by gravity drainage was greatly improved Acceleration of Oil Recover with Hoi izontal Wells The productivity of a vertical well is proportional to the product cf the formation permeability and the net pay thickness exposed to the wel...

  4. 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.

  5. Earthquakes and depleted gas reservoirs: which comes first?

    NASA Astrophysics Data System (ADS)

    Mucciarelli, M.; Donda, F.; Valensise, G.

    2014-12-01

    While scientists are paying increasing attention to the seismicity potentially induced by hydrocarbon exploitation, little is known about the reverse problem, i.e. the impact of active faulting and earthquakes on hydrocarbon reservoirs. The recent 2012 earthquakes in Emilia, Italy, raised concerns among the public for being possibly human-induced, but also shed light on the possible use of gas wells as a marker of the seismogenic potential of an active fold-and-thrust belt. Based on the analysis of over 400 borehole datasets from wells drilled along the Ferrara-Romagna Arc, a large oil and gas reserve in the southeastern Po Plain, we found that the 2012 earthquakes occurred within a cluster of sterile wells surrounded by productive ones. Since the geology of the productive and sterile areas is quite similar, we suggest that past earthquakes caused the loss of all natural gas from the potential reservoirs lying above their causative faults. Our findings have two important practical implications: (1) they may allow major seismogenic zones to be identified in areas of sparse seismicity, and (2) suggest that gas should be stored in exploited reservoirs rather than in sterile hydrocarbon traps or aquifers as this is likely to reduce the hazard of triggering significant earthquakes.

  6. Fluid and heat flow in gas-rich geothermal reservoirs

    SciTech Connect

    O'Sullivan, M.J.; Bodvarsson, G.S.; Pruess, K.; Blakeley, M.R.

    1983-07-01

    Numerical-simulation techniques are used to study the effects of noncondensible gases (CO/sub 2/) on geothermal reservoir behavior in the natural state and during exploitation. It is shown that the presence of CO/sub 2/ has large effects on the thermodynamic conditions of a reservoir in the natural state, especially on temperature distributions and phase compositions. The gas will expand two-phase zones and increase gas saturations to enable flow of CO/sub 2/ through the system. During exploitation, the early pressure drop is primarily due to degassing of the system. This process can cause a very rapid initial pressure drop, on the order of tens of bars, depending upon the initial partial pressure of CO/sub 2/. The following gas content from wells can provide information on in-place gas saturations and relative permeability curves that apply at a given geothermal resource. Site-specific studies are made for the gas-rich two-phase reservoir at the Ohaki geothermal field in New Zealand. A simple lumped-parameter model and a vertical column model are applied to the field data. The results obtained agree well with the natural thermodynamic state of the Ohaki field (pressure and temperature profiles) and a partial pressure of 15 to 25 bars is calculated in the primary reservoirs. The models also agree reasonably well with field data obtained during exploitation of the field. The treatment of thermophysical properties of H/sub 2/O-CO/sub 2/ mixtures for different phase compositions is summarized.

  7. Naturally fractured tight gas reservoir detection optimization

    SciTech Connect

    NONE

    1999-04-30

    In March, work continued on characterizing probabilities for determining natural fracturing associated with the GGRB for the Upper Cretaceous tight gas plays. Structural complexity, based on potential field data and remote sensing data was completed. A resource estimate for the Frontier and Mesa Verde play was also completed. Further, work was also conducted to determine threshold economics for the play based on limited current production in the plays in the Wamsutter Ridge area. These analyses culminated in a presentation at FETC on 24 March 1999 where quantified natural fracture domains, mapped on a partition basis, which establish ''sweet spot'' probability for natural fracturing, were reviewed. That presentation is reproduced here as Appendix 1. The work plan for the quarter of January 1, 1999--March 31, 1999 comprised five tasks: (1) Evaluation of the GGRB partitions for structural complexity that can be associated with natural fractures, (2) Continued resource analysis of the balance of the partitions to determine areas with higher relative gas richness, (3) Gas field studies, (4) Threshold resource economics to determine which partitions would be the most prospective, and (5) Examination of the area around the Table Rock 4H well.

  8. Analysis of a geopressured gas reservoir using solution plot method

    E-print Network

    Hussain, Syed Muqeedul

    1992-01-01

    dependent formation compressibility and water influx require extensive study of the reservoir core samples and aquifer characteristics that are not commonly conducted. Poston and Chen solved this problem by re-arranging the material balance equation... such that the input variables are the readily available pressure and production data. The output of the resulting plot, known as the Solution plot, is the original gas in place, effective compressibility and possibly water influx history. The early time data from a...

  9. Performance of fractured horizontal well with stimulated reservoir volume in unconventional gas reservoir

    NASA Astrophysics Data System (ADS)

    Zhao, Yu-Long; Zhang, Lie-Hui; Luo, Jian-Xin; Zhang, Bo-Ning

    2014-05-01

    This paper extended the conventional multiple hydraulic fractured horizontal (MFH) well into a composite model to describe the stimulated reservoir volume (SRV) caused by hydraulic fracturing. Employing the Laplace transform, Source function, and Dirac delta function methods, the continuous linear source function for general composite dual-porosity is derived, and the solution of the MFH well in a composite gas reservoir is obtained with the numerical discrete method. Through the Stehfest numerical algorithm and Gauss elimination method, the transient pressure responses for well producing at a constant production rate and the production rate vs. time for constant bottomhole pressure are analyzed. The effects of related parameters such as natural permeability and radial of the SRV region, formation permeability and interporosity coefficient on transient pressure and production performance are analyzed as well. The presented model and obtained results in this paper not only enrich the well testing models of such unconventional reservoir, but also can use to interpret on-site data which have significance on efficient reservoir development.

  10. Characterization of the deep microbial life in the Altmark natural gas reservoir

    Microsoft Academic Search

    D. Morozova; M. Alawi; A. Vieth-Hillebrand; D. Kock; M. Krüger; H. Wuerdemann

    2010-01-01

    Within the framework of the CLEAN project (CO2 Largescale Enhanced gas recovery in the Altmark Natural gas field) technical basics with special emphasis on process monitoring are explored by injecting CO2 into a gas reservoir. Our study focuses on the investigation of the in-situ microbial community of the Rotliegend natural gas reservoir in the Altmark, located south of the city

  11. Prediction of Gas Injection Performance for Heterogeneous Reservoirs

    SciTech Connect

    Franklin M. Orr, Jr; Martin J. Blunt

    1998-03-31

    This project performs research in four main areas: laboratory experiments to measure three-phase relative permeability; network modeling to predict three-phase relative perme- ability; benchmark simulations of gas injection and waterfl ooding at the field scale; and the development of fast streamline techniques to study field-scale oil. The aim of the work is to achieve a comprehensive description of gas injection processes from the pore to the core to the reservoir scale. In this report we provide a detailed description of our measurements of three-phase relative permeability.

  12. The performance of a volatile oil reservoir overlain by a gas cap 

    E-print Network

    Ellis, Joseph Ralph, Jr

    1960-01-01

    for liquid, gas and their relationships such as gas-oil ratio, gravities, etc. DISCUSSION OF RESULTS Initially two methods of treating equilibrium relations between reservoir fluids of a gas cap overlying a volatile oil reservoir were decided upon...THE PERFORMANCE OF A VOLATILE OIL RESERVOIR OVERLAIN BY A GAS CAP A Thesis By J. RALPH ELLIS, JR. Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements for the degree...

  13. Modeling of performance behavior in gas condensate reservoirs using a variable mobility concept 

    E-print Network

    Wilson, Benton Wade

    2004-09-30

    used for the analysis of well test data from gas condensate reservoirs consider the radial composite reservoir model, which utilizes a "step change" in permeability at some radial distance away from the wellbore. Using our proposed solution we can...

  14. Fracture Modeling and Flow Behavior in Shale Gas Reservoirs Using Discrete Fracture Networks 

    E-print Network

    Ogbechie, Joachim Nwabunwanne

    2012-02-14

    Gen and NFflow) for fracture modeling of a shale gas reservoir and also studies the interaction of the different fracture properties on reservoir response. The most important results of the study are that a uniform fracture network distribution and fracture...

  15. Reservoir and stimulation analysis of a Devonian shale gas field

    SciTech Connect

    Shaw, J.S.; Gatens, J.M. III (Eastern Reservoir Services, Kingsport, TN (US)); Lancaster, D.E. (S.A. Holditch and Associates (US)); Terry, D.P. (Equitable Resources Exploration Inc. (US)); Lee, W.J. (Petroleum Engineering at Texas A and M Univ. (US)); Avary, K.L. (West Virginia Geological and Economics Survey (US))

    1989-11-01

    This paper presents a study of a shallow, low-productivity Devonian shale gas field consisting of 48 wells in Mason County, WV. Gas production from wells in the field was found to be associated with zones of substantial free-gas porosity in the presence of high kerogen (organic) content. Most wells are poor producers; the best wells are located in the northwest portion of the field, which corresponds to an area of natural fracturing identified by remote sensing imagery. The authors identified and mapped quality reservoir areas and predicted performance for all wells in the field. The stimulation treatments conducted on all wells in the field successfully initiated gas production from the shales, but these treatments generally failed to achieve the degree of stimulation expected from such jobs.

  16. Prediction of Gas Injection Performance for Heterogeneous Reservoirs

    SciTech Connect

    Blunt, Martin J.; Orr, Franklin M.

    1999-05-17

    This report describes research carried out in the Department of Petroleum Engineering at Stanford University from September 1997 - September 1998 under the second year of a three-year grant from the Department of Energy on the "Prediction of Gas Injection Performance for Heterogeneous Reservoirs." The research effort is an integrated study of the factors affecting gas injection, from the pore scale to the field scale, and involves theoretical analysis, laboratory experiments, and numerical simulation. The original proposal described research in four areas: (1) Pore scale modeling of three phase flow in porous media; (2) Laboratory experiments and analysis of factors influencing gas injection performance at the core scale with an emphasis on the fundamentals of three phase flow; (3) Benchmark simulations of gas injection at the field scale; and (4) Development of streamline-based reservoir simulator. Each state of the research is planned to provide input and insight into the next stage, such that at the end we should have an integrated understanding of the key factors affecting field scale displacements.

  17. Prediction of Gas Injection Performance for Heterogeneous Reservoirs

    SciTech Connect

    Blunt, Michael J.; Orr, Franklin M.

    1999-05-26

    This report describes research carried out in the Department of Petroleum Engineering at Stanford University from September 1996 - September 1997 under the first year of a three-year Department of Energy grant on the Prediction of Gas Injection Performance for Heterogeneous Reservoirs. The research effort is an integrated study of the factors affecting gas injection, from the pore scale to the field scale, and involves theoretical analysis, laboratory experiments and numerical simulation. The original proposal described research in four main areas; (1) Pore scale modeling of three phase flow in porous media; (2) Laboratory experiments and analysis of factors influencing gas injection performance at the core scale with an emphasis on the fundamentals of three phase flow; (3) Benchmark simulations of gas injection at the field scale; and (4) Development of streamline-based reservoir simulator. Each stage of the research is planned to provide input and insight into the next stage, such that at the end we should have an integrated understanding of the key factors affecting field scale displacements.

  18. Evaluation of Travis Peak gas reservoirs, west margin of the East Texas Basin 

    E-print Network

    Li, Yamin

    2009-05-15

    Gas production from low-permeability (tight) gas sandstones is increasingly important in the USA as conventional gas reservoirs are being depleted, and its importance will increase worldwide in future decades. Travis Peak tight sandstones have...

  19. Modeling of performance behavior in gas condensate reservoirs using a variable mobility concept

    E-print Network

    Wilson, Benton Wade

    2004-09-30

    The proposed work provides a concept for predicting well performance behavior in a gas condensate reservoir using an empirical model for gas mobility. The proposed model predicts the behavior of the gas permeability (or mobility) function...

  20. Predicting gas, oil, and water intervals in Niger delta reservoirs using gas chromatography

    SciTech Connect

    Baskin, D.K.; Hwang, R.J. [Chevron Petroleum Technology Co., La Habra, CA (United States); Purdy, R.K. [Chevron Overseas Petroleum, Inc., San Ramon, CA (United States)

    1995-03-01

    Formation evaluation experts usually have little difficulty in interpreting wireline logs to assess the type of reservoir fluid (oil/gas/water) in sand-shale sequences. This assessment is usually accomplished by a combination neutron-density tool that detects low hydrogen and low electron densities typical of gas zones, and the repeat formation tester (RFT), which uses both the pressure gradient and sample acquisition techniques to evaluate reservoir fluid. In the Niger Delta, however, many of the sands exhibit a poor neutron-density response to gas, and RFT testing has been largely eliminated because poor hole conditions commonly result in stuck tools. Oil fingerprinting of residual hydrocarbons from sidewall core extracts can provide an independent means of identifying reservoir fluid type.

  1. SAGD PERFORMANCE IMPROVEMENT IN RESERVOIRS WITH HIGH SOLUTION GAS-OIL RATIO

    Microsoft Academic Search

    T. R. Ibatullin

    2009-01-01

    Paper addresses the issue of Steam Assisted Gravity Drainage (SAGD) performance in the reservoirs with various solution gas-oil ratios (GOR). Results of extensive reservoir simula- tion study show that during the steam injection gas comes out of solution and accumulates at the edge of the steam chamber. In cases of high methane content in the bitumen the effect of gas

  2. Gas injection with radioactive tracer to determine reservoir continuity, East Coalinga field, California

    Microsoft Academic Search

    Tinker

    1972-01-01

    The Temblor Zone II reservoir consists of intervals of movable oil associated with intervals of high gas saturation or desaturated intervals. Natural gas injection into these desaturated intervals, using tritium and krypton as radioactive tracers has served to determine reservoir continuity. In these example cases, the desaturated intervals contained nearly all carbon dioxide gas. The injection tests also have furnished

  3. Estimation of initial reservoir pressure in tight gas sands

    E-print Network

    Leach, Susan Ann

    1984-01-01

    ESTIMATION OF INITIAL RESERVOIR PRESSURE IN TIGHT GAS SANDS A Thesis by SUSAN ANN LEACH Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1984... pressure by hundreds of pounds per square inch. The estimate of initial pressure can be improved by using longer shut-in periods and by taking periodic pressure readings during the shut-in time. A Horner plot , (producing time + shut-in time...

  4. The effects of production rates and some reservoir parameters on recovery in a strong water drive gas reservoir 

    E-print Network

    Soemarso, Christophorus

    1978-01-01

    gas. Laboratory imbibition tests from cores indicated a residual gas saturation of 28. 7/. From a single field in situ residual gas measurement using a tracer technique conducted in 1974 a value of 25. 4/ residual gas saturation was obtained... of gravity drainage, and is defined as: ll KLA GRR = gaoslnn The nomenclature is given at the end of the paper. The expression of production rates in terms of GRR enables the results to be generalized with respect to reservoir parameters...

  5. Greenhouse gas emissions from reservoirs of the western United States

    NASA Astrophysics Data System (ADS)

    Soumis, Nicolas; Duchemin, ÉRic; Canuel, René; Lucotte, Marc

    2004-09-01

    Six reservoirs located in the Western United States (F. D. Roosevelt, Dworshak, Wallula, Shasta, Oroville, and New Melones) were sampled in order to estimate their greenhouse gas (GHG) emissions. Two types of fluxes were assessed: (1) diffusive fluxes of methane (CH4) and carbon dioxide (CO2) at the air/water interface and (2) degassing fluxes of CH4 and CO2 from water passing through the turbine spillways. Diffusive flux measurements indicated that the surface of the reservoirs were a source of CH4 during the sampling period (from +3.2 to +9.5 mg CH4 m-2 d-1). Oroville (+1026 mg CO2 m-2 d-1) and Shasta (+1247 mg CO2 m-2 d-1) surfaces were also sources of CO2. In contrast, the surface of all the other reservoirs constituted sinks for CO2 (from -349 to -1195 mg CO2 m-2 d-1). Degassing fluxes ranged from +0.003 to +0.815 t CH4 d-1, and from +16 to +324 t CO2 d-1. Daily GHG budgets ranged from +0.146 to +2.228 t CH4 d-1, and from -15 to +224 t CO2 d-1. Degassing fluxes represented an important term of these budgets. A significant correlation was observed between the magnitude of CO2 diffusive fluxes and the water pH (R2 = 0.81; p < 0.0001). All other correlations between GHG diffusive fluxes and independent variables tested were weak and/or not significant. Finally, while attempting to resolve the spatial variability in diffusive fluxes, we were able to cluster reservoirs neither according to geological nor ecological criteria.

  6. Analytical Estimation of CO2 Storage Capacity in Depleted Oil and Gas Reservoirs Based on Thermodynamic State Functions 

    E-print Network

    Valbuena Olivares, Ernesto

    2012-02-14

    to estimate the ultimate CO2 storage in depleted oil and gas reservoirs by implementing a volume constrained thermodynamic equation of state (EOS) using the reservoir?s average pressure and fluid composition. This method was implemented in an algorithm...

  7. Importance of Low Permeability Natural Gas Reservoirs (released in AEO2010)

    EIA Publications

    2010-01-01

    Production from low-permeability reservoirs, including shale gas and tight gas, has become a major source of domestic natural gas supply. In 2008, low-permeability reservoirs accounted for about 40% of natural gas production and about 35% of natural gas consumption in the United States. Permeability is a measure of the rate at which liquids and gases can move through rock. Low-permeability natural gas reservoirs encompass the shale, sandstone, and carbonate formations whose natural permeability is roughly 0.1 millidarcies or below. (Permeability is measured in darcies.)

  8. Optimizing recovery from a strong water-drive West Texas gas reservoir through integrated reservoir simulation studies

    SciTech Connect

    Hulme, J.R.; Colleary, W.M.; Van Kirk, C.W.

    1995-12-31

    This paper presents a field study funded by the Gas Research Institute (GRI) to determine reservoir management and production strategies to economically maximize recovery from the Vermejo/Moore-Hooper strong water-drive gas reservoir in West Texas. The reservoir is greater than 16,000 feet deep and contains high pressure sour gas, and it is composed of geologically complex fractured dolomite and chert. The water drive is exceptionally strong, the reservoir has experienced no more than 5 percent pressure depletion during its 20-year history, and late in life the field is beginning to re-pressurize. Detailed Engineering and Geologic studies were performed and reservoir simulation of the field tested the most effective methods to economically maximize recovery. The management strategies evaluated were comprised of various methods to maximize field productivity, reduce bottom-hole flowing pressure, improve the ability of the wellbore to unload water and reduce/retard aquifer influx. Specific strategies that were tested included the drilling of an infill well, placing the wells on compression, installation of coiled tubing, installation of gas lift, installation of an optimal tubing string, injection of a permeability barrier into the reservoir and de-pressuring the aquifer by downdip water production. It was concluded that the most economic method to deplete the field was to place the remaining wells on compression at 200 psia wellhead pressure and to install coiled tubing when the wells begin to experience water load-up problems. The gas-lift and optimal tubing cases predicted higher recoveries, but were economically less favorable. The methods tested to reduce aquifer influx to the reservoir actually decreased recovery of gas reserves. The study also identified the need for a multiphase flow correlation which fully handles the complexity involved with high water-gas-ratio systems (up to 10 stb/mscf).

  9. Atlas of Northern Gulf of Mexico Gas and Oil Reservoirs: Procedures and examples of resource distribution

    SciTech Connect

    Seni, S.J.; Finley, R.J.

    1995-06-01

    The objective of the program is to produce a reservoir atlas series of the Gulf of Mexico that (1) classifies and groups offshore oil and gas reservoirs into a series of geologically defined reservoir plays, (2) compiles comprehensive reservoir play information that includes descriptive and quantitative summaries of play characteristics, cumulative production, reserves, original oil and gas in place, and various other engineering and geologic data, (3) provides detailed summaries of representative type reservoirs for each play, and (4) organizes computerized tables of reservoir engineering data into a geographic information system (GIS). The primary product of the program will be an oil and gas atlas series of the offshore Northern Gulf of Mexico and a computerized geographical information system of geologic and engineering data linked to reservoir location.

  10. Advanced reservoir management for independent oil and gas producers

    SciTech Connect

    Sgro, A.G.; Kendall, R.P.; Kindel, J.M.; Webster, R.B.; Whitney, E.M.

    1996-11-01

    There are more than fifty-two hundred oil and gas producers operating in the United States today. Many of these companies have instituted improved oil recovery programs in some form, but very few have had access to state-of-the-art modeling technologies routinely used by major producers to manage these projects. Since independent operators are playing an increasingly important role in the production of hydrocarbons in the United States, it is important to promote state-of-the-art management practices, including the planning and monitoring of improved oil recovery projects, within this community. This is one of the goals of the Strategic Technologies Council, a special interest group of independent oil and gas producers. Reservoir management technologies have the potential to increase oil recovery while simultaneously reducing production costs. These technologies were pioneered by major producers and are routinely used by them. Independent producers confront two problems adopting this approach: the high cost of acquiring these technologies and the high cost of using them even if they were available. Effective use of reservoir management tools requires, in general, the services of a professional (geoscientist or engineer) who is already familiar with the details of setting up, running, and interpreting computer models.

  11. Advanced Hydraulic Fracturing Technology for Unconventional Tight Gas Reservoirs

    SciTech Connect

    Stephen Holditch; A. Daniel Hill; D. Zhu

    2007-06-19

    The objectives of this project are to develop and test new techniques for creating extensive, conductive hydraulic fractures in unconventional tight gas reservoirs by statistically assessing the productivity achieved in hundreds of field treatments with a variety of current fracturing practices ranging from 'water fracs' to conventional gel fracture treatments; by laboratory measurements of the conductivity created with high rate proppant fracturing using an entirely new conductivity test - the 'dynamic fracture conductivity test'; and by developing design models to implement the optimal fracture treatments determined from the field assessment and the laboratory measurements. One of the tasks of this project is to create an 'advisor' or expert system for completion, production and stimulation of tight gas reservoirs. A central part of this study is an extensive survey of the productivity of hundreds of tight gas wells that have been hydraulically fractured. We have been doing an extensive literature search of the SPE eLibrary, DOE, Gas Technology Institute (GTI), Bureau of Economic Geology and IHS Energy, for publicly available technical reports about procedures of drilling, completion and production of the tight gas wells. We have downloaded numerous papers and read and summarized the information to build a database that will contain field treatment data, organized by geographic location, and hydraulic fracture treatment design data, organized by the treatment type. We have conducted experimental study on 'dynamic fracture conductivity' created when proppant slurries are pumped into hydraulic fractures in tight gas sands. Unlike conventional fracture conductivity tests in which proppant is loaded into the fracture artificially; we pump proppant/frac fluid slurries into a fracture cell, dynamically placing the proppant just as it occurs in the field. From such tests, we expect to gain new insights into some of the critical issues in tight gas fracturing, in particular the roles of gel damage, polymer loading (water-frac versus gel frac), and proppant concentration on the created fracture conductivity. To achieve this objective, we have designed the experimental apparatus to conduct the dynamic fracture conductivity tests. The experimental apparatus has been built and some preliminary tests have been conducted to test the apparatus.

  12. A Modified Genetic Algorithm Applied to Horizontal Well Placement Optimization in Gas Condensate Reservoirs

    E-print Network

    Morales, Adrian

    2011-02-22

    A MODIFIED GENETIC ALGORITHM APPLIED TO HORIZONTAL WELL PLACEMENT OPTIMIZATION IN GAS CONDENSATE RESERVOIRS A Thesis by ADRIAN NICOLAS MORALES Submitted to the Office of Graduate Studies of Texas A&M University in partial... Condensate Reservoirs Copyright 2010 Adrian Nicolas Morales A MODIFIED GENETIC ALGORITHM APPLIED TO HORIZONTAL WELL PLACEMENT OPTIMIZATION IN GAS CONDENSATE RESERVOIRS A Thesis by ADRIAN NICOLAS MORALES Submitted to the Office of Graduate...

  13. A Modified Genetic Algorithm Applied to Horizontal Well Placement Optimization in Gas Condensate Reservoirs 

    E-print Network

    Morales, Adrian

    2011-02-22

    A MODIFIED GENETIC ALGORITHM APPLIED TO HORIZONTAL WELL PLACEMENT OPTIMIZATION IN GAS CONDENSATE RESERVOIRS A Thesis by ADRIAN NICOLAS MORALES Submitted to the Office of Graduate Studies of Texas A&M University in partial... Condensate Reservoirs Copyright 2010 Adrian Nicolas Morales A MODIFIED GENETIC ALGORITHM APPLIED TO HORIZONTAL WELL PLACEMENT OPTIMIZATION IN GAS CONDENSATE RESERVOIRS A Thesis by ADRIAN NICOLAS MORALES Submitted to the Office of Graduate...

  14. Effect of the reservoir size on gas adsorption in inhomogeneous porous media E. Kierlik,1

    E-print Network

    Paris-Sud XI, Université de

    Effect of the reservoir size on gas adsorption in inhomogeneous porous media E. Kierlik,1 J characterized by many local minima, i.e. metastable states.[2, 3, 4] The above picture of gas adsorption: September 12, 2008) We study the influence of the relative size of the reservoir on the adsorption isotherms

  15. An Advisory System For Selecting Drilling Technologies and Methods in Tight Gas Reservoirs 

    E-print Network

    Pilisi, Nicolas

    2010-01-16

    , to extract the same amount of natural gas out of the reservoir, many more wells will have to be drilled and stimulated to efficiently develop and produce these reservoirs. Thus, the risk involved is much higher than the development of conventional gas...

  16. Gas atomized chemical reservoir ODS ferritic stainless steels

    SciTech Connect

    Rieken, J.R.; Anderson, I.E.; Kramer, M.J.

    2010-06-27

    Gas atomization reaction synthesis was used to surface oxidize ferritic stainless steel powders (i.e., Fe-16.0Cr-(0.1-0.2)Y-(0.1-0.5)(Ti or Hf) at.%) during the primary break-up and solidification of the molten alloy. This rapid surface reaction resulted in envelopment of the powders by an ultra thin (i.e., t < 100nm) metastable Cr-enriched oxide shell. This metastable oxide phase was subsequently dissociated, and used as an oxygen reservoir for the formation of more thermodynamically favored Y-(Ti,Hf) nano-metric oxide precipitates during elevated temperature heat treatment of the as-consolidated powders. This oxygen exchange reaction promoted the formation of nano-metric oxide dispersoids throughout the alloy microstructure. The atomization processing parameters were adjusted to tailor the oxygen content in as-atomized powders. Microstructure phase analysis was completed using transmission electron microscopy and X-ray powder diffraction.

  17. Performance of multiple fractured horizontal wells in shale gas reservoirs with consideration of multiple mechanisms

    NASA Astrophysics Data System (ADS)

    Wang, Hai-Tao

    2014-03-01

    Gas flow in shales is believed to result from a combination of several mechanisms, including desorption, diffusion, viscous flow and the effect of stress-sensitivity of reservoir permeability. However, little work has been done in literature to simultaneously incorporate all these mechanisms in well testing models for shale gas reservoirs. This paper presents a new well testing model for multiple fractured horizontal wells (MFHW) in shale gas reservoirs with consideration of desorption, diffusive flow, viscous flow and stress-sensitivity of reservoir permeability. Comparing with current well testing models for MFHW, the model presented here takes into consideration more mechanisms controlling shale gas flow, which is more in line with the actual reservoir situation. Laplace transformation, point source function, perturbation method, numerical discrete method and Gaussian elimination method are employed to solve the well testing model. The pressure transient responses are then inverted into real time space with Stehfest numerical inversion algorithm. Type curves are plotted, and different flow regimes in shale gas reservoirs are identified. The effects of relevant parameters are analyzed as well. The presented model can be used to interpret pressure data more accurately for shale gas reservoirs and provide more accurate dynamic parameters which are important for efficient reservoir development.

  18. Feasibility of waterflooding Soku E7000 gas-condensate reservoir 

    E-print Network

    Ajayi, Arashi

    2002-01-01

    . To achieve this recovery, the reservoir should return to natural depletion after four years of water injection, before water invades the producing wells. Factors that affect the effectiveness of water injection in this reservoir include aquifer strength...

  19. Characterization of oil and gas reservoirs and recovery technology deployment on Texas State Lands

    SciTech Connect

    Tyler, R.; Major, R.P.; Holtz, M.H. [Univ. of Texas, Austin, TX (United States)] [and others

    1997-08-01

    Texas State Lands oil and gas resources are estimated at 1.6 BSTB of remaining mobile oil, 2.1 BSTB, or residual oil, and nearly 10 Tcf of remaining gas. An integrated, detailed geologic and engineering characterization of Texas State Lands has created quantitative descriptions of the oil and gas reservoirs, resulting in delineation of untapped, bypassed compartments and zones of remaining oil and gas. On Texas State Lands, the knowledge gained from such interpretative, quantitative reservoir descriptions has been the basis for designing optimized recovery strategies, including well deepening, recompletions, workovers, targeted infill drilling, injection profile modification, and waterflood optimization. The State of Texas Advanced Resource Recovery program is currently evaluating oil and gas fields along the Gulf Coast (South Copano Bay and Umbrella Point fields) and in the Permian Basin (Keystone East, Ozona, Geraldine Ford and Ford West fields). The program is grounded in advanced reservoir characterization techniques that define the residence of unrecovered oil and gas remaining in select State Land reservoirs. Integral to the program is collaboration with operators in order to deploy advanced reservoir exploitation and management plans. These plans are made on the basis of a thorough understanding of internal reservoir architecture and its controls on remaining oil and gas distribution. Continued accurate, detailed Texas State Lands reservoir description and characterization will ensure deployment of the most current and economically viable recovery technologies and strategies available.

  20. Advancing New 3D Seismic Interpretation Methods for Exploration and Development of Fractured Tight Gas Reservoirs

    Microsoft Academic Search

    James Reeves

    2005-01-01

    In a study funded by the U.S. Department of Energy and GeoSpectrum, Inc., new P-wave 3D seismic interpretation methods to characterize fractured gas reservoirs are developed. A data driven exploratory approach is used to determine empirical relationships for reservoir properties. Fractures are predicted using seismic lineament mapping through a series of horizon and time slices in the reservoir zone. A

  1. CO2 Utilization and Storage in Shale Gas Reservoirs

    NASA Astrophysics Data System (ADS)

    Schaef, T.; Glezakou, V.; Owen, T.; Miller, Q.; Loring, J.; Davidson, C.; McGrail, P.

    2013-12-01

    Surging natural gas production from fractured shale reservoirs and the emerging concept of utilizing anthropogenic CO2 for secondary recovery and permanent storage is driving the need for understanding fundamental mechanisms controlling gas adsorption and desorption processes, mineral volume changes, and impacts to transmissivity properties. Early estimates indicate that between 10 and 30 gigatons of CO2 storage capacity may exist in the 24 shale gas plays included in current USGS assessments. However, the adsorption of gases (CO2, CH4, and SO2) is not well understood and appears unique for individual clay minerals. Using specialized experimental techniques developed at PNNL, pure clay minerals were examined at relevant pressures and temperatures during exposure to CH4, CO2, and mixtures of CO2-SO2. Adsorbed concentrations of methane displayed a linear behavior as a function of pressure as determined by a precision quartz crystal microbalance. Acid gases produced differently shaped adsorption isotherms, depending on temperature and pressure. In the instance of kaolinite, gaseous CO2 adsorbed linearly, but in the presence of supercritical CO2, surface condensation increased significantly to a peak value before desorbing with further increases in pressure. Similarly shaped CO2 adsorption isotherms derived from natural shale samples and coal samples have been reported in the literature. Adsorption steps, determined by density functional theory calculations, showed they were energetically favorable until the first CO2 layer formed, corresponding to a density of ~0.35 g/cm3. Interlayer cation content (Ca, Mg, or Na) of montmorillonites influenced adsorbed gas concentrations. Measurements by in situ x-ray diffraction demonstrate limited CO2 diffusion into the Na-montmorillonite interlayer spacing, with structural changes related to increased hydration. Volume changes were observed when Ca or Mg saturated montmorillonites in the 1W hydration state were exposed to supercritical CO2. Additional experiments were conducted with pressurized attenuated total reflectance infrared spectroscopy technique that tracked clay hydration, gas adsorption, and water concentrations in the fluids during exposure to CO2 and CH4. These fundamental physico-chemical data are being collected into a database for parameterization of multiphase flow and reactive transport simulations of the CO2 injection, trapping, and secondary methane in fractured shales.

  2. Impact of relative permeability models on fluid flow behavior for gas condensate reservoirs 

    E-print Network

    Zapata Arango, Jose? Francisco

    2002-01-01

    and on the quantification of their impact on reservoir fluid flow and well performance. We selected three relative permeability models to compare the results obtained in the modeling of relative permeabilities for a published North Sea gas condensate reservoir. The models...

  3. Application of the Continuous EUR Method to Estimate Reserves in Unconventional Gas Reservoirs

    E-print Network

    Currie, Stephanie M.

    2010-10-12

    EXAMPLES FROM FIELD D ...................................................................... 253 APPENDIX H EXAMPLE FROM FIELD E......................................................................... 263 VITA... fracture (Ilk et al., 2008a). Table 1.1 ? Reservoir and fluid properties for numerical simulation case (single layer tight gas well with hydraulic fracture). Reservoir Properties: Wellbore Radius, r w = 0.333 ft Estimated net pay thickness, h...

  4. 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.

  5. Experimental and simulation studies of sequestration of supercritical carbon dioxide in depleted gas reservoirs 

    E-print Network

    Seo, Jeong Gyu

    2004-09-30

    he feasibility of sequestering supercritical CO2 in depleted gas reservoirs. The experimental runs involved the following steps. First, the 1 ft long by 1 in. diameter carbonate core is inserted into a viton Hassler sleeve and placed inside...

  6. Optimal Process Design for Coupled CO2 Sequestration and Enhanced Gas Recovery in Carbonate Reservoirs 

    E-print Network

    Odi, Uchenna

    2013-12-09

    in meeting the global energy needs, but have the undesirable outcome of producing carbon dioxide. Carbon dioxide (CO_(2)) injection in reservoirs is an appealing Enhanced Oil/Gas Recovery method for increasing hydrocarbon production by using the miscible...

  7. Experimental and simulation studies of sequestration of supercritical carbon dioxide in depleted gas reservoirs

    E-print Network

    Seo, Jeong Gyu

    2004-09-30

    he feasibility of sequestering supercritical CO2 in depleted gas reservoirs. The experimental runs involved the following steps. First, the 1 ft long by 1 in. diameter carbonate core is inserted into a viton Hassler sleeve and placed inside...

  8. A quadratic cumulative production model for the material balance of an abnormally pressured gas reservoir 

    E-print Network

    Gonzalez, Felix Eduardo

    2005-02-17

    The premise of this research is the concept, development, and application of an approximate relation for the material balance of abnormally-pressured gas reservoirs. The approximation is formulated directly from the ...

  9. Well-test analysis for solution-gas-drive reservoirs. Part 2; Buildup analysis

    SciTech Connect

    Serra, K.V.; Peres, A.M.M. (PETROBRAS, Rio de Janeiro, RJ (Brazil)); Reynolds, A.C. (Tulsa Univ., OK (USA))

    1990-06-01

    This work presents new analysis methods for pressure-buildup data from a well completed in a solution-gas-drive reservoir. New procedures for estimating effective phase permeabilities as functions of pressure and saturation are presented.

  10. Facies, faults and potential sweet spots in a tight gas reservoir: Almond Formation, Wyoming

    Microsoft Academic Search

    R. Martinsen; W. Iverson; R. Surdam

    1996-01-01

    The Almond Formation is a major producer of gas in southwestern Wyoming. Although exploration generally is aimed at finding conventional reservoirs in upper Almond marine sandstones, the majority of Almond gas is contained in the underlying main Almond, a succession of dominantly non-marine, interbedded tight sandstones, siltstones, carbonaceous shales and coals. Production data indicate that some of the best gas

  11. The effects of production rate and gravitational segregation on gas injection performance of oil reservoirs 

    E-print Network

    Ferguson, Ed Martin

    1972-01-01

    that the probable reason for the discrepancy between actual and predicted performances was the vertical segregation of fluids under the influence of gravity. By means of numerical simu- lation, performances of horizontal oil reservoirs under gas injec- tion were... Profiles 14 8. Comparison of Laboratory K /K Curve Calculated g 0 from Simulation Performance without Gravity Effects 9. Compairson of Reservoir Simulations for PSG = 1000. 18 10. Position of Gas-Oil Cpntact at Various Stages of Depletion for PSG...

  12. Analysis of condensate banking dynamics in a gas condensate reservoir under different injection schemes

    E-print Network

    Sandoval Rodriguez, Angelica Patricia

    2002-01-01

    ANALYSIS OF CONDENSATE BANKING DYNAMICS IN A GAS CONDENSATE RESERVOIR UNDER DIFFERENT INJECTION SCHEMES A Thesis by ANGELICA PATRICIA SANDOVAL RODRIGUEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial... fulfillment of the requirements for the degree of MASTER OF SCIENCE August 2002 Major Subject: Petroleum Engineering ANALYSIS OF CONDENSATE BANKING DYNAMICS IN A GAS CONDENSATE RESERVOIR UNDER DIFFERENT INJECTION SCHEMES A Thesis by ANGELICA PATRICIA...

  13. Controls of shallow gas accumulations in low-permeability reservoirs of Northern Great Plains

    Microsoft Academic Search

    Dudley D. Rice

    1984-01-01

    Significant resources (about 100 tcf in place) in natural gas are entrapped in low-permeability, low-pressure reservoirs at depths less than 3000 ft (900 m) in Montana and the Dakotas. The gas occurs in fine-grained sequences of Late Cretaceous age deposited on a shallow, open-marine shelf. The low-permeability reservoirs were deposited during progradations and consist of discontinuous lenses and laminae of

  14. Production of Natural Gas and Fluid Flow in Tight Sand Reservoirs

    SciTech Connect

    Maria Cecilia Bravo

    2006-06-30

    This document reports progress of this research effort in identifying relationships and defining dependencies between macroscopic reservoir parameters strongly affected by microscopic flow dynamics and production well performance in tight gas sand reservoirs. These dependencies are investigated by identifying the main transport mechanisms at the pore scale that should affect fluids flow at the reservoir scale. A critical review of commercial reservoir simulators, used to predict tight sand gas reservoir, revealed that many are poor when used to model fluid flow through tight reservoirs. Conventional simulators ignore altogether or model incorrectly certain phenomena such as, Knudsen diffusion, electro-kinetic effects, ordinary diffusion mechanisms and water vaporization. We studied the effect of Knudsen's number in Klinkenberg's equation and evaluated the effect of different flow regimes on Klinkenberg's parameter b. We developed a model capable of explaining the pressure dependence of this parameter that has been experimentally observed, but not explained in the conventional formalisms. We demonstrated the relevance of this, so far ignored effect, in tight sands reservoir modeling. A 2-D numerical simulator based on equations that capture the above mentioned phenomena was developed. Dynamic implications of new equations are comprehensively discussed in our work and their relative contribution to the flow rate is evaluated. We performed several simulation sensitivity studies that evidenced that, in general terms, our formalism should be implemented in order to get more reliable tight sands gas reservoirs' predictions.

  15. GLOBAL GREENHOUSE GAS EMISSIONS FROM RESERVOIRS: A MATTER OF METHANE

    EPA Science Inventory

    More than a decade ago, St. Louis et al. demonstrated that, collectively, manmade reservoirs play an important role in the global balance of greenhouse gases (GHGs). To update and build upon this important seminal work, we compiled reservoir CO2, CH4, and N2O flux estimates from...

  16. Study of Multi-scale Transport Phenomena in Tight Gas and Shale Gas Reservoir Systems 

    E-print Network

    Freeman, Craig Matthew

    2013-11-25

    will then be validated against core analyses and experiments, and surface flowing gas composition data. Finally the numerical model will be used to generate a model-based analysis technique with the aim of reducing uncertainty in reservoir characteristics. 1... are not analogous to those of coal (Schettler and Parmely 1991). The Langmuir model was based on the theory described above. In its application to desorption in shales and coal, it has been treated as semi-empirically, where the two values of the parameters...

  17. Study of Multi-scale Transport Phenomena in Tight Gas and Shale Gas Reservoir Systems

    E-print Network

    Freeman, Craig Matthew

    2013-11-25

    will then be validated against core analyses and experiments, and surface flowing gas composition data. Finally the numerical model will be used to generate a model-based analysis technique with the aim of reducing uncertainty in reservoir characteristics. 1... are not analogous to those of coal (Schettler and Parmely 1991). The Langmuir model was based on the theory described above. In its application to desorption in shales and coal, it has been treated as semi-empirically, where the two values of the parameters...

  18. Characterization and reservoir evaluation of a hydraulically fractured, shaly gas reservoir 

    E-print Network

    Santiago Molina, Cesar Alfonso

    1991-01-01

    . . . . , . 2 3 . . . . . 3 . . . . 4 . . . . 4 2. 1 2. 2 2. 3 2. 4 2. 5 2. 6 Application of Logs. Reservoir Rock Composition Porosity and Permeability Shale or Clay Distribution in Shaly Sands . Effects of Clays on Log Response Shale Volume... clay in sandstones . . . 14 2. 5. Effect of authigenic pore clays (dispersed) on permeability to air. . . . . . . . 15 3. 1 Flow periods in a vertically fractured well 24 3. 2. Typical pressure behavior for a hydraulically fractured reservoir...

  19. Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity

    SciTech Connect

    Mancini, E.A.

    1990-01-01

    The objectives of this project are to augment the National Reservoir Database (TORIS database) and to increase our understanding of geologic heterogeneities that affect the recoveries of oil and gas from carbonate reservoirs in the State of Alabama and to identify those resources that are producible at moderate cost. These objectives will be achieved through detailed geological, engineering, and geostatistical characterization of typical Jurassic Smackover Formation hydrocarbon reservoirs in selected productive fields in the State of Alabama. The results of these studies will be used to develop and test mathematical models for prediction of the effects of reservoir heterogeneities in hydrocarbon production. Work to date has focused on the completion of Subtasks 1, 2, and 3. Subtask 1 included the survey and tabulation of available reservoir engineering and geological data relevant to the Smackover reservoir in southwestern Alabama. Subtask 2 comprises the geological and engineering characterization of Smackover reservoir lithofacies. This has been accomplished through detailed examination and analysis of geophysical well logs, core material, well cuttings, and well-test data from wells penetrating Smackover reservoirs in southwestern Alabama. From these data, reservoir heterogeneities, such as lateral and vertical changes in lithology, porosity, permeability, and diagenetic overprint, have been recognized and used to produce maps, cross sections, graphs, and other graphic representations to aid in interpretation of the geologic parameters that affect these reservoirs. Subtask 3 includes the geologic modeling of reservoir heterogeneities for Smackover reservoirs. This research has been based primarily on the evaluation of key geologic and engineering data from selected Smackover fields. 1 fig.

  20. Advancing New 3D Seismic Interpretation Methods for Exploration and Development of Fractured Tight Gas Reservoirs

    SciTech Connect

    James Reeves

    2005-01-31

    In a study funded by the U.S. Department of Energy and GeoSpectrum, Inc., new P-wave 3D seismic interpretation methods to characterize fractured gas reservoirs are developed. A data driven exploratory approach is used to determine empirical relationships for reservoir properties. Fractures are predicted using seismic lineament mapping through a series of horizon and time slices in the reservoir zone. A seismic lineament is a linear feature seen in a slice through the seismic volume that has negligible vertical offset. We interpret that in regions of high seismic lineament density there is a greater likelihood of fractured reservoir. Seismic AVO attributes are developed to map brittle reservoir rock (low clay) and gas content. Brittle rocks are interpreted to be more fractured when seismic lineaments are present. The most important attribute developed in this study is the gas sensitive phase gradient (a new AVO attribute), as reservoir fractures may provide a plumbing system for both water and gas. Success is obtained when economic gas and oil discoveries are found. In a gas field previously plagued with poor drilling results, four new wells were spotted using the new methodology and recently drilled. The wells have estimated best of 12-months production indicators of 2106, 1652, 941, and 227 MCFGPD. The latter well was drilled in a region of swarming seismic lineaments but has poor gas sensitive phase gradient (AVO) and clay volume attributes. GeoSpectrum advised the unit operators that this location did not appear to have significant Lower Dakota gas before the well was drilled. The other three wells are considered good wells in this part of the basin and among the best wells in the area. These new drilling results have nearly doubled the gas production and the value of the field. The interpretation method is ready for commercialization and gas exploration and development. The new technology is adaptable to conventional lower cost 3D seismic surveys.

  1. Numerical simulation of the environmental impact of hydraulic fracturing of tight/shale gas reservoirs on near-surface groundwater: Background, base cases, shallow reservoirs, short-term gas, and water transport

    NASA Astrophysics Data System (ADS)

    Reagan, Matthew T.; Moridis, George J.; Keen, Noel D.; Johnson, Jeffrey N.

    2015-04-01

    Hydrocarbon production from unconventional resources and the use of reservoir stimulation techniques, such as hydraulic fracturing, has grown explosively over the last decade. However, concerns have arisen that reservoir stimulation creates significant environmental threats through the creation of permeable pathways connecting the stimulated reservoir with shallower freshwater aquifers, thus resulting in the contamination of potable groundwater by escaping hydrocarbons or other reservoir fluids. This study investigates, by numerical simulation, gas and water transport between a shallow tight-gas reservoir and a shallower overlying freshwater aquifer following hydraulic fracturing operations, if such a connecting pathway has been created. We focus on two general failure scenarios: (1) communication between the reservoir and aquifer via a connecting fracture or fault and (2) communication via a deteriorated, preexisting nearby well. We conclude that the key factors driving short-term transport of gas include high permeability for the connecting pathway and the overall volume of the connecting feature. Production from the reservoir is likely to mitigate release through reduction of available free gas and lowering of reservoir pressure, and not producing may increase the potential for release. We also find that hydrostatic tight-gas reservoirs are unlikely to act as a continuing source of migrating gas, as gas contained within the newly formed hydraulic fracture is the primary source for potential contamination. Such incidents of gas escape are likely to be limited in duration and scope for hydrostatic reservoirs. Reliable field and laboratory data must be acquired to constrain the factors and determine the likelihood of these outcomes.

  2. Reservoir-Wellbore Coupled Simulation of Liquid Loaded Gas Well Performance

    E-print Network

    Riza, Muhammad Feldy

    2013-11-12

    .................................................................................. 27 Table 3.4 — Critical Velocity Models and Flow Pattern Well Veeken-#19 ................... 36 Table 4.1 —Well #27 Dataset (Veeken et al. 2010) ........................................................ 48 Table 4.2 — Synthetic Reservoir and Fluid... in different thermodynamic states: as dry gas, wet gas, and as retrograde-condensate. Each state has different characteristics and classified based on its composition and its PVT diagram. During the production of gas well, liquid would co-produced with gas...

  3. Fractured gas well analysis: evaluation of in situ reservoir properties of low permeability gas wells stimulated by finite conductivity hydraulic fractures 

    E-print Network

    Makoju, Charles Adoiza

    1978-01-01

    of Dimensionless Fracture Conductivity. Porosity Formation Permeabi1 i ty Thickness Drainage Radius Fracture Length Reservoir Temperature Gas Gravity 10K 0. 1 md 50 feet 20, 000 feet 200 feet 150 F 0. 65 Original Reservoir Pressure 5000 psia Rate... Runs to Determine Time to Attain Pseudo-Steady-State Flow in a Finite Acting Reservoir, as a Function of Fracture Length and Fracture Penetration. Porosity Formation Permeability Thickness Well Spacing Reservoir Temperature Gas Gravity Original...

  4. Evaluation of in situ stress changes with gas depletion of coalbed methane reservoirs

    NASA Astrophysics Data System (ADS)

    Liu, Shimin; Harpalani, Satya

    2014-08-01

    A sound knowledge of the stress path for coalbed methane (CBM) reservoirs is critical for a variety of applications, including dynamic formation stability evaluation, long-term gas production management, and carbon sequestration in coals. Although this problem has been extensively studied for traditional oil and gas reservoirs, it is somewhat unclear for CBM reservoirs. The difference between the stress paths followed in the two reservoir types is expected to be significant given the unique sorption-induced deformation phenomenon associated with gas production from coal. This results in an additional reservoir volumetric strain, which induces a rather "abnormal" loss of horizontal stress with depletion, leading to continuous changes in the subsurface formation stresses, both effective as well as total. It is suspected that stress changes within the reservoir triggers formation failure after significant depletion. This paper describes an experimental study, carried out to measure the horizontal stress under in situ depletion conditions. The results show that the horizontal stress decreases linearly with depletion under in situ conditions. The dynamic stress evolution is theoretically analyzed, based on modified poroelasticity associated with sorption-induced strain effect. Additionally, the failure tendency of the reservoir under in situ conditions is analyzed using the traditional Mohr-Coulomb failure criterion. The results indicate that depletion may lead to coal failure, particularly in deeper coalbeds and ones exhibiting large matrix shrinkage.

  5. The Performance of Fractured Horizontal Well in Tight Gas Reservoir 

    E-print Network

    Lin, Jiajing

    2012-02-14

    of semi-analytical response of a rectilinear reservoir with closed outer boundaries. A statistically assigned fracture network is used in the study to represent natural fractures based on the spacing between fractures and fracture geometry. The multiple...

  6. Factors affecting the development of the pressure differential in Upper Paleozoic gas reservoirs in the Sulige and Yulin areas of the Ordos Basin, China

    Microsoft Academic Search

    Hao Xu; Dazhen Tang; Junfeng Zhang; Wei Yin; Wenzhong Zhang; Wenji Lin

    2011-01-01

    The Sulige gas field and the Yulin gas field are located in the north of the Ordos Basin. Reservoir pressure in the Sulige area is subnormal, whereas reservoirs in the Yulin area have normal hydrostatic pressure. This paper provides an explanation of this difference. The characteristics of reservoir sediment and formation water chemistry in the gas reservoirs of these two

  7. DEVELOPMENT OF MORE-EFFICIENT GAS FLOODING APPLICABLE TO SHALLOW RESERVOIRS

    Microsoft Academic Search

    William R. Rossen; Russell T. Johns; Gary A. Pope

    2003-01-01

    The objective of this research is to widen the applicability of gas flooding to shallow oil reservoirs by reducing the pressure required for miscibility using gas enrichment and increasing sweep efficiency with foam. Task 1 examines the potential for improved oil recovery with enriched gases. Subtask 1.1 examines the effect of dispersion processes on oil recovery and the extent of

  8. Downhole Geochemical Analysis of Gas Content and Critical Desorption Pressure for Carbonaceous Reservoirs

    Microsoft Academic Search

    John Pope; Daniel Buttry; Robert Lamarre; Bret Noecker; Steven MacDonald; Brian LaReau; Patrick Malone; Neil Van Lieu; Daniel Petroski; Matthew Accurso; David Harak; Richard Kutz; Stephen Luker; Raymond Martin

    This paper describes research directed at developing a new method to determine critical desorption pressure and gas content. This method is facilitated by development of a Raman- spectroscopy based sensor capable of detecting and quantifying trace amounts of solution gas. In this report, we describe the reservoir physics that makes the method possible, we share laboratory results that illustrate and

  9. Geologic characteristics of low-permeability gas reservoirs in Greater Green River basin of Wyoming, Colorado, and Utah

    Microsoft Academic Search

    Ben E. Law

    1984-01-01

    Large gas resources occur in low-permeability Upper Cretaceous and Lower Tertiary reservoirs in the Greater Green River basin of Wyoming, Colorado, and Utah. Most of the gas-bearing reservoirs are overpressured, beginning at depths of 8000-11,500 ft (2440-3500 m). The reservoirs are typically lenticular nonmarine and marginal marine sandstones. In situ permeabilities to gas are generally less than 0.1 md, and

  10. Gas-field deliverability forecasting: A coupled reservoir simulator and surface facilities model

    SciTech Connect

    Trick, M.D. [Neotechnology Consultants Ltd. (United States); Agarwal, R. [Computer Modelling Group (United States); Ammer, J.R.; Mercer, J.C. [USDOE Morgantown Energy Technology Center, WV (United States); Harris, R.P. [National Fuel Gas Supply Corp. (United States)

    1994-08-01

    To determine if a gas contract can be satisified now and in the future, it is necessary to forecast the performance of the gas reservoir, the gas inflow into the sandface, the multiphase pressure losses in the wellbore and gathering system and the field facilities. Surface production models which rigorously model from the sandface to the plant gate are available. However, these surface packages model reservoirs simply, in most cases as tank-type reservoirs. Comprehensive 3 dimensional reservoir simulators are available, but typically only include simple surface networks which don`t adequately model multiphase flow in complex gathering systems. This paper describes the procedures used in a joint venture by two software vendors to combine an existing reservoir simulator and an existing surface facilities model into a single forecasting tool. Relatively small changes were made to each program. In the new model, the black oil reservoir simulator provides the formation pressure and water to gas ratio for each well. The surface facilities model then calculates the multiphase flow pressure losses in the wellbore and gathering system, plus the corresponding flow rates for each well. The actual production required from each well to satisfy the pipeline contractual requirements, over each time step, is computed by the surface facilities model and relayed back to the reservoir simulator. The time step is determined dynamically according to the requirements of each program. The performance and results from the coupled model are compared to that of running each model separately for a gas storage field in the USA and for a gas production field with bottom-water. It is shown that running each model separately does not account for all the factors affecting the forecast.

  11. Variations in dissolved gas compositions of reservoir fluids from the Coso geothermal field

    SciTech Connect

    Williams, Alan E.; Copp, John F.

    1991-01-01

    Gas concentrations and ratios in 110 analyses of geothermal fluids from 47 wells in the Coso geothermal system illustrate the complexity of this two-phase reservoir in its natural state. Two geographically distinct regions of single-phase (liquid) reservoir are present and possess distinctive gas and liquid compositions. Relationships in soluble and insoluble gases preclude derivation of these waters from a common parent by boiling or condensation alone. These two regions may represent two limbs of fluid migration away from an area of two-phase upwelling. During migration, the upwelling fluids mix with chemically evolved waters of moderately dissimilar composition. CO{sub 2} rich fluids found in the limb in the southeastern portion of the Coso field are chemically distinct from liquids in the northern limb of the field. Steam-rich portions of the reservoir also indicate distinctive gas compositions. Steam sampled from wells in the central and southwestern Coso reservoir is unusually enriched in both H{sub 2}S and H{sub 2}. Such a large enrichment in both a soluble and insoluble gas cannot be produced by boiling of any liquid yet observed in single-phase portions of the field. In accord with an upflow-lateral mixing model for the Coso field, at least three end-member thermal fluids having distinct gas and liquid compositions appear to have interacted (through mixing, boiling and steam migration) to produce the observed natural state of the reservoir.

  12. Geology, reservoir engineering and methane hydrate potential of the Walakpa Gas Field, North Slope, Alaska

    SciTech Connect

    Glenn, R.K.; Allen, W.W.

    1992-12-01

    The Walakpa Gas Field, located near the city of Barrow on Alaska's North Slope, has been proven to be methane-bearing at depths of 2000--2550 feet below sea level. The producing formation is a laterally continuous, south-dipping, Lower Cretaceous shelf sandstone. The updip extent of the reservoir has not been determined by drilling, but probably extends to at least 1900 feet below sea level. Reservoir temperatures in the updip portion of the reservoir may be low enough to allow the presence of in situ methane hydrates. Reservoir net pay however, decreases to the north. Depths to the base of permafrost in the area average 940 feet. Drilling techniques and production configuration in the Walakpa field were designed to minimize formation damage to the reservoir sandstone and to eliminate methane hydrates formed during production. Drilling development of the Walakpa field was a sequential updip and lateral stepout from a previously drilled, structurally lower confirmation well. Reservoir temperature, pressure, and gas chemistry data from the development wells confirm that they have been drilled in the free-methane portion of the reservoir. Future studies in the Walakpa field are planned to determine whether or not a component of the methane production is due to the dissociation of updip in situ hydrates.

  13. Gross greenhouse gas fluxes from hydro-power reservoir compared to thermo-power plants

    Microsoft Academic Search

    Marco Aurelio dos Santos; Luiz Pinguelli Rosa; Bohdan Sikar; Elizabeth Sikar; Ednaldo Oliveira dos Santos

    2006-01-01

    This paper presents the findings of gross carbon dioxide and methane emissions measurements in several Brazilian hydro-reservoirs, compared to thermo power generation.The term ‘gross emissions’ means gas flux measurements from the reservoir surface without natural pre-impoundment emissions by natural bodies such as the river channel, seasonal flooding and terrestrial ecosystems. The net emissions result from deducting pre-existing emissions by the

  14. Long-term greenhouse gas emissions from hydroelectric reservoirs in tropical forest regions

    Microsoft Academic Search

    Corinne Galy-Lacaux; Robert Delmas; Georges Kouadio; Sandrine Richard; Philippe Gosse

    1999-01-01

    The objective of this work is to quantify long-term emissions of two major greenhouse gases, CO2 and CH4, produced by the decomposition of the flooded organic matter in tropical artificial reservoirs. In a previous paper [Galy-Lacaux et al., 1997], gas emissions from the tropical reservoir of Petit Saut (French Guiana) were quantified over the first two years after impounding. This

  15. A new p/z technique for the analysis of abnormally pressured gas reservoirs

    E-print Network

    Gan, Ronald Gunawan

    2001-01-01

    knowledge of formation and fluid compressibility data. This method honors both the rock collapse and shale water influx theories through the use of a pressure-dependent compressibility function. The specific tasks achieved in this work include... . . . . . . . . 44 . . . . . . 45 . . . . . . . . 46 . . 47 FIGURE 4. 15 Correlation for the p/z Inflection Point Derived from Field Data Inventory. Page 50 LIST OF TABLES TABLE 4. 1 Reservoir and Fluid Properties for Dry Gas Reservoir Example. . . . 4. 2...

  16. A critical compilation of 1,500 large onshore gas reservoirs in Texas Gulf Coast and East Texas

    Microsoft Academic Search

    E. C. Kosters; R. J. Finley; N. Tyler

    1988-01-01

    About 1,500 gas reservoirs in the Texas Gulf Coast and east Texas have a cumulative production of at least 10 bcf. The Gulf Coast contains nearly 90% of these reservoirs. One-third of all reservoirs have produced more than 30 bcf, and another 10% have produced more than 100 bcf. In the Gulf Coast, total production from the greater than 30

  17. Characterization of oil and gas reservoir heterogeneity. Final report

    SciTech Connect

    Tyler, N.; Barton, M.D.; Bebout, D.G.; Fisher, R.S.; Grigsby, J.D.; Guevara, E.; Holtz, M.; Kerans, C.; Nance, H.S.; Levey, R.A.

    1992-10-01

    Research described In this report addresses the internal architecture of two specific reservoir types: restricted-platform carbonates and fluvial-deltaic sandstones. Together, these two reservoir types contain more than two-thirds of the unrecovered mobile oil remaining ill Texas. The approach followed in this study was to develop a strong understanding of the styles of heterogeneity of these reservoir types based on a detailed outcrop description and a translation of these findings into optimized recovery strategies in select subsurface analogs. Research targeted Grayburg Formation restricted-platform carbonate outcrops along the Algerita Escarpment and In Stone Canyon In southeastern New Mexico and Ferron deltaic sandstones in central Utah as analogs for the North Foster (Grayburg) and Lake Creek (Wilcox) units, respectively. In both settings, sequence-stratigraphic style profoundly influenced between-well architectural fabric and permeability structure. It is concluded that reservoirs of different depositional origins can therefore be categorized Into a ``heterogeneity matrix`` based on varying intensity of vertical and lateral heterogeneity. The utility of the matrix is that it allows prediction of the nature and location of remaining mobile oil. Highly stratified reservoirs such as the Grayburg, for example, will contain a large proportion of vertically bypassed oil; thus, an appropriate recovery strategy will be waterflood optimization and profile modification. Laterally heterogeneous reservoirs such as deltaic distributary systems would benefit from targeted infill drilling (possibly with horizontal wells) and improved areal sweep efficiency. Potential for advanced recovery of remaining mobile oil through heterogeneity-based advanced secondary recovery strategies In Texas is projected to be an Incremental 16 Bbbl. In the Lower 48 States this target may be as much as 45 Bbbl at low to moderate oil prices over the near- to mid-term.

  18. Processes affecting greenhouse gas production in experimental boreal reservoirs

    NASA Astrophysics Data System (ADS)

    Venkiteswaran, Jason J.; Schiff, Sherry L.; St. Louis, Vincent L.; Matthews, Cory J. D.; Boudreau, Natalie M.; Joyce, Elizabeth M.; Beaty, Kenneth G.; Bodaly, R. Andrew

    2013-04-01

    Flooding land for water reservoir creation has many environmental impacts including the production of the greenhouse gases (GHG) carbon dioxide (CO2) and methane (CH4). To assess processes governing GHG emissions from the flooding of terrestrial carbon, three experimental reservoirs were constructed in upland boreal forest areas of differing carbon stores as part of the Flooded Upland Dynamics Experiment (FLUDEX). We calculated process-based GHG budgets for these reservoirs over 5 years following the onset of flooding. Stable isotopic budgets of carbon were necessary to separate community respiration (CR), which produces CO2, from net primary production (NPP), which consumes CO2, and to separate CH4 production from CH4 consumption via oxidation. NPP removed up to 44% of the CO2 produced from CR. CR and NPP exhibited different year-after-year trends. CH4 flux to the atmosphere increased about twofold over 3 years, yet isotopic budgets showed CH4 production in flooded soils increased nearly tenfold. CH4 oxidation near the flooded soil-water interface greatly decreased the CH4 flux from the water column to the atmosphere. Ebullition was the most important conduit of CH4 to the atmosphere after 3 years. Although CH4 production increased with time, the total GHG flux, in CO2 equivalents, declined. Contrary to expectations, neither CR nor total GHG fluxes were directly related to the quantity of organic carbon flooded. Instead, these reservoirs produced a strikingly similar amount of CO2 equivalents over 5 years.

  19. Spatial and Temporal Variations in Greenhouse Gas Emissions from an Agricultural Reservoir

    NASA Astrophysics Data System (ADS)

    Smolenski, R. L.; Beaulieu, J.; Townsend-Small, A.; Nietch, C.

    2012-12-01

    Reservoirs are being built at an increasing rate each year to provide humans with resources such as hydroelectric power and drinking water. These man-made systems have provided society with important services, but these have come at the cost of enhanced greenhouse gas (GHG) emissions. Recent estimates suggest reservoirs are a globally significant source of GHG emissions, but these estimates are largely based on studies of oligotrophic boreal and tropical reservoirs. Reservoirs draining agricultural basins are common throughout much of the developed world and are subject to high nutrient loading rates from the watershed. Excess nutrient loading stimulates algae blooms and degrades water quality in these reservoirs, but surprisingly little is known about how nutrients and algal blooms affect GHG dynamics. To assess GHG dynamics in an agricultural reservoir we measured GHG emission rates, dissolved concentrations, and nutrient chemistry in William H. Harsha Lake, an agricultural reservoir located in southwestern Ohio (USA), on a monthly basis since October, 2011. Dissolved N2O was negatively related to nitrate (r2=.91, p<0.001) in October 2011, suggesting denitrification was an important source of N2O in the reservoir during fall turnover. Relationships between dissolved N2O and nitrate concentrations were inconsistent during the winter and spring, suggesting nitrate was not limited during these seasons. There was no consistent pattern in dissolved gas concentrations across the length of the reservoir, but concentrations were greater in hypolimnetic than eplimnetic waters during warmer months. The highest N2O and CH4 emissions occurred during lake turn over in the fall (CH4 flux= 4.76E+1 mg CH4 hr-1m-2, N2O flux= 9.24E+1 ?g N2O-N hr-1m-2, and CO2 flux = 8.62E+2 mg CO2 hr-1m-2), while the lowest emission rates were observed during the winter. We found no clear spatial pattern in GHG emission rates across the length of the reservoir. On an annual basis, we estimate the reservoir emits 1.52E+6 kg CH4-C/yr, equivalent to ~11,000 head of dairy cattle. On a per unit area basis, the reservoir was a hotspot of N2O emissions compared to the surrounding agricultural land; however, total annual N2O emissions from the reservoir (3.00E+3 kg N2O-N/yr) constitute only 1% of total watershed N2O emissions due to the much greater area of agricultural lands.

  20. Radon in unconventional natural gas from gulf coast geopressured-geothermal reservoirs

    USGS Publications Warehouse

    Kraemer, T.F.

    1986-01-01

    Radon-222 has been measured in natural gas produced from experimental geopressured-geothermal test wells. Comparison with published data suggests that while radon activity of this unconventional natural gas resource is higher than conventional gas produced in the gulf coast, it is within the range found for conventional gas produced throughout the U.S. A method of predicting the likely radon activity of this unconventional gas is described on the basis of the data presented, methane solubility, and known or assumed reservoir conditions of temperature, fluid pressure, and formation water salinity.

  1. Developing a tight gas sand advisor for completion and stimulation in tight gas reservoirs worldwide 

    E-print Network

    Bogatchev, Kirill Y.

    2009-05-15

    while completing and stimulating TGS reservoirs. The modules include Perforation Selection and Proppant Selection. Based on input well/reservoir parameters these subroutines provide unambiguous recommendations concerning which perforation strategy(s...

  2. Developing a tight gas sand advisor for completion and stimulation in tight gas reservoirs worldwide 

    E-print Network

    Bogatchev, Kirill Y

    2008-10-10

    while completing and stimulating TGS reservoirs. The modules include Perforation Selection and Proppant Selection. Based on input well/reservoir parameters these subroutines provide unambiguous recommendations concerning which perforation strategy(s...

  3. Developing a tight gas sand advisor for completion and stimulation in tight gas reservoirs worldwide

    E-print Network

    Bogatchev, Kirill Y.

    2009-05-15

    while completing and stimulating TGS reservoirs. The modules include Perforation Selection and Proppant Selection. Based on input well/reservoir parameters these subroutines provide unambiguous recommendations concerning which perforation strategy...

  4. Structural and sedimentological controls and diagenesis in the Ravenspurn north gas reservoir United Kingdom southern North Sea

    Microsoft Academic Search

    P. Turner; M. Jones; J. Prosser; G. Williams

    1993-01-01

    The Ravenspurn area is divided into two main northwest-southeast-trending fault blocks which are markedly different in terms of their diagenetic evolution and reservoir performance. The northeasterly B structure contained gas earlier and was unaffected by Middle to Late Jurassic illitization. The southwesterly A structure was uplifted later and received accumulated gas after reservoir quality was reduced by pervasive illitization. The

  5. Characterization of Tight Gas Reservoir Pore Structure Using USANS/SANS and Gas Adsorption Analysis

    SciTech Connect

    Clarkson, Christopher R [ORNL; He, Lilin [ORNL; Agamalian, Michael [ORNL; Melnichenko, Yuri B [ORNL; Mastalerz, Maria [Indiana Geological Survey; Bustin, Mark [University of British Columbia, Vancouver; Radlinski, Andrzej Pawell [ORNL; Blach, Tomasz P [ORNL

    2012-01-01

    Small-angle and ultra-small-angle neutron scattering (SANS and USANS) measurements were performed on samples from the Triassic Montney tight gas reservoir in Western Canada in order to determine the applicability of these techniques for characterizing the full pore size spectrum and to gain insight into the nature of the pore structure and its control on permeability. The subject tight gas reservoir consists of a finely laminated siltstone sequence; extensive cementation and moderate clay content are the primary causes of low permeability. SANS/USANS experiments run at ambient pressure and temperature conditions on lithologically-diverse sub-samples of three core plugs demonstrated that a broad pore size distribution could be interpreted from the data. Two interpretation methods were used to evaluate total porosity, pore size distribution and surface area and the results were compared to independent estimates derived from helium porosimetry (connected porosity) and low-pressure N{sub 2} and CO{sub 2} adsorption (accessible surface area and pore size distribution). The pore structure of the three samples as interpreted from SANS/USANS is fairly uniform, with small differences in the small-pore range (< 2000 {angstrom}), possibly related to differences in degree of cementation, and mineralogy, in particular clay content. Total porosity interpreted from USANS/SANS is similar to (but systematically higher than) helium porosities measured on the whole core plug. Both methods were used to estimate the percentage of open porosity expressed here as a ratio of connected porosity, as established from helium adsorption, to the total porosity, as estimated from SANS/USANS techniques. Open porosity appears to control permeability (determined using pressure and pulse-decay techniques), with the highest permeability sample also having the highest percentage of open porosity. Surface area, as calculated from low-pressure N{sub 2} and CO{sub 2} adsorption, is significantly less than surface area estimates from SANS/USANS, which is due in part to limited accessibility of the gases to all pores. The similarity between N{sub 2} and CO{sub 2}-accessible surface area suggests an absence of microporosity in these samples, which is in agreement with SANS analysis. A core gamma ray profile run on the same core from which the core plug samples were taken correlates to profile permeability measurements run on the slabbed core. This correlation is related to clay content, which possibly controls the percentage of open porosity. Continued study of these effects will prove useful in log-core calibration efforts for tight gas.

  6. Using multi-layer models to forecast gas flow rates in tight gas reservoirs

    E-print Network

    Jerez Vera, Sergio Armando

    2007-04-25

    Plot of the Cum Production for Reservoir Model Case (a)........... 32 3.3 History Match Plot of the Flow Rate for Reservoir Model Case (a).................... 33 3.4 History Match Plot of the Cum Production for Reservoir Model Case (b...)........... 33 3.5 History Match Plot of the Flow Rate for Reservoir Model Case (b) ................... 34 3.6 History Match Plot of the Cum Production for Reservoir Model Case (c)........... 34 3.7 History Match Plot of the Flow Rate...

  7. Constant-pressure production in solution-gas-drive reservoirs; Transient flow

    SciTech Connect

    Camacho, R.G. (National Univ. of Mexico/PEMEX (MX))

    1991-06-01

    This paper presents procedures to obtain reservoir parameters from constant-pressure drawdown data in solution-gas-drive reservoirs. A novel procedure to determine the mechanical skin factor is introduced. Examples, including a field case, illustrate the use of this procedure. An estimate of the drainage area can be obtained with the derivative of rate data. A theoretical basis for analyzing data by the pressure-squared, p{sup 2}, approach is presented; this procedure permits the approximate determination of sandface effective permeabilities in the transient flow period. For damaged wells, it is possible to obtain rough estimates of the size of the skin zone and the ratio of reservoir/skin-zone permeability when early transient data are available. The expression of the appropriate dimensionless rate in terms of physical properties for solution-gas-drive systems is presented. Finally, this paper presents a procedure to obtain an estimate of the change in sandface saturation during the transient flow period.

  8. Post Doctoral Research Fellowship Simulating the greenhouse gas emission from boreal region reservoirs

    E-print Network

    Post Doctoral Research Fellowship Simulating the greenhouse gas emission from boreal region reservoirs We are seeking a post-doctoral research fellow to work on the simulation of the emission climate and land-use change scenarios. The post-doctoral fellowship is initially for one year

  9. Naturally fractured tight gas reservoir detection optimization. Quarterly report, January 1 - March 31, 1996

    SciTech Connect

    NONE

    1996-12-31

    The objective is to determine methods for detection and mapping of naturally fractured systems for economic production of natural gas from fractured reservoirs. This report contains: 3D P-wave alternate processing; down hole 3C geophone analysis; fracture pattern analysis of the Fort Union and Wind River Basin; 3D-3C seismic processing; and technology transfer.

  10. Naturally fractured tight gas reservoir detection optimization. Quarterly technical progress report, April 1995--June 1995

    SciTech Connect

    NONE

    1995-08-01

    Research continued on methods to detect naturally fractured tight gas reservoirs. This report contains a seismic survey map, and reports on efforts towards a source test to select the source parameters for a 37 square mile compressional wave 3-D seismic survey. Considerations of the source tests are discussed.

  11. Naturally fractured tight gas reservoir detection optimization. Quarterly report, January--March 1995

    SciTech Connect

    NONE

    1995-05-01

    The objective is to determine methods for detection and mapping of natural fracture systems for economic production of natural gas from fractured reservoirs. This progress report covers: 3D P-wave survey; additional processing of 3D P-wave survey; review of multicomponent recording feasibility tests; minivibrator studies; and modeling of 3D-3C acquisition parameters.

  12. Seismic Modeling of AcidGas Injection in a Deep Saline Reservoir

    Microsoft Academic Search

    Charles Ursenbach; Donald Lawton

    Summary A case is studied of non-aqueous acid gas injection into a saline dolostone reservoir. The feasibility of monitoring is judged by the sensitivity of traveltimes and reflection coefficients to fluid substitution. Using acid-gas properties from the Peng-Robinson equation of state and fluid substitution effects from Gassmann's equations, the traveltime difference is seen to be on the order of a

  13. Naturally fractured tight gas reservoir detection optimization. Quarterly report, January 1, 1997--March 31, 1997

    SciTech Connect

    NONE

    1998-04-01

    This document contains the quarterly report dated January 1-March 31, 1997 for the Naturally Fractured Tight Gas Reservoir Detection Optimization project. Topics covered in this report include AVOA modeling using paraxial ray tracing, AVOA modeling for gas- and water-filled fractures, 3-D and 3-C processing, and technology transfer material. Several presentations from a Geophysical Applications Workshop workbook, workshop schedule, and list of workshop attendees are also included.

  14. Numerical Simulation of Subsurface Transport and Groundwater Impacts from Hydraulic Fracturing of Tight/Shale Gas Reservoirs

    NASA Astrophysics Data System (ADS)

    Reagan, M. T.; Moridis, G. J.; Keen, N. D.

    2014-12-01

    The use of reservoir stimulation techniques, such as hydraulic fracturing, has grown tremendously over the last decade, and concerns have arisen that reservoir stimulation creates environmental threats through the creation of permeable pathways that could connect the stimulated reservoir to shallower groundwater aquifers. This study investigates, by numerical simulation, gas and water transport between a deeper tight-gas reservoir and a shallower overlying groundwater aquifer following hydraulic fracturing operations, assuming that the formation of a connecting pathway has already occurred. We focus on two general transport scenarios: 1) communication between the reservoir and aquifer via a connecting fracture or fault and 2) communication via a deteriorated, preexisting nearby well. The simulations explore a range of permeabilities and geometries over time scales, and evaluate the mechanisms and factors that could lead to the escape of gas or reservoir fluid and the contamination of groundwater resources. We also examine the effects of overpressured reservoirs, and explore long-term transport processes as part of a continuing study. We conclude that the key factors driving short-term transport of gas include high permeability for the connecting pathway and the overall volume of the connecting feature. Gas production from the reservoir via a horizontal well is likely to mitigate release through the reduction of available free gas and the lowering of reservoir pressure. We also find that fractured tight-gas reservoirs are unlikely to act as a continuing source of large volumes of migrating gas, and incidents of gas escape are likely to be limited in duration and scope. Reliable field and laboratory data must be acquired to constrain the factors and determine the likelihood of these outcomes.

  15. Induced seismicity in the gas reservoirs of the Netherlands

    NASA Astrophysics Data System (ADS)

    Kraaijpoel, D.; Goutbeek, F.; Sleeman, R.; Dost, B.

    2009-04-01

    The Netherlands contains a large number of natural gas fields of various sizes, including the Groningen field, the largest in Western Europe. Gas production started in 1960 and is expected to be continued for more than two decades ahead. In due course, more and more of the smaller fields will become depleted and potentially available for underground gas storage. A number of fields are already being used as buffer storage for natural gas. Plans for CO2 storage in other fields are reaching an advanced stage. Currently, most industrial activity in the gas fields is still related to gas extraction rather than storage. The monitoring and analysis of induced seismicity that is observed today will be crucial for the assessment of storage opportunities in the near future. Induced seismicity due to gas extraction was not observed or recognized until a first widely felt event of magnitude 3.2 (ML) in 1986, only after several decades of production. Since then a steady rate of seismicity is observed, distributed over several fields. The largest events (up to ML=3.5 so far) cause some none-structural damage and much concern to the public. The monitoring network currently consists of 11 shallow (200m) borehole sensors and a pool of 19 accelerometers. The regional location threshold is around ML=1. The induced seismic catalogue contains more than 550 events to date and is growing at a rate of 30-50 events annually. The current work is aimed at improving source location accuracy using 3D velocity models obtained from the gas industry and the association of events with specific fault planes. The observed seismicity pattern provides insight on the behaviour of (compartments of) the gas fields under changing stress conditions.

  16. Biogeochemical and microbial analyses around gas wells and in the reservoir in a long-term used gas field

    NASA Astrophysics Data System (ADS)

    Kock, Dagmar; Krüger, Martin

    2010-05-01

    As part of a joint research project microbial communities in the area of the second largest natural gas field in Europe in the Altmark, Germany are analyzed. The Altmark gas field operated by GDF SUEZ E&P Germany GmbH is located at the southern edge of the Northeast German Basin. The reservoir horizons belong to the Permian Rotliegend formation (Saxon) and have an average depth of about 3300 m. CO2 will be injected to enhance the recovery of gas in this with conventional extraction methods nearly depleted gas field (Enhanced Gas Recovery - EGR, BMBF project CLEAN). Microbiological analyses are used to supplement a continuous gas monitoring program at the soil surface above the EGR-site. Microbial production and consumption of CH4 and CO2 are determined together with the carbon isotopic compositions to separate these indigenous biological activities from possibly upward migrating reservoir gases including CO2. The ?13C of CO2 collected in situ was similar to those in incubations, confirming a biological origin. Archaeal cell numbers were approximately one magnitude lower than bacterial cell numbers. In all samples the total number of detectable microorganisms was high in contrast to a generally low activity for CO2 and CH4 production and oxidation. For monitoring of the deep reservoir microbiological and isotopic analyses are used to investigate the microbial community before and after injection of CO2. The ?13C of CO2 and CH4 collected in situ in production waters indicate a thermogenic origin. High cell numbers for bacteria and archaea were detected in production waters from different wells. In contrast microbial activities for CO2 and CH4 production and oxidation were relatively low. So far microbial activities in reservoir fluids collected with in situ samplers at 3512m depth could not be determined in this hypersaline (salinity of 400 per mille) and hot (around 130° C) environment.

  17. Optimizing Development Strategies to Increase Reserves in Unconventional Gas Reservoirs 

    E-print Network

    Turkarslan, Gulcan

    2011-10-21

    The ever increasing energy demand brings about widespread interest to rapidly, profitably and efficiently develop unconventional resources, among which tight gas sands hold a significant portion. However, optimization of development strategies...

  18. Selection of fracture fluid for stimulating tight gas reservoirs

    E-print Network

    Malpani, Rajgopal Vijaykumar

    2007-04-25

    ..........................................51 6 Water Fracture Fluid Description ..............................................................56 7 Gel Fracture Fluid Description ..................................................................56 8 Proppant Description... Based on Proppant Concentration ........................66 24 Cumulative Frequency Distribution for 3-Year Cumulative Gas Production for Both Groups and Both Treatments (Carthage...

  19. Greenhouse Gas Emissions from Hydroelectric Reservoirs in Tropical Regions

    Microsoft Academic Search

    Luiz Pinguelli Rosa; Marco Aurelio dos Santos; Bohdan Matvienko; Ednaldo Oliveira dos Santos; Elizabeth Sikar

    2004-01-01

    This paper discusses emissions by power-dams in the tropics. Greenhouse gas emissions from tropical power-dams are produced underwater through biomass decomposition by bacteria. The gases produced in these dams are mainly nitrogen, carbon dioxide and methane. A methodology was established for measuring greenhouse gases emitted by various power-dams in Brazil. Experimental measurements of gas emissions by dams were made to

  20. Mineral content prediction for unconventional oil and gas reservoirs based on logging data

    NASA Astrophysics Data System (ADS)

    Maojin, Tan; Youlong, Zou; Guoyue

    2012-09-01

    Coal bed methane and shale oil &gas are both important unconventional oil and gas resources, whose reservoirs are typical non-linear with complex and various mineral components, and the logging data interpretation model are difficult to establish for calculate the mineral contents, and the empirical formula cannot be constructed due to various mineral. The radial basis function (RBF) network analysis is a new method developed in recent years; the technique can generate smooth continuous function of several variables to approximate the unknown forward model. Firstly, the basic principles of the RBF is discussed including net construct and base function, and the network training is given in detail the adjacent clustering algorithm specific process. Multi-mineral content for coal bed methane and shale oil &gas, using the RBF interpolation method to achieve a number of well logging data to predict the mineral component contents; then, for coal-bed methane reservoir parameters prediction, the RBF method is used to realized some mineral contents calculation such as ash, volatile matter, carbon content, which achieves a mapping from various logging data to multimineral. To shale gas reservoirs, the RBF method can be used to predict the clay content, quartz content, feldspar content, carbonate content and pyrite content. Various tests in coalbed and gas shale show the method is effective and applicable for mineral component contents prediction

  1. Wellbore stability in shale gas reservoirs, a case study of the Barnett Shale (USA).

    NASA Astrophysics Data System (ADS)

    Ouadfeul, Sid-Ali; Aliouane, Leila

    2015-04-01

    Wellbore stability in shale gas reservoirs is one of the major problems during the drilling phase; bad stability can induce the breakouts and drilling induced fractures. Wellbore stability requires the good knowledge of horizontal maximum and minimum stress, the overburden stress and the pore pressure. In this paper, we show a case study of the wellbore stability and how to estimate the mud weight in shale gas reservoir of the Barnett shale formation before drilling. The overburden stress is calculated from the seismic inversion, the minimum stress is calculated using the poro-elastic model, and however the pore pressure is calculated using the Eaton's model. Keywords: Wellbore stability, shale gas, maximum stress, minimum stress, overburden, mud weight, pore pressure.

  2. Control of coupling among three major factors for formation of high-efficiency gas reservoir—A case study on the oolitic beach gas reservoir in Feixianguan Formation in the northeast Sichuan Basin

    Microsoft Academic Search

    ZeCheng Wang; WenZhi Zhao; ShuiChang Zhang; HongJun Wang; Qian Yu

    2007-01-01

    Through a case study of the high-efficiency gas reservoir in Feixianguan Formation in the northeast Sichuan Basin, quantitative\\u000a and semi-quantitative analyses of key elements such as hydrocarbon generation, migration and accumulation, and reservoir evolution\\u000a as well as their interplay in the critical moment of reservoir formation controlled by the energy field were carried out,\\u000a by means of numerical modeling of

  3. Criteria for displacement by gas versus water in oil reservoirs 

    E-print Network

    Piper, Larry Dean

    1981-01-01

    ) where t is the time 1n years. Figure 5 presents the ma1n result of the study . Oil recovery by gravity drainage (up-dip gas injection at rates less than the critical rate) is compared with recovery by down-dip water injection at DFOR between 5 and 50... rate were also omitted. This means the gas injection curves reflect gravity drainage performance. The dashed lines are the loci of the dimensionless critical rates with points above these lines representing stable displacements. These regions may...

  4. Thermal effects during loading of vehicle-borne pressurizing gas tanks from reservoir tanks

    NASA Technical Reports Server (NTRS)

    Wing, L. D.

    1976-01-01

    Two theoretical methods of analyzing the process of filling vehicle-borne, high pressure gas tanks from gas reservoirs are presented. The first method assumes that a given weight of gas at ambient temperature and a specified pressure is required in the vehicle tank and selects a tank volume to exactly accommodate these conditions. The second method assumes the vehicle tank has a given volume and then predicts the temperature overshoot that results from loading a fixed weight of gas to a predetermined pressure and, thereafter, the final gas pressure after the vehicle tank and its contents have returned to ambient temperature. In addition, a means is presented for predicting to what pressure the vehicle tank must be loaded such that, after returning to ambient temperature, it will contain at least the desired weight of gas at the desired pressure.

  5. Selection of fracture fluid for stimulating tight gas reservoirs 

    E-print Network

    Malpani, Rajgopal Vijaykumar

    2007-04-25

    is reduced which contributes to improved fracture conductivity. Harris et al. 18 shows that how metal and borate cross-linked fluids, linear gel fluids, and surfactant gel fluids can support proppant transport. The capability of polymer based fluids... Based on Proppant Concentration ........................66 24 Cumulative Frequency Distribution for 3-Year Cumulative Gas Production for Both Groups and Both Treatments (Carthage...

  6. Prediction of Gas Injection Performance for Heterogeneous Reservoirs

    SciTech Connect

    Blunt, M.J.; Orr, F.M. Jr.

    2001-03-26

    This report was an integrated study of the physics and chemistry affecting gas injection, from the pore scale to the field scale, and involved theoretical analysis, laboratory experiments and numerical simulation. Specifically, advances were made on streamline-based simulation, analytical solutions to 1D compositional displacements, and modeling and experimental measures of three-phase flow.

  7. Low permeability gas reservoir production using large hydraulic fractures 

    E-print Network

    Holditch, Stephen A

    1970-01-01

    , eatending two hundred feet past the cavity. The situation simulated was for production with a con- stant well bore pressure. Production rate and cumulative gas produced were monitored as functions of time. From these par- ameters an economic evaluation... TABLE OF CONTENTS Page ACKNOWLEDGEMENTS LIST OF TABLES LIST OF FIGURES INT ROD UC T ION PROCEDURE . THEORY RESULTS Effect of Stimulation on Flow Rate Effect of Well Bore Pressure Effect of Formation Permeability Effect of Stimulation...

  8. Impes modeling of volumetric dry gas reservoirs with mobile water 

    E-print Network

    Forghany, Saeed

    2004-09-30

    . ................................................................................................................(3.6) 2) Otherwise, () ()[] )kk = r 4/1 y 4 2 2/1 o k/k ykkkk x y ?? . .......................................................(3.7) There are essentially two methods for representing a well in a simulator: by rate constraint... of two wells with different pwf .............................................68 4.27 Block pressure projection of layer 7 at the 10th timestep........................................69 4.28 Ratio of the gas rate of well 2 over that of well 1...

  9. Deep microbial life in the Altmark natural gas reservoir: baseline characterization prior CO2 injection

    NASA Astrophysics Data System (ADS)

    Morozova, Daria; Shaheed, Mina; Vieth, Andrea; Krüger, Martin; Kock, Dagmar; Würdemann, Hilke

    2010-05-01

    Within the framework of the CLEAN project (CO2 Largescale Enhanced gas recovery in the Altmark Natural gas field) technical basics with special emphasis on process monitoring are explored by injecting CO2 into a gas reservoir. Our study focuses on the investigation of the in-situ microbial community of the Rotliegend natural gas reservoir in the Altmark, located south of the city Salzwedel, Germany. In order to characterize the microbial life in the extreme habitat we aim to localize and identify microbes including their metabolism influencing the creation and dissolution of minerals. The ability of microorganisms to speed up dissolution and formation of minerals might result in changes of the local permeability and the long-term safety of CO2 storage. However, geology, structure and chemistry of the reservoir rock and the cap rock as well as interaction with saline formation water and natural gases and the injected CO2 affect the microbial community composition and activity. The reservoir located at the depth of about 3500m, is characterised by high salinity fluid and temperatures up to 127° C. It represents an extreme environment for microbial life and therefore the main focus is on hyperthermophilic, halophilic anaerobic microorganisms. In consequence of the injection of large amounts of CO2 in the course of a commercial EGR (Enhanced Gas Recovery) the environmental conditions (e.g. pH, temperature, pressure and solubility of minerals) for the autochthonous microorganisms will change. Genetic profiling of amplified 16S rRNA genes are applied for detecting structural changes in the community by using PCR- SSCP (PCR-Single-Strand-Conformation Polymorphism) and DGGE (Denaturing Gradient Gel Electrophoresis). First results of the baseline survey indicate the presence of microorganisms similar to representatives from other saline, hot, anoxic, deep environments. However, due to the hypersaline and hyperthermophilic reservoir conditions, cell numbers are low, so that the quantification of those microorganisms as well as the determination of microbial activity was not yet possible. Microbial monitoring methods have to be further developed to study microbial activities under these extreme conditions to access their influence on the EGR technique and on enhancing the long term safety of the process by fixation of carbon dioxide by precipitation of carbonates. We would like to thank GDF SUEZ for providing the data for the Rotliegend reservoir, sample material and enabling sampling campaigns. The CLEAN project is funded by the German Federal Ministry of Education and Research (BMBF) in the frame of the Geotechnologien Program.

  10. Inflow performance relationship for perforated wells producing from solution gas drive reservoir

    SciTech Connect

    Sukarno, P. [Inst. Teknologi Bandung (Indonesia); Tobing, E.L.

    1995-10-01

    The IPR curve equations, which are available today, are developed for open hole wells. In the application of Nodal System Analysis in perforated wells, an accurate calculation of pressure loss in the perforation is very important. Nowadays, the equation which is widely used is Blount, Jones and Glaze equation, to estimate pressure loss across perforation. This equation is derived for single phase flow, either oil or gas, therefore it is not suitable for two-phase production wells. In this paper, an IPR curve equation for perforated wells, producing from solution gas drive reservoir, is introduced. The equation has been developed using two phase single well simulator combine to two phase flow in perforation equation, derived by Perez and Kelkar. A wide range of reservoir rock and fluid properties and perforation geometry are used to develop the equation statistically.

  11. Role of organic matter fractions in the Montney tight gas reservoir quality

    NASA Astrophysics Data System (ADS)

    Sanei, Hamed; Wood, James M.; Haeri Ardakani, Omid; Clarkson, Chris R.

    2015-04-01

    This study presents a new approach in Rock-Eval analysis to quantify various organic matter fractions in unconventional reservoirs. The results of study on core samples from the Triassic Montney Formation tight gas reservoir in the Western Canadian Sedimentary Basin show that operationally-defined S1 and S2 hydrocarbon peaks from conventional Rock-Eval analysis may not adequately characterize the organic constituents of unconventional reservoir rocks. Modification of the thermal recipe for Rock-Eval analysis, in conjunction with manual peak integration, provides important information with significance for the evaluation of reservoir quality. An adapted Rock-Eval method, herein called the extended slow heating (ESH) cycle, was developed in which the heating rate was slowed to 10°C per minute over an extended temperature range (150 to 650°C). For Montney core samples from the wet gas window, this method provided quantitative distinctions between major organic matter components of the rock. We show that the traditional S1 and S2 peaks can now be quantitatively divided into three components: (S1ESH) free light oil, (S2a ESH) condensed hydrocarbon residue (CHCR), and (S2b ESH + residual carbon) solid bitumen (refractory, consolidated bitumen/pyrobitumen). The majority of the total organic carbon (TOC) in the studied Montney core samples consists of solid bitumen that represents a former liquid oil phase which migrated into the larger paleo-intergranular pore spaces. Subsequent physicochemical changes to the oil environment led to the precipitation of asphaltene aggregates. Further diagenetic and thermal maturity processes consolidated these asphaltene aggregates into "lumps" of solid bitumen (or pyrobitumen at higher thermal maturity). Solid bitumen obstructs porosity and hinders fluid flow, and thus shows strong negative correlations with reservoir qualities such as porosity and pore throat size. We also find a strong positive correlation between the quantities of solid bitumen and pyrite, a relationship confirmed by petrographic evidence showing a close spatial association of bacterially-derived framboidal pyrite with solid bitumen accumulations in the intergranular paleo-pore spaces. These relationships suggest that solid bitumen and framboidal pyrite were both early products of bacterial sulphate reduction of liquid hydrocarbons following initial oil charging of the Montney Formation. Although the CHCR fraction constitutes a small portion of the mass and volume of TOC in Montney samples it has important implications for reservoir quality. This fraction represents a thin film of condensed, heavy molecular hydrocarbon adsorbed onto mineral surfaces and may represent the lighter component of the paleo-oil that migrated into the Montney reservoir. The CHCR fraction potentially plays an important role in wettability alteration by creating hydrophobic matrix pore networks in portions of the reservoir that were not already filled with solid bitumen.

  12. Percolation Pore Network Study on the Residue Gas Saturation of Dry Reservoir Rocks

    NASA Astrophysics Data System (ADS)

    Cheng, T.; Tang, Y. B.; Zou, G. Y.; Jiang, K.; Li, M.

    2014-12-01

    We tried to model the effect of pore size heterogeneity and pore connectivity on the residue gas saturation for dry gas reservoir rocks. If we consider that snap-off does not exist and only piston displacement takes place in all pores with the same size during imbibition process, in the extreme case, the residue gas saturation will be equal to zero. Thus we can suppose that the residue gas saturation of dry rocks is mainly controlled by the pore size distribution. To verify the assumption, percolation pore networks (i.e., three-dimensional simple cubic (SC) and body-center cubic (BCC)) were used in the study. The connectivity and the pore size distribution in percolation pore network could be changed randomly. The concept of water phase connectivity zw(i.e., water coordination number) and gas phase connectivity zg (i.e., gas coordination number) was introduced here. zw and zg will change during simulation and can be estimated numerically from the results of simulations through gradually saturated networks by water. The Simulation results show that when zg less than or equal to 1.5 during water quasi - static imbibition, the gas will be trapped in rock pores. Network simulation results also shows that the residue gas saturation Srg follows a power law relationship (i.e.,Srg??r?, where ?r is normalized standard deviation of the pore radius distribution, and exponent ? is a function of coordination number). This indicates that the residue gas saturation has no explicit relationship with porosity and permeability as it should have in light of previous study, pore radius distribution is the principal factor in determining the residue gas saturation of dry reservoir rocks.

  13. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    SciTech Connect

    Franklin M. Orr, Jr.

    2001-06-30

    This report outlines progress in the third 3 quarter of the first year of the DOE project ''High Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs.'' A simple theoretical formulation of vertical flow with capillary/gravity equilibrium is described. Also reported are results of experimental measurements for the same systems. The results reported indicate that displacement behavior is strongly affected by the interfacial tension of phases that form on the tie line that extends through the initial oil composition.

  14. Vertical composition gradient effects on original hydrocarbon in place volumes and liquid recovery for volatile oil and gas condensate reservoirs

    E-print Network

    Jaramillo Arias, Juan Manuel

    2000-01-01

    Around the world, volatile oil and retrograde gas reservoirs are considered as complex thermodynamic systems and even more when they exhibit vertical composition variations. Those systems must be characterized by an equation of state (EOS...

  15. Gulf of Mexico Oil and Gas Atlas Series: Play analysis of oligocene and miocene reservoirs from Texas State Offshore Waters

    Microsoft Academic Search

    S. J. Seni; R. J. Finley

    1993-01-01

    The objective of the Offshore Northern Gulf of Mexico Oil and Gas Resource Atlas Series is to define hydrocarbon plays by integrating geologic and engineering data for oil and gas reservoirs with large-scale patterns of depositional basin fill and geologic age. The primary product of the program will be an oil and gas atlas set for the offshore northern Gulf

  16. Hydrocarbon transfer pathways from Smackover source rocks to younger reservoir traps in the Monroe gas field, NE Louisiana

    SciTech Connect

    Zimmerman, R.K. (Louisiana State Univ., Baton Rouge, LA (United States))

    1993-09-01

    The Monroe gas field contained more than 7 tcf of gas in its virgin state. Much of the original gas reserves have been produced through wells penetrating the Upper Cretaceous Monroe Gas Rock Formation reservoir. Other secondary reservoirs in the field area are Eocene Wilcox, the Upper Cretaceous Arkadelphia, Nacatoch, Ozan, Lower Cretaceous, Hosston, Jurassic Schuler, and Smackover. As producing zones, these secondary producing zones reservoirs have contributed an insignificant amount gas to the field. The source of much of this gas appears to have been in the lower part of the Jurassic Smackover Formation. Maturation and migration of the hydrocarbons from a Smackover source into Upper Cretaceous traps was enhanced and helped by igneous activity, and wrench faults/unconformity conduits, respectively. are present in the pre-Paleocene section. Hydrocarbon transfer pathways appear to be more vertically direct in the Jurassic and Lower Cretaceous section than the complex pattern present in the Upper Cretaceous section.

  17. Effect of connate water on miscible displacement of reservoir oil by flue gas 

    E-print Network

    Maxwell, H. D.

    1960-01-01

    into the gas cap at 1000 psi pressure. Being heavier than any of the other fluids, it migrated through the others by gravity, thereby insuring a more thorough mixing than was obtained in the previous method used. After all the liquids had been added natural...EFFECT OF CONNATE WATER ON MISCIBLE DISPLACEMENT OF RESERVOIR OIL BY FLUE GAS A Thesis By H. D. MAXWELL, JR. Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements...

  18. A critical compilation of 1,500 large onshore gas reservoirs in Texas Gulf Coast and East Texas

    SciTech Connect

    Kosters, E.C.; Finley, R.J.; Tyler, N.

    1988-01-01

    About 1,500 gas reservoirs in the Texas Gulf Coast and east Texas have a cumulative production of at least 10 bcf. The Gulf Coast contains nearly 90% of these reservoirs. One-third of all reservoirs have produced more than 30 bcf, and another 10% have produced more than 100 bcf. In the Gulf Coast, total production from the greater than 30 bcf reservoirs is 66 to 75% of the cumulative production of all greater than 10 bcf reservoirs, the Oligocene Frio Formation accounting for about 55% of reservoirs and cumulative production. In east Texas, the greater than 30 bcf reservoirs represent 75 to 80% of the cumulative production. Reservoirs are segregated into plays, each identified on the basis of structural and depositional setting, trapping mechanism, and lithology. In the Gulf Coast, 33 gas plays, including 20 subplays, are defined. East Texas contains 12 plays with 7 subplays. Important gas plays occurs in multiple formations in each region. Fluviodeltaic sandstones of the upper Vicksburg and lower Frio Formations, overlying the south Texas Vicksburg fault zone, form the most prolific play of both regions. Other important Tertiary plays are south Texas upper Wilcox shelf-edge deltaic and reworked shallow marine sandstones, deltaic Yegua sandstones in the Houston salt basin, and Miocene stream-plain reservoirs in the central coastal region. Play designation enhances understanding of critical geologic and engineering parameters and is crucial to increasing effectiveness in exploration and production. Future detailed development studies of representative reservoirs within important plays will help define reservoir behavior, allow predictions of potential ultimate recovery, and where applicable, aid in suggesting appropriate recovery enhancement techniques such as infill drilling and recompletion of bypassed zones.

  19. Well-Production Data and Gas-Reservoir Heterogeneity -- Reserve Growth Applications

    USGS Publications Warehouse

    Dyman, Thaddeus S.; Schmoker, James W.

    2003-01-01

    Oil and gas well production parameters, including peakmonthly production (PMP), peak-consecutive-twelve month production (PYP), and cumulative production (CP), are tested as tools to quantify and understand the heterogeneity of reservoirs in fields where current monthly production is 10 percent or less of PMP. Variation coefficients, defined as VC= (F5-F95)/F50, where F5, F95, and F50 are the 5th, 95th, and 50th (median) fractiles of a probability distribution, are calculated for peak and cumulative production and examined with respect to internal consistency, type of production parameter, conventional versus unconventional accumulations, and reservoir depth. Well-production data for this study were compiled for 69 oil and gas fields in the Lower Pennsylvanian Morrow Formation of the Anadarko Basin, Oklahoma. Of these, 47 fields represent production from marine clastic facies. The Morrow data were supplemented by data from the Upper Cambrian and Lower Ordovician Arbuckle Group, Middle Ordovician Simpson Group, Middle Pennsylvanian Atoka Formation, and Silurian and Lower Devonian Hunton Group of the Anadarko Basin, one large gas field in Upper Cretaceous reservoirs of north-central Montana (Bowdoin field), and three areas of the Upper Devonian and Lower Mississippian Bakken Formation continuous-type (unconventional) oil accumulation in the Williston Basin, North Dakota and Montana. Production parameters (PMP, PYP, and CP) measure the net result of complex geologic, engineering, and economic processes. Our fundamental hypothesis is that well-production data provide information about subsurface heterogeneity in older fields that would be impossible to obtain using geologic techniques with smaller measurement scales such as petrographic, core, and well-log analysis. Results such as these indicate that quantitative measures of production rates and production volumes of wells, expressed as dimensionless variation coefficients, are potentially valuable tools for documenting reservoir heterogeneity in older fields for field redevelopment and risk analysis.

  20. DEVELOPMENT OF MORE-EFFICIENT GAS FLOODING APPLICABLE TO SHALLOW RESERVOIRS

    SciTech Connect

    William R. Rossen; Russell T. Johns; Gary A. Pope

    2003-08-21

    The objective of this research is to widen the applicability of gas flooding to shallow oil reservoirs by reducing the pressure required for miscibility using gas enrichment and increasing sweep efficiency with foam. Task 1 examines the potential for improved oil recovery with enriched gases. Subtask 1.1 examines the effect of dispersion processes on oil recovery and the extent of enrichment needed in the presence of dispersion. Subtask 1.2 develops a fast, efficient method to predict the extent of enrichment needed for crude oils at a given pressure. Task 2 develops improved foam processes to increase sweep efficiency in gas flooding. Subtask 2.1 comprises mechanistic experimental studies of foams with N2 gas. Subtask 2.2 conducts experiments with CO{sub 2} foam. Subtask 2.3 develops and applies a simulator for foam processes in field application.

  1. Drilling and production statistics for major US coalbed methane and gas shale reservoirs. Topical report, June-August 1995

    SciTech Connect

    Kelso, B.S.; Lombardi, T.E.; Kuuskraa, J.A.

    1995-12-01

    The objective of this work is to provide GRI with a review and analysis of the oil and gas industry`s activity level and associated production from the major coalbed methane and gas shale reservoirs in the U.S. The authors specifically focused on the pre- and post-Section 29 qualifying deadline of December 1992 for unconventional gas Tax Credits. The primary plays investigated include the coalbed methane reservoirs in the San Juan, Warrier, Appalachian, Uinta, Powder River, and Pieceance basins and the gas shale plays in the Michigan, Fort Worth, Appalachian, Denver, and Illinois basins. A projection for future activity and production levels is made based on historic trends for each of the reservoir types. Telephone surveys were conducted with numerous operators to determine current activity status and to assist in projecting future activity of the two gas resources.

  2. Gas reservoir potential of the Lower Ordovician Beekmantown Group, Quebec Lowlands, Canada discussion

    SciTech Connect

    Friedman, G.M. [Univ. of New York, Brooklyn, NY (United States)

    1996-10-01

    Dykstra and Longman (1995), in an interesting paper, discussed the gas-reservoir potential of the Lower Ordovician Beekmantown Group of Quebec, Canada. They pointed out that the dolomites of this group provide an important exploration target in both the autochthon and the overlying thrust sheets. They then compare their rocks with those of correlative units in Oklahoma. Nowhere in their paper do they relate their study to the extensive work on these same rocks in the contiguous parts of the same basin in neighboring New York state. The purpose of this discussion is to fill in this lack and provide information on prospective Cambrian-Ordovician reservoirs in New York state, for which the Oil and Gas Investor (Anonymous, 1995a) has predicted counties of western New York are the next frontier for the Cambrian-Ordovician play. Dykstra and Longman (1995) compare their Quebec rocks with those of correlative rocks in faraway Oklahoma and completely overlook those in the same basin in nearby New York. At least one of the boreholes that we have studied in the St. Lawrence Valley is only tens of miles from their boreholes (Harris and Friedman, 1982). During the past 31 yr our team alone has published at least 50 papers and abstracts on the surface and subsurface geology of the Beekmantown Group in New York state. Dykstra and Longman`s (1995) paper provides data identical to those we have obtained for the contiguous New York Beekmantown (for a partial reference list see Friedman, 1993, 1994a, b, 1995). Because no reference to New York state is included in their reference section, I want to quote from an abstract titled {open_quotes}Gas Potential of the Eastern Overthrust...New York{close_quotes}(Friedman, s1992), which compares with their title {open_quotes}Gas Reservoir Potential...of Quebec, Canada{close_quotes} (Dykstra and Longman, 1995).

  3. Gas hydrate saturations estimated from fractured reservoir at Site NGHP-01-10, Krishna-Godavari Basin, India

    USGS Publications Warehouse

    Lee, M.W.; Collett, T.S.

    2009-01-01

    During the Indian National Gas Hydrate Program Expedition 01 (NGHP-Ol), one of the richest marine gas hydrate accumulations was discovered at Site NGHP-01-10 in the Krishna-Godavari Basin. The occurrence of concentrated gas hydrate at this site is primarily controlled by the presence of fractures. Assuming the resistivity of gas hydratebearing sediments is isotropic, th?? conventional Archie analysis using the logging while drilling resistivity log yields gas hydrate saturations greater than 50% (as high as ???80%) of the pore space for the depth interval between ???25 and ???160 m below seafloor. On the other hand, gas hydrate saturations estimated from pressure cores from nearby wells were less than ???26% of the pore space. Although intrasite variability may contribute to the difference, the primary cause of the saturation difference is attributed to the anisotropic nature of the reservoir due to gas hydrate in high-angle fractures. Archie's law can be used to estimate gas hydrate saturations in anisotropic reservoir, with additional information such as elastic velocities to constrain Archie cementation parameters m and the saturation exponent n. Theory indicates that m and n depend on the direction of the measurement relative to fracture orientation, as well as depending on gas hydrate saturation. By using higher values of m and n in the resistivity analysis for fractured reservoirs, the difference between saturation estimates is significantly reduced, although a sizable difference remains. To better understand the nature of fractured reservoirs, wireline P and S wave velocities were also incorporated into the analysis.

  4. Integration of water and gas chemistry in an unconventional Devonian black shale gas reservoir: Microbial vs. thermogenic origin

    SciTech Connect

    Martini, A.M.; Budai, J.M.; Walter, L.M. [Univ. of Michigan, Ann Arbor, MI (United States)] [and others

    1995-12-31

    The upper Devonian Antrim Shale is a self-sourced, fractured gas reservoir that has been the target of intensive exploitation around the margin of the Michigan Basin. Significant amounts of water are commonly produced with methane in regions adjacent to subcrop of the Antrim Shale. Chemical and isotopic properties measured in the formation waters show significant regional variations and probably delineate zones of increased flow controlled by the fracture network within the Antrim Shale. The isotopic composition of Antrim methane ({gamma}{sup 13}C = -49 to -59{per_thousand}) was used to suggest that the gas is of thermtogenic origin. However, the highly {sup 13}C-enriched carbon of co-produced CO{sub 2} gas ({gamma}{sup 13}C {approx} +22{per_thousand}) and DIC in associated Antrim brines ({gamma}{sup 13}C = +19 to +31{per_thousand}) are consistent with bacterially mediated fractionation. Deuterium values in the methane ({gamma}D = -200 to -260{per_thousand}) also support a bacterial origin for methane. Preliminary correlation of deuterium in methane with that of the Antrim waters implies that methane is being generated via CO{sub 2} reduction within the reservoir.

  5. Simulating the gas hydrate production test at Mallik using the pilot scale pressure reservoir LARS

    NASA Astrophysics Data System (ADS)

    Heeschen, Katja; Spangenberg, Erik; Schicks, Judith M.; Priegnitz, Mike; Giese, Ronny; Luzi-Helbing, Manja

    2014-05-01

    LARS, the LArge Reservoir Simulator, allows for one of the few pilot scale simulations of gas hydrate formation and dissociation under controlled conditions with a high resolution sensor network to enable the detection of spatial variations. It was designed and built within the German project SUGAR (submarine gas hydrate reservoirs) for sediment samples with a diameter of 0.45 m and a length of 1.3 m. During the project, LARS already served for a number of experiments simulating the production of gas from hydrate-bearing sediments using thermal stimulation and/or depressurization. The latest test simulated the methane production test from gas hydrate-bearing sediments at the Mallik test site, Canada, in 2008 (Uddin et al., 2011). Thus, the starting conditions of 11.5 MPa and 11°C and environmental parameters were set to fit the Mallik test site. The experimental gas hydrate saturation of 90% of the total pore volume (70 l) was slightly higher than volumes found in gas hydrate-bearing formations in the field (70 - 80%). However, the resulting permeability of a few millidarcy was comparable. The depressurization driven gas production at Mallik was conducted in three steps at 7.0 MPa - 5.0 MPa - 4.2 MPa all of which were used in the laboratory experiments. In the lab the pressure was controlled using a back pressure regulator while the confining pressure was stable. All but one of the 12 temperature sensors showed a rapid decrease in temperature throughout the sediment sample, which accompanied the pressure changes as a result of gas hydrate dissociation. During step 1 and 2 they continued up to the point where gas hydrate stability was regained. The pressure decreases and gas hydrate dissociation led to highly variable two phase fluid flow throughout the duration of the simulated production test. The flow rates were measured continuously (gas) and discontinuously (liquid), respectively. Next to being discussed here, both rates were used to verify a model of gas hydrate dissociation applying the foamy oil approach, a method earlier adopted to model the Mallik production test (see abstract Abendroth et al., this volume). Combined with a dense set of data from a cylindrical electrical resistance tomography (ERT) array (see abstract Priegnitz et al., this volume), very valuable information were gained on the spatial as well as temporal formation and dissociation of gas hydrates as well as changes in permeability and resulting pathways for the fluid flow. Here we present the set-up and execution of the experiment and discuss the results from temperature and flow measurements with respect to the gas hydrate dissociation and characteristics of resulting fluid flow. Uddin, M., Wright, F., and Coombe, D. 2011. Numerical Study of Gas Evolution and Transport Behaviours in Natural Gas-Hydrate Reservoirs. Journal of Canadian Petroleum Technology 50, 70-89.

  6. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    SciTech Connect

    Franklin M. Orr, Jr.

    2002-03-31

    This report outlines progress in the second quarter of the second year of the DOE project ''High Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs''. A three-dimensional streamline simulator, developed at Stanford University, has been modified in order to use analytical one-dimensional dispersion-free solutions to multicomponent gas injection processes. The use of analytical one-dimensional solutions in combination with streamline simulation is demonstrated to speedup compositional simulations of miscible gas injection processes by orders of magnitude compared to a conventional finite difference simulator. Two-dimensional and three-dimensional examples are reported to demonstrate the potential of this technology. Finally, the assumptions of the approach and possible extensions to include the effects of gravity are discussed.

  7. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    SciTech Connect

    Franklin M. Orr, Jr.

    2001-12-31

    This report outlines progress in the first quarter of the second year of the DOE project ''High Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs''. The application of the analytical theory for gas injection processes, including the effects of volume change on mixing, has up to now been limited to fully self-sharpening systems, systems where all solution segments that connect the key tie lines present in the displacement are shock fronts. In the following report, we describe the extension of the analytical theory to include systems with rarefactions (continuous composition and saturation variations) between key tie lines. With the completion of this analysis, a completely general procedure has been developed for finding solutions for problems in which a multicomponent gas displaces a multicomponent oil.

  8. Reservoir characterization of marine and permafrost associated gas hydrate accumulations with downhole well logs

    USGS Publications Warehouse

    Collett, T.S.; Lee, M.W.

    2000-01-01

    Gas volumes that may be attributed to a gas hydrate accumulation depend on a number of reservoir parameters, one of which, gas-hydrate saturation, can be assessed with data obtained from downhole well-logging devices. This study demonstrates that electrical resistivity and acoustic transit-time downhole log data can be used to quantify the amount of gas hydrate in a sedimentary section. Two unique forms of the Archie relation (standard and quick look relations) have been used in this study to calculate water saturations (S(w)) [gas-hydrate saturation (S(h)) is equal to (1.0 - S(w))] from the electrical resistivity log data in four gas hydrate accumulations. These accumulations are located on (1) the Blake Ridge along the Southeastern continental margin of the United States, (2) the Cascadia continental margin off the pacific coast of Canada, (3) the North Slope of Alaska, and (4) the Mackenzie River Delta of Canada. Compressional wave acoustic log data have also been used in conjunction with the Timur, modified Wood, and the Lee weighted average acoustic equations to calculate gas-hydrate saturations in all four areas assessed.

  9. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    SciTech Connect

    Franklin M. Orr, Jr.

    2004-05-01

    This final technical report describes and summarizes results of a research effort to investigate physical mechanisms that control the performance of gas injection processes in heterogeneous reservoirs and to represent those physical effects in an efficient way in simulations of gas injection processes. The research effort included four main lines of research: (1) Efficient compositional streamline methods for 3D flow; (2) Analytical methods for one-dimensional displacements; (3) Physics of multiphase flow; and (4) Limitations of streamline methods. In the first area, results are reported that show how the streamline simulation approach can be applied to simulation of gas injection processes that include significant effects of transfer of components between phases. In the second area, the one-dimensional theory of multicomponent gas injection processes is extended to include the effects of volume change as components change phase. In addition an automatic algorithm for solving such problems is described. In the third area, results on an extensive experimental investigation of three-phase flow are reported. The experimental results demonstrate the impact on displacement performance of the low interfacial tensions between the gas and oil phases that can arise in multicontact miscible or near-miscible displacement processes. In the fourth area, the limitations of the streamline approach were explored. Results of an experimental investigation of the scaling of the interplay of viscous, capillary, and gravity forces are described. In addition results of a computational investigation of the limitations of the streamline approach are reported. The results presented in this report establish that it is possible to use the compositional streamline approach in many reservoir settings to predict performance of gas injection processes. When that approach can be used, it requires substantially less (often orders of magnitude) computation time than conventional finite difference compositional simulation.

  10. Geophysical assessments of renewable gas energy compressed in geologic pore storage reservoirs.

    PubMed

    Al Hagrey, Said Attia; Köhn, Daniel; Rabbel, Wolfgang

    2014-01-01

    Renewable energy resources can indisputably minimize the threat of global warming and climate change. However, they are intermittent and need buffer storage to bridge the time-gap between production (off peak) and demand peaks. Based on geologic and geochemical reasons, the North German Basin has a very large capacity for compressed air/gas energy storage CAES in porous saltwater aquifers and salt cavities. Replacing pore reservoir brine with CAES causes changes in physical properties (elastic moduli, density and electrical properties) and justify applications of integrative geophysical methods for monitoring this energy storage. Here we apply techniques of the elastic full waveform inversion FWI, electric resistivity tomography ERT and gravity to map and quantify a gradually saturated gas plume injected in a thin deep saline aquifer within the North German Basin. For this subsurface model scenario we generated different synthetic data sets without and with adding random noise in order to robust the applied techniques for the real field applications. Datasets are inverted by posing different constraints on the initial model. Results reveal principally the capability of the applied integrative geophysical approach to resolve the CAES targets (plume, host reservoir, and cap rock). Constrained inversion models of elastic FWI and ERT are even able to recover well the gradual gas desaturation with depth. The spatial parameters accurately recovered from each technique are applied in the adequate petrophysical equations to yield precise quantifications of gas saturations. Resulting models of gas saturations independently determined from elastic FWI and ERT techniques are in accordance with each other and with the input (true) saturation model. Moreover, the gravity technique show high sensitivity to the mass deficit resulting from the gas storage and can resolve saturations and temporal saturation changes down to ±3% after reducing any shallow fluctuation such as that of groundwater table. PMID:24936391

  11. The effects of fracture fluid cleanup upon the analysis of pressure buildup tests in tight gas reservoirs 

    E-print Network

    Johansen, Atle Thomas

    1988-01-01

    for several inches into the formation before any long term adverse effects on gas production will occur. If the reservoir rock permeability is not damaged by the fracture fluid invasion, no serious water block to gas flow will occur. However gas production... not appear to be a problem when the capillary pressure and water mobility are large enough to rapidly imbibe the fracture water into the formation. If the reservoir rock permeability in the invaded zone is not severely damaged and the pressure drawdown...

  12. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    SciTech Connect

    Franklin M. Orr, Jr.

    2001-03-31

    This report outlines progress in the second 3 months of the first year of the DOE project ''High Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs.'' The development of an automatic technique for analytical solution of one-dimensional gas flow problems with volume change on mixing is described. The aim of this work is to develop a set of ultra-fast compositional simulation tools that can be used to make field-scale predictions of the performance of gas injection processes. To achieve the necessary accuracy, these tools must satisfy the fundamental physics and chemistry of the displacement from the pore to the reservoir scales. Thus this project focuses on four main research areas: (1) determination of the most appropriate methods of mapping multicomponent solutions to streamlines and streamtubes in 3D; (2) development of techniques for automatic generation of analytical solutions for one-dimensional flow along a streamline; (3) experimental investigations to improve the representation of physical mechanisms that govern displacement efficiency along a streamline; and (4) theoretical and experimental investigations to establish the limitations of the streamline/streamtube approach. In this report they briefly review the status of the research effort in each area. They then give a more in depth discussion of their development of techniques for analytic solutions along a streamline including volume change on mixing for arbitrary numbers of components.

  13. Analysis of the Development of Messoyakha Gas Field: A Commercial Gas Hydrate Reservoir 

    E-print Network

    Omelchenko, Roman 1987-

    2012-12-11

    Natural gas is an important energy source that contributes up to 25% of the total US energy reserves (DOE 2011). An increase in natural gas demand spurs further development of unconventional resources, including methane ...

  14. Developing a tight gas sand advisor for completion and stimulation in tight gas reservoirs worldwide

    E-print Network

    Bogatchev, Kirill Y

    2008-10-10

    consolidations with adequate strengths after being exposed to extended pump times in water-based fracturing fluids and high temperatures.44 TABLE 2 - TYPICAL PROPPANT PROPERTIES Proppant type Sand Precured Resin Coated Sand Partially Cured Resin.... The modules include Perforation Selection and Proppant Selection. Based on input well/reservoir parameters these subroutines provide unambiguous recommendations concerning which perforation strategy(s) and what proppant(s) are applicable for a given well...

  15. Development of improved technologies and techniques for reducing base gas requirements in underground gas storage facilities: Simulation study of hanson field gas storage reservoir. Final report, May 1989-November 1989

    SciTech Connect

    Modine, A.D.

    1989-11-01

    Base gas requirements in the U.S. amount to a few trillion cubic feet. The Gas Research Institute has proposed a gas storage operating plan whereby an inert gas or a low BTU gas could be injected to replace part of the hydrocarbon gas. A reservoir simulator has been developed, enhanced and tested to solve gas-water reservoir problems where the gas may be treated as a two-component miscible mixture. The previously developed reservoir simulator was further enhanced to include a local grid refinement option, which allows the engineer to study a portion of the field in more detail compared to the rest of the field. The simulator was tested for correctness and completeness. A simulation study was conducted for the Hanson Field Gas Storage Reservoir using two models with different layering. The reservoir history matching was duplicated and several prediction cases were run to study the effectiveness of the replacement of base gas with an inert gas. The results show that replacement of a portion of the hydrocarbon base gas with an inert gas can be an attractive alternative for the gas storage industry.

  16. Relief-well requirements to kill a high-rate gas blowout from a deepwater reservoir

    SciTech Connect

    Warriner, R.A. (Triton Engineering Services Co. (US)); Cassity, T.G. (Cameron Iron Works (US))

    1988-12-01

    Relief-well requirements were investigated for a dynamic kill of a high-rate gas blowout from a deepwater reservoir to define any necessary special procedures or equipment. Results of the investigation show that a high injection rate and a special-design large-diameter injection riser are required to dynamically kill such a blowout with seawater. The injection riser is necessary to limit surface pump pressure during the high-rate kill operation. Procedures to complete the kill operation hydrostatically with heavy fluid following the dynamic kill are outlined.

  17. Timing and Duration of Gas Charge-Driven Fracturing in Tight-Gas Sandstone Reservoirs Based on Fluid Inclusion Observations: Piceance Basin, Colorado

    NASA Astrophysics Data System (ADS)

    Fall, A.; Eichhubl, P.; Laubach, S.; Bodnar, R. J.

    2012-12-01

    Natural fractures are universally present in tight-gas sandstone reservoirs. Fractures are recognized to enhance permeability of the reservoir, provide gas-migration pathways during charge, and boost connectivity with well bore during production of natural gas. "Sweet spots", or higher than average permeability and production regions, have been attributed to the presence of open fractures in the reservoir. Thus it is essential to understand the opening history of natural fractures, such as the timing with respect to hydrocarbon generation and migration in the reservoirs. The natural opening-mode fractures in the tight-gas sandstone of the Mesaverde Group in the Piceance Basin, Colorado, are partially or completely cemented by quartz and/or calcite that precipitated syn- or postkinematically relative to fracture opening. Fluid inclusions trapped in the cements record pressure, temperature, and fluid composition during subsequent fracture opening and cementation. SEM-CL imaging of cements combined with fluid inclusion microthermometry and Raman spectroscopy constrain fluid evolution trends during fracturing, and timing of fracture opening in the tight-gas sandstone reservoirs. Fluid inclusions indicate a thermal history varying from ~150°C to ~188°C to ~140°C in sandstones of the Piceance Basin. Based on microthermometry, Raman spectroscopy, and equation of state modeling calculated pore-fluid pressures varied from ~40 to 100 MPa suggesting fracture opening under significant pore-fluid overpressures. Observed variability in pore-fluid pressure over time is interpreted to reflect dynamic conditions of episodic gas charge. Models of gas and oil generation in the Piceance Basin suggest that fracture opening and elevated pore-fluid pressures coincided with maximum gas generation within the Mesaverde Group. These observations demonstrate that protracted growth of the pervasive fracture system was the consequence of gas maturation and reservoir charge, and that fracture opening lasted for ~35 m.y.

  18. Characterization of the deep microbial life in the Altmark natural gas reservoir

    NASA Astrophysics Data System (ADS)

    Morozova, D.; Alawi, M.; Vieth-Hillebrand, A.; Kock, D.; Krüger, M.; Wuerdemann, H.; Shaheed, M.

    2010-12-01

    Within the framework of the CLEAN project (CO2 Largescale Enhanced gas recovery in the Altmark Natural gas field) technical basics with special emphasis on process monitoring are explored by injecting CO2 into a gas reservoir. Our study focuses on the investigation of the in-situ microbial community of the Rotliegend natural gas reservoir in the Altmark, located south of the city Salzwedel, Germany. In order to characterize the microbial life in the extreme habitat we aim to localize and identify microbes including their metabolism influencing the creation and dissolution of minerals. The ability of microorganisms to speed up dissolution and formation of minerals might result in changes of the local permeability and the long-term safety of CO2 storage. However, geology, structure and chemistry of the reservoir rock and the cap rock as well as interaction with saline formation water and natural gases and the injected CO2 affect the microbial community composition and activity. The reservoir located at the depth of approximately 3500 m, is characterised by high salinity (420 g/l) and temperatures up to 127°C. It represents an extreme environment for microbial life and therefore the main focus is on hyperthermophilic, halophilic anaerobic microorganisms. In consequence of the injection of large amounts of CO2 in the course of a commercial EGR (Enhanced Gas Recovery), the environmental conditions (e.g. pH, temperature, pressure and solubility of minerals) for the autochthonous microorganisms will change. Genetic profiling of amplified 16S rRNA genes are applied for detecting structural changes in the community by using PCR- SSCP (PCR-Single-Strand-Conformation Polymorphism), DGGE (Denaturing Gradient Gel Electrophoresis) and 16S rRNA cloning. First results of the baseline survey indicate the presence of microorganisms similar to representatives from other deep environments. The sequence analyses revealed the presence of several H2-oxidising bacteria (Hydrogenophaga sp., Adicdovorax sp., Ralstonia sp., Pseudomonas sp.), thiosulfate-oxidising bacteria (Diaphorobacter sp.) and biocorrosive thermophilic microorganisms, which have not previously been cultivated. Furthermore, several uncultivated microorganisms were found, that were similar to representatives from other saline, hot, anoxic, deep environments. However, due to the hypersaline and hyperthermophilic reservoir conditions, cell numbers are low, so that the quantification of those microorganisms as well as the determination of microbial activity was not yet possible. Microbial monitoring methods have to be further developed to study microbial activities under these extreme conditions to access their influence on the EGR technique and on enhancing the long term safety of the process by fixation of carbon dioxide by precipitation of carbonates. We thank GDF SUEZ for providing the data for the Rotliegend reservoir, sample material and supporting sampling campaigns. The CLEAN project is funded by the German Federal Ministry of Education and Research (BMBF) in the framework of the GEOTECHNOLOGIEN Program.

  19. New method for gas and oil shale reservoirs characterisation using magnetic analysis

    NASA Astrophysics Data System (ADS)

    Ivakhnenko, Aleksandr; Telman, Meruert; Makarova, Maria; Zhaksylyk, Zhanaim; Abirov, Rustem; Makhatova, Meruyert

    2015-04-01

    This research describes proposed method for determination of total organic content (TOC), clay typing and relative degree of maturation in shale unconventional reservoirs based on analysis of magnetic properties of shales. Experimental measurements were undertaken in shales from United Kingdom (Edinburgh shales) and Kazakhstan for comparison of their magnetic properties, including low field and high field magnetic susceptibilities, together with SEM and XRD analysis. The results showed that studied shales comprised of various clay types had different capacity in accumulation of organic matter, thus, affecting the total organic content and magnetic properties. Based on the results we proposed magnetic indicators (MI) of productive gas and oil shale intervals in order to determine relative TOC, clay typing and a degree of maturation. The set of magnetic measurements, used as a logging tool or core scanning procedure, can potentially provide data about selecting the best shale productive reservoir horizons. This can be a non-destructive and rapid method for shale reservoir characterization, being used routinely in both laboratory and field conditions.

  20. Spatial and temporal patterns of greenhouse gas emissions from Three Gorges Reservoir of China

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Wu, B. F.; Zeng, Y.

    2013-02-01

    Anthropogenic activity has led to significant emissions of greenhouse gas (GHG), which is thought to play important roles in global climate changes. It remains unclear about the kinetics of GHG emissions, including carbon dioxide (CO2), methane (CH4) and nitrous Oxide (N2O) from the Three Gorges Reservoir (TGR) of China, which was formed after the construction of the famous Three Gorges Dam. Here we report monthly measurements for one year of the fluxes of these gases at multiple sites within the TGR region, including three major tributaries, six mainstream sites, two downstream sites and one upstream site. The tributary areas have lower CO2 fluxes than the main storage; CH4 fluxes in the tributaries and upper reach mainstream sites are relative higher. Overall, TGR showed significantly lower CH4 emission rates than most new reservoirs in temperate and tropical regions. We attribute this to the well-oxygenated deep water and high water velocities that may facilitate the consumption of CH4. TGR's CO2 fluxes were lower than most tropical reservoirs and higher than most temperate systems. This could be explained by the high load of labile soil carbon delivered through erosion to the Yangtze River. Compared to fossil-fuelled power plants of equivalent power output, TGR is a very small GHG emitter - annual CO2-equivalent emissions are approximately 1.7% of that of a coal-fired generating plant of comparable power output.

  1. Geology, reservoir engineering and methane hydrate potential of the Walakpa Gas Field, North Slope, Alaska. Final report

    SciTech Connect

    Glenn, R.K.; Allen, W.W.

    1992-12-01

    The Walakpa Gas Field, located near the city of Barrow on Alaska`s North Slope, has been proven to be methane-bearing at depths of 2000--2550 feet below sea level. The producing formation is a laterally continuous, south-dipping, Lower Cretaceous shelf sandstone. The updip extent of the reservoir has not been determined by drilling, but probably extends to at least 1900 feet below sea level. Reservoir temperatures in the updip portion of the reservoir may be low enough to allow the presence of in situ methane hydrates. Reservoir net pay however, decreases to the north. Depths to the base of permafrost in the area average 940 feet. Drilling techniques and production configuration in the Walakpa field were designed to minimize formation damage to the reservoir sandstone and to eliminate methane hydrates formed during production. Drilling development of the Walakpa field was a sequential updip and lateral stepout from a previously drilled, structurally lower confirmation well. Reservoir temperature, pressure, and gas chemistry data from the development wells confirm that they have been drilled in the free-methane portion of the reservoir. Future studies in the Walakpa field are planned to determine whether or not a component of the methane production is due to the dissociation of updip in situ hydrates.

  2. Numerical simulations of the Macondo well blowout reveal strong control of oil flow by reservoir permeability and exsolution of gas

    PubMed Central

    Oldenburg, Curtis M.; Freifeld, Barry M.; Pruess, Karsten; Pan, Lehua; Finsterle, Stefan; Moridis, George J.

    2012-01-01

    In response to the urgent need for estimates of the oil and gas flow rate from the Macondo well MC252-1 blowout, we assembled a small team and carried out oil and gas flow simulations using the TOUGH2 codes over two weeks in mid-2010. The conceptual model included the oil reservoir and the well with a top boundary condition located at the bottom of the blowout preventer. We developed a fluid properties module (Eoil) applicable to a simple two-phase and two-component oil-gas system. The flow of oil and gas was simulated using T2Well, a coupled reservoir-wellbore flow model, along with iTOUGH2 for sensitivity analysis and uncertainty quantification. The most likely oil flow rate estimated from simulations based on the data available in early June 2010 was about 100,000 bbl/d (barrels per day) with a corresponding gas flow rate of 300 MMscf/d (million standard cubic feet per day) assuming the well was open to the reservoir over 30 m of thickness. A Monte Carlo analysis of reservoir and fluid properties provided an uncertainty distribution with a long tail extending down to 60,000 bbl/d of oil (170 MMscf/d of gas). The flow rate was most strongly sensitive to reservoir permeability. Conceptual model uncertainty was also significant, particularly with regard to the length of the well that was open to the reservoir. For fluid-entry interval length of 1.5 m, the oil flow rate was about 56,000 bbl/d. Sensitivity analyses showed that flow rate was not very sensitive to pressure-drop across the blowout preventer due to the interplay between gas exsolution and oil flow rate. PMID:21730177

  3. The performance of a volatile oil reservoir overlain by a gas cap

    E-print Network

    Ellis, Joseph Ralph, Jr

    1960-01-01

    . Figure 3 Flow Chart for Main Program Routine First Equilibrium and Fluid Distribution Assumpt(on Input (xt), K-values at Pb, Vot, m-factor I o' ( GC), Vu (M ), (M ), (M ) ( ) o' oo' go' GCI' u o ' g Read PJ, K-values at PJ, (pc), (p ). oJ' SJ 3'lash... hydrocarbon voluxne, (V~)i, and total hydrocarbon reservoir voluxxxe, V . OOZ i and moles of gas in gas cap, (M ) . Subscript (i) gGC i for initial may be replaced with (j-l). Fig Fl Cb t(*MI P g A Ml I ik Mgqcd*. dgiid IPdl I ~ K- I tPb, v, I i' (Vl...

  4. Reservoir engineering study of low-permeability Western gas sands. Final report

    SciTech Connect

    Bixel, H.C.

    1982-10-01

    The parameters of formation permeability, porosity, gas saturation net pay thickness, and well spacing were investigated to develop a multiple-well transient test. Long test times were found to be required for interference or pulse testing in low permeability gas reservoirs; however, well spacing has been optimized. The new type curves developed account for the length of time a well was on production prior to shut-in for the buildup test. Estimates of permeability, fracture half-length, and fracture conductivity are given by analysis of the pressure buildup using the curves. It was found that the results from Horner analysis of a vertically fractured well's pressure analysis are affected by the length of time a well produces prior to starting the buildup test. Long dimensionless flow times are needed for the Horner straight line to develop, thus requiring long flowtimes for Horner analysis of fractured wells in low permeability reservoirs. Several examples using the new curves are presented. The uniqueness study indicated that when certain parameters are accurately known through rock analysis and pressure studies, the simulations are unique. If a few key parameters are unknown and must be determined through history-matching with the simulator, uncertainty arises as to whether the solution is unique. Additional studies concerning fracture skin and wellbore storage, fracture geometry, and fracture fluid remaining in and around the fracture were performed to determine their effects on the pressure transient response and production forecast of a well. 68 figures, 10 tables.

  5. Noble gas evidence for two fluids in the Baca (Valles Caldera) geothermal reservoir

    NASA Astrophysics Data System (ADS)

    Smith, S. P.; Kennedy, B. M.

    1985-04-01

    Noble gas elemental and isotopic abundances were measured in steam from four wells in the Baca geothermal reservoir located in the Valles Caldera, New Mexico. The 40Ar /36Ar ratio and noble gas elemental abundances relative to 36Ar are all strongly correlated with 1/ 36Ar, the inverse of the argon content. Ratios of ( ?, n)-produced 21Ne? and radiogenic 40Ar? to total 4He (dominantly radiogenic) are nearly constant at 2.1 × 10-8 and 0.20, respectively. The 3He /4He ratio covers a restricted range of 3.9 to 4.8 times atmospheric. The high 3He content of the gas indicates the presence of a helium component ultimately derived from the mantle. Kr and Xe isotopic compositions are close to atmospheric; excess 129Xe? is <0.25% of the total 129Xe. The high degree of linear correlation among the various noble gas results strongly suggests that the Baca reservoir contains two distinct fluids that are produced in varying proportions from individual wells. The noble gases in fluid A (~2900 mg/1 C1) are air-like, but with lighter gases and isotopes preferentially enriched. The fluid A 36Ar content is low, only 13% that of 10°C air-saturated water (ASW). The second fluid, B (~ 1700 mg/1 C1), is the dominant carrier of the radiogenic and mantle-derived gases. The heavier non-radiogenic gases are preferentially enriched in fluid B, and its 36Ar content is very low, only 5-7% ASW. The source of the noble gases in fluid A is tentatively ascribed to leaching of the relatively young (<1.4 m.y.) volcanic Bandelier Tuff. The radiogenic gases and mantle-derived helium in fluid B suggest a deeper source, possibly including gases escaping from a magma.

  6. Niobrara gas play: exploration and development of a low pressure, low permeability gas reservoir

    Microsoft Academic Search

    C. A. Brown; J. W. Crafton; J. G. Golson

    1981-01-01

    The Niobrara Gas Play in eastern Colorado, northwestern Kansas and western Nebraska is an exemplary model for developing an integrated interdisciplinary exploration and exploitation strategy. This paper demonstrates a method to incorporate all types of analyses including geology and gas origin, petrology, drilling and completion, log interpretation, fracture stimulation and producing methods. Together these analyses are integrated into a rigorous

  7. Accounting for Adsorbed gas and its effect on production bahavior of Shale Gas Reservoirs 

    E-print Network

    Mengal, Salman Akram

    2010-10-12

    in previous literature are reviewed to include adsorbed gas in them. More over end of the transient time data can also be used to estimate OGIP. Kings modified z* and Bumb and McKee’s adsorption compressibility factor for adsorbed gas are used in this work...

  8. Coupling Hydraulic Fracturing Propagation and Gas Well Performance for Simulation of Production in Unconventional Shale Gas Reservoirs

    NASA Astrophysics Data System (ADS)

    Wang, C.; Winterfeld, P. H.; Wu, Y. S.; Wang, Y.; Chen, D.; Yin, C.; Pan, Z.

    2014-12-01

    Hydraulic fracturing combined with horizontal drilling has made it possible to economically produce natural gas from unconventional shale gas reservoirs. An efficient methodology for evaluating hydraulic fracturing operation parameters, such as fluid and proppant properties, injection rates, and wellhead pressure, is essential for the evaluation and efficient design of these processes. Traditional numerical evaluation and optimization approaches are usually based on simulated fracture properties such as the fracture area. In our opinion, a methodology based on simulated production data is better, because production is the goal of hydraulic fracturing and we can calibrate this approach with production data that is already known. This numerical methodology requires a fully-coupled hydraulic fracture propagation and multi-phase flow model. In this paper, we present a general fully-coupled numerical framework to simulate hydraulic fracturing and post-fracture gas well performance. This three-dimensional, multi-phase simulator focuses on: (1) fracture width increase and fracture propagation that occurs as slurry is injected into the fracture, (2) erosion caused by fracture fluids and leakoff, (3) proppant subsidence and flowback, and (4) multi-phase fluid flow through various-scaled anisotropic natural and man-made fractures. Mathematical and numerical details on how to fully couple the fracture propagation and fluid flow parts are discussed. Hydraulic fracturing and production operation parameters, and properties of the reservoir, fluids, and proppants, are taken into account. The well may be horizontal, vertical, or deviated, as well as open-hole or cemented. The simulator is verified based on benchmarks from the literature and we show its application by simulating fracture network (hydraulic and natural fractures) propagation and production data history matching of a field in China. We also conduct a series of real-data modeling studies with different combinations of hydraulic fracturing parameters and present the methodology to design these operations with feedback of simulated production data. The unified model aids in the optimization of hydraulic fracturing design, operations, and production.

  9. An evaluation of the deep reservoir conditions of the Bacon-Manito geothermal field, Philippines using well gas chemistry

    SciTech Connect

    D'Amore, Franco; Maniquis-Buenviaje, Marinela; Solis, Ramonito P.

    1993-01-28

    Gas chemistry from 28 wells complement water chemistry and physical data in developing a reservoir model for the Bacon-Manito geothermal project (BMGP), Philippines. Reservoir temperature, THSH, and steam fraction, y, are calculated or extrapolated from the grid defined by the Fischer-Tropsch (FT) and H2-H2S (HSH) gas equilibria reactions. A correction is made for H2 that is lost due to preferential partitioning into the vapor phase and the reequilibration of H2S after steam loss.

  10. Numerical simulations of depressurization-induced gas production from gas hydrate reservoirs at the Walker Ridge 312 site, northern Gulf of Mexico

    SciTech Connect

    Myshakin, Evgeniy M.; Gaddipati, Manohar; Rose, Kelly; Anderson, Brian J.

    2012-06-01

    In 2009, the Gulf of Mexico (GOM) Gas Hydrates Joint-Industry-Project (JIP) Leg II drilling program confirmed that gas hydrate occurs at high saturations within reservoir-quality sands in the GOM. A comprehensive logging-while-drilling dataset was collected from seven wells at three sites, including two wells at the Walker Ridge 313 site. By constraining the saturations and thicknesses of hydrate-bearing sands using logging-while-drilling data, two-dimensional (2D), cylindrical, r-z and three-dimensional (3D) reservoir models were simulated. The gas hydrate occurrences inferred from seismic analysis are used to delineate the areal extent of the 3D reservoir models. Numerical simulations of gas production from the Walker Ridge reservoirs were conducted using the depressurization method at a constant bottomhole pressure. Results of these simulations indicate that these hydrate deposits are readily produced, owing to high intrinsic reservoir-quality and their proximity to the base of hydrate stability. The elevated in situ reservoir temperatures contribute to high (5–40 MMscf/day) predicted production rates. The production rates obtained from the 2D and 3D models are in close agreement. To evaluate the effect of spatial dimensions, the 2D reservoir domains were simulated at two outer radii. The results showed increased potential for formation of secondary hydrate and appearance of lag time for production rates as reservoir size increases. Similar phenomena were observed in the 3D reservoir models. The results also suggest that interbedded gas hydrate accumulations might be preferable targets for gas production in comparison with massive deposits. Hydrate in such accumulations can be readily dissociated due to heat supply from surrounding hydrate-free zones. Special cases were considered to evaluate the effect of overburden and underburden permeability on production. The obtained data show that production can be significantly degraded in comparison with a case using impermeable boundaries. The main reason for the reduced productivity is water influx from the surrounding strata; a secondary cause is gas escape into the overburden. The results dictate that in order to reliably estimate production potential, permeability of the surroundings has to be included in a model.

  11. Numerical modeling of gas migration into and through faulted sand reservoirs in Pabst Field (Main Pass East Block 259), northern Gulf of Mexico 

    E-print Network

    Li, Yuqian

    2006-08-16

    The further exploration and development of Pabst Gas Field with faulted sand reservoirs require an understanding of the properties and roles of faults, particularly Low Throw near Vertical Faults (LTNVFs), in gas migration and accumulation at a...

  12. E ect of the reservoir size on gas adsorption in inhomogeneous porous media E. Kierlik, 1 J. Puibasset, 2 and G. Tarjus 1

    E-print Network

    Recanati, Catherine

    E#11;ect of the reservoir size on gas adsorption in inhomogeneous porous media E. Kierlik, 1 J characterized by many local minima, i.e. metastable states.[2{4] The above picture of gas adsorption of the reservoir on the adsorption isotherms of a uid in disordered or inhomogeneous mesoporous solids. We

  13. Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity. [Jurassic Smackover Formation

    SciTech Connect

    Kopaska-Merkel, D.C.; Moore, H.E. Jr.; Mann, S.D.; Hall, D.R.

    1992-06-01

    This volume contains maps, well logging correlated to porosity and permeability, structural cross section, graph of production history, porosity vs. natural log permeability plot, detailed core log, paragenetic sequence and reservoir characterization sheet of the following fields in southwest Alabama: Appleton oil field; Barnett oil field; Barrytown oil field; Big Escambia Creek gas and condensate field; Blacksher oil field; Broken Leg Creed oil field; Bucatunna Creed oil field; Chappell Hill oil field; Chatom gas and condensate field; Choctaw Ridge oil field; Chunchula gas and condensate field; Cold Creek oil field; Copeland gas and condensate field; Crosbys Creed gas and condensate field; and East Barnett oil field. (AT)

  14. Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity. Appendix 1, Volume 1

    SciTech Connect

    Kopaska-Merkel, D.C.; Moore, H.E. Jr.; Mann, S.D.; Hall, D.R.

    1992-06-01

    This volume contains maps, well logging correlated to porosity and permeability, structural cross section, graph of production history, porosity vs. natural log permeability plot, detailed core log, paragenetic sequence and reservoir characterization sheet of the following fields in southwest Alabama: Appleton oil field; Barnett oil field; Barrytown oil field; Big Escambia Creek gas and condensate field; Blacksher oil field; Broken Leg Creed oil field; Bucatunna Creed oil field; Chappell Hill oil field; Chatom gas and condensate field; Choctaw Ridge oil field; Chunchula gas and condensate field; Cold Creek oil field; Copeland gas and condensate field; Crosbys Creed gas and condensate field; and East Barnett oil field. (AT)

  15. Electrical anisotropy of gas hydrate-bearing sand reservoirs in the Gulf of Mexico

    USGS Publications Warehouse

    Cook, Anne E.; Anderson, Barbara I.; Rasmus, John; Sun, Keli; Li, Qiming; Collett, Timothy S.; Goldberg, David S.

    2012-01-01

    We present new results and interpretations of the electricalanisotropy and reservoir architecture in gashydrate-bearingsands using logging data collected during the Gulf of MexicoGasHydrate Joint Industry Project Leg II. We focus specifically on sandreservoirs in Hole Alaminos Canyon 21 A (AC21-A), Hole Green Canyon 955 H (GC955-H) and Hole Walker Ridge 313 H (WR313-H). Using a new logging-while-drilling directional resistivity tool and a one-dimensional inversion developed by Schlumberger, we resolve the resistivity of the current flowing parallel to the bedding, R| and the resistivity of the current flowing perpendicular to the bedding, R|. We find the sandreservoir in Hole AC21-A to be relatively isotropic, with R| and R| values close to 2 ? m. In contrast, the gashydrate-bearingsandreservoirs in Holes GC955-H and WR313-H are highly anisotropic. In these reservoirs, R| is between 2 and 30 ? m, and R| is generally an order of magnitude higher. Using Schlumberger's WebMI models, we were able to replicate multiple resistivity measurements and determine the formation resistivity the gashydrate-bearingsandreservoir in Hole WR313-H. The results showed that gashydrate saturations within a single reservoir unit are highly variable. For example, the sand units in Hole WR313-H contain thin layers (on the order of 10-100 cm) with varying gashydrate saturations between 15 and 95%. Our combined modeling results clearly indicate that the gashydrate-bearingsandreservoirs in Holes GC955-H and WR313-H are highly anisotropic due to varying saturations of gashydrate forming in thin layers within larger sand units.

  16. GHG Emissions from Hydropower Reservoirs The role of hydropower reservoirs in contributing to greenhouse gas (GHG) emissions is poorly

    E-print Network

    to greenhouse gas (GHG) emissions is poorly understood, but recent studies have indicated that GHG emissions inverted funnels for ebullitive gas emissions (24 hours), floating dome for diffusive gas emissions (10 minutes), and water sample analysis for dissolved gas concentrations. Findings CO2 emissions from

  17. Gas hydrate saturations estimated from fractured reservoir at Site NGHP-01-10, Krishna-Godavari Basin, India

    NASA Astrophysics Data System (ADS)

    Lee, M. W.; Collett, T. S.

    2009-07-01

    During the Indian National Gas Hydrate Program Expedition 01 (NGHP-01), one of the richest marine gas hydrate accumulations was discovered at Site NGHP-01-10 in the Krishna-Godavari Basin. The occurrence of concentrated gas hydrate at this site is primarily controlled by the presence of fractures. Assuming the resistivity of gas hydrate-bearing sediments is isotropic, the conventional Archie analysis using the logging while drilling resistivity log yields gas hydrate saturations greater than 50% (as high as ˜80%) of the pore space for the depth interval between ˜25 and ˜160 m below seafloor. On the other hand, gas hydrate saturations estimated from pressure cores from nearby wells were less than ˜26% of the pore space. Although intrasite variability may contribute to the difference, the primary cause of the saturation difference is attributed to the anisotropic nature of the reservoir due to gas hydrate in high-angle fractures. Archie's law can be used to estimate gas hydrate saturations in anisotropic reservoir, with additional information such as elastic velocities to constrain Archie cementation parameters m and the saturation exponent n. Theory indicates that m and n depend on the direction of the measurement relative to fracture orientation, as well as depending on gas hydrate saturation. By using higher values of m and n in the resistivity analysis for fractured reservoirs, the difference between saturation estimates is significantly reduced, although a sizable difference remains. To better understand the nature of fractured reservoirs, wireline P and S wave velocities were also incorporated into the analysis.

  18. Characteristics of possible methane gas hydrate reservoirs: the Cretaceous Nanushuk and Colville groups, National Petroleum Reserve in Alaska

    SciTech Connect

    Hilton, D.; Mroz, T.H.

    1986-04-01

    Methane gas hydrates are known to exist in nature and represent a resource of large potential. Conditions necessary for methane hydrate formation occur in a wide variety of environments, including the permafrost regions of the National Petroleum Reserve in Alaska (NPRA). Water and methane gas are required to form methane gas hydrates, and their presence is dependent, in part, on the porosity and permeability of the potential reservoir rocks in the NPRA. Fifty-two very-fine- to medium-grained sandstone samples from 19 wells and core tests in the NPRA were examined. Gas producing and nonproducing strata from both the Cretaceous Nanushuk and Colville groups strata were sampled. Visual and statistical examinations indicated significant differences in petrologic constituents, grain size, porosity, and permeability between the Nanushuk and Colville samples. Differences also existed between gas producing and nonproducing units. High clay content, severe compaction, and the presence of swelling clays have reduced the porosity, permeability, and reservoir potential of the sampled strata. The inability to test extremely friable material from the Simpson Wells and Core Tests may have reduced the mean values of porosity and permeability of the samples. Further study should be focused on reservoir characteristics of the rocks in the methane gas hydrate stability zone in the Simpson area of the NPRA. Consideration should be given to swelling clays and the possibility that their presence in a well may mimic the characteristics of methane gas hydrate. 36 refs., 9 figs., 12 tabs.

  19. Carbon dioxide and helium emissions from a reservoir of magmatic gas beneath Mammoth Mountain, California

    SciTech Connect

    Sorey, M.L.; Evans, W.C. [U.S. Geological Survey, Menlo Park, California (United States)] Kennedy, B.M. [Lawrence Berkeley National Laboratory, Berkeley, California (United States)] Farrar, C.D. [U.S. Geological Survey, Carnelian Bay, California (United States)] Hainsworth, L.J. [Chemistry Department, Emory and Henry College, Emory, Virginia (United States)] Hausback, B. [Geology Department, California State University, Sacramento

    1998-07-01

    Carbon dioxide and helium with isotopic compositions indicative of a magmatic source ({delta}thinsp{sup 13}C={minus}4.5 to {minus}5{per_thousand}, {sup 3}He/{sup 4}He=4.5 to 6.7 R{sub A}) are discharging at anomalous rates from Mammoth Mountain, on the southwestern rim of the Long Valley caldera in eastern California. The gas is released mainly as diffuse emissions from normal-temperature soils, but some gas issues from steam vents or leaves the mountain dissolved in cold groundwater. The rate of gas discharge increased significantly in 1989 following a 6-month period of persistent earthquake swarms and associated strain and ground deformation that has been attributed to dike emplacement beneath the mountain. An increase in the magmatic component of helium discharging in a steam vent on the north side of Mammoth Mountain, which also began in 1989, has persisted until the present time. Anomalous CO{sub 2} discharge from soils first occurred during the winter of 1990 and was followed by observations of several areas of tree kill and/or heavier than normal needlecast the following summer. Subsequent measurements have confirmed that the tree kills arc associated with CO{sub 2} concentrations of 30{endash}90{percent} in soil gas and gas flow rates of up to 31,000 gthinspm{sup {minus}2}thinspd{sup {minus}1} at the soil surface. Each of the tree-kill areas and one area of CO{sub 2} discharge above tree line occurs in close proximity to one or more normal faults, which may provide conduits for gas flow from depth. We estimate that the total diffuse CO{sub 2} flux from the mountain is approximately 520 t/d, and that 30{endash}50 t/d of CO{sub 2} are dissolved in cold groundwater flowing off the flanks of the mountain. Isotopic and chemical analyses of soil and fumarolic gas demonstrate a remarkable homogeneity in composition, suggesting that the CO{sub 2} and associated helium and excess nitrogen may be derived from a common gas reservoir whose source is associated with some combination of magmatic degassing and thermal metamorphism of metasedimentary rocks. Furthermore, N{sub 2}/Ar ratios and nitrogen isotopic values indicate that the Mammoth Mountain gases are derived from sources separate from those that supply gas to the hydrothermal system within the Long Valley caldera. Various data suggest that the Mammoth Mountain gas reservoir is a large, low-temperature cap over an isolated hydrothermal system, that it predates the 1989 intrusion, and that it could remain a source of gas discharge for some time. {copyright} 1998 American Geophysical Union

  20. Control of water coning in gas reservoirs by injecting gas into the aquifer 

    E-print Network

    Haugen, Sigurd Arild

    1980-01-01

    of water in the producing well. fiost research on water coning has been directed toward minimizing water production by reduced well penetration or production rate con- tro1. An alternative method for gas wells with water coning problems, is to inject.... This gives high water cuts in the early stages of the succeeding production, when gas is injected deep in the aquifer. This was not a significant problem for the high permeability ratio. When the well is put on production, the established cone overrides...

  1. DEVELOPMENT OF MORE-EFFICIENT GAS FLOODING APPLICABLE TO SHALLOW RESERVOIRS

    SciTech Connect

    William R. Rossen; Russell T. Johns; Gary A. Pope

    2003-01-28

    The objective of this research is to widen the applicability of gas flooding to shallow oil reservoirs by reducing the pressure required for miscibility using gas enrichment and increasing sweep efficiency with foam. Task 1 examines the potential for improved oil recovery with enriched gases. Subtask 1.1 examines the effect of dispersion processes on oil recovery and the extent of enrichment needed in the presence of dispersion. Subtask 1.2 develops a fast, efficient method to predict the extent of enrichment needed for crude oils at a given pressure. Task 2 develops improved foam processes to increase sweep efficiency in gas flooding. Subtask 2.1 comprises mechanistic experimental studies of foams with N{sup 2} gas. Subtask 2.2 conducts experiments with CO{sup 2} foam. Subtask 2.3 develops and applies a simulator for foam processes in field application. Regarding Task 1, several results related to subtask 1.1 are given. In this period, most of our research centered on how to estimate the dispersivity at the field scale. Simulation studies (Solano et al. 2001) show that oil recovery for enriched gas drives depends on the amount of dispersion in reservoir media. But the true value of dispersion, expressed as dispersivity, at the field scale, is unknown. This research investigates three types of dispersion in permeable media to obtain realistic estimates of dispersive mixing at the field scale. The dispersivity from single-well tracer tests (SWTT), also known as echo dispersivity, is the dispersivity that is unaffected by fluid flow direction. Layering in permeable media tends to increase the observed dispersivity in well-to-well tracer tests, also known as transmission dispersivity, but leaves the echo dispersivity unaffected. A collection of SWTT data is analyzed to estimate echo dispersivity at the SWTT scale. The estimated echo dispersivities closely match a published trend with length scale in dispersivities obtained from groundwater tracer tests. This unexpected result--it was thought that transmission dispersivity should be greater than echo dispersivity--is analyzed with numerical simulation. A third type of dispersive mixing is local dispersivity, or the mixing observed at a point as tracer flows past it. Numerical simulation results show that the local dispersivity is always less than the transmission dispersivity and greater than the echo dispersivity limits. It is closer to one limit or the other depending on the amount and type of heterogeneity, the autocorrelation structure of the medium's permeability, and the lateral (vertical) permeability. The agreement between the SWTT echo dispersivities and the field trend suggests that the field data are measuring local dispersivities. All dispersivities appear to grow with length. Regarding Task 2, two results are described: (1) An experimental study of N{sup 2} foam finds the two steady-state foam-flow regimes at elevated temperature and with acid, adding evidence that the two regimes occur widely, if not universally, in foam in porous media. (2) A simulation finds that the optimal injection strategy for overcoming gravity override in homogeneous reservoirs is injection of large alternating slugs of surfactant and gas at fixed, maximum attainable injection rates. A simple model for the process explains why the this strategy works so well. Before conducting simulations of SAG displacements, however, it is important to analyze the given foam model using fractional-flow theory. Fractional-flow theory predicts that some foam processes will give foam collapse immediately behind the gas front. In simulations, numerical dispersion leads to a false impression of good sweep efficiency. In this case simply grid refinement may not warn of the inaccuracy of the simulation.

  2. DOE THREE-DIMENSIONAL STRUCTURE AND PHYSICAL PROPERTIES OF A METHANE HYDRATE DEPOSIT AND GAS RESERVOIR, BLAKE RIDGE

    SciTech Connect

    W. Steven Holbrook

    2004-11-11

    This report contains a summary of work conducted and results produced under the auspices of award DE-FC26-00NT40921, ''DOE Three-Dimensional Structure and Physical Properties of a Methane Hydrate Deposit and Gas Reservoir, Blake Ridge.'' This award supported acquisition, processing, and interpretation of two- and three-dimensional seismic reflection data over a large methane hydrate reservoir on the Blake Ridge, offshore South Carolina. The work supported by this project has led to important new conclusions regarding (1) the use of seismic reflection data to directly detect methane hydrate, (2) the migration and possible escape of free gas through the hydrate stability zone, and (3) the mechanical controls on the maximum thickness of the free gas zone and gas escape.

  3. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    SciTech Connect

    Franklin M. Orr, Jr.

    2002-06-30

    This report outlines progress in the third quarter of the second year of the DOE project ''High Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs''. High order finite difference schemes for one-dimensional, two-phase, multicomponent displacements are investigated. Numerical tests are run using a three component fluid description for a case when the interaction between phase behavior and flow is strong. Some currently used total variation diminishing (TVD) methods produce unstable results. A third order essentially non-oscillatory (ENO) method captures the effects of phase behavior for this test case. Possible modifications to ensure stability are discussed along with plans to incorporate higher order schemes into the 3DSL streamline simulator.

  4. Simulation of fracture fluid cleanup and its effect on long-term recovery in tight gas reservoirs 

    E-print Network

    Wang, Yilin

    2009-05-15

    proppants have been placed at a high enough concentration to “prop open” the fracture. The “effective length” is the portion of the propped fracture that cleans up and allows gas flow from the reservoir into the fracture then down the fracture...

  5. Performance analysis of compositional and modified black-oil models for rich gas condensate reservoirs with vertical and horizontal wells 

    E-print Network

    Izgec, Bulent

    2004-09-30

    It has been known that volatile oil and gas condensate reservoirs cannot be modeled accurately with conventional black-oil models. One variation to the black-oil approach is the modified black-oil (MBO) model that allows the use of a simple...

  6. Enhanced gas-phase hydrogen-deuterium exchange of oligonucleotide and protein ions stored in an external multipole ion reservoir.

    PubMed

    Hofstadler, S A; Sannes-Lowery, K A; Griffey, R H

    2000-01-01

    Rapid gas-phase hydrogen-deuterium (H-D) exchange from D(2)O and ND(3) into oligonucleotide and protein ions was achieved during storage in a hexapole ion reservoir. Deuterated gas is introduced through a capillary line that discharges directly into the low-pressure region of the reservoir. Following exchange, the degree of H-D exchange is determined using Fourier transform ion cyclotron resonance mass spectrometry. Gas-phase H-D exchange experiments can be conducted more than 100 times faster than observed using conventional in-cell exchange protocols that require lower gas pressures and additional pump-down periods. The short experimental times facilitate the quantitation of the number of labile hydrogens for less reactive proteins and structured oligonucleotides. For ubiquitin, we observe approximately 65 H-D exchanges after 20 s. Exchange rates of > 250 hydrogens s(-1) are observed for oligonucleotide ions when D(2)O or ND(3) is admitted directly into the external ion reservoir owing to the high local pressure in the hexapole. Partially deuterated oligonucleotide ions have been fragmented in the reservoir using infrared multiphoton dissociation (IRMPD). The resulting fragment ions show that exchange predominates at charged sites on the 5'- and 3'-ends of the oligonucleotide, whereas exchange is slower in the core. This hardware configuration is independent of the mass detector and should be compatible with other mass spectrometric platforms including quadrupole ion trap and time-of-flight mass spectrometers. PMID:10633235

  7. Simulation of fracture fluid cleanup and its effect on long-term recovery in tight gas reservoirs

    E-print Network

    Wang, Yilin

    2009-05-15

    proppants have been placed at a high enough concentration to “prop open” the fracture. The “effective length” is the portion of the propped fracture that cleans up and allows gas flow from the reservoir into the fracture then down the fracture...

  8. Total Organic Carbon prediction in shale gas reservoirs using fuzzy logic

    NASA Astrophysics Data System (ADS)

    Ouadfeul, Sid-Ali; Aliouane, Leila

    2015-04-01

    Here, we suggest the use the fuzzy logic approach for the prediction of the Total Organic Carbon (TOC) from well-logs data in shale gas reservoirs, two models are used for the estimation of the TOC from well-logs data; the first one is called the Schmoker's model while the second one is called the Passey's model. Scmocker's model requires the continuous measurement of the Bulk density, in case of absence of the bulk density measurement the Schmoker's model is not able to predict the TOC. In this case we suggest the use fuzzy logic system able to predict the total organic carbon in shale gas formations. The input of the fuzzy system is the four raw well-logs data measurements corresponding to the natural gamma ray, the neutron porosity, the slowness of the primary and shear waves. The desired output is the calculated TOC using the Schmoker's model. Application to well-logs data of two horizontal wells drilled in the lower Barnett shale clearly shows the ability of the fuzzy logic approach to suggest values of the total organic carbon in case of no bulk density measurement. Keywords TOC, Schmoker's model, Fuzzy logic, shale gas, Barnett shale, prediction.

  9. The influence of microbial activity on rock fluid interaction: Baseline characterization of deep biosphere for Enhanced Gas Recovery in the Altmark natural gas reservoir

    Microsoft Academic Search

    Daria Morozova; Mashal Alawi; Mina Shaheed; Martin Krüger; Dagmar Kock; Hilke Würdemann

    2011-01-01

    In this study the first results of the microbial monitoring within the framework of the CLEAN project are described. The microbial community of a 3.5 km deep depleted gas reservoir in Altmark, Germany was analyzed by molecular genetic techniques. Sequence analyses indicated the presence of microorganisms similar to previously identified microbes from saline, thermophilic and anaerobic environments in the deep hypersaline

  10. PRELIMINARY CHARACTERIZATION OF CO2 SEPARATION AND STORAGE PROPERTIES OF COAL GAS RESERVOIRS

    SciTech Connect

    John Kemeny; Satya Harpalani

    2004-03-01

    An attractive alternative of sequestering CO{sub 2} is to inject it into coalbed methane reservoirs, particularly since it has been shown to enhance the production of methane during near depletion stages. The basis for enhanced coalbed methane recovery and simultaneous sequestration of carbon dioxide in deep coals is the preferential sorption property of coal, with its affinity for carbon dioxide being significantly higher than that for methane. Yet, the sorption behavior of coal under competitive sorptive environment is not fully understood. Hence, the original objective of this research study was to carry out a laboratory study to investigate the effect of studying the sorption behavior of coal in the presence of multiple gases, primarily methane, CO{sub 2} and nitrogen, in order to understand the mechanisms involved in displacement of methane and its movement in coal. This had to be modified slightly since the PVT property of gas mixtures is still not well understood, and any laboratory work in the area of sorption of gases requires a definite equation of state to calculate the volumes of different gases in free and adsorbed forms. This research study started with establishing gas adsorption isotherms for pure methane and CO{sub 2}. The standard gas expansion technique based on volumetric analysis was used for the experimental work with the additional feature of incorporating a gas chromatograph for analysis of gas composition. The results were analyzed first using the Langmuir theory. As expected, the Langmuir analysis indicated that CO{sub 2} is more than three times as sorptive as methane. This was followed by carrying out a partial desorption isotherm for methane, and then injecting CO{sub 2} to displace methane. The results indicated that CO{sub 2} injection at low pressure displaced all of the sorbed methane, even when the total pressure continued to be high. However, the displacement appeared to be occurring due to a combination of the preferential sorption property of coal and reduction in the partial pressure of methane. As a final step, the Extended Langmuir (EL) model was used to model the coal-methane-CO{sub 2} binary adsorption system. The EL model was found to be very accurate in predicting adsorption of CO{sub 2}, but not so in predicting desorption of methane. The selectivity of CO{sub 2} over methane was calculated to be 4.3:1. This is, of course, not in very good agreement with the measured values which showed the ratio to be 3.5:1. However, the measured results are in good agreement with the field observation at one of the CO{sub 2} injection sites. Based on the findings of this study, it was concluded that low pressure injection of CO{sub 2} can be fairly effective in displacing methane in coalbed reservoirs although this might be difficult to achieve in field conditions. Furthermore, the displacement of methane appears to be not only due to the preferential sorption of methane, but reduction in partial pressure as well. Hence, using a highly adsorbing gas, such as CO{sub 2}, has the advantages of inert gas stripping and non-mixing since the injected gas does not mix with the recovered methane.

  11. Naturally fractured tight gas: Gas reservoir detection optimization. Quarterly report, January 1--March 31, 1997

    SciTech Connect

    NONE

    1997-12-31

    Economically viable natural gas production from the low permeability Mesaverde Formation in the Piceance Basin, Colorado requires the presence of an intense set of open natural fractures. Establishing the regional presence and specific location of such natural fractures is the highest priority exploration goal in the Piceance and other western US tight, gas-centered basins. Recently, Advanced Resources International, Inc. (ARI) completed a field program at Rulison Field, Piceance Basin, to test and demonstrate the use of advanced seismic methods to locate and characterize natural fractures. This project began with a comprehensive review of the tectonic history, state of stress and fracture genesis of the basin. A high resolution aeromagnetic survey, interpreted satellite and SLAR imagery, and 400 line miles of 2-D seismic provided the foundation for the structural interpretation. The central feature of the program was the 4.5 square mile multi-azimuth 3-D seismic P-wave survey to locate natural fracture anomalies. The interpreted seismic attributes are being tested against a control data set of 27 wells. Additional wells are currently being drilled at Rulison, on close 40 acre spacings, to establish the productivity from the seismically observed fracture anomalies. A similar regional prospecting and seismic program is being considered for another part of the basin. The preliminary results indicate that detailed mapping of fault geometries and use of azimuthally defined seismic attributes exhibit close correlation with high productivity gas wells. The performance of the ten new wells, being drilled in the seismic grid in late 1996 and early 1997, will help demonstrate the reliability of this natural fracture detection and mapping technology.

  12. Integrated Reservoir Characterization and Simulation Studies in Stripper Oil and Gas Fields

    E-print Network

    Wang, Jianwei

    2010-01-14

    field, I integrated geologic and engineering data to build a detailed reservoir characterization model of the Second White Specks (SSPK) reservoir in Garden Plains field, Alberta, Canada. The objectives of this model were to provide insights to controls...

  13. DEVELOPMENT OF MORE-EFFICIENT GAS FLOODING APPLICABLE TO SHALLOW RESERVOIRS

    SciTech Connect

    William R. Rossen; Russell T. Johns; Gary A. Pope

    2003-01-28

    The objective of this research is to widen the applicability of gas flooding to shallow oil reservoirs by reducing the pressure required for miscibility using gas enrichment and increasing sweep efficiency with foam. Task 1 examines the potential for improved oil recovery with enriched gases. Subtask 1.1 examines the effect of dispersion processes on oil recovery and the extent of enrichment needed in the presence of dispersion. Subtask 1.2 develops a fast, efficient method to predict the extent of enrichment needed for crude oils at a given pressure. Task 2 develops improved foam processes to increase sweep efficiency in gas flooding. Subtask 2.1 comprises mechanistic experimental studies of foams with N{sup 2} gas. Subtask 2.2 conducts experiments with CO{sup 2} foam. Subtask 2.3 develops and applies a simulator for foam processes in field application. Regarding Task 1, several key results are described in this report relating to subtask 1.1. In particular, we show how for slimtube experiments, oil recoveries do not increase significantly with enrichments greater than the MME. For field projects, however, the optimum enrichment required to maximize recovery on a pattern scale may be different from the MME. The optimum enrichment is likely the result of greater mixing in reservoirs than in slimtubes. In addition, 2-D effects such as channeling, gravity tonguing, and crossflow can impact the enrichment selected. We also show the interplay between various mixing mechanisms, enrichment level, and numerical dispersion. The mixing mechanisms examined are mechanical dispersion, gravity crossflow, and viscous crossflow. UTCOMP is used to evaluate the effect of these mechanisms on recovery for different grid refinements, reservoir heterogeneities, injection boundary conditions, relative permeabilities, and numerical weighting methods including higher-order methods. For all simulations, the reservoir fluid used is a twelve-component oil displaced by gases enriched above the MME. The results for subtask 1.1 show that for 1-D enriched-gas floods, the recovery difference between displacements above the MME and those at or near the MME increases significantly with dispersion. The trend, however, is not monotonic and shows a maximum at a dispersivity (mixing level) of about 4 ft. The trend is independent of relative permeabilities and gas trapping for dispersivities less than about 4 ft. For 2-D enriched gas floods with slug injection, the difference in recovery generally increases as dispersion and crossflow increase. The magnitude of the recovery differences is less than observed for the 1-D displacements. Recovery differences for 2-D models are highly dependent on relative permeabilities and gas trapping. For water alternating gas (WAG) injection, the differences in recovery increase slightly as dispersion decreases. That is, the recovery difference is significantly greater with WAG at low levels of dispersion than with slug injection. For the cases examined, the magnitude of recovery difference varies from about 1 to 8 percent of the original oil-in-place (OOIP). Regarding Task 2, three results are described in this report: (1) New experiments with N{sup 2} foam examined the mobility of liquid injected following foam in alternating-slug (SAG) foam processes. These experiments were conducted in parallel with a simulation study of foam for acid diversion in well stimulation. The new experiments qualitatively confirm several of the trends predicted by simulation. (2) A literature study finds that the two steady-state foam-flow regimes seen with a wide variety of N{sup 2} foams also appears in many studies of CO{sup 2} foams, if the data are replotted in a format that makes these regimes clear. A new experimental study of dense CO{sup 2} foam here failed to reproduce these trends, however; the reason remains under investigation. (3) A number of published foam models were examined in terms of the two foam-flow regimes and using fractional-flow theory. At least two of the foam models predict the two foam-flow regimes. Fractional-flow t

  14. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    SciTech Connect

    Franklin M. Orr, Jr.

    2003-03-31

    This report outlines progress in the second quarter of the third year of the DOE project ''High Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs''. This report presents results of an investigation of the effects of variation in interfacial tension (IFT) on three-phase relative permeability. We report experimental results that demonstrate the effect of low IFT between two of three phases on the three-phase relative permeabilities. In order to create three-phase systems, in which IFT can be controlled systematically, we employed analog liquids composing of hexadecane, n-butanol, isopropanol, and water. Phase composition, phase density and viscosity, and IFT of three-phase system were measured and are reported here. We present three-phase relative permeabilities determined from recovery and pressure drop data using the Johnson-Bossler-Naumann (JBN) method. The phase saturations were obtained from recovery data by the Welge method. The experimental results indicate that the wetting phase relative permeability was not affected by IFT variation whereas the other two-phase relative permeabilities were clearly affected. As IFT decreases the ''oil'' and ''gas'' phases become more mobile at the same phase saturations.

  15. Investigation of gas hydrate-bearing sandstone reservoirs at the "Mount Elbert" stratigraphic test well, Milne Point, Alaska

    SciTech Connect

    Boswell, R.M.; Hunter, R. (ASRC Energy Services, Anchorage, AK); Collett, T. (USGS, Denver, CO); Digert, S. (BP Exploration (Alaska) Inc., Anchorage, AK); Hancock, S. (RPS Energy Canada, Calgary, Alberta, Canada); Weeks, M. (BP Exploration (Alaska) Inc., Anchorage, AK); Mt. Elbert Science Team

    2008-01-01

    In February 2007, the U.S. Department of Energy, BP Exploration (Alaska), Inc., and the U.S. Geological Survey conducted an extensive data collection effort at the "Mount Elbert #1" gas hydrates stratigraphic test well on the Alaska North Slope (ANS). The 22-day field program acquired significant gas hydrate-bearing reservoir data, including a full suite of open-hole well logs, over 500 feet of continuous core, and open-hole formation pressure response tests. Hole conditions, and therefore log data quality, were excellent due largely to the use of chilled oil-based drilling fluids. The logging program confirmed the existence of approximately 30 m of gashydrate saturated, fine-grained sand reservoir. Gas hydrate saturations were observed to range from 60% to 75% largely as a function of reservoir quality. Continuous wire-line coring operations (the first conducted on the ANS) achieved 85% recovery through 153 meters of section, providing more than 250 subsamples for analysis. The "Mount Elbert" data collection program culminated with open-hole tests of reservoir flow and pressure responses, as well as gas and water sample collection, using Schlumberger's Modular Formation Dynamics Tester (MDT) wireline tool. Four such tests, ranging from six to twelve hours duration, were conducted. This field program demonstrated the ability to safely and efficiently conduct a research-level openhole data acquisition program in shallow, sub-permafrost sediments. The program also demonstrated the soundness of the program's pre-drill gas hydrate characterization methods and increased confidence in gas hydrate resource assessment methodologies for the ANS.

  16. Research on the methods of splitting and prediction point by point in tight sandstone gas reservoir productivity

    NASA Astrophysics Data System (ADS)

    Sheng-fu, Wen; Bao-zhi, Pan; Bi-ci, Jiang; Li-hua, Zhang; Dan, Liu; Wen-bin, Liu; Yu-hang, Guo

    2015-06-01

    Single-point productivity evaluation and prediction are of important significance for the exploration and development in a tight sandstone gas field. The method of production splitting, multiple linear regression (MLR), and support vector machine regression (SVR) was used to establish the relationship between logging data and the gas production split point-to-point in tight sandstone gas reservoirs. In this study, the western region of the Sulige area in the Ordos Basin was the object of our research. Compared with the traditional KH splitting, the KHK splitting method was better.

  17. DEVELOPMENT OF MORE-EFFICIENT GAS FLOODING APPLICABLE TO SHALLOW RESERVOIRS

    SciTech Connect

    William R. Rossen; Russell T. Johns; Gary A. Pope

    2003-01-28

    The objective of this research is to widen the applicability of gas flooding to shallow oil reservoirs by reducing the pressure required for miscibility using gas enrichment and increasing sweep efficiency with foam. Task 1 examines the potential for improved oil recovery with enriched gases. Subtask 1.1 examines the effect of dispersion processes on oil recovery and the extent of enrichment needed in the presence of dispersion. Subtask 1.2 develops a fast, efficient method to predict the extent of enrichment needed for crude oils at a given pressure. Task 2 develops improved foam processes to increase sweep efficiency in gas flooding. Subtask 2.1 comprises mechanistic experimental studies of foams with N{sub 2} gas. Subtask 2.2 conducts experiments with CO{sub 2} foam. Subtask 2.3 develops and applies a simulator for foam processes in field application. Regarding Task 1, several very important results were achieved this period for subtask 1.2. In particular, we successfully developed a robust Windows-based code to calculate MMP and MME for fluid characterizations that consist of any number of pseudocomponents. We also were successful in developing a new technique to quantify the displacement mechanism of a gas flood--that is, to determine the fraction of a displacement that is vaporizing or condensing. These new technologies will be very important to develop new correlations and to determine important parameters for the design of gas injection floods. Regarding Task 2, several results were achieved: (1) A detailed study of the accuracy of foam simulation validates the model with fits to analytical fractional-flow solutions. It shows that there is no way to represent surfactant-concentration effects on foam without some numerical artifacts. (2) New results on capillary crossflow with foam show that this is much less detrimental than earlier studies had argued. (3) It was shown that the extremely useful model of Stone for gravity segregation with foam is rigorously true as long as the standard assumptions of fractional-flow theory apply. Without this proof, it was always possible that this powerful model would break down in some important application.

  18. Influence of environmental variables on diffusive greenhouse gas fluxes at hydroelectric reservoirs in Brazil.

    PubMed

    Rogério, J P; Santos, M A; Santos, E O

    2013-11-01

    For almost two decades, studies have been under way in Brazil, showing how hydroelectric reservoirs produce biogenic gases, mainly methane (CH4) and carbon dioxide (CO2), through the organic decomposition of flooded biomass. This somewhat complex phenomenon is due to a set of variables with differing levels of interdependence that directly or indirectly affect greenhouse gas (GHG) emissions. The purpose of this paper is to determine, through a statistical data analysis, the relation between CO2, CH4 diffusive fluxes and environmental variables at the Furnas, Itumbiara and Serra da Mesa hydroelectric reservoirs, located in the Cerrado biome on Brazil's high central plateau. The choice of this region was prompted by its importance in the national context, covering an area of some two million square kilometers, encompassing two major river basins (Paraná and Tocantins-Araguaia), with the largest installed power generation capacity in Brazil, together accounting for around 23% of Brazilian territory. This study shows that CH4 presented a moderate negative correlation between CO2 and depth. Additionally, a moderate positive correlation was noted for pH, water temperature and wind. The CO2 presented a moderate negative correlation for pH, wind speed, water temperature and air temperature. Additionally, a moderate positive correlation was noted for CO2 and water temperature. The complexity of the emission phenomenon is unlikely to occur through a simultaneous understanding of all the factors, due to difficulties in accessing and analyzing all the variables that have real, direct effects on GHG production and emission. PMID:24789391

  19. Evaluation of the 3-D channeling flow in a fractured type of oil/gas reservoir

    NASA Astrophysics Data System (ADS)

    Ishibashi, T.; Watanabe, N.; Tsuchiya, N.; Tamagawa, T.

    2013-12-01

    An understanding of the flow and transport characteristics through rock fracture networks is of critical importance in many engineering and scientific applications. These include effective recovery of targeted fluid such as oil/gas, geothermal, or potable waters, and isolation of hazardous materials. Here, the formation of preferential flow path (i.e. channeling flow) is one of the most significant characteristics in considering fluid flow through rock fracture networks; however, the impact of channeling flow remains poorly understood. In order to deepen our understanding of channeling flow, the authors have developed a novel discrete fracture network (DFN) model simulator, GeoFlow. Different from the conventional DFN model simulators, we can characterize each fracture not by a single aperture value but by a heterogeneous aperture distribution in GeoFlow [Ishibashi et al., 2012]. As a result, the formation of 3-D preferential flow paths within fracture network can be considered by using this simulator. Therefore, we would challenge to construct the precise fracture networks whose fractures have heterogeneous aperture distributions in field scale, and to analyze fluid flows through the fracture networks by GeoFlow. In the present study, the Yufutsu oil/gas field in Hokkaido, Japan is selected as the subject area for study. This field is known as the fractured type of reservoir, and reliable DFN models can be constructed for this field based on the 3-D seismic data, well logging, in-situ stress measurement, and acoustic emission data [Tamagawa et al., 2012]. Based on these DFN models, new DFN models for 1,080 (East-West) × 1,080 (North-South) × 1,080 (Depth) m^3, where fractures are represented by squares of 44-346 m on a side, are re-constructed. In these new models, scale-dependent aperture distributions are considered for all fractures constructing the fracture networks. Note that the multi-scale modeling of fracture flow has been developed by the authors [Ishibashi et al., in preparation]. For the DFN models with aperture distributions, fluid flow simulations are conducted by GeoFlow. Before entering upon a discussion of the GeoFlow simulations, we show the interesting fact that approximately three-orders-of-magnitude difference in productivity is observed between two neighboring wells in the Yufutsu field. The conventional DFN model simulations can predict which productivity is high between these two wells, but they never reproduce the huge difference in well productivity. One of the reasons for this result is that the conventional DFN simulations ignored the concept of channeling flow. With these views in our mind, we see the result of the GeoFlow simulations. In the GeoFlow simulations, the huge difference in well productivity in the Yufutsu oil/gas field is successfully reproduced. This means that proper evaluation of 3D channeling flow is the key to predict well productivity in fractured reservoirs. Moreover, it is also clarified that the actual flow area is estimated to be around 20-50% of the flow area predicted by conventional DFN models. In this presentation, we will show the detail of the precise fracture network modeling and fluid flow analysis within them. The suggested method would be one of the most effective methods to improve our understanding of 3D channeling flow in fractured type of reservoirs.

  20. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2002-09-01

    Borehole seismology is the highest resolution geophysical imaging technique available to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This proposal takes direct aim at this shortcoming. P/GSI is developing a 400 level 3C clamped downhole seismic receiver array for borehole seismic 3D imaging. This array will remove the acquisition barrier to record the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for economic use of 3D borehole seismic imaging for reservoir characterization and monitoring. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore facilitate 9C reservoir imaging. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  1. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P Paulsson

    2002-05-01

    Borehole seismology is the highest resolution geophysical imaging technique available to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This proposal takes direct aim at this shortcoming. P/GSI is developing a 400 level 3C clamped downhole seismic receiver array for borehole seismic 3D imaging. This array will remove the acquisition barrier to record the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for economic use of 3D borehole seismic imaging for reservoir characterization and monitoring. By using 3C surface seismic or borehole seismic sources the 400 level receiver array will furthermore facilitate 9C reservoir imaging. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  2. Integrated Multi-Well Reservoir and Decision Model to Determine Optimal Well Spacing in Unconventional Gas Reservoirs

    E-print Network

    Ortiz Prada, Rubiel Paul

    2012-02-14

    and hence the optimal development strategy. The integrated model includes two development stages with a varying Stage-1 time span. The integrated tools were applied to an illustrative example in Deep Basin (Gething D) tight gas sands in Alberta, Canada...

  3. Relative diffusion flux: A practical concept for characterizing fracture to matrix gas transfer-application to fractured reservoir model

    SciTech Connect

    Sener, I.

    1986-01-01

    This paper introduces the concept of ''relative diffusion flux'', a new and practical approach to characterize the dissolution and diffusion regulated transfer of gas from the gas filled fracture space to the matrix oil in a dual porosity/permeability system. The proposed concept is analogous to the relative permeability concept in that the ''effective diffusion (or transfer) flux'' is determined as the product of the ''absolute (maximum) diffusion flux'' capacity of the matrix and the current level of ''relative diffusion flux''. It is shown that the latter can be expressed as a function of the current dissolved gas concentration in the matrix oil. This functional relationship between the ''relative diffusion flux'' and the dissolved gas concentration in the matrix oil is similar, in concept, to that between the relative permeability to a phase and its saturation level. It is also shown that, using the proposed method, representation of the gas transfer mechanism is reduced to a simple exchange-type relationship between the fractures and the matrix. This is achieved without having to determine an appropriate diffusion coefficient and the task of handling gas transfer by diffusion is significantly facilitated for fractured reservoir simulators. In the paper the concept of ''relative diffusion flux'' is developed, a method for obtaining the required data from a suitable laboratory experiment is provided, and the basic equations for the application of the new concept to fractured reservoir simulation are derived.

  4. Naturally fractured tight gas reservoir detection optimization. Annual report, September 1993--September 1994

    SciTech Connect

    NONE

    1994-10-01

    This report is an annual summarization of an ongoing research in the field of modeling and detecting naturally fractured gas reservoirs. The current research is in the Piceance basin of Western Colorado. The aim is to use existing information to determine the most optimal zone or area of fracturing using a unique reaction-transport-mechanical (RTM) numerical basin model. The RTM model will then subsequently help map subsurface lateral and vertical fracture geometries. The base collection techniques include in-situ fracture data, remote sensing, aeromagnetics, 2-D seismic, and regional geologic interpretations. Once identified, high resolution airborne and spaceborne imagery will be used to verify the RTM model by comparing surficial fractures. If this imagery agrees with the model data, then a further investigation using a three-dimensional seismic survey component will be added. This report presents an overview of the Piceance Creek basin and then reviews work in the Parachute and Rulison fields and the results of the RTM models in these fields.

  5. Satellite linear features and pressure variations in Cretaceous shallow gas reservoirs, southern Bowdoin dome, Montana

    SciTech Connect

    Shurr, G.W.; Tozer, M.K.; Tweed, A.D. (St. Cloud State Univ., MN (United States)); Wosick, F.D. (Williston Basin Interstate Pipeline Co., Bismarck, ND (United States))

    1991-06-01

    For three decades prior to 1960, shallow gas was produced in the southern part of Bowdoin dome from the Cretaceous Bowdoin Sandstone of the Carlile Formation and the Phillips Sandstone of the Greenhorn Formation. Historical production records from this period suggest that patterns of pressure decline are closely related to the geometry of linear features visible on satellite images. Linear features mapped at a scale of 1:1,000,000 on multispectral scanner Landsat images correspond with geomorphic elements of the Milk River, Beaver Creek, and White Water Creek drainage systems. Regional lineament zones interpreted from linear features are believed to outline basement blocks which controlled deposition and deformation on Bowdoin Dome and in other areas of the northern Great Plains. Initial formation pressures on southern Bowdoin dome are lower in a zone marked by northwest linear features, and subsequent pressure declines through several decades show areas of greatest change are bounded by linear features. A series of pressure maps illustrate isobars elongated along the northwest trend and shifting to the northwest as production continues. In the western part of the field, isobars also parallel a northeast-trending linear feature. Correspondence of isobar patterns and linear features may be related to increased fracture porosity and permeability along a basement block boundary, or it may be influenced by other geologic features related to block geometry such as depth of burial or reservoir distribution.

  6. Well-test analysis for solution-gas-drive reservoirs: Part 1; Determination of relative and absolute permeabilities

    SciTech Connect

    Serra, K.V.; Peres, A.M.M. (PETROBRAS, Rio de Janeiro, RJ (Brazil)); Reynolds, A.C. (Tulsa Univ., OK (USA))

    1990-06-01

    For transient radial flow to a well producing a solution-gas-drive reservoir, it is shown that estimates of effective phase permeabilities as functions of pressure can be obtained directly from the measured flowing wellbore pressure and the flow rates. Rough estimates of effective permeabilities as functions of oil saturation also can be obtained. It is also shown that a semilog plot of pressure squared vs. time can be used to estimate effective permeabilities and the skin factor.

  7. Secondary natural gas recovery: Targeted applications for infield reserve growth in midcontinent reservoirs, Boonsville Field, Fort Worth Basin, Texas. Topical report, May 1993--June 1995

    SciTech Connect

    Hardage, B.A.; Carr, D.L.; Finley, R.J.; Tyler, N.; Lancaster, D.E.; Elphick, R.Y.; Ballard, J.R.

    1995-07-01

    The objectives of this project are to define undrained or incompletely drained reservoir compartments controlled primarily by depositional heterogeneity in a low-accommodation, cratonic Midcontinent depositional setting, and, afterwards, to develop and transfer to producers strategies for infield reserve growth of natural gas. Integrated geologic, geophysical, reservoir engineering, and petrophysical evaluations are described in complex difficult-to-characterize fluvial and deltaic reservoirs in Boonsville (Bend Conglomerate Gas) field, a large, mature gas field located in the Fort Worth Basin of North Texas. The purpose of this project is to demonstrate approaches to overcoming the reservoir complexity, targeting the gas resource, and doing so using state-of-the-art technologies being applied by a large cross section of Midcontinent operators.

  8. Implementation of the Ensemble Kalman Filter in the Characterization of Hydraulic Fractures in Shale Gas Reservoirs by Integrating Downhole Temperature Sensing Technology 

    E-print Network

    Moreno, Jose A

    2014-08-12

    Multi-stage hydraulic fracturing in horizontal wells has demonstrated successful results for developing unconventional low-permeability oil and gas reservoirs. Despite being vastly implemented by different operators across North America, hydraulic...

  9. Role of reservoir engineering in the assessment of undiscovered oil and gas resources in the National Petroleum Reserve, Alaska

    USGS Publications Warehouse

    Verma, M.K.; Bird, K.J.

    2005-01-01

    The geology and reservoir-engineering data were integrated in the 2002 U.S. Geological Survey assessment of the National Petroleum Reserve in Alaska (NPRA). VVhereas geology defined the analog pools and fields and provided the basic information on sizes and numbers of hypothesized petroleum accumulations, reservoir engineering helped develop necessary equations and correlations, which allowed the determination of reservoir parameters for better quantification of in-place petroleum volumes and recoverable reserves. Seismic- and sequence-stratigraphic study of the NPRA resulted in identification of 24 plays. Depth ranges in these 24 plays, however, were typically greater than depth ranges of analog plays for which there were available data, necessitating the need for establishing correlations. The basic parameters required were pressure, temperature, oil and gas formation volume factors, liquid/gas ratios for the associated and nonassociated gas, and recovery factors. Finally, the re sults of U.S. Geological Survey deposit simulation were used in carrying out an economic evaluation, which has been separately published. Copyright ?? 2005. The American Association of Petroleum Geologists. All rights reserved.

  10. Gas Migration from a Tight-/Shale-Gas Reservoir to an Overlying Aquifer Through Long Fractures, Conductive Faults and Abandoned Older Wells

    NASA Astrophysics Data System (ADS)

    Moridis, G. J.; Freeman, C. M.

    2012-12-01

    Natural gas from shale reservoirs has become an increasingly important energy resource in recent years. However, the environmental challenges posed by hydraulic fracturing (a necessary stimulation method in tight- and shale-gas reservoirs) remain poorly characterized. There exist theoretical risks of leakage of contaminants from such reservoirs through hydraulically-induced fractures into groundwater resources, but no rigorous model-based analysis has been performed to assess the magnitude of these risks. The mechanisms and quantities of fluids that may realistically be transmitted through induced fractures and faults between geological strata are unknown. Possible exacerbating factors in shale gas well completion or stimulation design are likewise unknown. Quantification of these factors is necessary to quantify possible environmental risks and to aid the industry in the continuing development of sustainable hydraulic fracturing practices. We used the TOUGH+RealGasH2O code to model the two-phase flow of water and gas through long conductive features (such as fractures, conductive faults and abandoned older wells) connecting shale gas systems to shallower aquifers. The complex 3D domains in this study involve Voronoi grids describing challenging geometries that include vertical wells (in the aquifers and abandoned older gas wells), the hydraulically fractured system along long horizontal wells, and thin vertically extensive features intersecting multiple geologic strata. We investigate various configurations of the fractured system, we determine the upper limit if the possible contaminant transport solutions stemming from "worst-case scenarios", and we conduct a thorough sensitivity analysis to determine the dominant mechanisms, conditions and parameters. These include the conductivity of vertically extensive faults and fractures, the relative pressure differential of the underlying shale layer and the aquifer, the permeabilities of the productive intervals, the vertical distances between layers, etc..

  11. Layered Pseudo-Steady-State Models for tight commingled gas reservoirs 

    E-print Network

    El-Banbi, Ahmed

    1995-01-01

    equation is given by Eq. 6. 11 1. 987x10 518 ? p T lm(p) nt(p~)) ln ? + s +Dq where the radius of drainage rd is defmed by Eq. 7 for circular reservoirs, and by Eq. 8 for irregular reservoirs, r'4 = 0. 472re (7) 10. 06A (g) Wattenbarger and Ramey...

  12. Sedimentology and permeability architecture of Atokan Valley-fill natural gas reservoirs, Boonsville Field, north-central Texas

    SciTech Connect

    Burn, M.J.; Carr, D.L. [Univ. of Texas, Austin, TX (United States); Stuede, J. [Scientific Measurement Systems, Inc., Austin, TX (United States)

    1994-09-01

    The Boonsville {open_quotes}Bend Conglomerate{close_quotes} gas field in Jack and Wise counties comprises numerous thin (10-20 ft) conglomerate sandstone reservoirs within an approximately 1000-ft-thick section of Atokan strata. Reservoir sandstone bodies commonly overlie sequence-boundary unconformities and exhibit overall upward-fining grain-size trends. Many represent incised valleyfill deposits that accumulated during postunconformity baselevel rise. This stratal architecture is repeated at several levels throughout the Bend Conglomerate, suggesting that sediment accumulation occurred in a moderate-to low-accommodation setting and that base level fluctuated frequently. The reservoir units were deposited by low-sinuosity fluvial processes, causing a hierarchy of bed forms and grain-avalanche bar-front processes to produce complex grain-size variations. Permeability distribution is primarily controlled by depositional factors but may also be affected by secondary porosity created by the selective dissolution of chert clasts. High-permeability zones (up to 2.8 darcys) are characterized by macroscopic vugs comprised of clast-shaped moldic voids (up to 5 mm in diameter). Tight (low-permeability) zones are heavily cemented by silica, calcite, dolomite, and ankerite and siderite cements. Minipermeameter, x-radiograph, and petrographic studies and facies analysis conducted on cores from two Bend Conglomerate reservoirs illustrate the hierarchy of sedimentological and diagenetic controls on permeability architecture.

  13. Sedimentology and permeability architecture of Atokan Valley-Fill natural gas reservoirs, Boonsville Field, North-Central Texas

    SciTech Connect

    Burn, M.J.; Carr, D.L. [Univ. of Texas, Austin, TX (United States); Stuede, J. [Scientific Measurement Systems, Inc., Austin, TX (United States)

    1994-12-31

    The Boonsville {open_quotes}Bend Conglomerate{close_quotes} gas field in Jack and Wise Counties comprises numerous thin (10-20 ft) conglomeratic sandstone reservoirs within an approximately 1,000-ft-thick section of Atokan strata. Reservoir sandstone bodies commonly overlie sequence-boundary unconformities and exhibit overall upward-fining grain-size trends. Many represent incised valley-fill deposits that accumulated during postunconformity base-level rise. This stratal architectures is repeated at several levels throughout the Bend Conglomerate, suggesting that sediment accumulation occurred in a moderate- to low-accommodation setting and that base level fluctuated frequently. The reservoir units were deposited by low-sinuosity fluvial processes, causing a hierarchy of bed forms and grain-avalanche bar-front processes to produce complex grain-size variations. Permeability distribution is primarily controlled by depositional factors but may also be affected by secondary porosity created by the selective dissolution of chert clasts. High-permeability zones ({approximately}2.8 darcys) are characterized by macroscopic vugs composed of clast-shaped moldic voids ({approximately}5 mm in diameter). Tight (low-permeability) zones are heavily cemented by silica, calcite, dolomite, and ankerite and siderate cements. Minipermeameter, x-radiography, and petrographic studies and facies analysis conducted on cores from two Bend Conglomerate reservoirs (Threshold Development Company, I.G. Yates 33, and OXY U.S.A. Sealy {open_quotes}C{close_quotes} 2) illustrate the hierarchy of sedimentological and diagenetic controls on permeability architecture.

  14. Petrophysical Analysis and Geographic Information System for San Juan Basin Tight Gas Reservoirs

    SciTech Connect

    Martha Cather; Robert Lee; Robert Balch; Tom Engler; Roger Ruan; Shaojie Ma

    2008-10-01

    The primary goal of this project is to increase the availability and ease of access to critical data on the Mesaverde and Dakota tight gas reservoirs of the San Juan Basin. Secondary goals include tuning well log interpretations through integration of core, water chemistry and production analysis data to help identify bypassed pay zones; increased knowledge of permeability ratios and how they affect well drainage and thus infill drilling plans; improved time-depth correlations through regional mapping of sonic logs; and improved understanding of the variability of formation waters within the basin through spatial analysis of water chemistry data. The project will collect, integrate, and analyze a variety of petrophysical and well data concerning the Mesaverde and Dakota reservoirs of the San Juan Basin, with particular emphasis on data available in the areas defined as tight gas areas for purpose of FERC. A relational, geo-referenced database (a geographic information system, or GIS) will be created to archive this data. The information will be analyzed using neural networks, kriging, and other statistical interpolation/extrapolation techniques to fine-tune regional well log interpretations, improve pay zone recognition from old logs or cased-hole logs, determine permeability ratios, and also to analyze water chemistries and compatibilities within the study area. This single-phase project will be accomplished through four major tasks: Data Collection, Data Integration, Data Analysis, and User Interface Design. Data will be extracted from existing databases as well as paper records, then cleaned and integrated into a single GIS database. Once the data warehouse is built, several methods of data analysis will be used both to improve pay zone recognition in single wells, and to extrapolate a variety of petrophysical properties on a regional basis. A user interface will provide tools to make the data and results of the study accessible and useful. The final deliverable for this project will be a web-based GIS providing data, interpretations, and user tools that will be accessible to anyone with Internet access. During this project, the following work has been performed: (1) Assimilation of most special core analysis data into a GIS database; (2) Inventorying of additional data, such as log images or LAS files that may exist for this area; (3) Analysis of geographic distribution of that data to pinpoint regional gaps in coverage; (4) Assessment of the data within both public and proprietary data sets to begin tuning of regional well logging analyses and improve payzone recognition; (5) Development of an integrated web and GIS interface for all the information collected in this effort, including data from northwest New Mexico; (6) Acquisition and digitization of logs to create LAS files for a subset of the wells in the special core analysis data set; and (7) Petrophysical analysis of the final set of well logs.

  15. Multi-Method Monitoring of Shallow Gas Injection in Saline Coastal Reservoir at Maguelone (Languedoc coastline, France)

    NASA Astrophysics Data System (ADS)

    Denchik, N.; Pezard, P. A.; Lofi, J.; Luquot, L.; Neyens, D.; Jaafar, O.; Perroud, H.; Abdelghafour, H.; Henry, G.; Levannier, A.

    2014-12-01

    Geological storage of CO2 is still a recent technology and many questions remain open, particularly for saline formations. Geological storage in accessible saline formations is, in fact, expected to become over time more important than that in depleted hydrocarbon reservoirs. The Maguelone shallow experimental site, located near Montpellier (Languedoc, France) has been used over the past few years to perform CO2 injection experiments. The geology, petrophysics and hydrology of this site are well known from previous studies. The presence of small saline coastal reservoirs bounded above and below by clay-rich layers provides an opportunity to study a saline formation for geological storage at field laboratory scale with a set of hydrogeophysical (seismic, electrical, sonic, pressure) and geochemical (pH, minor and major ion concentrations) methods, either downhole or at surface. Series of experiments can be run at moderate costs from the shallow depth of one of these reservoirs (13-16 m), offering flexibility for testing different monitoring configurations, performing repeated injection releases with variable injection parameters and type of gas (e.g., N2, CO2), and cross-calibrating the monitoring methods. Moreover, additional methods/boreholes can be easily implemented at this experimental site. Three N2 injections were thus undertaken at Maguelone in 2012 to measure the site response to neutral gas injection. An experiment involving the release of CO2 was successively conducted in January 2013. A volume of 111 m3 of CO2 was injected during 3.5 hours. Both the N2 and CO2 gas plumes were detected by all monitoring techniques, and the response to gas propagation was instantaneous. Integrating the lesson learned from past injection experiments, the next stage of the project will allow to establish the best guidelines for CO2 injection and post-injection monitoring and, in perspective, not only to detect the CO2 plume but to quantify CO2 migration in the subsurface.

  16. Stochastic Modeling of a Fracture Network in a Hydraulically Fractured Shale-Gas Reservoir 

    E-print Network

    Mhiri, Adnene

    2014-08-10

    The fundamental behavior of fluid production from shale/ultra-low permeability reservoirs that are produced under a constant wellbore pressure remains difficult to quantify, which is believed to be (at least in part) due ...

  17. A Novel Approach For the Simulation of Multiple Flow Mechanisms and Porosities in Shale Gas Reservoirs

    E-print Network

    Yan, Bicheng

    2013-07-15

    flow capacity. However, recent extensive microscopic studies reveal that there exist massive micro- and nano- pore systems in shale matrices. Because of this, the actual flow mechanisms in shale reservoirs are considerably more complex than can...

  18. Modeling heterogeneity in a low-permeability gas reservoir using geostatistical techniques, Hyde field, southern North Sea

    SciTech Connect

    Sweet, M.L.; Carter, A.M.; Mills, C.A. [BP Exploration, Aberdeen (United Kingdom)] [and others

    1996-11-01

    Hyde field is a small (133 Gcf reserves) gas field in the United Kingdom southern North Sea. The reservoir, the Permian Rotliegende group, contains eolian, fluvial, and sabkha facies. The eolian facies constitute the dominant flow units. Illite cementation results in low reservoir quality. In the eolian facies permeability averages 2.5 md and rarely exceeds 10 md. To maximize recovery from this field, with its thin gas column and low reservoir quality, Hyde has been developed with three long-reach horizontal wells. A reservoir model that could accurately predict future production had to include a full range of heterogeneities from the effects of thin muddy laminations at the core-plug scale to the spatial distribution of eolian, fluvial, and sabkha facies over the entire field at the largest scale. By carefully defining the model`s layering scheme, we incorporated strongly deterministic elements where facies trends were influenced by laterally extensive stratigraphic surfaces. The distribution of facies within stratigraphic units was modeled using geostatistical techniques. Average permeability for the eolian and sandy sabkha facies were determined by upscaling models of their internal permeability structure. The resulting distribution of permeabilities across the field, present in a 2.2-million-cell model, was upscaled into a coarser grid suitable for simulating the full field. This new model produced a significantly better match to dynamic data than did an earlier simple layer model that was used to take the field to sanction. The results of our work suggest that stochastic modeling allowed us to represent a level of heterogeneity that was not captured by the earlier simple layer model. By capturing this level of heterogeneity, we were able to achieve a significantly better match of model predictions to production data.

  19. Detailed evaluation of gas hydrate reservoir properties using JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well downhole well-log displays

    USGS Publications Warehouse

    Collett, T.S.

    1999-01-01

    The JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well project was designed to investigate the occurrence of in situ natural gas hydrate in the Mallik area of the Mackenzie Delta of Canada. Because gas hydrate is unstable at surface pressure and temperature conditions, a major emphasis was placed on the downhole logging program to determine the in situ physical properties of the gas-hydrate-bearing sediments. Downhole logging tool strings deployed in the Mallik 2L-38 well included the Schlumberger Platform Express with a high resolution laterolog, Array Induction Imager Tool, Dipole Shear Sonic Imager, and a Fullbore Formation Microlmager. The downhole log data obtained from the log- and core-inferred gas-hydrate-bearing sedimentary interval (897.25-1109.5 m log depth) in the Mallik 2L-38 well is depicted in a series of well displays. Also shown are numerous reservoir parameters, including gas hydrate saturation and sediment porosity log traces, calculated from available downhole well-log and core data. The gas hydrate accumulation delineated by the Mallik 2L-38 well has been determined to contain as much as 4.15109 m3 of gas in the 1 km2 area surrounding the drill site.

  20. A Gas-assisted Gravity Drainage Process in Naturally Fractured Reservoirs

    Microsoft Academic Search

    N. Kasiri; A. Bashiri

    2011-01-01

    Water alternating gas injection or simultaneous water and gas injection have been proposed as a good candidate to minimize gravity segregation and provide more efficient enhanced oil recovery performance in comparison to conventional continuous gas injection. However, water alternating gas-based processes can cause some difficulties with an increase in water saturation (e.g., water shielding) including diminished gas injectivity (Rao et

  1. Western cretaceous coal seam project economic and reserve evaluation of San Juan Basin, fruitland formation coalbed natural gas reservoirs. Topical report, January 1988-December 1991

    SciTech Connect

    Mavor, M.J.

    1991-11-15

    One of the objectives of the Western Cretaceous Coal Seam Project is to investigate and improve formation evaluation techniques for estimating the future performance of Fruitland Formation (Upper Cretaceous) coalbed natural gas reservoirs in the San Juan Basin of Colorado and New Mexico. This information is required to accurately estimate the future fluid production performance. One of the questions that is frequently asked is 'What reservoir properties are required for coalbed methane reservoir development.' An evaluation of the economic results of investment and sales of natural gas is required to fully answer this question. Two papers were prepared to address the methodology of economic evaluation. The first of these papers entitled Evaluation of Fruitland Coal Properties and Development Economics, San Juan Basin, Colorado and New Mexico, is included in Section 1 of this report. The second paper entitled Economic and Reserve Evaluation of Coalbed Methane Reservoirs is included in section 2.

  2. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS.

    SciTech Connect

    Bjorn N.P Paulsson

    2003-01-01

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  3. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2003-12-01

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  4. Development of a 400 Level 3C Clamped Downhole Seismic Receiver Array for 3D Borehole Seismic Imaging of Gas Reservoirs

    SciTech Connect

    Bjorn N.P Paulsson

    2006-05-05

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently hampered by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver arrays will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  5. Development of a 400 Level 3C Clamped Downhole Seismic Receiver Array for 3D Borehole Seismic Imaging of Gas Reservoirs

    SciTech Connect

    Bjorn N. P. Paulsson

    2005-09-30

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently hampered by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver arrays will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  6. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2004-06-30

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  7. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2005-03-31

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently hampered by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver arrays will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  8. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P Paulsson

    2003-07-01

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  9. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2002-12-01

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  10. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2004-12-31

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver arrays will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  11. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2004-05-31

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  12. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2004-09-30

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver arrays will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  13. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2004-05-01

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  14. Development of a 400 Level 3C Clamped Downhole Seismic Receiver Array for 3D Borehole Seismic Imaging of Gas Reservoirs

    SciTech Connect

    Bjorn N.P. Paulsson

    2005-08-21

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently hampered by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver arrays will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  15. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P Paulsson

    2003-09-01

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  16. TSR versus non-TSR processes and their impact on gas geochemistry and carbon stable isotopes in Carboniferous, Permian and Lower Triassic marine carbonate gas reservoirs in the Eastern Sichuan Basin, China

    NASA Astrophysics Data System (ADS)

    Liu, Q. Y.; Worden, R. H.; Jin, Z. J.; Liu, W. H.; Li, J.; Gao, B.; Zhang, D. W.; Hu, A. P.; Yang, C.

    2013-01-01

    The Palaeozoic and lowermost Mesozoic marine carbonate reservoirs of the Sichuan Basin in China contain variably sour and very dry gas. The source of the gas in the Carboniferous, Permian and Lower Triassic reservoirs is not known for certain and it has proved difficult to discriminate and differentiate the effects of thermal cracking- and TSR-related processes for these gases. Sixty-three gas samples were collected and analysed for their composition and carbon stable isotope values. The gases are all typically very dry (alkane gases being >97.5% methane), with low (<1%) nitrogen and highly variable H2S and CO2. Carboniferous gas is negligibly sour while the Lower Triassic gas tends to be most sour. The elevated H2S (up to 62%) is due to thermochemical sulphate reduction with the most sour Triassic and Permian reservoirs being deeper than 4800 m. The non-TSR affected Carboniferous gas is a secondary gas that was derived from the cracking of sapropelic kerogen-derived oil and primary gas and is highly mature. Carboniferous (and non-sour Triassic and Permian) gas has unusual carbon isotopes with methane and propane being isotopically heavier than ethane (a reversal of typical low- to moderate-maturity patterns). The gas in the non-sour Triassic and Permian reservoirs has the same geochemical and isotopic characteristics (and therefore the same source) as the Carboniferous gas. TSR in the deepest Triassic reservoirs altered the gas composition reaching 100% dryness in the deepest, most sour reservoirs showing that ethane and propane react faster than methane during TSR. Ethane evolves to heavier carbon isotope values than methane during TSR leading to removal of the reversed alkane gas isotope trend found in the Carboniferous and non-sour Triassic and Permian reservoirs. However, methane was directly involved in TSR as shown by the progressive increase in its carbon isotope ratio as gas souring proceeded. CO2 increased in concentration as gas souring proceeded, but typical CO2 carbon isotope ratios in sour gases remained about -4‰ V-PDB showing that it was not solely derived from the oxidation of alkanes. Instead CO2 may partly result from reaction of sour gas with carbonate reservoir minerals, such as Fe-rich dolomite or calcite, resulting in pyrite growth as well as CO2-generation.

  17. CHARACTERIZATION OF CONDITIONS OF NATURAL GAS STORAGE RESERVOIRS AND DESIGN AND DEMONSTRATION OF REMEDIAL TECHNIQUES FOR DAMAGE MECHANISMS FOUND THEREIN

    SciTech Connect

    J.H. Frantz; K.G. Brown

    2003-02-01

    There are four primary goals of contract DE-FG26-99FT40703: (1) We seek to better understand how and why a specific iron-related inorganic precipitant, siderite, occurs at the reservoir/wellbore interface in gas storage wells. (2) We plan on testing potential prevention and remediation strategies related to this damage mechanism in the laboratory. (3) We expect to demonstrate in the field, cost-effective prevention and remediation strategies that laboratory testing deems viable. (4) We will investigate new technology for the gas storage industry that will provide operators with a cost effective method to reduce non-darcy turbulent flow effects on flow rate. For the above damage mechanism, our research efforts will demonstrate the diagnostic technique for determining the damage mechanisms associated with lost deliverability as well as demonstrate and evaluate the remedial techniques in the laboratory setting and in actual gas storage reservoirs. We plan on accomplishing the above goals by performing extensive lab analyses of rotary sidewall cores taken from at least two wells, testing potential remediation strategies in the lab, and demonstrating in the field the applicability of the proposed remediation treatments. The benefits from this work will be quantified from this study and extrapolated to the entire storage industry. The technology and project results will be transferred to the industry through DOE dissemination and through the industry service companies that work on gas storage wells. Achieving these goals will enable the underground gas storage industry to more cost-effectively mitigate declining deliverability in their storage fields.

  18. The production characteristics of a solution gas-drive reservoir as measured on a centrifugal model 

    E-print Network

    Goodwin, Robert Jennings

    1955-01-01

    and Fluid Mixing Cylinder Physical Characteristics oi' Kerosene-Natural Gas Mixtures 1 and 2 at 110 F Physical Characteristics of Cetus Oil ? Natural Gas Mixtures 3 and 4 at 110o F Pressure-Viscosity Relati. onshi. ps at 110 F for Kerosene- Natural Gas... density (gm/cc) Fluid gl Fluid P2 Fluid. 83 Fluid /t'4 Kerosene Kerosene Cetus oil- Cetus oil?' Nat. gas?~ Nat. gas?~ Nat. gas'~ Nat. gas"+ 1. 29 1. 29 25. 62 25. 62 . 782 . 782 . 902 . 902 Texas Company trade-name ?e' Gas analysis...

  19. Synthesis of fluorinated nano-silica and its application in wettability alteration near-wellbore region in gas condensate reservoirs

    NASA Astrophysics Data System (ADS)

    Mousavi, M. A.; Hassanajili, Sh.; Rahimpour, M. R.

    2013-05-01

    Fluorinated silica nanoparticles were prepared to alter rock wettability near-wellbore region in gas condensate reservoirs. Hence fluorinated silica nanoparticles with average diameter of about 80 nm were prepared and used to alter limestone core wettability from highly liquid-wet to intermediate gas-wet state. Water and n-decane contact angles for rock were measured before and after treatment. The contact angle measured 147° for water and 61° for n-decane on the core surface. The rock surface could not support the formation of any water or n-decane droplets before treatment. The functionalized fluorinated silica nanoparticles have been confirmed by the Csbnd F bond along with Sisbnd Osbnd Si bond as analyzed by FT-IR. The elemental composition of treated limestone core surface was determined using energy dispersive X-ray spectroscopy analyses. The final evaluation of the fluorinated nanosilica treatment in terms of its effectiveness was measured by core flood experimental tests.

  20. Integrated exploration strategy for locating areas capable of high gas rate cavity completion in coalbed methane reservoirs

    SciTech Connect

    Klawitter, A.L.; Hoak, T.E.; Decker, A.D.

    1995-10-01

    In 1993, the San Juan Basin accounted for approximately 605 Bcf of the 740 Bcf of all coalbed gas produced in the United States. The San Juan {open_quotes}cavitation fairway{close_quotes} in which production occurs in open-hole cavity completions, is responsible for over 60% of all U.S. coalbed methane production. Perhaps most striking is the fact that over 17,000 wells had penetrated the Fruitland formation in the San Juan Basin prior to recognition of the coalbed methan potential. To understand the dynamic cavity fairway reservoir in the San Juan Basin, an exploration rationale for coalbed methan was developed that permits a sequential reduction in total basin exploration area based on four primary exploration criteria. One of the most significant criterion is the existence of thick, thermally mature, friable coals. A second criterion is the existence of fully gas-charged coals. Evaluation of this criterion requires reservoir geochemical data to delineate zones of meteoric influx where breaching has occurred. A third criterion is the presence of adequate reservoir permeability. Natural fracturing in coals is due to cleating and tectonic processes. Because of the general relationship between coal cleating and coal rank, coal cleating intensity can be estimated by analysis of regional coal rank maps. The final criterion is determining whether natural fractures are open or closed. To make this determination, remote sensing imagery interpretation is supported by ancillary data compiled from regional tectonic studies. Application of these four criteria to the San Juan Basin in a heuristic, stepwise process resulted in an overall 94% reduction in total basin exploration area. Application of the first criterion reduced the total basin exploration area by 80%. Application of the second criterion further winnows this area by an addition 9%. Application of the third criterion reduces the exploration area to 6% of the total original exploration area.

  1. CHARACTERIZATION OF CONDITIONS OF NATURAL GAS STORAGE RESERVOIRS AND DESIGN AND DEMONSTRATION OF REMEDIAL TECHNIQUES FOR DAMAGE MECHANISMS FOUND THEREIN

    SciTech Connect

    J.H. Frantz; K.E. Brown

    2003-02-01

    There are four primary goals of contract DE-FG26-99FT40703: (1) We seek to better understand how and why two damage mechanisms--(1) inorganic precipitants, and (2) hydrocarbons and organic residues, occur at the reservoir/wellbore interface in gas storage wells. (2) We plan on testing potential prevention and remediation strategies related to these two damage mechanisms in the laboratory. (3) We expect to demonstrate in the field, cost-effective prevention and remediation strategies that laboratory testing deems viable. (4) We will investigate new technology for the gas storage industry that will provide operators with a cost effective method to reduce non-darcy turbulent flow effects on flow rate. For the above damage mechanisms, our research efforts will demonstrate the diagnostic technique for determining the damage mechanisms associated with lost deliverability as well as demonstrate and evaluate the remedial techniques in the laboratory setting and in actual gas storage reservoirs. We plan on accomplishing the above goals by performing extensive lab analyses of rotary sidewall cores taken from at least two wells, testing potential remediation strategies in the lab, and demonstrating in the field the applicability of the proposed remediation treatments. The benefits from this work will be quantified from this study and extrapolated to the entire storage industry. The technology and project results will be transferred to the industry through DOE dissemination and through the industry service companies that work on gas storage wells. Achieving these goals will enable the underground gas storage industry to more cost-effectively mitigate declining deliverability in their storage fields. Work completed to date includes the following: (1) Solicited potential participants from the gas storage industry; (2) Selected one participant experiencing damage from inorganic precipitates; (3) Developed laboratory testing procedures; (4) Collected cores from National Fuel Gas Summit No.1527 Well; (5) Analyzed cores from National Fuel Gas Summit No.1527 Well; (6) Began investigating methods to remove damage identified in Summit No.1527 cores; and (7) Began investigating methods to reduce non-darcy turbulent effects.

  2. FRACTURE MODELING AND FAULT ZONE CHARACTERISTICS APPLIED TO RESERVOIR CHARACTERIZATION OF THE RULISON GAS FIELD,

    E-print Network

    FRACTURE MODELING AND FAULT ZONE CHARACTERISTICS APPLIED TO RESERVOIR CHARACTERIZATION the interpretation of three dimensional seismic. Shale Gouge Ratios along the seismically mapped fault surfaces have the dilation tendency of faults and fractures within the field to be calculated and analyzed. The mapped faults

  3. Potential hazards of compressed air energy storage in depleted natural gas reservoirs

    Microsoft Academic Search

    Paul W. Cooper; Mark Charles Grubelich; Stephen J. Bauer

    2011-01-01

    This report is a preliminary assessment of the ignition and explosion potential in a depleted hydrocarbon reservoir from air cycling associated with compressed air energy storage (CAES) in geologic media. The study identifies issues associated with this phenomenon as well as possible mitigating measures that should be considered. Compressed air energy storage (CAES) in geologic media has been proposed to

  4. Integral field spectroscopy of H-alpha emission in cooling flow cluster cores: disturbing the molecular gas reservoir

    E-print Network

    R. J. Wilman; A. C. Edge; A. M. Swinbank

    2006-06-13

    We present optical integral field spectroscopy of the H-alpha-luminous (>1E42 erg/s) central cluster galaxies in the cores of the cooling flows A1664, A1835, A2204 and Zw8193. From the [NII]+H-alpha complex we derive 2-D views of the distribution and kinematics of the emission line gas, and further diagnostics from the [SII] and [OI] lines. The H-alpha emission shows a variety of disturbed morphologies with velocity gradients and splittings of several hundred km/s on scales of 20 kpc or more. Despite the small sample size, there are some generic features. The most disturbed H-alpha emission appears to be associated with secondary galaxies within 10-20 kpc (projected) of the central galaxy and close in velocity to the H-alpha. The global H-alpha kinematics match those of CO(1-0) emission in single-dish data. The [NII]/H-alpha, [SII]/H-alpha and [OI]/H-alpha ratios vary little with position, local H-alpha surface brightness or between clusters. We propose that the H-alpha and CO emission arise in molecular clouds heated by a starburst which has been triggered by interaction with a secondary galaxy. Such CO emission is known to trace massive (>1E10 M_sun) compact (reservoirs of cool molecular gas, which an infalling galaxy may disturb, distorting the H-alpha morphology and initiating widespread star formation. We suggest that cloud-cloud collisions in the undisturbed molecular gas reservoir might be an important excitation source for the emission line gas in the cores of lower H-alpha luminosity cluster cores with less intense star formation (abridged).

  5. Fundamentals of numericl reservoir simulation

    Microsoft Academic Search

    D. W. Peaceman

    1977-01-01

    Computers are being widely used for numerical simulations of oil and gas reservoirs. This book is intended for the reservoir engineer. The first chapter reviews the basic reservoir mechanics and derives the differential equations that reservoir simulators are designed to solve. The next four chapters provide basic theory on the numerical solution of simple partial differential equations. The final chapter

  6. Conference on the topic: {open_quotes}Exploration and production of petroleum and gas from chalk reservoirs worldwide{close_quotes}

    SciTech Connect

    Kuznetsov, V.G.

    1995-07-01

    More than 170 delegates from 14 countries in Europe, North America, Africa, and Asia took part in a conference on the topic: Exploration and Production of Petroleum and Gas from Chalk Reservoirs Worldwide. The conference was held in Copenhagen, Denmark in September,1994, and was a joint meeting of the American Association of Petroleum Geologists (AAPG), and the European Association of Petroleum Geoscientists and Engineers (EAPG). In addition to the opening remarks, 25 oral and nine poster reports were presented. The topics included chalk deposits as reservoir rocks, the occurrence of chalk deposits worldwide, the North Sea oil and gas fields, and other related topics.

  7. Exploratory Simulation Studies of Caprock Alteration Induced byStorage of CO2 in Depleted Gas Reservoirs

    SciTech Connect

    Gherardi, Fabrizio; Xu, Tianfu; Pruess, Karsten

    2005-11-23

    This report presents numerical simulations of isothermalreactive flows which might be induced in the caprock of an Italiandepleted gas reservoir by the geological sequestration of carbon dioxide.Our objective is to verify that CO2 geological disposal activitiesalready planned for the study area are safe and do not induce anyundesired environmental impact.Gas-water-rock interactions have beenmodelled under two different intial conditions, i.e., assuming that i)caprock is perfectly sealed, or ii) partially fractured. Field conditionsare better approximated in terms of the "sealed caprock model". Thefractured caprock model has been implemented because it permits toexplore the geochemical beahvior of the system under particularly severeconditions which are not currently encountered in the field, and then todelineate a sort of hypothetical maximum risk scenario.Major evidencessupporting the assumption of a sealed caprock stem from the fact that nogas leakages have been detected during the exploitation phase, subsequentreservoir repressurization due to the ingression of a lateral aquifer,and during several cycles of gas storage in the latest life of reservoirmanagement.An extensive program of multidisciplinary laboratory tests onrock properties, geochemical and microseismic monitoring, and reservoirsimulation studies is underway to better characterize the reservoir andcap-rock behavior before the performance of a planned CO2 sequestrationpilot test.In our models, fluid flow and mineral alteration are inducedin the caprock by penetration of high CO2 concentrations from theunderlying reservoir, i.e., it was assumed that large amounts of CO2 havebeen already injected at depth. The main focus is on the potential effectof these geochemical transformations on the sealing efficiency of caprockformations. Batch and multi-dimensional 1D and 2D modeling has been usedto investigate multicomponent geochemical processes. Our simulationsaccount for fracture-matrix interactions, gas phase participation inmultiphase fluid flow and geochemical reactions, and kinetics offluid-rock interactions.The main objectives of the modeling are torecognize the geochemical processes or parameters to which theadvancement of high CO2 concentrations in the caprock is most sensitive,and to describe the most relevant mineralogical transformations occurringin the caprock as a consequence of such CO2 storage in the underlyingreservoir. We also examine the feedback of these geochemical processes onphysical properties such as porosity, and evaluate how the sealingcapacity of the caprock evolves in time.

  8. Evaluating reservoir production strategies in miscible and immiscible gas-injection projects 

    E-print Network

    Farzad, Iman

    2004-11-15

    Miscible gas injection processes could be among the most widely used enhanced oil recovery processes. Successful design and implementation of a miscible gas injection project depends upon the accurate determination of the minimum miscibility...

  9. Using Carbon Dioxide to Enhance Recovery of Methane from Gas Hydrate Reservoirs: Final Summary Report

    Microsoft Academic Search

    B. Peter McGrail; Herbert T. Schaef; Mark D. White; Tao Zhu; Abhijeet S. Kulkarni; Robert B. Hunter; Shirish L. Patil; Antionette T. Owen; P F. Martin

    2007-01-01

    Carbon dioxide sequestration coupled with hydrocarbon resource recovery is often economically attractive. Use of CO2 for enhanced recovery of oil, conventional natural gas, and coal-bed methane are in various stages of common practice. In this report, we discuss a new technique utilizing CO2 for enhanced recovery of an unconventional but potentially very important source of natural gas, gas hydrate. We

  10. Naturally fractured tight gas reservoir detection optimization. Quarterly report, October 1--December 31, 1994

    SciTech Connect

    NONE

    1995-01-30

    This progress report covers the following tasks: Computational geochemistry (Indiana University Laboratory); and geologic assessment of the Piceance Basin. Computational geochemistry covers; three- dimensional basin simulator; stress solver; two-dimensional basin simulator; organic reactions and multi-phase flow; grid optimization; database calibration and data input; and Piceance Basin initial simulation. Sub-tasks under geologic assessment of the Piceance Basin include: structural analysis; reservoir characterization; stratigraphic interpretation; seismic interpretation; and remote sensing interpretation.

  11. Pore Pressure prediction in shale gas reservoirs using neural network and fuzzy logic with an application to Barnett Shale.

    NASA Astrophysics Data System (ADS)

    Aliouane, Leila; Ouadfeul, Sid-Ali; Boudella, Amar

    2015-04-01

    The main goal of the proposed idea is to use the artificial intelligence such as the neural network and fuzzy logic to predict the pore pressure in shale gas reservoirs. Pore pressure is a very important parameter that will be used or estimation of effective stress. This last is used to resolve well-bore stability problems, failure plan identification from Mohr-Coulomb circle and sweet spots identification. Many models have been proposed to estimate the pore pressure from well-logs data; we can cite for example the equivalent depth model, the horizontal model for undercompaction called the Eaton's model…etc. All these models require a continuous measurement of the slowness of the primary wave, some thing that is not easy during well-logs data acquisition in shale gas formtions. Here, we suggest the use the fuzzy logic and the multilayer perceptron neural network to predict the pore pressure in two horizontal wells drilled in the lower Barnett shale formation. The first horizontal well is used for the training of the fuzzy set and the multilayer perecptron, the input is the natural gamma ray, the neutron porosity, the slowness of the compression and shear wave, however the desired output is the estimated pore pressure using Eaton's model. Data of another horizontal well are used for generalization. Obtained results clearly show the power of the fuzzy logic system than the multilayer perceptron neural network machine to predict the pore pressure in shale gas reservoirs. Keywords: artificial intelligence, fuzzy logic, pore pressure, multilayer perecptron, Barnett shale.

  12. Controls on reservoir quality in the giant Yacheng gas field, South China Sea

    SciTech Connect

    Bloch, S.; Atkinson, C.D. (ARCO Oil and Gas Co., Plano, TX (USA))

    1990-05-01

    Middle Tertiary sandstones from the giant Yacheng field, South China Sea were derived from a basement uplift and range in composition from lithic arkoses to feldspathic litharenites. The effect of chemical diagenesis on the framework composition is relatively limited, as suggested by the compositional similarity between uncemented samples and samples completely cemented by early calcite. Calcite cementation however, is not widespread. Reservoir quality and its distribution in the sandstones is primarily a function of textural and mineralogical parameters related to deposition in different types of paleoenvironments. The paleoenvironments range from basement regoliths and proximal fan-deltaic sediments deposited in lacustrine settings through increasingly more marine, tidally influenced distal fan-delta braided streams and estuarine channels, and eventually littoral beaches and offshore sublittoral bars. A petrologic classification was developed which relates rock composition to depositional environments which explains observed variations in reservoir quality. For a given burial history, there is an excellent correlation between permeability and porosity (dependent variables) and the following depositional facies-controlled, independent physical variables: grain size, sorting, and abundance of matrix and ductile grains. This correlation, in conjunction with a predictive facies distribution model, can be used to predict reservoir quality in future wells in the Yacheng field.

  13. Nurturing the geology-reservoir engineering team: Vital for efficient oil and gas recovery

    SciTech Connect

    Sessions, K.P.; Lehman, D.H. (Exxon Co., Houston, TX (USA))

    1990-05-01

    Of an estimated 482 billion bbl (76.6 Gm{sup 3}) of in-place oil discovered in the US, 158 billion (25.1 Gm{sup 3}) can be recovered with existing technology and economic conditions. The cost-effective recovery through infill drilling and enhanced oil recovery methods to recover any portion of the remaining 323 billion bbl (51.4 Gm3) will require a thorough understanding of reservoirs and the close cooperation of production geologists and reservoir engineers. This paper presents the concept of increased interaction between geologists and reservoir engineers through multifunctional teams and cross-training between the disciplines. A discussion of several factors supporting this concept is covered, including educational background, technical manpower trends, employee development, and job satisfaction. There are several ways from an organizational standpoint to achieve this cross-training, with or without a formal change in job assignment. This paper outlines three approaches, including case histories where each of the approaches has been implemented and the resulting benefits.

  14. Prediction of gas injection performance for heterogenous reservoirs, semi-annual technical report, October 1, 1996--March 31, 1997

    SciTech Connect

    Blunt, M.J.

    1997-04-30

    The current project is a systematic research effort that will lead to a new generation of predictive tools for gas injection processes in heterogeneous reservoirs. The project is aimed at quantifying the impact of heterogeneity on oil recovery from pore level to reservoir scales. This research effort is, therefore, divided into four areas: (1) Laboratory Gas Injection Experiments (2) Network Modeling of Three-Phase Flow (3) Benchmark Simulation of Gas Injection Processes (4) Streamline Simulator Development. The status of the research effort in each area is reviewed briefly in the following section. Project Status Laboratory Gas Injection Experiments Gravity drainage of oil in the presence of gas and water has found to result in high recovery efficiency. Numerical representation of the high recovery efficiency requires a good understanding of three-phase relative permeabilities, especially at low oil saturations. Ph.D student Akshay Sahni has analyzed experimental results of selected three-phase displacements in the literature and compared them with the newly developed mathematical theory of three-phase flow in porous media. He approximated the relative permeability of each phase as a polynomial function of the saturation of that phase. An excellent agreement has been obtained between the measured and the calculated saturation paths. The analytical solution has also been checked by performing numerical simulations. Fig. 1 is an example of the comparisons of experiments, mathematical theory and numerical simulations. Fig. 1 shows a situation in which gas is injected into a system with high oil saturation and the formation of an oil bank is observed. The experiments in the literature were generally conducted at relatively high oil saturations. We have designed a series of gravity drainage experiments to measure three-phase relative permeability at low oil saturations. The CT scanner in the Petroleum Engineering Department at Stanford has been modified to measure in-situ saturations of vertically-placed samples, which is necessary in gravity drainage experiments. Akshay Sahni has finished a series of gravity drainage experiments in sand packs using different model oils to calibrate the scanner and to investigate the effect of spreading coefficient on three-phase relative permeability. A procedure has been developed for calculating relative permeabilities from measured in-situ saturations.

  15. The Optimization of Well Spacing in a Coalbed Methane Reservoir 

    E-print Network

    Sinurat, Pahala Dominicus

    2012-02-14

    Numerical reservoir simulation has been used to describe mechanism of methane gas desorption process, diffusion process, and fluid flow in a coalbed methane reservoir. The reservoir simulation model reflects the response of a reservoir system...

  16. Development of a 400 Level 3C Clamped Downhole Seismic Receiver Array for 3D Borehole Seismic Imaging of Gas Reservoirs

    SciTech Connect

    Bjorn N. P. Paulsson

    2006-09-30

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to perform high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology has been hampered by the lack of acquisition technology necessary to record large volumes of high frequency, high signal-to-noise-ratio borehole seismic data. This project took aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array has removed the technical acquisition barrier for recording the data volumes necessary to do high resolution 3D VSP and 3D cross-well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that promise to take the gas industry to the next level in their quest for higher resolution images of deep and complex oil and gas reservoirs. Today only a fraction of the oil or gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of detailed compartmentalization of oil and gas reservoirs. In this project, we developed a 400 level 3C borehole seismic receiver array that allows for economic use of 3D borehole seismic imaging for reservoir characterization and monitoring. This new array has significantly increased the efficiency of recording large data volumes at sufficiently dense spatial sampling to resolve reservoir complexities. The receiver pods have been fabricated and tested to withstand high temperature (200 C/400 F) and high pressure (25,000 psi), so that they can operate in wells up to 7,620 meters (25,000 feet) deep. The receiver array is deployed on standard production or drill tubing. In combination with 3C surface seismic or 3C borehole seismic sources, the 400 level receiver array can be used to obtain 3D 9C data. These 9C borehole seismic data provide both compressional wave and shear wave information that can be used for quantitative prediction of rock and pore fluid types. The 400-level borehole receiver array has been deployed successfully in a number of oil and gas wells during the course of this project, and each survey has resulted in marked improvements in imaging of geologic features that are critical for oil or gas production but were previously considered to be below the limits of seismic resolution. This added level of reservoir detail has resulted in improved well placement in the oil and gas fields that have been drilled using the Massive 3D VSP{reg_sign} images. In the future, the 400-level downhole seismic receiver array is expected to continue to improve reservoir characterization and drilling success in deep and complex oil and gas reservoirs.

  17. A new p/z technique for the analysis of abnormally pressured gas reservoirs 

    E-print Network

    Gan, Ronald Gunawan

    2001-01-01

    form: (p/z)/(p; /z;) $ . (3. 18) We propose the Eq. 3. 18 as our primary plotting function ? where log(c?(p, ? p) ) is plotted versus (p/z)/(p, /z, ) (we use this presentation for clarity the semilog format helps to smooth the data points... for matching). As noted earlier, Eq. 3. 18 (and its predecessor, Eq. 3. 2) accounts for both the effects of compressibility and/or water influx from a shale or limited reservoir (expressed in terms of c, ). In order to calculate the c, (p, ? p) function from...

  18. Modeling of fault activation and seismicity by injection directly into a fault zone associated with hydraulic fracturing of shale-gas reservoirs

    EPA Science Inventory

    We conducted three-dimensional coupled fluid-flow and geomechanical modeling of fault activation and seismicity associated with hydraulic fracturing stimulation of a shale-gas reservoir. We simulated a case in which a horizontal injection well intersects a steeply dipping fault, ...

  19. Geologic, geochemical, and geographic controls on NORM in produced water from Texas oil, gas, and geothermal reservoirs. Final report

    SciTech Connect

    Fisher, R.

    1995-08-01

    Water from Texas oil, gas, and geothermal wells contains natural radioactivity that ranges from several hundred to several thousand Picocuries per liter (pCi/L). This natural radioactivity in produced fluids and the scale that forms in producing and processing equipment can lead to increased concerns for worker safety and additional costs for handling and disposing of water and scale. Naturally occurring radioactive materials (NORM) in oil and gas operations are mainly caused by concentrations of radium-226 ({sup 226}Ra) and radium-228 ({sup 228}Ra), daughter products of uranium-238 ({sup 238}U) and thorium-232 ({sup 232}Th), respectively, in barite scale. We examined (1) the geographic distribution of high NORM levels in oil-producing and gas-processing equipment, (2) geologic controls on uranium (U), thorium (Th), and radium (Ra) in sedimentary basins and reservoirs, (3) mineralogy of NORM scale, (4) chemical variability and potential to form barite scale in Texas formation waters, (5) Ra activity in Texas formation waters, and (6) geochemical controls on Ra isotopes in formation water and barite scale to explore natural controls on radioactivity. Our approach combined extensive compilations of published data, collection and analyses of new water samples and scale material, and geochemical modeling of scale Precipitation and Ra incorporation in barite.

  20. Radionuclide Migration at the Rio Blanco Site, A Nuclear-stimulated Low-permeability Natural Gas Reservoir

    SciTech Connect

    Clay A. Cooper; Ming Ye; Jenny Chapman; Craig Shirley

    2005-10-01

    The U.S. Department of Energy and its predecessor agencies conducted a program in the 1960s and 1970s that evaluated technology for the nuclear stimulation of low-permeability gas reservoirs. The third and final project in the program, Project Rio Blanco, was conducted in Rio Blanco County, in northwestern Colorado. In this experiment, three 33-kiloton nuclear explosives were simultaneously detonated in a single emplacement well in the Mesaverde Group and Fort Union Formation, at depths of 1,780, 1,899, and 2,039 m below land surface on May 17, 1973. The objective of this work is to estimate lateral distances that tritium released from the detonations may have traveled in the subsurface and evaluate the possible effect of postulated natural-gas development on radionuclide migration. Other radionuclides were considered in the analysis, but the majority occur in relatively immobile forms (such as nuclear melt glass). Of the radionuclides present in the gas phase, tritium dominates in terms of quantity of radioactivity in the long term and contribution to possible whole body exposure. One simulation is performed for {sup 85}Kr, the second most abundant gaseous radionuclide produced after tritium.

  1. Numerical simulation of the environmental impact of hydraulic fracturing of tight/shale gas reservoirs on near-surface groundwater: Background, base cases, shallow reservoirs,short-term gas, and water transport

    EPA Science Inventory

    Hydrocarbon production from unconventional resources and the use of reservoir stimulation techniques, such as hydraulic fracturing, has grown explosively over the last decade. However, concerns have arisen that reservoir stimulation creates significant environmental threats throu...

  2. Method for identifying subsurface fluid migration and drainage pathways in and among oil and gas reservoirs using 3-D and 4-D seismic imaging

    DOEpatents

    Anderson, Roger N. (New York, NY); Boulanger, Albert (New York, NY); Bagdonas, Edward P. (Brookline, MA); Xu, Liqing (New Milford, NJ); He, Wei (New Milford, NJ)

    1996-01-01

    The invention utilizes 3-D and 4-D seismic surveys as a means of deriving information useful in petroleum exploration and reservoir management. The methods use both single seismic surveys (3-D) and multiple seismic surveys separated in time (4-D) of a region of interest to determine large scale migration pathways within sedimentary basins, and fine scale drainage structure and oil-water-gas regions within individual petroleum producing reservoirs. Such structure is identified using pattern recognition tools which define the regions of interest. The 4-D seismic data sets may be used for data completion for large scale structure where time intervals between surveys do not allow for dynamic evolution. The 4-D seismic data sets also may be used to find variations over time of small scale structure within individual reservoirs which may be used to identify petroleum drainage pathways, oil-water-gas regions and, hence, attractive drilling targets. After spatial orientation, and amplitude and frequency matching of the multiple seismic data sets, High Amplitude Event (HAE) regions consistent with the presence of petroleum are identified using seismic attribute analysis. High Amplitude Regions are grown and interconnected to establish plumbing networks on the large scale and reservoir structure on the small scale. Small scale variations over time between seismic surveys within individual reservoirs are identified and used to identify drainage patterns and bypassed petroleum to be recovered. The location of such drainage patterns and bypassed petroleum may be used to site wells.

  3. Method for identifying subsurface fluid migration and drainage pathways in and among oil and gas reservoirs using 3-D and 4-D seismic imaging

    DOEpatents

    Anderson, R.N.; Boulanger, A.; Bagdonas, E.P.; Xu, L.; He, W.

    1996-12-17

    The invention utilizes 3-D and 4-D seismic surveys as a means of deriving information useful in petroleum exploration and reservoir management. The methods use both single seismic surveys (3-D) and multiple seismic surveys separated in time (4-D) of a region of interest to determine large scale migration pathways within sedimentary basins, and fine scale drainage structure and oil-water-gas regions within individual petroleum producing reservoirs. Such structure is identified using pattern recognition tools which define the regions of interest. The 4-D seismic data sets may be used for data completion for large scale structure where time intervals between surveys do not allow for dynamic evolution. The 4-D seismic data sets also may be used to find variations over time of small scale structure within individual reservoirs which may be used to identify petroleum drainage pathways, oil-water-gas regions and, hence, attractive drilling targets. After spatial orientation, and amplitude and frequency matching of the multiple seismic data sets, High Amplitude Event (HAE) regions consistent with the presence of petroleum are identified using seismic attribute analysis. High Amplitude Regions are grown and interconnected to establish plumbing networks on the large scale and reservoir structure on the small scale. Small scale variations over time between seismic surveys within individual reservoirs are identified and used to identify drainage patterns and bypassed petroleum to be recovered. The location of such drainage patterns and bypassed petroleum may be used to site wells. 22 figs.

  4. Optimal Process Design for Coupled CO2 Sequestration and Enhanced Gas Recovery in Carbonate Reservoirs

    E-print Network

    Odi, Uchenna

    2013-12-09

    Increasing energy demand combined with public concern for the environment obligates the oil industry to supply oil and natural gas to the public while minimizing the carbon footprint due to its activities. Today, fossil fuels are essential...

  5. Reservoir-Wellbore Coupled Simulation of Liquid Loaded Gas Well Performance 

    E-print Network

    Riza, Muhammad Feldy

    2013-11-12

    Liquid loading of gas wells causes production difficulty and reduces ultimate recovery from these wells. In 1969, Turner proposed that existence of annular two-phase flow at the wellhead is necessary for the well to avoid ...

  6. An Advisory System For Selecting Drilling Technologies and Methods in Tight Gas Reservoirs

    E-print Network

    Pilisi, Nicolas

    2010-01-16

    been collected and documented within the industry literature. The main objective of this research project is to develop a computer program dedicated to applying the drilling technologies and methods selection for drilling tight gas sandstone formations...

  7. General screening criteria for shale gas reservoirs and production data analysis of Barnett shale 

    E-print Network

    Deshpande, Vaibhav Prakashrao

    2009-05-15

    group is found in Tarrant and Parker counties and acts as a frac barrier between the Barnett and the Ellenburger formation. The Ellenburger formation is a very porous, karsted aquifer 22 that if fractured will produce copious amounts of highly saline... Basin 23 The three most important production related structures in the basin include both major and minor faulting, fracturing, and karst-related collapse features 25 . Fracturing is important to gas production because it provides a conduit for gas...

  8. Inflow Performance Relationships (IPR) for Solution Gas Drive Reservoirs -- a Semi-Analytical Approach

    E-print Network

    Nass, Maria A.

    2010-07-14

    ).............................................................................. 38 3.7 Effect of GOR and API on the computed ?-parameter............................................................... 39 3.8 Effect of reservoir temperature (T Res ) on the computed ?-parameter.......................................... 40 3....71 1.50 1789 271 1.14 690 3.98 1.61 2144 336 1.17 836 3.39 1.74 2499 403 1.20 976 2.91 1.88 2854 473 1.23 1107 2.52 2.02 3208 544 1.26 1225 2.21 2.16 3563 616 1.29 1332 1.94 2.30 3918 690 1.33 1427 1.72 2...

  9. Permeability variation in propped hydraulic fractures with changing fracture stress state in gas reservoirs

    SciTech Connect

    Ochs, D.E.

    1995-12-31

    Most hydraulic fracture design optimization models do not account for any change in the permeability of a propped hydraulic fracture due to the changing stress on the proppant pack with time. The assumption that this change is not significant may cause a serious overprediction of the future production of a fractured well leading to a non-optimal treatment design. This problem is investigated here through the use of an integrated fracture propagation, reservoir production, and economic computer simulation based on published analytical models. This simulation changes the permeability of the hydraulic fracture as the stress on the fracture increases over time, demonstrating the sensitivity of the fracture design optimization process to this parameter in terms of the net present value of the stimulation project.

  10. Study of Flow Regimes in Multiply-Fractured Horizontal Wells in Tight Gas and Shale Gas Reservoir Systems 

    E-print Network

    Freeman, Craig M.

    2010-07-14

    . ? Richard Feynman I do not think there is any thrill that can go through the human heart like that felt by the inventor as he sees some creation of the brain unfolding to success. ? Nikola Tesla v ACKNOWLEDGEMENTS I want to express..., porosity, and permeability to the gas phase, all of which are correlated with the ?-parameter. A relation determined by Kutasov (1993) (Eq. 2.7), based on experiment results, computes the ?-parameter as a function of effective permeability to gas as well...

  11. Effect of flue gas impurities on the process of injection and storage of carbon dioxide in depleted gas reservoirs 

    E-print Network

    Nogueira de Mago, Marjorie Carolina

    2005-11-01

    Previous experiments - injecting pure CO2 into carbonate cores - showed that the process is a win-win technology, sequestrating CO2 while recovering a significant amount of hitherto unrecoverable natural gas that could help defray the cost of CO2...

  12. Regional and reservoir-scale analysis of fault systems and structural development of Pagerungan Gas Field, East Java Sea, Indonesia

    SciTech Connect

    Davies, R.K.; Medwedeff, D.A. [Arco Exploration and Production Technology, Plano, TX (United States)

    1996-12-31

    Pagerungan gas field lies on a complexly faulted and folded anticline just north of the major Sakala-Paliat Fault System (SPFS) offshore Bali. The Eocene clastic reservoir is affected by two generations of faults: Eocene normal and Neogene compressional faults. Fault geometry, timing and connectivity is determined by combining regional and field-scale methods. Restored regional structure maps and sections indicate the field is located on the L. Eocene, footwall-paleo-high of the south-dipping SPFS. Within the field, smaller normal faults nucleated sub-parallel to the SPFS with both synthetic and antithetic dips. Neogene to Present compression folded the strata creating closure in the field, reversed slip on selected preexisting normal faults, and nucleated new reverse fault sets. Some normal faults are completely inverted, others have net normal offset after some reverse slip, and still others are not reactivated. Reverse faults strike sub-parallel to earlier formed normal faults. The eastern and western parts of the field are distinguished by the style and magnitude of early compressional deformation. 3D seismic analysis indicates the geometry of reservoir faults is similar to the regional fault systems: sub-parallel segments share displacement at their terminations either by distributed deformation in the rock between adjacent terminations or through short cross-faults oriented at a high angle to the principal fault sets. Anomalous trends in the contours of throw projected onto fault surfaces predict the connectivity of complex fault patterns. Integration of regional and field-scale analysis provides the most accurate prediction of fault geometry and lays the foundation for field development.

  13. Regional and reservoir-scale analysis of fault systems and structural development of Pagerungan Gas Field, East Java Sea, Indonesia

    SciTech Connect

    Davies, R.K.; Medwedeff, D.A. (Arco Exploration and Production Technology, Plano, TX (United States))

    1996-01-01

    Pagerungan gas field lies on a complexly faulted and folded anticline just north of the major Sakala-Paliat Fault System (SPFS) offshore Bali. The Eocene clastic reservoir is affected by two generations of faults: Eocene normal and Neogene compressional faults. Fault geometry, timing and connectivity is determined by combining regional and field-scale methods. Restored regional structure maps and sections indicate the field is located on the L. Eocene, footwall-paleo-high of the south-dipping SPFS. Within the field, smaller normal faults nucleated sub-parallel to the SPFS with both synthetic and antithetic dips. Neogene to Present compression folded the strata creating closure in the field, reversed slip on selected preexisting normal faults, and nucleated new reverse fault sets. Some normal faults are completely inverted, others have net normal offset after some reverse slip, and still others are not reactivated. Reverse faults strike sub-parallel to earlier formed normal faults. The eastern and western parts of the field are distinguished by the style and magnitude of early compressional deformation. 3D seismic analysis indicates the geometry of reservoir faults is similar to the regional fault systems: sub-parallel segments share displacement at their terminations either by distributed deformation in the rock between adjacent terminations or through short cross-faults oriented at a high angle to the principal fault sets. Anomalous trends in the contours of throw projected onto fault surfaces predict the connectivity of complex fault patterns. Integration of regional and field-scale analysis provides the most accurate prediction of fault geometry and lays the foundation for field development.

  14. Carbon dioxide and helium emissions from a reservoir of magmatic gas beneath Mammoth Mountain, California

    Microsoft Academic Search

    M. L. Sorey; W. C. Evans; B. M. Kennedy; C. D. Farrar; L. J. Hainsworth; B. Hausback

    1998-01-01

    Carbon dioxide and helium with isotopic compositions indicative of a magmatic source (δthinsp¹³C=-4.5 to -5{per_thousand}, ³He\\/⁴He=4.5 to 6.7 R{sub A}) are discharging at anomalous rates from Mammoth Mountain, on the southwestern rim of the Long Valley caldera in eastern California. The gas is released mainly as diffuse emissions from normal-temperature soils, but some gas issues from steam vents or leaves

  15. Reservoir sedimentology

    SciTech Connect

    Tillman, R.W.; Weber, K.J.

    1987-01-01

    Collection of papers focuses on sedimentology of siliclastic sandstone and carbonate reservoirs. Shows how detailed sedimentologic descriptions, when combined with engineering and other subsurface geologic techniques, yield reservoir models useful for reservoir management during field development and secondary and tertiary EOR. Sections cover marine sandstone and carbonate reservoirs; shoreline, deltaic, and fluvial reservoirs; and eolian reservoirs. References follow each paper.

  16. Reservoir engineering in coal seams

    Microsoft Academic Search

    Gray

    1983-01-01

    This study examines the behavior of coal seam gas reservoirs which are found to exhibit significantly different behavior from conventional gas reservoirs. These differences involve the nature of permeability variations and the method of gas storage. The permeability variations appear to be caused primarily by effective stress variations and to a lesser extent to water saturation changes. These effective stress

  17. A Novel Approach For the Simulation of Multiple Flow Mechanisms and Porosities in Shale Gas Reservoirs 

    E-print Network

    Yan, Bicheng

    2013-07-15

    and organic portions of shale matrix are treated as sub-blocks with different attributes, such as wettability and pore structures. In the organic matter or kerogen, gas desorption and diffusion are the dominant physics. Since the flow regimes are sensitive...

  18. Fracture Modeling and Flow Behavior in Shale Gas Reservoirs Using Discrete Fracture Networks

    E-print Network

    Ogbechie, Joachim Nwabunwanne

    2012-02-14

    deviation Frac Fracture Cv Coefficient of variation CI Connectivity index HF Hydraulic fracture cum Cumulative FA Fracture aperture FD Fracture density FL Fracture length HFA Hydraulic fracture aperture HFL Hydraulic fracture length NFS Number... .................................................................................................... 58 5.6 Change in cum. gas produced due to increase in fracture aperture for case 1 .................................................................................................... 58 5.7 Change in pressure response due to decrease...

  19. Increasing Production from Low-Permeability Gas Reservoirs by Optimizing Zone Isolation for Successful Stimulation Treatments

    SciTech Connect

    Fred Sabins

    2005-03-31

    Maximizing production from wells drilled in low-permeability reservoirs, such as the Barnett Shale, is determined by cementing, stimulation, and production techniques employed. Studies show that cementing can be effective in terms of improving fracture effectiveness by 'focusing' the frac in the desired zone and improving penetration. Additionally, a method is presented for determining the required properties of the set cement at various places in the well, with the surprising result that uphole cement properties in wells destined for multiple-zone fracturing is more critical than those applied to downhole zones. Stimulation studies show that measuring pressure profiles and response during Pre-Frac Injection Test procedures prior to the frac job are critical in determining if a frac is indicated at all, as well as the type and size of the frac job. This result is contrary to current industry practice, in which frac jobs are designed well before the execution, and carried out as designed on location. Finally, studies show that most wells in the Barnett Shale are production limited by liquid invasion into the wellbore, and determinants are presented for when rod or downhole pumps are indicated.

  20. Scientific Challenges of Producing Natural Gas from Organic-Rich Shales - From the Nano-Scale to the Reservoir Scale (Louis Néel Medal Lecture)

    NASA Astrophysics Data System (ADS)

    Zoback, Mark D.

    2013-04-01

    In this talk I will discuss several on-going research projects with the PhD students and post-Docs in my group that are investigating the wide variety of factors affecting the success of stimulating gas production from extremely low permeability organic-rich shales. First, I will present laboratory measurements of pore structure, adsorption and nano-scale fluid transport on samples of the Barnett, Eagle Ford, Haynesville, Marcellus and Horn River shale (all in North America). I will also discuss how these factors affect ultimate gas recovery. Second, I present several lines of evidence that indicate that during hydraulic fracturing stimulation of shale gas reservoirs there is pervasive slow slip occurring on pre-existing fractures and faults that are not detected by standard microseismic monitoring. I will also present laboratory and modeling studies that demonstrate why slowly slipping faults are to be expected. In many cases, slow slip on faults may be the most important process responsible for stimulating gas production in the reservoirs. Finally, I discuss our research on the viscoplastic behavior of the shales and what viscoplasticity implies for the evolution of the physical properties of the reservoir and in situ stress magnitudes.

  1. Estimating Effective Seismic Anisotropy Of Coal Seam Gas Reservoirs from Sonic Log Data Using Orthorhombic Buckus-style Upscaling

    NASA Astrophysics Data System (ADS)

    Gross, Lutz; Tyson, Stephen

    2015-04-01

    Fracture density and orientation are key parameters controlling productivity of coal seam gas reservoirs. Seismic anisotropy can help to identify and quantify fracture characteristics. In particular, wide offset and dense azimuthal coverage land seismic recordings offers the opportunity for recovery of anisotropy parameters. In many coal seam gas reservoirs (eg. Walloon Subgroup in the Surat Basin, Queensland, Australia (Esterle et al. 2013)) the thickness of coal-beds and interbeds (e.g mud-stone) are well below the seismic wave length (0.3-1m versus 5-15m). In these situations, the observed seismic anisotropy parameters represent effective elastic properties of the composite media formed of fractured, anisotropic coal and isotropic interbed. As a consequence observed seismic anisotropy cannot directly be linked to fracture characteristics but requires a more careful interpretation. In the paper we will discuss techniques to estimate effective seismic anisotropy parameters from well log data with the objective to improve the interpretation for the case of layered thin coal beds. In the first step we use sonic log data to reconstruct the elasticity parameters as function of depth (at the resolution of the sonic log). It is assumed that within a sample fractures are sparse, of the same size and orientation, penny-shaped and equally spaced. Following classical fracture model this can be modeled as an elastic horizontally transversely isotropic (HTI) media (Schoenberg & Sayers 1995). Under the additional assumption of dry fractures, normal and tangential fracture weakness is estimated from slow and fast shear wave velocities of the sonic log. In the second step we apply Backus-style upscaling to construct effective anisotropy parameters on an appropriate length scale. In order to honor the HTI anisotropy present at each layer we have developed a new extension of the classical Backus averaging for layered isotropic media (Backus 1962) . Our new method assumes layered HTI media with constant anisotropy orientation as recovered in the first step. It leads to an effective horizontal orthorhombic elastic model. From this model Thomsen-style anisotropy parameters are calculated to derive azimuth-dependent normal move out (NMO) velocities (see Grechka & Tsvankin 1998). In our presentation we will show results of our approach from sonic well logs in the Surat Basin to investigate the potential of reconstructing S-wave velocity anisotropy and fracture density from azimuth dependent NMO velocities profiles.

  2. Effect of connate water on miscible displacement of reservoir oil by flue gas

    E-print Network

    Maxwell, H. D.

    1960-01-01

    . 818 . 816 . 682 . 815 . 8ZO 19 methane fraction also greatly encouraged the retrograde vaporisation phenomenon associated with the high-pressure gas drive when nitrogen was the displacing fluid. In the present work, the inclusion of carbon... Fluid Composition on Ultimate Recovery, Break-Through Recovery, and Misci- 13 22 25 bil it y Pressure 6. Recovery as a. Function of Displacing Pressure, Displacing Fluid Composition and Connate Water Salinity . 28 TABLES 1. Liquid Composition...

  3. Sweet spots discrimination in shale gas reservoirs using seismic and well-logs data. A case study from the Worth basin in the Barnett shale

    NASA Astrophysics Data System (ADS)

    Aliouane, Leila; Ouadfeul, Sid-Ali; Boudella, Amar

    2014-05-01

    Here, we present a case study of sweet spots discrimination in shale gas reservoirs located in the Worth basin of the Barnett shale using seismic and well-logs data. Seismic attributes such the Chaos and the ANT-Tracking are used for natural fractures system identification from seismic data, the maps of the stress and the Poisson ratio obtained from the upscaling of well-logs data of a horizontal well are able to provide an information about the drilling direction which is usually in the minimum horizontal stress profile, the map of the Poisson ratio can provide an information hardness of the source rock. The set of well logs data is used for geo-mechanical and petrophysical discrimination of the sweet spots, after discrimination the identified zones are useful for reserves estimation from unconventional shale gas reservoir.

  4. GAS RESERVOIRS AND STAR FORMATION IN A FORMING GALAXY CLUSTER AT zbsime0.2

    SciTech Connect

    Jaffe, Yara L.; Poggianti, Bianca M. [INAF-Osservatorio Astronomico di Padova, vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Verheijen, Marc A. W.; Deshev, Boris Z. [Kapteyn Astronomical Institute, Landleven 12, 9747-AD Groningen (Netherlands); Van Gorkom, Jacqueline H., E-mail: yara.jaffe@oapd.inaf.it [Department of Astronomy, Columbia University, Mail Code 5246, 550 W 120th Street, New York, NY 10027 (United States)

    2012-09-10

    We present first results from the Blind Ultra-Deep H I Environmental Survey of the Westerbork Synthesis Radio Telescope. Our survey is the first direct imaging study of neutral atomic hydrogen gas in galaxies at a redshift where evolutionary processes begin to show. In this Letter we investigate star formation, H I content, and galaxy morphology, as a function of environment in Abell 2192 (at z = 0.1876). Using a three-dimensional visualization technique, we find that Abell 2192 is a cluster in the process of forming, with significant substructure in it. We distinguish four structures that are separated in redshift and/or space. The richest structure is the baby cluster itself, with a core of elliptical galaxies that coincides with (weak) X-ray emission, almost no H I detections, and suppressed star formation. Surrounding the cluster, we find a compact group where galaxies pre-process before falling into the cluster, and a scattered population of 'field-like' galaxies showing more star formation and H I detections. This cluster proves to be an excellent laboratory to understand the fate of the H I gas in the framework of galaxy evolution. We clearly see that the H I gas and the star formation correlate with morphology and environment at z {approx} 0.2. In particular, the fraction of H I detections is significantly affected by the environment. The effect starts to kick in in low-mass groups that pre-process the galaxies before they enter the cluster. Our results suggest that by the time the group galaxies fall into the cluster, they are already devoid of H I.

  5. CHARACTERIZATION OF CONDITIONS OF NATURAL GAS STORAGE RESERVOIRS AND DESIGN AND DEMONSTRATION OF REMEDIAL TECHNIQUES FOR DAMAGE MECHANISMS FOUND THEREIN

    SciTech Connect

    J.H. Frantz Jr; K.G. Brown; W.K. Sawyer; P.A. Zyglowicz; P.M. Halleck; J.P. Spivey

    2004-12-01

    The underground gas storage (UGS) industry uses over 400 reservoirs and 17,000 wells to store and withdrawal gas. As such, it is a significant contributor to gas supply in the United States. It has been demonstrated that many UGS wells show a loss of deliverability each year due to numerous damage mechanisms. Previous studies estimate that up to one hundred million dollars are spent each year to recover or replace a deliverability loss of approximately 3.2 Bscf/D per year in the storage industry. Clearly, there is a great potential for developing technology to prevent, mitigate, or eliminate the damage causing deliverability losses in UGS wells. Prior studies have also identified the presence of several potential damage mechanisms in storage wells, developed damage diagnostic procedures, and discussed, in general terms, the possible reactions that need to occur to create the damage. However, few studies address how to prevent or mitigate specific damage types, and/or how to eliminate the damage from occurring in the future. This study seeks to increase our understanding of two specific damage mechanisms, inorganic precipitates (specifically siderite), and non-darcy damage, and thus serves to expand prior efforts as well as complement ongoing gas storage projects. Specifically, this study has resulted in: (1) An effective lab protocol designed to assess the extent of damage due to inorganic precipitates; (2) An increased understanding of how inorganic precipitates (specifically siderite) develop; (3) Identification of potential sources of chemical components necessary for siderite formation; (4) A remediation technique that has successfully restored deliverability to storage wells damaged by the inorganic precipitate siderite (one well had nearly a tenfold increase in deliverability); (5) Identification of the types of treatments that have historically been successful at reducing the amount of non-darcy pressure drop in a well, and (6) Development of a tool that can be used by operators to guide treatment selection in wells with significant non-darcy damage component. In addition, the effectiveness of the remediation treatment designed to reduce damage caused by the inorganic precipitate siderite was measured, and the benefits of this work are extrapolated to the entire U.S. storage industry. Similarly the potential benefits realized from more effective identification and treatment of wells with significant nondarcy damage component are also presented, and these benefits are also extrapolated to the entire U.S. storage industry.

  6. Optimization of hydraulic fracture design - application to a gas storage reservoir

    SciTech Connect

    Balan, B.

    1996-12-31

    A two-step unconventional method that uses neural networks for accurately estimating post fracture deliverability, and genetic algorithms for optimizing the hydraulic fracture design is proposed in this study. The genetic algorithm, being a global search algorithm, was able to find the optimum combination of seventeen frac parameters that maximizes post-frac deliverability of a well. This method has been applied to a large natural gas storage field where accurate post fracture well performance estimates and optimized fractreatment design have become crucial to ensure continued deliverability gains. A database containing basic well information, past fracture designs, and performance history for that field has been developed, without additional cost. The hybrid model was implemented into a user-friendly, Windows95 based, computer program.

  7. Gas geochemistry of the magmatic-hydrothermal fluid reservoir in the Copahue-Caviahue Volcanic Complex (Argentina)

    NASA Astrophysics Data System (ADS)

    Agusto, M.; Tassi, F.; Caselli, A. T.; Vaselli, O.; Rouwet, D.; Capaccioni, B.; Caliro, S.; Chiodini, G.; Darrah, T.

    2013-05-01

    Copahue volcano is part of the Caviahue-Copahue Volcanic Complex (CCVC), which is located in the southwestern sector of the Caviahue volcano-tectonic depression (Argentina-Chile). This depression is a pull-apart basin accommodating stresses between the southern Liquiñe-Ofqui strike slip and the northern Copahue-Antiñir compressive fault systems, in a back-arc setting with respect to the Southern Andean Volcanic Zone. In this study, we present chemical (inorganic and organic) and isotope compositions (?13C-CO2, ?15N, 3He/4He, 40Ar/36Ar, ?13C-CH4, ?D-CH4, and ?D-H2O and ?18O-H2O) of fumaroles and bubbling gases of thermal springs located at the foot of Copahue volcano sampled in 2006, 2007 and 2012. Helium isotope ratios, the highest observed for a Southern American volcano (R/Ra up to 7.94), indicate a non-classic arc-like setting, but rather an extensional regime subdued to asthenospheric thinning. ?13C-CO2 values (from - 8.8‰ to - 6.8‰ vs. V-PDB), ?15N values (+ 5.3‰ to + 5.5‰ vs. Air) and CO2/3He ratios (from 1.4 to 8.8 × 109) suggest that the magmatic source is significantly affected by contamination of subducted sediments. Gases discharged from the northern sector of the CCVC show contribution of 3He-poor fluids likely permeating through local fault systems. Despite the clear mantle isotope signature in the CCVC gases, the acidic gas species have suffered scrubbing processes by a hydrothermal system mainly recharged by meteoric water. Gas geothermometry in the H2O-CO2-CH4-CO-H2 system suggests that CO and H2 re-equilibrate in a separated vapor phase at 200°-220 °C. On the contrary, rock-fluid interactions controlling CO2, CH4 production from Sabatier reaction and C3H8 dehydrogenation seem to occur within the hydrothermal reservoir at temperatures ranging from 250° to 300 °C. Fumarole gases sampled in 2006-2007 show relatively low N2/He and N2/Ar ratios and high R/Ra values with respect to those measured in 2012. Such compositional and isotope variations were likely related to injection of mafic magma that likely triggered the 2000 eruption. Therefore, changes affecting the magmatic system had a delayed effect on the chemistry of the CCVC gases due to the presence of the hydrothermal reservoir. However, geochemical monitoring activities mainly focused on the behavior of inert gas compounds (N2 and He), should be increased to investigate the mechanism at the origin of the unrest started in 2011.

  8. Drill Cuttings-based Methodology to Optimize Multi-stage Hydraulic Fracturing in Horizontal Wells and Unconventional Gas Reservoirs

    NASA Astrophysics Data System (ADS)

    Ortega Mercado, Camilo Ernesto

    Horizontal drilling and hydraulic fracturing techniques have become almost mandatory technologies for economic exploitation of unconventional gas reservoirs. Key to commercial success is minimizing the risk while drilling and hydraulic fracturing these wells. Data collection is expensive and as a result this is one of the first casualties during budget cuts. As a result complete data sets in horizontal wells are nearly always scarce. In order to minimize the data scarcity problem, the research addressed throughout this thesis concentrates on using drill cuttings, an inexpensive direct source of information, for developing: 1) A new methodology for multi-stage hydraulic fracturing optimization of horizontal wells without any significant increases in operational costs. 2) A new method for petrophysical evaluation in those wells with limited amount of log information. The methods are explained using drill cuttings from the Nikanassin Group collected in the Deep Basin of the Western Canada Sedimentary Basin (WCSB). Drill cuttings are the main source of information for the proposed methodology in Item 1, which involves the creation of three 'log tracks' containing the following parameters for improving design of hydraulic fracturing jobs: (a) Brittleness Index, (b) Measured Permeability and (c) An Indicator of Natural Fractures. The brittleness index is primarily a function of Poisson's ratio and Young Modulus, parameters that are obtained from drill cuttings and sonic logs formulations. Permeability is measured on drill cuttings in the laboratory. The indication of natural fractures is obtained from direct observations on drill cuttings under the microscope. Drill cuttings are also the main source of information for the new petrophysical evaluation method mentioned above in Item 2 when well logs are not available. This is important particularly in horizontal wells where the amount of log data is almost non-existent in the vast majority of the wells. By combining data from drill cuttings and previously available empirical relationships developed from cores it is possible to estimate water saturations, pore throat apertures, capillary pressures, flow units, porosity (or cementation) exponent m, true formation resistivity Rt, distance to a water table (if present), and to distinguish the contributions of viscous and diffusion-like flow in the tight gas formation. The method further allows the construction of Pickett plots using porosity and permeability obtained from drill cuttings, without previous availability of well logs. The method assumes the existence of intervals at irreducible water saturation, which is the case of the Nikanassin Group throughout the gas column. The new methods mentioned above are not meant to replace the use of detailed and sophisticated evaluation techniques. But the proposed methods provide a valuable and practical aid in those cases where geomechanical and petrophysical information are scarce.

  9. Pore- and fracture-filling gas hydrate reservoirs in the Gulf of Mexico Gas Hydrate Joint Industry Project Leg II Green Canyon 955 H well

    USGS Publications Warehouse

    Lee, M.W.; Collett, T.S.

    2012-01-01

    High-quality logging-while-drilling (LWD) downhole logs were acquired in seven wells drilled during the Gulf of MexicoGasHydrateJointIndustryProjectLegII in the spring of 2009. Well logs obtained in one of the wells, the GreenCanyon Block 955Hwell (GC955-H), indicate that a 27.4-m thick zone at the depth of 428 m below sea floor (mbsf; 1404 feet below sea floor (fbsf)) contains gashydrate within sand with average gashydrate saturations estimated at 60% from the compressional-wave (P-wave) velocity and 65% (locally more than 80%) from resistivity logs if the gashydrate is assumed to be uniformly distributed in this mostly sand-rich section. Similar analysis, however, of log data from a shallow clay-rich interval between 183 and 366 mbsf (600 and 1200 fbsf) yielded average gashydrate saturations of about 20% from the resistivity log (locally 50-60%) and negligible amounts of gashydrate from the P-wave velocity logs. Differences in saturations estimated between resistivity and P-wave velocities within the upper clay-rich interval are caused by the nature of the gashydrate occurrences. In the case of the shallow clay-rich interval, gashydrate fills vertical (or high angle) fractures in rather than fillingpore space in sands. In this study, isotropic and anisotropic resistivity and velocity models are used to analyze the occurrence of gashydrate within both the clay-rich and sand dominated gas-hydrate-bearing reservoirs in the GC955-Hwell.

  10. Experimental study on rock-water interaction due to CO2 injection under in-situ P-T condition of the Altmark gas reservoir, Germany

    NASA Astrophysics Data System (ADS)

    Huq, F.; Blum, P.; Nowak, M.; Haderlein, S.; Grathwohl, P.

    2012-04-01

    CO2 sequestration in depleted gas reservoir is an economically feasible option to mitigate global warming. The Altmark gas reservoir, located in the western part of the northeast German basin, was selected for enhanced gas recovery (EGR) by injecting CO2. Under reservoir conditions (50 bars and 125°C), the injected CO2 has very high solubility leading to subsequent dissolution and precipitation of minerals of the surrounding rock matrix. Therefore, the main objective of the current study is to investigate the geochemical changes in fluid composition due to dissolution of minerals under controlled laboratory conditions. Dry sandstone sample from the Altmark reservoir was mounted in an autoclave system and flushed by a pre-equilibrated mixture of water saturated with CO2 at a constant flow rate at 50 bars and 125°C. The experiment was conducted for 100 hours during which fluid samples were collected at regular intervals and analyzed by Ion Chromatography (IC) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). pH was also measured in partially de-gassed samples. Fluid analysis showed an increased concentration of Ca and SO4 at the beginning of the reaction time indicating the early dissolution of anhydrite. However, the Ca/SO4 molar ratio (>1) proved the dissolution of both calcite and anhydrite. The source of Na and K could be the dissolution of feldspars (albite and K-feldspar). Low concentrations of these two elements reflect the lower solubility and slow dissolution kinetics of feldspar minerals. Moreover, trace amounts of Mn, Mg, Zn, Cu and Fe might be derived from the dissolution of trace minerals in the sandstone. Besides, thermodynamic calculations of mineral saturation indices enabled an evaluation of the CO2-water-rock interactions and highlighted the dissolution of the Ca-bearing minerals in the studied solution.

  11. Hydroelectric Reservoirs -the Carbon Dioxide and Methane

    E-print Network

    Fischlin, Andreas

    Hydroelectric Reservoirs - the Carbon Dioxide and Methane Emissions of a "Carbon Free" Energy an overview on the greenhouse gas production of hydroelectric reservoirs. The goals are to point out the main how big the greenhouse gas emissions from hydroelectric reservoirs are compared to thermo-power plants

  12. Greenhouse gas (CO2 and CH4) emissions from a high altitude hydroelectric reservoir in the tropics (Riogrande II, Colombia)

    NASA Astrophysics Data System (ADS)

    Guérin, Frédéric; Leon, Juan

    2015-04-01

    Tropical hydroelectric reservoirs are considered as very significant source of methane (CH4) and carbon dioxide (CO2), especially when flooding dense forest. We report emissions from the Rio Grande II Reservoir located at 2000 m.a.s.l. in the Colombian Andes. The dam was built at the confluence of the Rio Grande and Rio Chico in 1990. The reservoir has a surface of 12 km2, a maximum depth of 40m and a residence time of 2.5 month. Water quality (temperature, oxygen, pH, conductivity), nitrate, ammonium, dissolved and particulate organic carbon (DOC and POC), CO2 and CH4 were monitored bi-monthly during 1.5 year at 9 stations in the reservoir. Diffusive fluxes of CO2 and CH4 and CH4 ebullition were measured at 5 stations. The Rio grande II Reservoir is weakly stratified thermally with surface temperature ranging from 20 to 24°C and a constant bottom temperature of 18°C. The reservoir water column is well oxygenated at the surface and usually anoxic below 10m depth. At the stations close to the tributaries water inputs, the water column is well mixed and oxygenated from the surface to the bottom. As reported for other reservoirs located in "clear water" watersheds, the concentrations of nutrients are low (NO3-<0.1ppm, NH4+<0.2ppm), the concentrations of DOC are high (2-8 mg L-1) and POC concentrations are low (< 3 mg L-1). Surface CH4 concentrations at the central stations of the reservoirs are 0.5 ?mol L-1 (0.07-2.14 ?mol L-1) and 3 times higher at the stations close to the tributaries inputs (up to 7 ?mol L-1). In the hypolimnion, CH4 concentration is <100 ?mol L-1 in the wet season and can reach up to 400 ?mol L-1 in the dry season. The spatial and temporal variability are lower for CO2. Surface CO2 concentration was on average 72 ?mol L-1 (up to 300) and hypolimnic concentration ranged between 250 and 1000 ?mol L-1. The CO2 diffusive flux is 517±331 mmol m-2 d-1 with little seasonal and spatial variations. At the center of the reservoir, the median diffusive flux of CH4 is 1.75 mmol m-2 d-1 and sporadic high fluxes (>10 mmol m-2 d-1) were observed during the dry season. Close to the tributaries water inputs where the water column is well mixed, the average diffusive flux is 8 mmol m-2 d-1. CH4 ebullition was 3.5 mmol m-2 d-1 and no ebullition was observed for a water depth higher than 5m. The zone under the influence of the water inputs from tributaries represents 25% of the surface of the reservoir but contributed half of total CH4 emissions from the reservoir (29MgC month-1). Ebullition contributed only to 12% of total CH4 emissions over a year but it contributed up to 60% during the dry season. CH4 emissions from the Rio Grande Reservoir contributed 30% of the total GHG emissions (38GgCO2eq y-1). Overall, this study show that the majority of CH4 emissions from this reservoir occur through hotspot and hot moments and that mountainous reservoir located in the tropics could have emission factors as high as Amazonian reservoirs.

  13. Numerical modeling of self-limiting and self-enhancing caprock alteration induced by CO2 storage in a depleted gas reservoir

    SciTech Connect

    Xu, Tianfu; Gherardi, Fabrizio; Xu, Tianfu; Pruess, Karsten

    2007-09-07

    This paper presents numerical simulations of reactive transport which may be induced in the caprock of an on-shore depleted gas reservoir by the geological sequestration of carbon dioxide. The objective is to verify that CO{sub 2} geological disposal activities currently being planned for the study area are safe and do not induce any undesired environmental impact. In our model, fluid flow and mineral alteration are induced in the caprock by penetration of high CO{sub 2} concentrations from the underlying reservoir, where it was assumed that large amounts of CO{sub 2} have already been injected at depth. The main focus is on the potential effect of precipitation and dissolution processes on the sealing efficiency of caprock formations. Concerns that some leakage may occur in the investigated system arise because the seal is made up of potentially highly-reactive rocks, consisting of carbonate-rich shales (calcite+dolomite averaging up to more than 30% of solid volume fraction). Batch simulations and multi-dimensional 1D and 2D modeling have been used to investigate multicomponent geochemical processes. Numerical simulations account for fracture-matrix interactions, gas phase participation in multiphase fluid flow and geochemical reactions, and kinetics of fluid-rock interactions. The geochemical processes and parameters to which the occurrence of high CO{sub 2} concentrations are most sensitive are investigated by conceptualizing different mass transport mechanisms (i.e. diffusion and mixed advection+diffusion). The most relevant mineralogical transformations occurring in the caprock are described, and the feedback of these geochemical processes on physical properties such as porosity is examined to evaluate how the sealing capacity of the caprock could evolve in time. The simulations demonstrate that the occurrence of some gas leakage from the reservoir may have a strong influence on the geochemical evolution of the caprock. In fact, when a free CO{sub 2}-dominated phase migrates into the caprock through fractures, or through zones with high initial porosity possibly acting as preferential flow paths for reservoir fluids, low pH values are predicted, accompanied by significant calcite dissolution and porosity enhancement. In contrast, when fluid-rock interactions occur under fully liquid-saturated conditions and a diffusion-controlled regime, pH will be buffered at higher values, and some calcite precipitation is predicted which leads to further sealing of the storage reservoir.

  14. Chemical, mineralogical and molecular biological characterization of the rocks and fluids from a natural gas storage deep reservoir as a baseline for the effects of geological hydrogen storage

    NASA Astrophysics Data System (ADS)

    Morozova, Daria; Kasina, Monika; Weigt, Jennifer; Merten, Dirk; Pudlo, Dieter; Würdemann, Hilke

    2014-05-01

    Planned transition to renewable energy production from nuclear and CO2-emitting power generation brings the necessity for large scale energy storage capacities. One possibility to store excessive energy produced is to transfer it to chemical forms like hydrogen which can be subsequently injected and stored in subsurface porous rock formations like depleted gas reservoirs and presently used gas storage sites. In order to investigate the feasibility of the hydrogen storage in the subsurface, the collaborative project H2STORE ("hydrogen to store") was initiated. In the scope of this project, potential reactions between microorganism, fluids and rocks induced by hydrogen injection are studied. For the long-term experiments, fluids of natural gas storage are incubated together with rock cores in the high pressure vessels under 40 bar pressure and 40° C temperature with an atmosphere containing 5.8% He as a tracer gas, 3.9% H2 and 90.3% N2. The reservoir is located at a depth of about 2 000 m, and is characterized by a salinity of 88.9 g l-1 NaCl and a temperature of 80° C and therefore represents an extreme environment for microbial life. First geochemical analyses showed a relatively high TOC content of the fluids (about 120 mg l-1) that were also rich in sodium, potassium, calcium, magnesium and iron. Remarkable amounts of heavy metals like zinc and strontium were also detected. XRD analyses of the reservoir sandstones revealed the major components: quartz, plagioclase, K-feldspar, anhydrite and analcime. The sandstones were intercalated by mudstones, consisting of quartz, plagioclase, K-feldspar, analcime, chlorite, mica and carbonates. Genetic profiling of amplified 16S rRNA genes was applied to characterize the microbial community composition by PCR-SSCP (PCR-Single-Strand-Conformation Polymorphism) and DGGE (Denaturing Gradient Gel Electrophoresis). First results indicate the presence of microorganisms belonging to the phylotypes alfa-, beta- and gamma-Proteobacteria and Actinobacteria. Sequences of these organisms have been found in subsurface environments before, e.g. in saline, hot, anoxic, and deep milieus. Due to the saline and hyperthermophilic reservoir conditions, the quantification of those microorganisms by DAPI staining revealed very low cell numbers of about 102 cells ml-1. Investigations of the microbial community composition, mineralogy and fluid chemistry after 6 months of incubation are in progress to determine to what extent hydrogen injection may contribute to a shift in the microbial community structure and abundance, microbial-mineral interactions and hydrogen-based methanogenesis.

  15. Modeling effects of diffusion and gravity drainage on oil recovery in naturally fractured reservoirs under gas injection

    E-print Network

    Jamili, Ahmad

    2010-04-22

    the mass transfer between a gas flowing in a fracture and a horizontal matrix block. The model accounts for diffusion and convection mechanisms in both gas and liquid phases in the porous matrix. The injected gas diffuses into the porous matrix through gas...

  16. Reservoir characterization of tight gas sand: Taylor sandstone (upper Cotton Valley group, upper Jurassic), Rusk County, Texas

    Microsoft Academic Search

    C. L. Vavra; M. H. Scheihing; J. D. Klein

    1989-01-01

    An integrated petrographic, sedimentologic, and log analysis study of the Taylor sandstone in Rusk County, Texas, was conducted to understand the geologic controls on reservoir performance and to identify pay zones for reserves calculations. The Taylor sandstone interval consists of tightly cemented, fine-grained quartzose sandstones interbedded with mudstones, siltstones, and carbonates that occur in upward-coarsening sequences. Helium permeability rarely exceeds

  17. The effect of high-pressure injection of gas on the reservoir volume factor of a crude oil 

    E-print Network

    Honeycutt, Baxter Bewitt

    1957-01-01

    . . . . . , . Gas Specific Gravity Determination. 14 - Determination of Formation Volume Factor. 14 6. Results. 7. Discussion of Results 16 17 8. Conclusions. 19 9. Acknowledgments. 21 10. References 22 11. Bibliography. 12. Appendix 25 LIST OF TABLES... of 39. 6 APX gravity using a relatively rich gas. Very high oil recovery is anticipated by high-pressure gas injection if a rich gas is used; however, beneficial results are also obtained by high-pressure injection of a lean gas. The present...

  18. Reservoir limnology

    SciTech Connect

    Thornton, K.W.; Kimmel, B.L.; Payne, F.E.

    1990-01-01

    This book addresses reservoirs as unique ecological systems and presents research indicating that reservoirs fall into two or three highly concatenated, interactive ecological systems ranging from riverine to lacustrine or hybrid systems. Includes some controversial concepts about the limnology of reservoirs.

  19. Modeling the Injection of Carbon Dioxide and Nitrogen into a Methane Hydrate Reservoir and the Subsequent Production of Methane Gas on the North Slope of Alaska

    NASA Astrophysics Data System (ADS)

    Garapati, N.; McGuire, P. C.; Liu, Y.; Anderson, B. J.

    2012-12-01

    HydrateResSim (HRS) is an open-source finite-difference reservoir simulation code capable of simulating the behavior of gas hydrate in porous media. The original version of HRS was developed to simulate pure methane hydrates, and the relationship between equilibrium temperature and pressure is given by a simple, 1-D regression expression. In this work, we have modified HydrateResSim to allow for the formation and dissociation of gas hydrates made from gas mixtures. This modification allows one to model the ConocoPhillips Ignik Sikumi #1 field test performed in early 2012 on the Alaska North Slope. The Ignik Sikumi #1 test is the first field-based demonstration of gas production through the injection of a mixture of carbon dioxide and nitrogen gases into a methane hydrate reservoir and thereby sequestering the greenhouse gas CO2 into hydrate form. The primary change to the HRS software is the added capability of modeling a ternary mixture consisting of CH4 + CO2 + N2 instead of only one hydrate guest molecule (CH4), therefore the new software is called Mix3HydrateResSim. This Mix3HydrateResSim upgrade to the software was accomplished by adding primary variables (for the concentrations of CO2 and N2), governing equations (for the mass balances of CO2 and N2), and phase equilibrium data. The phase equilibrium data in Mix3HydrateResSim is given as an input table obtained using a statistical mechanical method developed in our research group called the cell potential method. An additional phase state describing a two-phase Gas-Hydrate (GsH) system was added to consider the possibility of converting all available free water to form hydrate with injected gas. Using Mix3HydrateResSim, a methane hydrate reservoir with coexisting pure-CH4-hydrate and aqueous phases at 7.0 MPa and 5.5°C was modeled after the conditions of the Ignik Sikumi #1 test: (i) 14-day injection of CO2 and N2 followed by (ii) 30-day production of CH4 (by depressurization of the well). During the injection phase, the injection well is modeled as a fixed-condition boundary maintained as a gas phase (23% CO2+ 77% N2) at 9.65 MPa and 5.5 °C. Initially, there is an increase in the saturation of hydrate indicating the formation of secondary hydrate due to the injected gas and the available free water. There is also a slight increase in the temperature due to the exothermic reaction of hydrate formation. As the hydrate becomes saturated with the injected gases it releases CH4. After the initial 14 days of injection, a mixture of the three gases was produced through depressurization. This was modeled by maintaining the well as a fixed-state boundary at the bottom-hole pressure. The amount of CH4 released from the hydrate phase during the injection and production phases and the amount of CO2 and N2 gases sequestered as hydrates have been examined in this study. A model-based history-matching of the gas flow rates from the ConocoPhillips field test will be conducted to validate the code.

  20. Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity. [Jurassic Smackover Formation

    Microsoft Academic Search

    D. C. Kopaska-Merkel; H. E. Jr. Moore; S. D. Mann; D. R. Hall

    1992-01-01

    This volume contains maps, well logging, structural cross section, graph of production history, porosity vs. natural log permeability plots, detailed core log, paragenetic sequence, and reservoir characterization sheet for the following fields in southwest Alabama: North Smiths Church oil field; North Wallers Creek oil field; Northeast Barnett oil field; Northwest Range oil field; Pace Creek oil field; Palmers Crossroads oil

  1. Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity. Appendix 1, Volume 3

    Microsoft Academic Search

    D. C. Kopaska-Merkel; H. E. Jr. Moore; S. D. Mann; D. R. Hall

    1992-01-01

    This volume contains maps, well logging, structural cross section, graph of production history, porosity vs. natural log permeability plots, detailed core log, paragenetic sequence, and reservoir characterization sheet for the following fields in southwest Alabama: North Smiths Church oil field; North Wallers Creek oil field; Northeast Barnett oil field; Northwest Range oil field; Pace Creek oil field; Palmers Crossroads oil

  2. Analytical Estimation of CO2 Storage Capacity in Depleted Oil and Gas Reservoirs Based on Thermodynamic State Functions

    E-print Network

    Valbuena Olivares, Ernesto

    2012-02-14

    . Analytical model performs considerably faster than numerical simulation........................................................................... 111 xx Page Table 5.24? Reservoir size sensitivity on case d from numerical simulation.... ...................................... 75 Fig. 5.3? Case A?Semi-analytical model results. Prediction of injected moles in the small-injection range is not accurate. ............................. 76 Fig. 5.4? Case A?Partial molar volume comparison from analytical model and calculations...

  3. Reservoir characterization of tight gas sand: Taylor sandstone (upper Cotton Valley group, upper Jurassic), Rusk County, Texas

    SciTech Connect

    Vavra, C.L.; Scheihing, M.H.; Klein, J.D.

    1989-03-01

    An integrated petrographic, sedimentologic, and log analysis study of the Taylor sandstone in Rusk County, Texas, was conducted to understand the geologic controls on reservoir performance and to identify pay zones for reserves calculations. The Taylor sandstone interval consists of tightly cemented, fine-grained quartzose sandstones interbedded with mudstones, siltstones, and carbonates that occur in upward-coarsening sequences. Helium permeability rarely exceeds 0.1 md, and porosity is rarely greater than 10%. Relationships between porosity and permeability are diffuse because of a string diagenetic overprint. Six major rock types or petrofacies are distinguished on the basis of pore type and dominant cement mineralogy. Three sandstone petrofacies - primary macroporous quartz cemented, moldic macroporous quartz cemented, and microporous clay cemented - have reservoir potential. Although these petrofacies have similar porosities and permeabilities, fluid saturations differ considerably due to differences in pore geometry as indicated by petrographic and capillary pressure analyses. These three reservoir-quality petrofacies can each be identified directly on wireline logs by applying cutoffs to the porosity and normalized gamma-ray logs.

  4. A reservoir management strategy for multilayered reservoirs in eastern Venezuela

    E-print Network

    Espinel Diaz, Arnaldo Leopoldo

    1998-01-01

    , heptane plus mole percentage and oil formation volume value for black or volatile oils, retrograde gas condensate, and wet and dry gas are presented and discussed. Representative fluid samples must be analyzed in the laboratory, but "rules of thumb..., with different fluid properties, and well completion problems, the reservoir management teain faces even a more difficult challenge than normal. In this research, we have developed a reservoir management strategy for a field located in eastern Venezuela...

  5. CHARACTERIZING MARINE GAS-HYDRATE RESERVOIRS AND DETERMINING MECHANICAL PROPERTIES OF MARINE GAS-HYDRATE STRATA WITH 4COMPONENT OCEAN-BOTTOM-CABLE SEISMIC DATA

    Microsoft Academic Search

    B. A. Hardage; M. M. Backus; M. V. DeAngelo; R. J. Graebner; P. Murray

    2002-01-01

    The technical approach taken in this gas-hydrate research is unique because it is based on applying large-scale, 3-D, multi-component seismic surveys to improve the understanding of marine gas-hydrate systems. Other gas-hydrate research uses only single-component seismic technology. In those rare instances when multi-component seismic data have been acquired for gas-hydrate research, the data acquisition has involved only a few receiver

  6. CO2 gas/oil ratio prediction in a multi-component reservoir bycombined seismic and electromagnetic imaging

    SciTech Connect

    Hoversten, G.M.; Gritto, Roland; Washbourne, John; Daley, Tom

    2002-08-28

    Crosswell seismic and electromagnetic data sets taken before and during CO2 flooding of an oil reservoir are inverted to produce crosswell images of the change in compressional velocity, shear velocity and electrical conductivity during a CO2 injection pilot study. A rock properties model is developed using measured log porosity, fluid saturations, pressure, temperature, bulk density, sonic velocity and electrical conductivity. The parameters of the rock properties model are found by an L1-norm simplex minimization of predicted and observed compressional velocity and density. A separate minimization using Archie's law provides parameters for modeling the relations between water saturation, porosity and the electrical conductivity. The rock properties model is used to generate relationships between changes in geophysical parameters and changes in reservoir parameters. The electrical conductivity changes are directly mapped to changes in water saturation. The estimated changes in water saturation are used with the observed changes in shear wave velocity to predict changes in reservoir pressure. The estimation of the spatial extent and amount of CO2 relies on first removing the effects of the water saturation and pressure changes from the observed compressional velocity changes, producing a residual compressional velocity change. The residual compressional velocity change is then interpreted in terms of increases in the CO2 /oil ratio. Resulting images of CO2/oil ratio show CO2 rich zones that are well correlated with the location of injection perforations with the size of these zones also correlating to the amount of injected CO2. The images produced by this process are better correlated to the location and amount of injected CO2 than are any of the individual images of change in geophysical parameters.

  7. Gas seepage as an indicator of deeper prospective reservoirs. A study based on exploration 3D seismic data

    Microsoft Academic Search

    Roar Heggland

    1998-01-01

    Three periods of sustained gas seepage in geological time have been revealed in Danish block 5604\\/26 in the North Sea by the use of exploration 3D seismic data. The most recent period is indicated by a cluster of seismic chimneys which ties in to buried craters near the seabed, and possible present gas escape through the seabed, along with amplitude

  8. Reservoir engineering in coal seams

    SciTech Connect

    Gray, I.

    1983-11-01

    This study examines the behavior of coal seam gas reservoirs which are found to exhibit significantly different behavior from conventional gas reservoirs. These differences involve the nature of permeability variations and the method of gas storage. The permeability variations appear to be caused primarily by effective stress variations and to a lesser extent to water saturation changes. These effective stress changes are brought about both by fluid pressure variations and by coal matrix shrinkage and expansion with changing gas content. Directional permeability with cleat (joint) direction is shown to be important. Experimental work was conducted in underground mines of the Bowen Basin, Queensland, Australia.

  9. Performance analysis of compositional and modified black-oil models for rich gas condensate reservoirs with vertical and horizontal wells

    E-print Network

    Izgec, Bulent

    2004-09-30

    drain hole lengths were used. Contrary to the common belief that oil-gas ratio versus depth initialization gives better representation of original fluids in place, initializations with saturation pressure versus depth gave closer original fluids...

  10. Chemistry in protoplanetary disks: the gas-phase CO/H2 ratio and the carbon reservoir

    NASA Astrophysics Data System (ADS)

    Reboussin, L.; Wakelam, V.; Guilloteau, S.; Hersant, F.; Dutrey, A.

    2015-07-01

    Context. The gas mass of protoplanetary disks and the gas-to-dust ratio are two key elements driving the evolution of these disks and the formation of planetary system. Aims: We explore to what extent CO (or its isotopologues) can be used as a tracer of gas mass. Methods: We use a detailed gas-grain chemical model and study the evolution of the disk composition, starting from a dense prestellar core composition. We explore a range of disk temperature profiles, cosmic-ray ionization rates, and disk ages for a disk model representative of T Tauri stars. Results: At the high densities that prevail in disks, we find that because of fast reactions on grain surfaces, CO can be converted to less volatile forms (principally s-CO2, and to a lesser extent s-CH4) instead of being evaporated over a wide range of temperature. The canonical gas-phase abundance of 10-4 is only reached above about 30-35 K. The dominant carbon bearing entity depends on the temperature structure and age of the disk. The chemical evolution of CO is also sensitive to the cosmic-ray ionization rate. Larger gas phase CO abundances are found in younger disks. Initial conditions, such as parent cloud age and density, have a limited impact. Conclusions: This study reveals that CO gas-phase abundance is heavily dependent on grain surface processes, which remain very incompletely understood so far. The strong dependence on dust temperature profile makes CO a poor tracer of the gas-phase content of disks.

  11. Analysis of active microorganisms and their potential role in carbon dioxide turnover in the natural gas reservoirs Altmark and Schneeren (Germany)

    NASA Astrophysics Data System (ADS)

    Gniese, Claudia; Muschalle, Thomas; Mühling, Martin; Frerichs, Janin; Krüger, Martin; Kassahun, Andrea; Seifert, Jana; Hoth, Nils

    2010-05-01

    RECOBIO-2, part of the BMBF-funded Geotechnologien consortium, investigates the presence of active microorganisms and their potential role in CO2 turnover in the formation waters of the Schneeren and Altmark gas fields, which are both operated by GDF SUEZ E&P Germany GmbH. Located to the north west of Hannover the natural gas reservoir Schneeren is composed of compacted Westfal-C sandstones that have been naturally fractured into a subsalinar horst structure. This gas field is characterized by a depth of 2700 to 3500m, a bottom-hole temperature between 80 and 110° C as well as a moderate salinity (30-60g/l) and high sulfate contents (~1000mg/l). During RECOBIO-1 produced formation water collected at wells in Schneeren was already used to conduct long term laboratory experiments. These served to examine possible microbial processes of the autochthonous biocenosis induced by the injection of CO2 (Ehinger et al. 2009 submitted). Microorganisms in particular sulfate-reducing bacteria and methanogens were able to grow in the presence of powdered rock material, CO2 and H2 without any other added nutrients. The observed development of DOC was now proven in another long term experiment using labelled 13CO2. In contrast to Schneeren, the almost depleted natural gas reservoir Altmark exhibits an average depth of 3300m, a higher bottom-hole temperature (111° C to 120° C), a higher salinity (275-350g/l) but sulfate is absent. This Rotliegend formation is located in the southern edge of the Northeast German Basin and is of special interest for CO2 injection because of favourable geological properties. Using molecular biological techniques two types of samples are analyzed: formation water collected at the well head (November 2008) and formation water sampled in situ from a depth of around 3000m (May 2009). Some of the wells are treated frequently with a foaming agent while others are chemically untreated. Despite the extreme environmental conditions in the Altmark gas field, RNA of apparently active microorganisms was successfully extracted from all samples. Sequence analysis of 16S rRNA revealed mainly fermentative bacteria belonging to the phylogenetic group of Actinobacteria (e.g. Propionibacterium spp.) and ?-Proteobacteria (e.g. Hyphomicrobium spp.) possibly involved in the nitrogen cycle. Cell numbers were determined using a PCR-independent molecular detection method (CARD-FISH) with universal 16S rRNA-specific probes (EUB338, ARCH915). The fraction of bacterial cells comprised up to 104 cells per milliliter, which corresponds to the cell numbers obtained with a generic DNA stain (DAPI). Archaeal cells could not be detected by CARD-FISH, though archaeal 16S rRNA gene fragments were amplified from DNA extracts using PCR. So far differences have neither been observed between treated and untreated formation waters nor between well head and in situ sampled formation waters. Further investigations are underway to elucidate whether particular metabolic pathways are present in the microbial assemblage of the Altmark gas field fluids. In addition, microbe-mineral interactions will be assessed using electron microscopic approaches. Ehinger, S., Kassahun, A., Muschlle, T., Gniese, C., Schlömann, M., Hoth, N., Seifert, J. (2009 submitted) Sulfate reduction by novel Thermoanaerobacteriaceae in bioreactor inoculated with gas-field brine. Environmental Microbiology

  12. Carbonate petroleum reservoirs

    SciTech Connect

    Roehl, P.O.; Choquette, P.W.

    1985-01-01

    This book presents papers on the geology of petroleum deposits. Topics considered include diagenesis, porosity, dolomite reservoirs, deposition, reservoir rock, reefs, morphology, fracture-controlled production, Cenozoic reservoirs, Mesozoic reservoirs, and Paleozoic reservoirs.

  13. Chemistry in Protoplanetary Disks: the gas-phase CO/H2 ratio and the Carbon reservoir

    E-print Network

    Reboussin, L; Guilloteau, S; Hersant, F; Dutrey, A

    2015-01-01

    The gas mass of protoplanetary disks, and the gas-to-dust ratio, are two key elements driving the evolution of these disks and the formation of planetary system. We explore here to what extent CO (or its isotopologues) can be used as a tracer of gas mass. We use a detailed gas-grain chemical model and study the evolution of the disk composition, starting from a dense pre-stellar core composition. We explore a range of disk temperature profiles, cosmic rays ionization rates, and disk ages for a disk model representative of T Tauri stars. At the high densities that prevail in disks, we find that, due to fast reactions on grain surfaces, CO can be converted to less volatile forms (principally s-CO$_2$, and to a lesser extent s-CH$_4$) instead of being evaporated over a wide range of temperature. The canonical gas-phase abundance of 10$^{-4}$ is only reached above about 30-35 K. The dominant Carbon bearing entity depends on the temperature structure and age of the disk. The chemical evolution of CO is also sensit...

  14. Estimation of original gas in place from short-term shut-in pressure data for commingled tight gas reservoirs with no crossflow

    E-print Network

    Khuong, Chan Hung

    1995-01-01

    produceable at this BHFP. We denote this amount of gas by PGIP (theoretically Produceable Gas In Place). The PGIP will be used 200 150 4 100 50 0 ~ iow k, 0. 1 md ~high k, 0. 1 md -50 Backflow nto Lo k Layer Backflow into H g Layer -100 0. 01 0. 1... 18, one important observation can be made: all p/z 72 curves converge to the point of intersection of the static p/z traight line and the horizontal line pQz= constant. This point represents the theoretically produceable gas in place (PGIP...

  15. Fundamentals of gas flow in shale; What the unconventional reservoir industry can learn from the radioactive waste industry

    NASA Astrophysics Data System (ADS)

    Cuss, Robert; Harrington, Jon; Graham, Caroline

    2013-04-01

    Tight formations, such as shale, have a wide range of potential usage; this includes shale gas exploitation, hydrocarbon sealing, carbon capture & storage and radioactive waste disposal. Considerable research effort has been conducted over the last 20 years on the fundamental controls on gas flow in a range of clay-rich materials at the British Geological Survey (BGS) mainly focused on radioactive waste disposal; including French Callovo-Oxfordian claystone, Belgian Boom Clay, Swiss Opalinus Clay, British Oxford Clay, as well as engineered barrier material such as bentonite and concrete. Recent work has concentrated on the underlying physics governing fluid flow, with evidence of dilatancy controlled advective flow demonstrated in Callovo-Oxfordian claystone. This has resulted in a review of how advective gas flow is dealt with in Performance Assessment and the applicability of numerical codes. Dilatancy flow has been shown in Boom clay using nano-particles and is seen in bentonite by the strong hydro-mechanical coupling displayed at the onset of gas flow. As well as observations made at BGS, dilatancy flow has been shown by other workers on shale (Cuss et al., 2012; Angeli et al. 2009). As well as experimental studies using cores of intact material, fractured material has been investigated in bespoke shear apparatus. Experimental results have shown that the transmission of gas by fractures is highly localised, dependent on normal stress, varies with shear, is strongly linked with stress history, is highly temporal in nature, and shows a clear correlation with fracture angle. Several orders of magnitude variation in fracture transmissivity is seen during individual tests. Flow experiments have been conducted using gas and water, showing remarkably different behaviour. The radioactive waste industry has also noted a number of important features related to sample preservation. Differences in gas entry pressure have been shown across many laboratories and these may be attributed to different core preparation techniques. Careful re-stressing of core barrels and sealing techniques also ensure that experiments are conducted on near in situ condition. The construction of tunnels within shale clearly aids our understanding of the interaction of engineered operations (borehole drilling or tunnelling) on the behaviour of the rock. References: Angeli, M., Soldal, M., Skurtveit, E. and Aker, E., (2009) Experimental percolation of supercritical CO2 through a caprock. Energy Procedia 1, 3351-3358 Cuss, R.J., Harrington, J.F., Giot, R., and Auvray, C. (2012) Experimental observations of mechanical dilation at the onset of gas flow in Callovo-Oxfordian Claystone. Poster Presentation 5th International Meeting Clays in Natural and Engineered Barriers for Radioactive Waste Confinement, Montpellier, France October 22nd - 25th 2012.

  16. 30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...What tests must I conduct to determine reservoir characteristics? 250.407 Section...What tests must I conduct to determine reservoir characteristics? You must determine the presence, quantity, quality, and reservoir characteristics of oil, gas,...

  17. 30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...What tests must I conduct to determine reservoir characteristics? 250.407 Section...What tests must I conduct to determine reservoir characteristics? You must determine the presence, quantity, quality, and reservoir characteristics of oil, gas,...

  18. 30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...What tests must I conduct to determine reservoir characteristics? 250.407 Section...What tests must I conduct to determine reservoir characteristics? You must determine the presence, quantity, quality, and reservoir characteristics of oil, gas,...

  19. Gulf of Mexico Oil and Gas Atlas Series: Chronostratigraphically bound reservoir plays in Texas and federal offshore waters

    Microsoft Academic Search

    S. J. Seni; B. A. Desselle; A. Standen

    1994-01-01

    The search for additional hydrocarbons in the Gulf of Mexico is directing exploration toward both deep-water frontier trends and historically productive areas on the shelf. The University of Texas at Austin, Bureau of Economic Geology, in cooperation with the Minerals Management Service, the Gas Research Institute, and the U.S. Department of Energy, is responding to this need through a coordinated

  20. Greenhouse Gas Emissions from a Hydroelectric Reservoir (Brazil’s Tucuruí Dam) and the Energy Policy Implications

    Microsoft Academic Search

    Philip M. Fearnside

    2002-01-01

    Greenhouse gas emissions from hydroelectric dams are oftenportrayed as nonexistent by the hydropower industry, and havebeen largely ignored in global calculations of emissions fromland-use change. Brazil’s Tucuruí Dam provides an example with important lessons for policy debates on Amazonian development and on how to assess the global warming impact ofdifferent energy options. Tucuruí is better from the pointof view of

  1. Fracture characterization of multilayered reservoirs

    SciTech Connect

    Britt, L.K.; Larsen, M.J.

    1986-01-01

    Fracture treatment optimization techniques have been developed using Long-Spaced-Digital-Sonic (LSDS) log, pumpin-flowback, mini-frac, and downhole treating pressure data. These analysis techniques have been successfully applied in massive hydraulic fracturing (MHF) of ''tight gas'' wells. Massive hydraulic fracture stimulations have been used to make many tight gas reservoirs commercially attractive. However, studies have shown that short highly conductive fractures are optimum for the successful stimulation of wells in moderate permeability reservoirs. As a result, the ability to design and place optimal fractures in these reservoirs is critical. This paper illustrates the application of fracture analysis techniques to a moderate permeability multi-layered reservoir. These techniques were used to identify large zonal variations in rock properties and pore pressure which result from the complex geology. The inclusion of geologic factors in fracture treatment design allowed the placement of short highly conductive fractures which were used to improve injectivity and vertical sweep, and therefore, ultimate recovery.

  2. Reservoir engineering, transient pressure well testing, and petrophysical analyses of western gas sands. Annual report, July 1978-August 1979

    SciTech Connect

    Bixel, H.C.

    1981-11-01

    Improvement in gas deliverability by massive hydraulic fracturing of low permeability Western Gas Sands has been generally disappointing. This investigation uses petrophysical studies, transient pressure analysis of well performance, and parametric study of various fracture properties to aid in the understanding of the results of several DOE cost-shared MHF treatments. Both the transient pressure analysis and the parametric study utilize numerical simulation techniques. A generalized approach to pressure buildup analyses of tests with short flow periods is developed. The parametric analyses are focused on those variables of MHF treatments over which the operator and engineer have some control. Improvements in pressure measurement techniques are suggested as well as reasons why MHF treatments have had limited success.

  3. Gas reservoir sweet spot detection and delineation in Rocky Mountain laramide basins. Topical report, May 1993March 1996

    Microsoft Academic Search

    R. C. Surdam; W. O. Iverson; P. Yin

    1995-01-01

    The determination of the position and configuration of the pressure boundary between normal and anomalously pressured regimes, and the detection and delineation of porosity\\/permeability `sweet spots` below this boundary are the two most important elements in exploring for basin-center or deep-basin gas in Rocky Mountain Laramide Basins. These two exploration elements from the basis for a new exploration paradigm. To

  4. Characterization of Roabiba Sandstones Reservoir in Bintuni Field, Papua, Indonesia 

    E-print Network

    Vera, Riene

    2011-02-22

    Bintuni Field has two Middle Jurassic gas reservoirs, Upper and Lower Roabiba Sandstone reservoirs, with the estimated reserve from eight appraisal drilled wells of 6.08 tcf. The field has not been producing commercially. ...

  5. Project 5 -- Solution gas drive in heavy oil reservoirs: Gas and oil phase mobilities in cold production of heavy oils. Quarterly progress report, October 1--December 31, 1996

    SciTech Connect

    Firoozabadi, A.; Pooladi-Darvish, M.

    1996-12-31

    In this report, the authors present the results of their first experiment on a heavy crude of about 35,000 cp. A new visual coreholder was designed and built to accommodate the use of unconsolidated sand. From this work, several clear conclusions can be drawn: (1) oil viscosity does not decrease with the evolution of gas, (2) the critical gas saturation is in the range of 4--5%, and (3) the endpoint oil relative permeability is around 0.6. However, the most important parameter, gas phase mobility, is still unresolved. Gas flows intermittently, and therefore the length effect becomes important. Under the conditions that the authors run the experiment, recovery is minimal, about 7.5%. This recovery is still much higher than the recovery of the C{sub 1}/C{sub 10} model system which was 3%. After a duplicate test, they plan to conduct the experiment in the horizontal core. The horizontal core is expected to provide a higher recovery.

  6. Gas condensate damage in hydraulically fractured wells

    E-print Network

    Reza, Rostami Ravari

    2004-11-15

    -vaporize. This region is called the retrograde condensation zone and reservoirs experiencing this phenomenon are known as gas condensate reservoirs 1. 1.2.1 Gas condensate reservoir fluid modeling In compositional simulation of oil and gas reservoirs... Ayoola Adeyeye, this subject was studied when the effects of reservoir depletion were minimized by introduction of an injector well with fluid composition the same as the original reservoir fluid. He also used an infinite conductivity hydraulic...

  7. PHYSICS OF A PARTIALLY IONIZED GAS RELEVANT TO GALAXY FORMATION SIMULATIONS-THE IONIZATION POTENTIAL ENERGY RESERVOIR

    SciTech Connect

    Vandenbroucke, B.; De Rijcke, S.; Schroyen, J. [Department of Physics and Astronomy, Ghent University, Krijgslaan 281, S9, B-9000 Gent (Belgium); Jachowicz, N. [Department of Physics and Astronomy, Ghent University, Proeftuinstraat 86, B-9000 Gent (Belgium)

    2013-07-01

    Simulation codes for galaxy formation and evolution take on board as many physical processes as possible beyond the standard gravitational and hydrodynamical physics. Most of this extra physics takes place below the resolution level of the simulations and is added in a ''sub-grid'' fashion. However, these sub-grid processes affect the macroscopic hydrodynamical properties of the gas and thus couple to the ''on-grid'' physics that is explicitly integrated during the simulation. In this paper, we focus on the link between partial ionization and the hydrodynamical equations. We show that the energy stored in ions and free electrons constitutes a potential energy term which breaks the linear dependence of the internal energy on temperature. Correctly taking into account ionization hence requires modifying both the equation of state and the energy-temperature relation. We implemented these changes in the cosmological simulation code GADGET2. As an example of the effects of these changes, we study the propagation of Sedov-Taylor shock waves through an ionizing medium. This serves as a proxy for the absorption of supernova feedback energy by the interstellar medium. Depending on the density and temperature of the surrounding gas, we find that up to 50% of the feedback energy is spent ionizing the gas rather than heating it. Thus, it can be expected that properly taking into account ionization effects in galaxy evolution simulations will drastically reduce the effects of thermal feedback. To the best of our knowledge, this potential energy term is not used in current simulations of galaxy formation and evolution.

  8. A finite element simulation system in reservoir engineering

    SciTech Connect

    Gu, Xiaozhong

    1996-03-01

    Reservoir engineering is performed to predict the future performance of a reservoir based on its current state and past performance and to explore other methods for increasing the recovery of hydrocarbons from a reservoir. Reservoir simulations are routinely used for these purposes. A reservoir simulator is a sophisticated computer program which solves a system of partial differential equations describing multiphase fluid flow (oil, water, and gas) in a porous reservoir rock. This document describes the use of a reservoir simulator version of BOAST which was developed by the National Institute for Petroleum and Energy Research in July, 1991.

  9. Gas reservoir sweet spot detection and delineation in Rocky Mountain laramide basins. Topical report, May 1993-March 1996

    SciTech Connect

    Surdam, R.C.; Iverson, W.O.; Yin, P.

    1995-10-01

    The determination of the position and configuration of the pressure boundary between normal and anomalously pressured regimes, and the detection and delineation of porosity/permeability `sweet spots` below this boundary are the two most important elements in exploring for basin-center or deep-basin gas in Rocky Mountain Laramide Basins. These two exploration elements from the basis for a new exploration paradigm. To utilize this new paradigm, the following tasks need to be included in the exploration strategy: (1) determine the position of the pressure boundary; (2) evaluate the three-dimensional aspects of the pressure boundary surface; (3) determine which depositional facies has the greatest potential for enhances storage capacity and deliverability below the pressure boundary; (4) document the determinative factors that control sweet spot development in the targeted lithofacies; and (5) detect and delineate sweet spots using 2-D and 3-D models of eletric log responses and seismic data.

  10. Foam as an agent to reduce gravity override effect during gas injection in oil reservoirs. Final report

    SciTech Connect

    Chiang, J.C.; Sanyal, S.K.; Castanier, L.M.; Brigham, W.E.; Shah, D.O.

    1980-08-01

    A two-dimensional, vertical, rectangular plexiglas model holding a 45-1/2 in. high by 11-3/8 in. wide by 1/4 in. thick sandpack (1.147 x 0.237 x 0.008 m) was used to investigate gravity override of injected gases in gas drive processes. Saturation of the sandpack by a surfactant solution instead of pure water sharply increased liquid recovery and breakthrough time in a nitrogen flooding process. The improvement in production was shown to be due to a reduction of gravity override caused by in-situ generation of foam at the gas-liquid interface. Solutions of two different surfactants (Suntech IX and IV) of various concentrations with different amounts of alcohol were studied to determine their effectiveness as foamers. Surface tension and rate of drainage of the foamers as functions of surfactant concentration were measured. In-situ foaming in the model increased generally with surfactant concentration until an optimum concentration was reached; above this concentration, additional amounts of surfactant had very little effect on the phenomenon. Alcohols seem to improve the performance of low molecular weight surfactants and exhibitied a negative effect on the others. A similar increase of recovery and delay in the breakthrough time was observed in the oil flooding process. A slug of surfactant solution was injected into the pack which was saturated with a white mineral oil and water at irreducible water saturation, and then nitrogen was injected. Gravity override was much less than in the cases when no surfactant was present.

  11. FRACTURED PETROLEUM RESERVOIRS

    SciTech Connect

    Abbas Firoozabadi

    1999-06-11

    The four chapters that are described in this report cover a variety of subjects that not only give insight into the understanding of multiphase flow in fractured porous media, but they provide also major contribution towards the understanding of flow processes with in-situ phase formation. In the following, a summary of all the chapters will be provided. Chapter I addresses issues related to water injection in water-wet fractured porous media. There are two parts in this chapter. Part I covers extensive set of measurements for water injection in water-wet fractured porous media. Both single matrix block and multiple matrix blocks tests are covered. There are two major findings from these experiments: (1) co-current imbibition can be more efficient than counter-current imbibition due to lower residual oil saturation and higher oil mobility, and (2) tight fractured porous media can be more efficient than a permeable porous media when subjected to water injection. These findings are directly related to the type of tests one can perform in the laboratory and to decide on the fate of water injection in fractured reservoirs. Part II of Chapter I presents modeling of water injection in water-wet fractured media by modifying the Buckley-Leverett Theory. A major element of the new model is the multiplication of the transfer flux by the fractured saturation with a power of 1/2. This simple model can account for both co-current and counter-current imbibition and computationally it is very efficient. It can be orders of magnitude faster than a conventional dual-porosity model. Part II also presents the results of water injection tests in very tight rocks of some 0.01 md permeability. Oil recovery from water imbibition tests from such at tight rock can be as high as 25 percent. Chapter II discusses solution gas-drive for cold production from heavy-oil reservoirs. The impetus for this work is the study of new gas phase formation from in-situ process which can be significantly different from that of gas displacement processes. The work is of experimental nature and clarifies several misconceptions in the literature. Based on experimental results, it is established that the main reason for high efficiency of solution gas drive from heavy oil reservoirs is due to low gas mobility. Chapter III presents the concept of the alteration of porous media wettability from liquid-wetting to intermediate gas-wetting. The idea is novel and has not been introduced in the petroleum literature before. There are significant implications from such as proposal. The most direct application of intermediate gas wetting is wettability alteration around the wellbore. Such an alteration can significantly improve well deliverability in gas condensate reservoirs where gas well deliverability decreases below dewpoint pressure. Part I of Chapter III studies the effect of gravity, viscous forces, interfacial tension, and wettability on the critical condensate saturation and relative permeability of gas condensate systems. A simple phenomenological network model is used for this study, The theoretical results reveal that wettability significantly affects both the critical gas saturation and gas relative permeability. Gas relative permeability may increase ten times as contact angle is altered from 0{sup o} (strongly liquid wet) to 85{sup o} (intermediate gas-wetting). The results from the theoretical study motivated the experimental investigation described in Part II. In Part II we demonstrate that the wettability of porous media can be altered from liquid-wetting to gas-wetting. This part describes our attempt to find appropriate chemicals for wettability alteration of various substrates including rock matrix. Chapter IV provides a comprehensive treatment of molecular, pressure, and thermal diffusion and convection in porous media Basic theoretical analysis is presented using irreversible thermodynamics.

  12. Analysis of real-time reservoir monitoring : reservoirs, strategies, & modeling.

    SciTech Connect

    Mani, Seethambal S.; van Bloemen Waanders, Bart Gustaaf; Cooper, Scott Patrick; Jakaboski, Blake Elaine; Normann, Randy Allen; Jennings, Jim (University of Texas at Austin, Austin, TX); Gilbert, Bob (University of Texas at Austin, Austin, TX); Lake, Larry W. (University of Texas at Austin, Austin, TX); Weiss, Chester Joseph; Lorenz, John Clay; Elbring, Gregory Jay; Wheeler, Mary Fanett (University of Texas at Austin, Austin, TX); Thomas, Sunil G. (University of Texas at Austin, Austin, TX); Rightley, Michael J.; Rodriguez, Adolfo (University of Texas at Austin, Austin, TX); Klie, Hector (University of Texas at Austin, Austin, TX); Banchs, Rafael (University of Texas at Austin, Austin, TX); Nunez, Emilio J. (University of Texas at Austin, Austin, TX); Jablonowski, Chris (University of Texas at Austin, Austin, TX)

    2006-11-01

    The project objective was to detail better ways to assess and exploit intelligent oil and gas field information through improved modeling, sensor technology, and process control to increase ultimate recovery of domestic hydrocarbons. To meet this objective we investigated the use of permanent downhole sensors systems (Smart Wells) whose data is fed real-time into computational reservoir models that are integrated with optimized production control systems. The project utilized a three-pronged approach (1) a value of information analysis to address the economic advantages, (2) reservoir simulation modeling and control optimization to prove the capability, and (3) evaluation of new generation sensor packaging to survive the borehole environment for long periods of time. The Value of Information (VOI) decision tree method was developed and used to assess the economic advantage of using the proposed technology; the VOI demonstrated the increased subsurface resolution through additional sensor data. Our findings show that the VOI studies are a practical means of ascertaining the value associated with a technology, in this case application of sensors to production. The procedure acknowledges the uncertainty in predictions but nevertheless assigns monetary value to the predictions. The best aspect of the procedure is that it builds consensus within interdisciplinary teams The reservoir simulation and modeling aspect of the project was developed to show the capability of exploiting sensor information both for reservoir characterization and to optimize control of the production system. Our findings indicate history matching is improved as more information is added to the objective function, clearly indicating that sensor information can help in reducing the uncertainty associated with reservoir characterization. Additional findings and approaches used are described in detail within the report. The next generation sensors aspect of the project evaluated sensors and packaging survivability issues. Our findings indicate that packaging represents the most significant technical challenge associated with application of sensors in the downhole environment for long periods (5+ years) of time. These issues are described in detail within the report. The impact of successful reservoir monitoring programs and coincident improved reservoir management is measured by the production of additional oil and gas volumes from existing reservoirs, revitalization of nearly depleted reservoirs, possible re-establishment of already abandoned reservoirs, and improved economics for all cases. Smart Well monitoring provides the means to understand how a reservoir process is developing and to provide active reservoir management. At the same time it also provides data for developing high-fidelity simulation models. This work has been a joint effort with Sandia National Laboratories and UT-Austin's Bureau of Economic Geology, Department of Petroleum and Geosystems Engineering, and the Institute of Computational and Engineering Mathematics.

  13. The molecular gas reservoir of 6 low-metallicity galaxies from the Herschel Dwarf Galaxy Survey. A ground-based follow-up survey of CO(1-0), CO(2-1), and CO(3-2)

    NASA Astrophysics Data System (ADS)

    Cormier, D.; Madden, S. C.; Lebouteiller, V.; Hony, S.; Aalto, S.; Costagliola, F.; Hughes, A.; Rémy-Ruyer, A.; Abel, N.; Bayet, E.; Bigiel, F.; Cannon, J. M.; Cumming, R. J.; Galametz, M.; Galliano, F.; Viti, S.; Wu, R.

    2014-04-01

    Context. Observations of nearby starburst and spiral galaxies have revealed that molecular gas is the driver of star formation. However, some nearby low-metallicity dwarf galaxies are actively forming stars, but CO, the most common tracer of this reservoir, is faint, leaving us with a puzzle about how star formation proceeds in these environments. Aims: We aim to quantify the molecular gas reservoir in a subset of 6 galaxies from the Herschel Dwarf Galaxy Survey with newly acquired CO data and to link this reservoir to the observed star formation activity. Methods: We present CO(1-0), CO(2-1), and CO(3-2) observations obtained at the ATNF Mopra 22-m, APEX, and IRAM 30-m telescopes, as well as [C ii] 157?m and [O i] 63?m observations obtained with the Herschel/PACS spectrometer in the 6 low-metallicity dwarf galaxies: Haro 11, Mrk 1089, Mrk 930, NGC 4861, NGC 625, and UM 311. We derived their molecular gas masses from several methods, including using the CO-to-H2 conversion factor XCO (both Galactic and metallicity-scaled values) and dust measurements. The molecular and atomic gas reservoirs were compared to the star formation activity. We also constrained the physical conditions of the molecular clouds using the non-LTE code RADEX and the spectral synthesis code Cloudy. Results: We detect CO in 5 of the 6 galaxies, including first detections in Haro 11 (Z ~ 0.4 Z?), Mrk 930 (0.2 Z?), and UM 311 (0.5 Z?), but CO remains undetected in NGC 4861 (0.2 Z?). The CO luminosities are low, while [C ii] is bright in these galaxies, resulting in [C ii]/CO(1-0) ? 10 000. Our dwarf galaxies are in relatively good agreement with the Schmidt-Kennicutt relation for total gas. They show short molecular depletion timescales, even when considering metallicity-scaled XCO factors. Those galaxies are dominated by their H i gas, except Haro 11, which has high star formation efficiency and is dominated by ionized and molecular gas. We determine the mass of each ISM phase in Haro 11 using Cloudy and estimate an equivalent XCO factor that is 10 times higher than the Galactic value. Overall, our results confirm the emerging picture that CO suffers from significant selective photodissociation in low-metallicity dwarf galaxies.

  14. Numerical Investigation of Fractured Reservoir Response to Injection/Extraction Using a Fully Coupled Displacement Discontinuity Method

    E-print Network

    Lee, Byungtark

    2011-10-21

    In geothermal reservoirs and unconventional gas reservoirs with very low matrix permeability, fractures are the main routes of fluid flow and heat transport, so the fracture permeability change is important. In fact, reservoir development under...

  15. Pockmarks on either side of the Strait of Gibraltar: formation from overpressured shallow contourite gas reservoirs and internal wave action during the last glacial sea-level lowstand?

    NASA Astrophysics Data System (ADS)

    León, Ricardo; Somoza, Luis; Medialdea, Teresa; González, Francisco Javier; Gimenez-Moreno, Carmen Julia; Pérez-López, Raúl

    2014-06-01

    Integrating novel and published swath bathymetry (3,980 km2), as well as chirp and high-resolution 2D seismic reflection profiles (2,190 km), this study presents the mapping of 436 pockmarks at water depths varying widely between 370 and 1,020 m on either side of the Strait of Gibraltar. On the Atlantic side in the south-eastern Gulf of Cádiz near the Camarinal Sill, 198 newly discovered pockmarks occur in three well localized and separated fields: on the upper slope ( n=14), in the main channel of the Mediterranean outflow water (MOW, n=160), and on the huge contourite levee of the MOW main channel ( n=24) near the well-known TASYO field. These pockmarks vary in diameter from 60 to 919 m, and are sub-circular to irregularly elongated or lobate in shape. Their slope angles on average range from 3° to 25°. On the Mediterranean side of the strait on the Ceuta Drift of the western Alborán Basin, where pockmarks were already known to occur, 238 pockmarks were identified and grouped into three interconnected fields, i.e. a northern ( n=34), a central ( n=61) and a southern field ( n=143). In the latter two fields the pockmarks are mainly sub-circular, ranging from 130 to 400 m in diameter with slope angles averaging 1.5° to 15°. In the northern sector, by contrast, they are elongated up to 1,430 m, probably reflecting MOW activity. Based on seismo-stratigraphic interpretation, it is inferred that most pockmarks formed during and shortly after the last glacial sea-level lowstand, as they are related to the final erosional discontinuity sealed by Holocene transgressive deposits. Combining these findings with other existing knowledge, it is proposed that pockmark formation on either side of the Strait of Gibraltar resulted from gas and/or sediment pore-water venting from overpressured shallow gas reservoirs entrapped in coarse-grained contourites of levee deposits and Pleistocene palaeochannel infillings. Venting was either triggered or promoted by hydraulic pumping associated with topographically forced internal waves. This mechanism is analogous to the long-known effect of tidal pumping on the dynamics of unit pockmarks observed along the Norwegian continental margin.

  16. Damage tolerance of well-completion and stimulation techniques in coalbed methane reservoirs

    Microsoft Academic Search

    Hossein Jahediesfanjani; Faruk Civan

    2005-01-01

    Coalbed methane (CBM) reservoirs are characterized as naturally fractured, dual porosity, low permeability, and water saturated gas reservoirs. Initially, the gas, water and coal are at thermodynamic equilibrium under prevailing reservoir conditions. Dewatering is essential to promote gas production. This can be accomplished by suitable completion and stimulation techniques. This paper investigates the efficiency and performance of the openhole cavity,

  17. SMALL, GEOLOGICALLY COMPLEX RESERVOIRS CAN BENEFIT FROM RESERVOIR SIMULATION

    Microsoft Academic Search

    Richard E. Bennett

    2002-01-01

    The Cascade Sand zone of the Mission-Visco Lease in the Cascade Oil field of Los Angeles County, California, has been under water flood since 1970. Increasing water injection to increase oil production rates was being considered as an opportunity to improve oil recovery. However, a secondary gas cap had formed in the up-dip portion of the reservoir with very low

  18. Issues in geothermal reservoir engineering, modeling, and numerical simulation

    Microsoft Academic Search

    Pritchett

    1996-01-01

    The theoretical basis of geothermal reservoir engineering owes much of its origins to the oil and gas industries, but important differences in resource character and geological setting have resulted in substantial divergences from reservoir simulation as practiced in the petroleum industry. Geothermal reservoirs are hotter, contain different fluids, and are usually found within fractured volcanic formations with little or no

  19. Reservoir simulation; State of the art

    SciTech Connect

    Breitenbach, E.A. (Scientific Software-Intercomp, Inc. (US))

    1991-09-01

    This paper describes the state of the art in oil and natural gas reservoir simulation for the nonexpert, focusing primarily on advances that have occurred since a similar paper was published by Coats in 1982. For completeness, a history of simulation is given first, followed by a brief and simple review of the simulation process. Advances in simulation technology are then described, highlighting those in reservoir description and simulation of naturally fractured reservoirs, hydraulic fracturing, and horizontal wells. The future of reservoir simulation is discussed last.

  20. The effective approach for predicting viscosity of saturated and undersaturated reservoir oil 

    E-print Network

    Kulchanyavivat, Sawin

    2006-04-12

    and stock-tank oil gravity for saturated and undersaturated reservoir oil...............................................39 6 Relationship between reservoir oil viscosity and solution gas-oil ratio for saturated and undersaturated reservoir oil..., stock-tank oil gravity, solution gas-oil ratio, reservoir pressure, and oil density. Parameters that show the strong relationship with reservoir oil viscosity have a high potential to be used as influential parameters for correlating oil viscosity...

  1. Predicting reservoir sedimentation

    E-print Network

    Wooten, Stephanie

    1997-01-01

    Sediments accumulate in reservoirs and significantly decrease storage capacity. Predicting sedimentation is an important consideration in the design of new reservoir projects and in the management of existing reservoirs. Sedimentation rates may vary...

  2. Painter Reservoir, east Painter Reservoir and Clear Creek Fields, Uinta County, Wyoming

    Microsoft Academic Search

    J. R. Frank; S. Cluff; J. M. Bauman

    1982-01-01

    Painter Reservoir, East Painter Reservoir, and Clear Creek fields are part of a series of recent major hydrocarbon discoveries in the Thrust Belt Province of NE. Utah-SW. Wyoming that began with the discovery of the Pineview field in Utah. Oil and gas production in the fields is from the Triassic-Jurassic Nugget Sandstone. There the Nugget is a varicolored, fine- to

  3. Cretaceous reservoirs in Tunisia

    SciTech Connect

    Burollet, P.F.

    1988-08-01

    During the last 30 years, several oil and gas fields have been discovered in the Cretaceous Series of Tunisia. Oil shows or presently uneconomic accumulations were found in many wells. In every case the reservoir is made of carbonate, mostly dolomitic limestone. Thick bodies of sandstone exist in the Lower Cretaceous sequences of central and southern Tunisia. Due to active hydraulic circulation and lack of coverage until now, they have produced just water - mostly fresh water. Carbonate development is related to two main factors: (1) a latitudinal zonation grading from an internal shelf south to the open Tethys Sea on the north and (2) local structural features such as ridges, depocenter, tilted blocks, and diapirs. The reservoir character of the carbonates is due to various factors such as grainstone structure, reefs, moldic porosity, vadose or phreatic leaching, and fracturing. The beds with oil and gas indications are Aptian Serdj Formation; Cenomanian reef of Isis type; Turonian reefoid talus, calcarenite, and oolites; Campanian and Maestrichtian chalky Abiod Formation, either grading to rudistid reef or fractured. Since the exploration was led mainly to structural targets, good opportunities for discovery of stratigraphic or semistratigraphic traps remain in the field.

  4. NMR Properties of Petroleum Reservoir Fluids

    Microsoft Academic Search

    George J. Hirasaki; Ying Zhang

    NMR well logging of petroleum reservoir require the measurement of the NMR response of water, oil, and gas in the pore space of rocks at elevated temperatures and pressures. The viscosity of the oil may range from less than 1 cp to greater than 10,000 cp. Also, the oil and gas are not a single component but rather a broad

  5. NMR properties of petroleum reservoir fluids

    Microsoft Academic Search

    George J. Hirasaki; Sho-Wei Lo; Ying Zhang

    2003-01-01

    NMR well logging of petroleum reservoir require the measurement of the NMR response of water, oil, and gas in the pore space of rocks at elevated temperatures and pressures. The viscosity of the oil may range from less than 1 cp to greater than 10,000 cp. Also, the oil and gas are not a single component but rather a broad

  6. Optimization of fractured well performance of horizontal gas wells 

    E-print Network

    Magalhaes, Fellipe Vieira

    2009-06-02

    In low-permeability gas reservoirs, horizontal wells have been used to increase the reservoir contact area, and hydraulic fracturing has been further extending the contact between wellbores and reservoirs. This thesis presents an approach...

  7. Production-induced changes in reservoir geomechanics

    NASA Astrophysics Data System (ADS)

    Amoyedo, Sunday O.

    Sand production remains a source of concern in both conventional and heavy oil production. Porosity increase and changes in local stress magnitude, which often enhance permeability, have been associated with severe sanding. On the other hand, sand production has been linked to a large number of field incidences involving loss of well integrity, casing collapse and corrosion of down-hole systems. It also poses problems for separators and transport facilities. Numerous factors such as reservoir consolidation, well deviation angle through the reservoir, perforation size, grain size, capillary forces associated with water cut, flow rate and most importantly reservoir strain resulting from pore pressure depletion contribute to reservoir sanding. Understanding field-specific sand production patterns in mature fields and poorly consolidated reservoirs is vital in identifying sand-prone wells and guiding remedial activities. Reservoir strain analysis of Forties Field, located in the UK sector of the North Sea, shows that the magnitude of the production-induced strain, part of which is propagated to the base of the reservoir, is of the order of 0.2 %, which is significant enough to impact the geomechanical properties of the reservoir. Sand production analysis in the field shows that in addition to poor reservoir consolidation, a combined effect of repeated perforation, high well deviation, reservoir strain and high fluid flow rate have contributed significantly to reservoir sanding. Knowledge of reservoir saturation variation is vital for in-fill well drilling, while information on reservoir stress variation provides a useful guide for sand production management, casing design, injector placement and production management. Interpreting time-lapse difference is enhanced by decomposing time-lapse difference into saturation, pressure effects and changes in rock properties (e.g. porosity) especially in highly compacting reservoirs. Analyzing the stress and saturation sensitivity of the reservoir and overburden shale of Forties Field, I observe that while pore pressure variations have not been significant in most parts of the field, a relatively higher decrease in pore pressure in a region of the reservoir has affected the geomechanical properties of both reservoir and overlying rock strata . I found that strain development in the field accounts, in part, for increased reservoir sand production and a negative velocity change in the overburden, which provides an indication of dilation. I use changes in the AVO intercept and gradient calibrated with laboratory measurements to decouple the time-lapse (4D) difference into saturation and pressure changes. Furthermore, I propose a new modification to time-lapse AVO inversion workflows to account for the effect of porosity change in measurements of time-lapse difference. This is particularly crucial in highly-compacting chalk and poorly consolidated clastic reservoirs. Rock-physics-driven inversion of 3D pre-stack seismic data plays a prominent role in the characterization of both reservoir and overburden rocks. Understanding the rock physics of the overburden rock is required for efficient production of the reservoir and to safeguard wellbore, down-hole assembly and supporting surface facilities. Taking Forties Field as a case study, I observe that while instability and subsequent failure of the overburden in the field can be linked to the rapid decrease of the unconfined compressive strength (UCS) at inclinations close to 45 degrees to the bedding plan, some zones in the overburden are characterized by extreme weakness regardless of the well angle through the rock. I use the correlation between unconfined compressive strength and elastic moduli (Young's and Bulk moduli), coupled with the results of simultaneous inversion to derive 3D elastic moduli, calibrated to laboratory measurements, to characterize the zones of extreme weakness. Time-lapse gravimetry continues to find increasing application in reservoir monitoring, typically in gas reservoirs and reservoirs used for CO2 sequestration.

  8. Comprehensive Analysis of Enhanced CBM Production via CO2 Injection Using a Surrogate Reservoir Model Jalal Jalali, Shahab D. Mohaghegh, Dept. of Petroleum & Natural Gas Engineering, West Virginia University

    E-print Network

    Mohaghegh, Shahab

    Reservoir simulation is the industry standard for reservoir management. Complex reservoir models usually to develop new techniques to perform uncertainty analysis with less number of reservoir simulation modelsObjectiveObjectiveObjective This paper presents the utilization of a newly developed technique to perform uncertainty analysis

  9. Data quality enhancement in oil reservoir operations : an application of IPMAP

    E-print Network

    Lin, Paul Hong-Yi

    2012-01-01

    This thesis presents a study of data quality enhancement opportunities in upstream oil and gas industry. Information Product MAP (IPMAP) methodology is used in reservoir pressure and reservoir simulation data, to propose ...

  10. Multiscale Reservoir Simulation: Layer Design, Full Field Pseudoization and Near Well Modeling 

    E-print Network

    Du, Song

    2012-12-10

    . This has received increasing attention, especially when studying hydraulically fractured wells in unconventional reservoirs. We propose a multiscale reservoir simulation model combining local grid refinement (LGR) and pillar-based upscaling for tight gas...

  11. Adsorption of water vapor on reservoir rocks

    SciTech Connect

    Not Available

    1993-07-01

    Progress is reported on: adsorption of water vapor on reservoir rocks; theoretical investigation of adsorption; estimation of adsorption parameters from transient experiments; transient adsorption experiment -- salinity and noncondensible gas effects; the physics of injection of water into, transport and storage of fluids within, and production of vapor from geothermal reservoirs; injection optimization at the Geysers Geothermal Field; a model to test multiwell data interpretation for heterogeneous reservoirs; earth tide effects on downhole pressure measurements; and a finite-difference model for free surface gravity drainage well test analysis.

  12. Carbon emission from global hydroelectric reservoirs revisited.

    PubMed

    Li, Siyue; Zhang, Quanfa

    2014-12-01

    Substantial greenhouse gas (GHG) emissions from hydropower reservoirs have been of great concerns recently, yet the significant carbon emitters of drawdown area and reservoir downstream (including spillways and turbines as well as river reaches below dams) have not been included in global carbon budget. Here, we revisit GHG emission from hydropower reservoirs by considering reservoir surface area, drawdown zone and reservoir downstream. Our estimates demonstrate around 301.3 Tg carbon dioxide (CO2)/year and 18.7 Tg methane (CH4)/year from global hydroelectric reservoirs, which are much higher than recent observations. The sum of drawdown and downstream emission, which is generally overlooked, represents 42 % CO2 and 67 % CH4 of the total emissions from hydropower reservoirs. Accordingly, the global average emissions from hydropower are estimated to be 92 g CO2/kWh and 5.7 g CH4/kWh. Nonetheless, global hydroelectricity could currently reduce approximate 2,351 Tg CO2eq/year with respect to fuel fossil plant alternative. The new findings show a substantial revision of carbon emission from the global hydropower reservoirs. PMID:24943886

  13. Prestack seismic inversion and reservoir property prediction

    NASA Astrophysics Data System (ADS)

    Chi, Xingang

    In this dissertation, I have applied the method of prestack seismic inversion with uncertainty analysis. Also, I have developed the methods of the rock physics template analysis, the fluid modulus inversion and the reservoir property inversion from AVO attributes with and without constraint to improve the technique of reservoir characterization. I use the prestack seismic inversion to invert the elastic properties and use the statistical method to derive the posterior probability of the inverted elastic properties for the uncertainty analysis. I use the rock physics template drawn in the cross-plot of the inverted elastic properties to analyze the lithology and fluid property in the target reservoir. I develop the fluid modulus inversion method based on the simplified Gassmann's equation and the empirical rock physics relationship. Using the inverted fluid modulus, I estimate the gas saturation of the target reservoir before drilling. The reservoir property inversion is to predict the porosity, shale volume and water saturation of the reservoir from AVO attributes to enhance the reservoir interpretation and characterization. I apply this method with the statistical analysis together to execute the uncertainty analysis for the inversion results. Two methods of reservoir property inversion from AVO attributes are attempted in this dissertation: one is performed without constraint and the other is performed with the constrained relationship of the porosity and shale volume.

  14. Status of Norris Reservoir

    SciTech Connect

    Not Available

    1990-09-01

    This is one in a series of reports prepared by the Tennessee Valley Authority (TVA) for those interested in the conditions of TVA reservoirs. This overview of Norris Reservoir summarizes reservoir and watershed characteristics, reservoir uses, conditions that impair reservoir uses, water quality and aquatic biological conditions, and activities of reservoir management agencies. This information was extracted from the most up-to-date publications and data available, and from interviews with water resource professionals in various federal, state, and local agencies, and in public and private water supply and wastewater treatment facilities. 14 refs., 3 figs.

  15. Application of integrated reservoir management and reservoir characterization to optimize infill drilling

    SciTech Connect

    NONE

    1997-04-01

    This project has used a multi-disciplinary approach employing geology, geophysics, and engineering to conduct advanced reservoir characterization and management activities to design and implement an optimized infill drilling program at the North Robertson (Clearfork) Unit in Gaines County, Texas. The activities during the first Budget Period consisted of developing an integrated reservoir description from geological, engineering, and geostatistical studies, and using this description for reservoir flow simulation. Specific reservoir management activities were identified and tested. The geologically targeted infill drilling program currently being implemented is a result of this work. A significant contribution of this project is to demonstrate the use of cost-effective reservoir characterization and management tools that will be helpful to both independent and major operators for the optimal development of heterogeneous, low permeability shallow-shelf carbonate (SSC) reservoirs. The techniques that are outlined for the formulation of an integrated reservoir description apply to all oil and gas reservoirs, but are specifically tailored for use in the heterogeneous, low permeability carbonate reservoirs of West Texas.

  16. High-resolution reservoir characterization of midcontinent sandstones using wireline resistivity imaging, Boonsville (Bend Conglomerate) Gas Field, Fort Worth Basin, TX

    SciTech Connect

    Carr, D.L. (Consulting Geologist, Austin, TX (United States)); Elphick, R.Y. (Scientific Software-Intercomp, Denver, CO (United States)); Foulk, L.S. (Schlumberger Well Services, Englewood, CO (United States))

    1996-01-01

    In the absence of abundant core data, Formation MicroScanner* (FMS) and Fullbore Formation Microlmager* (FMI) wireline logs from 3 wells in Boonsville Field provided continuous geologic information in a 1000-foot thick, Pennsylvanian (Atoka) interval. Cores provided the most detailed sequence-stratigraphic information, but only 358 ft of core from 4 wells was available to evaluate the 30 mi[sup 2] project area. The FMS and FMI logs thus served as continuous, oriented [open quote]virtual cores[close quote] that expanded our stratigraphic database and improved our interpretations, which included the identification of key chronostratigraphic surfaces, lithofacies, sedimentary structures, faults, and fractures. Paleocurrents inferred from the FMS and FMI images suggest that most Bend Conglomerate sandstones are lowstand valley-fill deposits derived from the Muenster and Red River Uplifts, rather than Ouachita-derived deltas. Combined analysis of cores and wireline resistivity imaging technology enabled the development of a fine-scale, sequence-stratigraphic framework which formed the basis for correlation and mapping of the major Bend Conglomerate reservoir zones, and helped us to identify compartmentalization mechanisms within these complex reservoirs.

  17. High-resolution reservoir characterization of midcontinent sandstones using wireline resistivity imaging, Boonsville (Bend Conglomerate) Gas Field, Fort Worth Basin, TX

    SciTech Connect

    Carr, D.L. [Consulting Geologist, Austin, TX (United States); Elphick, R.Y. [Scientific Software-Intercomp, Denver, CO (United States); Foulk, L.S. [Schlumberger Well Services, Englewood, CO (United States)

    1996-12-31

    In the absence of abundant core data, Formation MicroScanner* (FMS) and Fullbore Formation Microlmager* (FMI) wireline logs from 3 wells in Boonsville Field provided continuous geologic information in a 1000-foot thick, Pennsylvanian (Atoka) interval. Cores provided the most detailed sequence-stratigraphic information, but only 358 ft of core from 4 wells was available to evaluate the 30 mi{sup 2} project area. The FMS and FMI logs thus served as continuous, oriented {open_quote}virtual cores{close_quote} that expanded our stratigraphic database and improved our interpretations, which included the identification of key chronostratigraphic surfaces, lithofacies, sedimentary structures, faults, and fractures. Paleocurrents inferred from the FMS and FMI images suggest that most Bend Conglomerate sandstones are lowstand valley-fill deposits derived from the Muenster and Red River Uplifts, rather than Ouachita-derived deltas. Combined analysis of cores and wireline resistivity imaging technology enabled the development of a fine-scale, sequence-stratigraphic framework which formed the basis for correlation and mapping of the major Bend Conglomerate reservoir zones, and helped us to identify compartmentalization mechanisms within these complex reservoirs.

  18. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-12-01

    We have developed and tested technology for a new type of direct hydrocarbon detection. The method uses inelastic rock properties to greatly enhance the sensitivity of surface seismic methods to the presence of oil and gas saturation. These methods include use of energy absorption, dispersion, and attenuation (Q) along with traditional seismic attributes like velocity, impedance, and AVO. Our approach is to combine three elements: (1) a synthesis of the latest rock physics understanding of how rock inelasticity is related to rock type, pore fluid types, and pore microstructure, (2) synthetic seismic modeling that will help identify the relative contributions of scattering and intrinsic inelasticity to apparent Q attributes, and (3) robust algorithms that extract relative wave attenuation attributes from seismic data. This project provides: (1) Additional petrophysical insight from acquired data; (2) Increased understanding of rock and fluid properties; (3) New techniques to measure reservoir properties that are not currently available; and (4) Provide tools to more accurately describe the reservoir and predict oil location and volumes. These methodologies will improve the industry's ability to predict and quantify oil and gas saturation distribution, and to apply this information through geologic models to enhance reservoir simulation. We have applied for two separate patents relating to work that was completed as part of this project.

  19. Imaging the Molecular Gas in a z=3.9 Quasar Host Galaxy at 0.3" Resolution: A Central, Sub-Kiloparsec Scale Star Formation Reservoir in APM 08279+5255

    E-print Network

    Dominik A. Riechers; Fabian Walter; Christopher L. Carilli; Geraint F. Lewis

    2008-09-04

    We have mapped the molecular gas content in the host galaxy of the strongly lensed high redshift quasar APM 08279+5255 (z=3.911) with the Very Large Array at 0.3" resolution. The CO(J=1-0) emission is clearly resolved in our maps. The CO(J=1-0) line luminosity derived from these maps is in good agreement with a previous single-dish measurement. In contrast to previous interferometer-based studies, we find that the full molecular gas reservoir is situated in two compact peaks separated by <~0.4". Our observations reveal, for the first time, that the emission from cold molecular gas is virtually cospatial with the optical/near-infrared continuum emission of the central AGN in this source. This striking similarity in morphology indicates that the molecular gas is situated in a compact region close to the AGN. Based on the high resolution CO maps, we present a revised model for the gravitational lensing in this system, which indicates that the molecular gas emission is magnified by only a factor of 4 (in contrast to previously suggested factors of 100). This model suggests that the CO is situated in a circumnuclear disk of ~550 pc radius that is possibly seen at an inclination of <~25 deg, i.e., relatively close to face-on. From the CO luminosity, we derive a molecular gas mass of M_gas=1.3x10^11 M_sun for this galaxy. From the CO structure and linewidth, we derive a dynamical mass of M_dyn(sin i)^2=4.0x10^10 M_sun. Based on a revised mass estimate for the central black hole of M_BH=2.3x10^10 M_sun and the results of our molecular line study, we find that the mass of the stellar bulge of APM 08279+5255 falls short of the local M_BH-sigma_bulge relationship of nearby galaxies by more than an order of magnitude, lending support to recent suggestions that this relation may evolve with cosmic time and/or change toward the high mass end.

  20. Thermal storage reservoirs

    SciTech Connect

    Scarlata, R.W.

    1980-06-03

    A thermal storage system for use with a solar collector and/or heat pump includes a plurality of discrete heat reservoirs having regular geometric shapes such as spheres or cylinders for forming a self-sorting array of the reservoirs when stacked in a storage bin. Each reservoir has a shell formed of heat conductive material defining an interior cavity that contains a material of high specific heat for storing heat in the reservoir. A preferred material for economy for reservoir shells in spherelike shapes is plastic with heat conductivity enhancers such as glass or metal particles incorporated into the plastic.

  1. Status of Cherokee Reservoir

    SciTech Connect

    Not Available

    1990-08-01

    This is the first in a series of reports prepared by Tennessee Valley Authority (TVA) for those interested in the conditions of TVA reservoirs. This overviews of Cherokee Reservoir summarizes reservoir and watershed characteristics, reservoir uses and use impairments, water quality and aquatic biological conditions, and activities of reservoir management agencies. This information was extracted from the most current reports, publications, and data available, and interviews with water resource professionals in various Federal, state, and local agencies and in public and private water supply and wastewater treatment facilities. 11 refs., 4 figs., 1 tab.

  2. Status of Wheeler Reservoir

    SciTech Connect

    Not Available

    1990-09-01

    This is one in a series of status reports prepared by the Tennessee Valley Authority (TVA) for those interested in the conditions of TVA reservoirs. This overview of Wheeler Reservoir summarizes reservoir purposes and operation, reservoir and watershed characteristics, reservoir uses and use impairments, and water quality and aquatic biological conditions. The information presented here is from the most recent reports, publications, and original data available. If no recent data were available, historical data were summarized. If data were completely lacking, environmental professionals with special knowledge of the resource were interviewed. 12 refs., 2 figs.

  3. The Role of Acidizing in Proppant Fracturing in Carbonate Reservoirs 

    E-print Network

    Densirimongkol, Jurairat

    2010-10-12

    Today, optimizing well stimulation techniques to obtain maximum return of investment is still a challenge. Hydraulic fracturing is a typical application to improve ultimate recovery from oil and gas reservoirs. Proppant fracturing has become one...

  4. Reservoir engineering in coal seams: Part 2 - Observations of gas movement in coal seams. [Movement of methane flow in coal seams

    SciTech Connect

    Gray, I.

    1987-02-01

    This paper, the second of two concerning the movement of gas in coal seams, covers observations of seam fluid pressures and flows in mines in northern and central Queensland, Australia. Techniques based primarily on underground measurement rather than measurements from surface boreholes were used to gain information on the seams. The techniques used for in-seam studies are described because they differ substantially from conventional oil and gas surface borehole techniques. The paper demonstrates the importance of cleats and joints in the control of fluid movement and records flow increases consistent with increasing permeability with production.

  5. Induced Microearthquake Patterns in Hydrocarbon and Geothermal Reservoirs: W. Scott Phillips

    E-print Network

    or production of fluids can induce microseismic events in hydrocarbon and geothermal reservoirs. By deploying Patterns in Reservoirs Key Words: induced microseismicity, geothermal, oil and gas, fluid flow, location-made geothermal reservoir. Although microseismic clouds have played a key role in the development of hot-dry- rock

  6. Reservoir engineering in coal seams: Part 2 - Observations of gas movement in coal seams. [Movement of methane flow in coal seams

    Microsoft Academic Search

    Gray

    1987-01-01

    This paper, the second of two concerning the movement of gas in coal seams, covers observations of seam fluid pressures and flows in mines in northern and central Queensland, Australia. Techniques based primarily on underground measurement rather than measurements from surface boreholes were used to gain information on the seams. The techniques used for in-seam studies are described because they

  7. Numerical modeling of gas migration into and through faulted sand reservoirs in Pabst Field (Main Pass East Block 259), northern Gulf of Mexico

    E-print Network

    Li, Yuqian

    2006-08-16

    ...............................................................52 34. RDSgTM1 vs. time ................................................................................................53 35. RDSgTM2 vs. Tf of TM2 at t=30 ky .....................................................................55... 36. Gas input rate vs. differential pressure (dP), TM3 at t=30 ky...............................57 xii FIGURE Page 37...

  8. Simulation of paraffin damage due to natural cooling in reservoirs

    E-print Network

    Peddibhotla, Sriram

    1993-01-01

    in the reservoir. Suitable modifications were made to model the paraffin precipitation due to natural cooling. The mechanisms which were modeled include (1) reduction in paraffin solubility due to evolution of dissolved gas and due to temperature changes, (2... independently, after which they were incorporated into a reservoir simulator. Then cases were run to simulate field conditions. Natural cooling is the temperature drop due to the gas leaving solution. The simulation results indicate that natural cooling...

  9. Geothermal-reservoir engineering research at Stanford University. Second annual report, October 1, 1981-September 30, 1982

    SciTech Connect

    Ramey, H.J. Jr.; Kruger, P.; Horne, R.N.; Brigham, W.E.; Miller, F.G.

    1982-09-01

    Progress in the following tasks is discussed: heat extraction from hydrothermal reservoirs, noncondensable gas reservoir engineering, well test analysis and bench-scale experiments, DOE-ENEL Cooperative Research, Stanford-IIE Cooperative Research, and workshop and seminars. (MHR)

  10. Technology and Economics Affecting Unconventional Reservoir Development 

    E-print Network

    Flores Campero, Cecilia P.

    2010-01-15

    recovery R&D and unconventional gas produc- tion. Data from 29 major US-based energy producing companies???? 11 2.1 History matching and forecasting for a natural gas producer reservoir as example???????????????????????............. 16 2...- vention of the combustion engine to power automobiles and airplanes, the US developed into a great industrial power based on oil. Major discoveries were found in East Texas in 1930s, and even larger reserves discovered in the Middle East, Iraq and Saudi...

  11. Global Carbon Reservoir Oxidative Ratios

    NASA Astrophysics Data System (ADS)

    Masiello, C. A.; Gallagher, M. E.; Hockaday, W. C.

    2010-12-01

    Photosynthesis and respiration move carbon and oxygen between the atmosphere and the biosphere at a ratio that is characteristic of the biogeochemical processes involved. This ratio is called the oxidative ratio (OR) of photosynthesis and respiration, and is defined as the ratio of moles of O2 per moles of CO2. This O2/CO2 ratio is a characteristic of biosphere-atmosphere gas fluxes, much like the 13C signature of CO2 transferred between the biosphere and the atmosphere has a characteristic signature. OR values vary on a scale of 0 (CO2) to 2 (CH4), with most ecosystem values clustered between 0.9 and 1.2. Just as 13C can be measured for both carbon fluxes and carbon pools, OR can also be measured for fluxes and pools and can provide information about the processes involved in carbon and oxygen cycling. OR values also provide information about reservoir organic geochemistry because pool OR values are proportional to the oxidation state of carbon (Cox) in the reservoir. OR may prove to be a particularly valuable biogeochemical tracer because of its ability to couple information about ecosystem gas fluxes with ecosystem organic geochemistry. We have developed 3 methods to measure the OR of ecosystem carbon reservoirs and intercalibrated them to assure that they yield accurate, intercomparable data. Using these tools we have built a large enough database of biomass and soil OR values that it is now possible to consider the implications of global patterns in ecosystem OR values. Here we present a map of the natural range in ecosystem OR values and begin to consider its implications. One striking pattern is an apparent offset between soil and biospheric OR values: soil OR values are frequently higher than that of their source biomass. We discuss this trend in the context of soil organic geochemistry and gas fluxes.

  12. Volume 3: Characterization of representative reservoirs -- South Marsh Island 73, B35K and B65G Reservoirs

    SciTech Connect

    Young, M.A.; Salamy, S.P.; Reeves, T.K. [BDM-Oklahoma, Inc., Bartlesville, OK (United States); Kimbrell, W.C. [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Petroleum Engineering; Sawyer, W.K. [Mathematical and Computer Services, Inc., Danville, VA (United States)

    1998-07-01

    This report documents the results of a detailed study of two Gulf of Mexico salt dome related reservoirs and the application of a publicly available PC-based black oil simulator to model the performances of gas injection processes to recover attic oil. The overall objective of the research project is to assess the oil reserve potential that could result from the application of proven technologies to recover bypassed oil from reservoirs surrounding piercement salt domes in the Gulf of Mexico. The specific study objective was to simulate the primary recovery and attic gas injection performance of the two subject reservoirs to: (1) validate the BOAST model; (2) quantify the attic volume; and (3) predict the attic oil recovery potential that could result from additional updip gas injection. The simulation studies were performed on the B-35K Reservoir and the B-65G Reservoir in the South Marsh Island Block 73 Field using data provided by one of the field operators. A modified PC-version of the BOAST II model was used to match the production and injection performances of these reservoirs in which numerous gas injection cycles had been conducted to recover attic oil. The historical performances of the gas injection cycles performed on both the B-35K Reservoir and B-65G Reservoir were accurately matched, and numerous predictive runs were made to define additional potential for attic oil recovery using gas injection. Predictive sensitivities were conducted to examine the impact of gas injection rate, injection volume, post-injection shut-in time, and the staging of gas injection cycles on oil recovery.

  13. Seasonal variability of methane ebullition in a temperate freshwater reservoir

    NASA Astrophysics Data System (ADS)

    Frouzova, Jaroslava; Tuser, Michal; Stanovsky, Petr; Picek, Tomas

    2015-04-01

    Seasonal variability of methane ebullition was observed in the temperate freshwater reservoir of ?ímov (Czech Republic) in 2014. The canyon-shaped reservoir with one main tributary covers 210 ha with a maximum depth of 40 m and serves as drinking water supply. The whole area of open water of the reservoir was acoustically investigated fortnightly all year round, except periods with ice cover. Anchored submerged funnels were then placed in ebullitive zones of the reservoir (the upper part) covering a depth range of 4 - 12 m. Sampled gas bubbles were analyzed using gas chromatography. Methane concentration in the sampled bubbles varied from 0 to 82 %. The main ebullition peak occurred in the beginning of July, reaching values up to 1200 mg of CH4 per square meter per day. These values support the assumption that reservoirs in the temperate zone are not negligible sources of methane.

  14. Continent ileocaecal urinary reservoir.

    PubMed Central

    Ashken, M H

    1978-01-01

    In 14 cases, a continent ureteroileocaecal urinary reservoir has been constructed. If a long-term ease of self catheterization can be maintained, some patients requiring an urinary diversion might prefer an appliance-free urinary reservoir to a freely draining conduit and urinary appliance. The indications and place for the continent urinary reservoir still need to be studied, modified and proven during the coming years. Images Figure 2. PMID:650648

  15. Coastal barrier reservoirs

    SciTech Connect

    Richardson, J.G.; Sangree, J.B.; Sneider, R.M.

    1988-09-01

    Coastal barriers are long, narrow, wave-built, sandy islands parallel to the shore. Part of the island has a beach, but many have sand dunes and areas of vegetation above the high-tide line. A lagoon or estuary is behind the barrier on the protected side away from the ocean. Coastal barrier reservoirs can hold major accumulations of oil and gas. Coastal barriers can build by three major processes; addition of sand washed onto the beach from breaker bars, addition on one end by sand washed from the other end and moved by riptides, and deposition of sand into the lagoon by waves breaking over the barrier during storms. Galveston Island, offshore Texas, is a good example of a modern coastal barrier. Waves in the Gulf of Mexico have sufficient energy to transport and deposit fine-grained sand on Galveston Island. (Fine-grained sand is the coarsest sand available in upper Texas coastal waters). Other examples of modern coastal barriers are found in the Gulf of California, where medium-sized sands are deposited. An example of an ancient deposit was found in the Elk City field, where the barrier beach was composed of well-sorted gravel and coarse sand.

  16. 95. BOUQUET RESERVOIR LOOKING UP VALLEY TO RESERVOIR LOOKING EAST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    95. BOUQUET RESERVOIR LOOKING UP VALLEY TO RESERVOIR LOOKING EAST - Los Angeles Aqueduct, From Lee Vining Intake (Mammoth Lakes) to Van Norman Reservoir Complex (San Fernando Valley), Los Angeles, Los Angeles County, CA

  17. Gas

    MedlinePLUS

    ... and pain in the belly—especially after a big meal. Foods that can cause gas Some people naturally produce ... your stomach or throw up . Your breasts are big and sore . The area around your nipples gets darker. You crave certain foods. Or you really dislike certain foods. You feel ...

  18. Gas Hydrates: It's A Gas!

    NSDL National Science Digital Library

    In this activity, students will investigate the occurrence of gas hydrates on the ocean floor. They will discover the importance of carbon, where carbon is stored on Earth, and that the largest reservoir of carbon is gas hydrates. Students will discover that Earth's climate changes, and how the greenhouse effect works. They will also learn about the potential of hydrates as a major new energy resource and explore the conditions under which hydrates form.

  19. Challenges in reservoir forecasting

    Microsoft Academic Search

    Clayton V. Deutsch; Thomas A. Hewett

    1996-01-01

    The combination of geostatistics-based numerical geological models and finite difference flow simulation has improved our ability to predict reservoir performance. The main contribution of geostatistical modeling has been more realistic representations of reservoir heterogeneity. Our understanding of the physics of fluid flow in porous media is reasonably captured by flow simulators in common usage. Notwithstanding the increasing application and success

  20. 3D reservoir visualization

    SciTech Connect

    Van, B.T.; Pajon, J.L.; Joseph, P. (Inst. Francais du Petrole (FR))

    1991-11-01

    This paper shows how some simple 3D computer graphics tools can be combined to provide efficient software for visualizing and analyzing data obtained from reservoir simulators and geological simulations. The animation and interactive capabilities of the software quickly provide a deep understanding of the fluid-flow behavior and an accurate idea of the internal architecture of a reservoir.

  1. Reservoir and injection technology and Heat Extraction Project

    SciTech Connect

    Horne, R.N.; Ramey, H.H. Jr.; Miller, F.G.; Brigham, W.E.; Kruger, P.

    1989-12-31

    For the Stanford Geothermal Program in the fiscal year 1989, the task areas include predictive modeling of reservoir behavior and tracer test interpretation and testing. Major emphasis is in reservoir technology, reinjection technology, and heat extraction. Predictive modeling of reservoir behavior consists of a multi-pronged approach to well test analysis under a variety of conditions. The efforts have been directed to designing and analyzing well tests in (1) naturally fractured reservoirs; (2) fractured wells; (3) complex reservoir geometries; and, (4) gas reservoirs including inertial and other effects. The analytical solutions for naturally fractured reservoirs are determined using fracture size distribution. In the study of fractured wells, an elliptical coordinate system is used to obtain semi-analytical solutions to finite conductivity fractures. Effort has also been directed to the modeling and creation of a user friendly computer program for steam/gas reservoirs including wellbore storage, skin and non-Darcy flow effects. This work has a complementary effort on modeling high flow rate wells including inertial effects in the wellbore and fractures. In addition, work on gravity drainage systems is being continued.

  2. Integrated reservoir study of the 8 reservoir of the Green Canyon 18 field 

    E-print Network

    Aniekwena, Anthony Udegbunam

    2004-11-15

    the hydrocarbon bearing reservoir, quantified the different resource categories as STOIIP/GIIP = 19.8/26.2 mmstb/Bscf, ultimate recovery = 9.92/16.01 mmstb/Bscf, and reserves (as of 9/2001) = 1.74/5.99 mmstb/Bscf of oil and gas, respectively. There does not appear...

  3. CO2 storage resources, reserves, and reserve growth: Toward a methodology for integrated assessment of the storage capacity of oil and gas reservoirs and saline formations

    USGS Publications Warehouse

    Burruss, R.C.

    2009-01-01

    Geologically based methodologies to assess the possible volumes of subsurface CO2 storage must apply clear and uniform definitions of resource and reserve concepts to each assessment unit (AU). Application of the current state of knowledge of geologic, hydrologic, geochemical, and geophysical parameters (contingencies) that control storage volume and injectivity allows definition of the contingent resource (CR) of storage. The parameters known with the greatest certainty are based on observations on known traps (KTs) within the AU that produced oil, gas, and water. The aggregate volume of KTs within an AU defines the most conservation volume of contingent resource. Application of the concept of reserve growth to CR volume provides a logical path for subsequent reevaluation of the total resource as knowledge of CO2 storage processes increases during implementation of storage projects. Increased knowledge of storage performance over time will probably allow the volume of the contingent resource of storage to grow over time, although negative growth is possible. ?? 2009 Elsevier Ltd. All rights reserved.

  4. Application of integrated reservoir management and reservoir characterization to optimize infill drilling. Annual report, June 13, 1994--June 12, 1995

    SciTech Connect

    Pande, P.K.

    1996-11-01

    This project has used a multi-disciplinary approach employing geology, geophysics, and engineering to conduct advanced reservoir characterization and management activities to design and implement an optimized infill drilling program at the North Robertson (Clearfork) Unit in Gaines County, Texas. The activities during the first Budget Period have consisted of developing an integrated reservoir description from geological, engineering, and geostatistical studies, and using this description for reservoir flow simulation. Specific reservoir management activities are being identified and tested. The geologically targeted infill drilling program will be implemented using the results of this work. A significant contribution of this project is to demonstrate the use of cost-effective reservoir characterization and management tools that will be helpful to both independent and major operators for the optimal development of heterogeneous, low permeability shallow-shelf carbonate (SSC) reservoirs. The techniques that are outlined for the formulation of an integrated reservoir description apply to all oil and gas reservoirs, but are specifically tailored for use in the heterogeneous, low permeability carbonate reservoirs of West Texas.

  5. Reservoir characterization of Pennsylvanian sandstone reservoirs. Final report

    SciTech Connect

    Kelkar, M.

    1995-02-01

    This final report summarizes the progress during the three years of a project on Reservoir Characterization of Pennsylvanian Sandstone Reservoirs. The report is divided into three sections: (i) reservoir description; (ii) scale-up procedures; (iii) outcrop investigation. The first section describes the methods by which a reservoir can be described in three dimensions. The next step in reservoir description is to scale up reservoir properties for flow simulation. The second section addresses the issue of scale-up of reservoir properties once the spatial descriptions of properties are created. The last section describes the investigation of an outcrop.

  6. Research program on fractured petroleum reservoirs. Fourth quarterly report, October 1--December 31, 1993

    SciTech Connect

    Firoozabadi, A.

    1993-01-31

    Progress reports are presented for project 2-supersaturation, critical saturation and residual gas saturation in porous media and for project 5-simulation of fractured reservoirs. Under project 2, a visual high-pressure core-holder has been designed and constructed to be used in critical gas saturation and some other measurements. The apparatus has been used to measure critical gas saturation for a low viscosity mixture. These measurements reconfirm the investigators` previously published data that critical gas saturation for low viscosity fluids are low-around 1 percent. The apparatus is being currently used to measure critical gas saturation of an 11 API oil. Unlike light oils, heavy oil reservoirs, especially fractured heavy oil reservoirs might have an extremely high recovery efficiency with solution gas-drive. The critical gas saturation is an important element of recovery efficiency for such reservoirs.

  7. Microseismic monitoring: a tool for reservoir characterization.

    NASA Astrophysics Data System (ADS)

    Shapiro, S. A.

    2011-12-01

    Characterization of fluid-transport properties of rocks is one of the most important, yet one of most challenging goals of reservoir geophysics. There are some fundamental difficulties related to using active seismic methods for estimating fluid mobility. However, it would be very attractive to have a possibility of exploring hydraulic properties of rocks using seismic methods because of their large penetration range and their high resolution. Microseismic monitoring of borehole fluid injections is exactly the tool to provide us with such a possibility. Stimulation of rocks by fluid injections belong to a standard development practice of hydrocarbon and geothermal reservoirs. Production of shale gas and of heavy oil, CO2 sequestrations, enhanced recovery of oil and of geothermal energy are branches that require broad applications of this technology. The fact that fluid injection causes seismicity has been well-established for several decades. Observations and data analyzes show that seismicity is triggered by different processes ranging from linear pore pressure diffusion to non-linear fluid impact onto rocks leading to their hydraulic fracturing and strong changes of their structure and permeability. Understanding and monitoring of fluid-induced seismicity is necessary for hydraulic characterization of reservoirs, for assessments of reservoir stimulation and for controlling related seismic hazard. This presentation provides an overview of several theoretical, numerical, laboratory and field studies of fluid-induced microseismicity, and it gives an introduction into the principles of seismicity-based reservoir characterization.

  8. Directly imaging damped Ly ? galaxies at z > 2 - III. The star formation rates of neutral gas reservoirs at z ˜ 2.7

    NASA Astrophysics Data System (ADS)

    Fumagalli, Michele; O'Meara, John M.; Prochaska, J. Xavier; Rafelski, Marc; Kanekar, Nissim

    2015-01-01

    We present results from a survey designed to probe the star formation properties of 32 damped Lyman ? systems (DLAs) at z ˜ 2.7. By using the `double-DLA' technique that eliminates the glare of the bright background quasars, we directly measure the rest-frame far-ultraviolet flux from DLAs and their neighbouring galaxies. At the position of the absorbing gas, we place stringent constraints on the unobscured star formation rates (SFRs) of DLAs to 2? limits of dot{? }<0.09-0.27M? yr-1, corresponding to SFR surface densities ?sfr < 10-2.6-10-1.5M? yr-1 kpc-2. The implications of these limits for the star formation law, metal enrichment, and cooling rates of DLAs are examined. By studying the distribution of impact parameters as a function of SFRs for all the galaxies detected around these DLAs, we place new direct constraints on the bright end of the UV luminosity function of DLA hosts. We find that ?13 per cent of the hosts have dot{? }?2M? yr-1 at impact parameters b_dla ? (dot{? }/{M_{?} yr^{-1}})^{0.8}+6 kpc, differently from current samples of confirmed DLA galaxies. Our observations also disfavour a scenario in which the majority of DLAs arise from bright Lyman-break galaxies at distances 20 ? bdla < 100 kpc. These new findings corroborate a picture in which DLAs do not originate from highly star-forming systems that are coincident with the absorbers, and instead suggest that DLAs are associated with faint, possibly isolated, star-forming galaxies. Potential shortcomings of this scenario and future strategies for further investigation are discussed.

  9. PROCEEDINGS, Thirty-Sixth Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California, January 31 -February 2, 2011

    E-print Network

    Stanford University

    PROCEEDINGS, Thirty-Sixth Workshop on Geothermal Reservoir Engineering Stanford University of geothermal utilization. Hydrogen sulfide is a colorless flammable and toxic gas with the characteristic odor

  10. Movement of atrazine and deethylatrazine through a midwestern reservoir

    USGS Publications Warehouse

    Fallon, J.D.; Tierney, D.P.; Thurman, E.M.

    2002-01-01

    The three-dimensional visualization of atrazine and deethylatrazine in a reservoir was determined by five "snapshots" over a one-year period using immunoassay analyses, confirmed by gas chromatography-mass spectrometry and visualized with a three-dimensional computer program. The surveys were conducted in Perry Lake in Kansas and showed that spring runoff laden with triazine herbicides entered the reservoir and did not mix immediately. Concentrations varied threefold between the inlet and the public water supply intakes located at the opposite end of the reservoir. The concentration range in the outflow varied much less than the concentration in the reservoir because of mixing throughout the season near the dam and outflow. A major conclusion from the study was that multiple analyses by a low-cost immunoassay technique coupled with computer visualization software gave a good three-dimensional view of the mass of herbicide present in a drinking water reservoir.

  11. USE OF CUTTING-EDGE HORIZONTAL AND UNDERBALANCED DRILLING TECHNOLOGIES AND SUBSURFACE SEISMIC TECHNIQUES TO EXPLORE, DRILL AND PRODUCE RESERVOIRED OIL AND GAS FROM THE FRACTURED MONTEREY BELOW 10,000 FT IN THE SANTA MARIA BASIN OF CALIFORNIA

    SciTech Connect

    George Witter; Robert Knoll; William Rehm; Thomas Williams

    2005-02-01

    This project was undertaken to demonstrate that oil and gas can be drilled and produced safely and economically from a fractured Monterey reservoir in the Santa Maria Basin of California by employing horizontal wellbores and underbalanced drilling technologies. Two vertical wells were previously drilled in this area by Temblor Petroleum with heavy mud and conventional completions; neither was commercially productive. A new well was drilled by the project team in 2004 with the objective of accessing an extended length of oil-bearing, high-resistivity Monterey shale via a horizontal wellbore, while implementing managed-pressure drilling (MPD) techniques to avoid formation damage. Initial project meetings were conducted in October 2003. The team confirmed that the demonstration well would be completed open-hole to minimize productivity impairment. Following an overview of the geologic setting and local field experience, critical aspects of the application were identified. At the pre-spud meeting in January 2004, the final well design was confirmed and the well programming/service company requirements assigned. Various design elements were reduced in scope due to significant budgetary constraints. Major alterations to the original plan included: (1) a VSP seismic survey was delayed to a later phase; (2) a new (larger) surface hole would be drilled rather than re-enter an existing well; (3) a 7-in. liner would be placed into the top of the Monterey target as quickly as possible to avoid problems with hole stability; (4) evaluation activities were reduced in scope; (5) geosteering observations for fracture access would be deduced from penetration rate, cuttings description and hydrocarbon in-flow; and (6) rather than use nitrogen, a novel air-injection MPD system was to be implemented. Drilling operations, delayed from the original schedule by capital constraints and lack of rig availability, were conducted from September 12 to November 11, 2004. The vertical and upper curved sections were drilled and lined through the problematic shale member without major stability problems. The top of the targeted Monterey was thought to be seen at the expected TVD of 10,000 ft where the 7-in. liner was set at a 60{sup o} hole angle. Significant oil and gas shows suggested the fractured interval anticipated at the heel location had been penetrated. A total of 2572 ft of 6.-in. near-horizontal interval was placed in the shale section, extending planned well length by approximately 470 ft. Very little hydrocarbon in-flow was observed from fractures along the productive interval. This may be a result of the well trajectory falling underneath the Monterey fractured zone. Hydrocarbon observations, cuttings analysis and gamma-ray response indicated additional fractured intervals were accessed along the last {+-}900 ft of well length. The well was completed with a 2 7/8-in. tubing string set in a production packer in preparation for flow and swab tests to be conducted later by a service rig. The planned well time was estimated as 39 days and overall cost as $2.4 million. The actual results are 66 days at a total cost of $3.4 million. Well productivity responses during subsequent flow and swabbing tests were negative. The well failed to inflow and only minor amounts (a few barrels) of light oil were recovered. The lack of production may suggest that actual sustainable reservoir pressure is far less than anticipated. Temblor is currently investigating the costs and operational viability of re-entering the well and conducting an FMI (fracture detection) log and/or an acid stimulation. No final decision or detailed plans have been made regarding these potential interventions at this time.

  12. New correlations for dew-point, specific gravity and producing yield for gas condensates 

    E-print Network

    Ovalle Cortissoz, Adriana Patricia

    2002-01-01

    This work presents four newly developed correlations to estimate dew-point pressure, current specific gravity and producing yield of gas condensate reservoirs. The first correlation may be used to predict the dew-point pressure of the reservoir gas...

  13. Non-uniqueness problem in estimating original gas in place 

    E-print Network

    El-Ahmady, Mohamed Hamed

    2000-01-01

    -Odeh technique) show a misleading behavior that can be misinterpreted to be of a closed (volumetric) reservoir, while actually it is for a water-drive gas reservoir of much less Original Gas in Place. Two models for reservoir/aquifer systems were developed...

  14. Simulation studies to evaluate the effect of fracture closure on the performance of fractured reservoirs; Final report

    Microsoft Academic Search

    I. Howrie; D. Dauben

    1994-01-01

    A three-year research program to evaluate the effect of fracture closure on the recovery of oil and gas from naturally fractured reservoirs has been completed. The overall objectives of the study were to: (1) evaluate the reservoir conditions for which fracture closure is significant, and (2) evaluate innovative fluid injection techniques capable of maintaining pressure within the reservoir. The evaluations

  15. High-resolution characterization and integrated study of a reservoir formation: the danian carbonate platform in the Aquitaine Basin (France)

    Microsoft Academic Search

    Adrian Cerepi; Jean-Pierre Barde; Nicolas Labat

    2003-01-01

    This paper provides an example of an integrated multi-scale study of a carbonate reservoir. The Danian Lower R2 carbonate reservoir is located in the South of the Aquitaine Basin (France) and represents a potential underground gas storage site for Gaz de France. The Danian Lower R2 reservoir was deposited as a prograding carbonate platform bordered by a reef barrier. The

  16. Potential mammalian filovirus reservoirs

    E-print Network

    Peterson, A. Townsend; Carroll, Darin S.; Mills, James N.; Johnson, Karl M.

    2004-12-01

    an approximate cut-off of raccoon (Procyon lotor) size, including ungu- lates, Manidae, Felidae, and others. Reservoir Not a Commensal Species Human filovirus infection index patients, when detailed information is available, have most frequently been men who work...

  17. Panorama of Amistad Reservoir

    USGS Multimedia Gallery

    Amistad National Recreation Area includes the Amistad Reservoir, a man-made lake along the Texas and Mexico border. It is fed by the Rio Grande, Devils River, and the Pecos River, among others.    ...

  18. Potential Mammalian Filovirus Reservoirs

    PubMed Central

    Carroll, Darin S.; Mills, James N.; Johnson, Karl M.

    2004-01-01

    Ebola and Marburg viruses are maintained in unknown reservoir species; spillover into human populations results in occasional human cases or epidemics. We attempted to narrow the list of possibilities regarding the identity of those reservoir species. We made a series of explicit assumptions about the reservoir: it is a mammal; it supports persistent, largely asymptomatic filovirus infections; its range subsumes that of its associated filovirus; it has coevolved with the virus; it is of small body size; and it is not a species that is commensal with humans. Under these assumptions, we developed priority lists of mammal clades that coincide distributionally with filovirus outbreak distributions and compared these lists with those mammal taxa that have been tested for filovirus infection in previous epidemiologic studies. Studying the remainder of these taxa may be a fruitful avenue for pursuing the identity of natural reservoirs of filoviruses. PMID:15663841

  19. Session: Reservoir Technology

    SciTech Connect

    Renner, Joel L.; Bodvarsson, Gudmundur S.; Wannamaker, Philip E.; Horne, Roland N.; Shook, G. Michael

    1992-01-01

    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five papers: ''Reservoir Technology'' by Joel L. Renner; ''LBL Research on the Geysers: Conceptual Models, Simulation and Monitoring Studies'' by Gudmundur S. Bodvarsson; ''Geothermal Geophysical Research in Electrical Methods at UURI'' by Philip E. Wannamaker; ''Optimizing Reinjection Strategy at Palinpinon, Philippines Based on Chloride Data'' by Roland N. Horne; ''TETRAD Reservoir Simulation'' by G. Michael Shook

  20. Seismic Imaging of Reservoir Structure at The Geysers Geothermal Reservoir

    NASA Astrophysics Data System (ADS)

    Gritto, R.; Yoo, S.; Jarpe, S.

    2013-12-01

    Three-dimensional Vp/Vs-ratio structure is presented for The Geysers geothermal field using seismic travel-time data. The data were recorded by the Lawrence Berkeley National Laboratory (LBNL) using a 34-station seismic network. The results are based on 32,000 events recorded in 2011 and represent the highest resolution seismic imaging campaign at The Geysers to date. The results indicate low Vp/Vs-ratios in the central section of The Geysers within and below the current reservoir. The extent of the Vp/Vs anomaly deceases with increasing depth. Spatial correlation with micro-seismicity, used as a proxy for subsurface water flow, indicates the following. Swarms of seismicity correlate well with areas of high and intermediate Vp/Vs estimates, while regions of low Vp/Vs estimates appear almost aseismic. This result supports past observations that high and low Vp/Vs-ratios are related to water and gas saturated zones, respectively. In addition, the correlation of seismicity to intermediate Vp/Vs-ratios is supportive of the fact that the process of water flashing to steam requires four times more energy than the initial heating of the injected water to the flashing point. Because this energy is dawn from the reservoir rock, the associated cooling of the rock generates more contraction and thus seismic events than water being heated towards the flashing point. The consequences are the presence of some events in regions saturated with water, most events in regions of water flashing to steam (low steam saturation) and the absence of seismicity in regions of high steam concentrations where the water has already been converted to steam. Furthermore, it is observed that Vp/Vs is inversely correlated to Vs but uncorrelated to Vp, leading support to laboratory measurements on rock samples from The Geysers that observe an increase in shear modulus while the core samples are dried out. As a consequence, traditional poroelastic theory is no applicable at The Geysers geothermal reservoir. We also conduct time-lapse seismic imaging to investigate the occurrence of temporal changes in the reservoir.

  1. An analytical solution for slug tracer tests in fractured reservoirs

    Microsoft Academic Search

    Chao Shan; Karsten Pruess

    2005-01-01

    The transport of chemicals or heat in fractured reservoirs is strongly affected by the fracture-matrix interfacial area. Under unsaturated conditions, such as in vapor-dominated geothermal reservoirs, this area can be estimated from inert gas tracer tests that produce a characteristic tail in tracer breakthrough curves (BTCs). For water-saturated conditions, molecular diffusion is orders of magnitude smaller, and tails in BTCs

  2. Paonia Reservoir Sediment Management

    NASA Astrophysics Data System (ADS)

    Kimbrel, S.; Collins, K.; Williams, C.

    2014-12-01

    Paonia Dam and Reservoir are located on Muddy Creek, a tributary of the North Fork Gunnison River in western Colorado. Since dam closure in 1962, the 2002 survey estimates an annual sedimentation rate of 153,000 m3/y, resulting in a 25% loss of total reservoir capacity. Long before sediment levels completely fill the reservoir, the outlet works have recently plugged with sediment and debris, adversely impacting operations, and emphasizing the urgency of formulating an effective sediment management plan. Starting in 2010-2011, operations were changed to lower the reservoir and flush sediment through the outlet works in early spring before filling the pool for irrigation. Even though the flushing strategy through the long, narrow reservoir (~5 km long and 0.3 km wide) has prevented outlet works plugging, a long term plan is needed to manage inflowing and deposited sediment more efficiently. Reclamation's Sedimentation and River Hydraulics Group is leading an effort to study the past and current sediment issues at Paonia Dam and Reservoir, evaluate feasible sediment management alternatives, and formulate a plan for future operations and monitoring. The study is building on previously collected data and the existing knowledge base to develop a comprehensive, sustainable sediment management plan. The study is being executed in three phases: Phase 1 consisted of an initial site visit to map and sample existing reservoir bottom sediments, a preliminary site evaluation upstream and downstream of the dam, and establishment of time-lapse photo sites and taking initial ground-based photos. Phase 2 includes a bathymetric survey of entire reservoir and 11 km of the river downstream of the dam, continuous suspended sediment monitoring upstream and downstream of the reservoir, and collection of additional core samples of reservoir bottom sediments. Phase 3 involves the evaluation of current and past operations and sediment management practices, evaluate feasible sediment management methods, and providing recommendations for future monitoring and sediment management operations. Data collected during Phases 1 and 2 are used in a one-dimensional numerical sediment transport model for evaluating past, current, and potential future sediment management options.

  3. Effect of pressure-dependent permeability on tight gas wells 

    E-print Network

    Franquet Barbara, Mariela

    2005-08-29

    Tight gas reservoirs are those reservoirs where the matrix has a low permeability range (k < 0.1 md). The literature documents laboratory experiments under restressed conditions that show stress dependent rock properties are more significant...

  4. Painter Reservoir, east Painter Reservoir and Clear Creek Fields, Uinta County, Wyoming

    SciTech Connect

    Frank, J.R.; Cluff, S.; Bauman, J.M.

    1982-01-01

    Painter Reservoir, East Painter Reservoir, and Clear Creek fields are part of a series of recent major hydrocarbon discoveries in the Thrust Belt Province of NE. Utah-SW. Wyoming that began with the discovery of the Pineview field in Utah. Oil and gas production in the fields is from the Triassic-Jurassic Nugget Sandstone. There the Nugget is a varicolored, fine- to medium-grained quartz arenite believed to be of eolian origin. Core porosity averages 12.5% and core permeability averages ca 5.4 md. All 3 fields occur in reverse-faulted, asymmetric folds on the hanging wall of the Absaroka thrust and overlie Cretaceous source rocks. The Painter Reservoir and Clear Creek structures are much steeper on the east whereas the East Painter structure is much steeper on the west.

  5. Optoelectronic Reservoir Computing

    E-print Network

    Yvan Paquot; François Duport; Anteo Smerieri; Joni Dambre; Benjamin Schrauwen; Marc Haelterman; Serge Massar

    2011-11-30

    Reservoir computing is a recently introduced, highly efficient bio-inspired approach for processing time dependent data. The basic scheme of reservoir computing consists of a non linear recurrent dynamical system coupled to a single input layer and a single output layer. Within these constraints many implementations are possible. Here we report an opto-electronic implementation of reservoir computing based on a recently proposed architecture consisting of a single non linear node and a delay line. Our implementation is sufficiently fast for real time information processing. We illustrate its performance on tasks of practical importance such as nonlinear channel equalization and speech recognition, and obtain results comparable to state of the art digital implementations.

  6. Naturally fractured tight gas reservoir detection optimization

    SciTech Connect

    NONE

    1998-11-15

    The three tasks were completed during this reporting period. During this quarter, work focused on a local structural analysis of the Table Rock field, greater Green River basin (GGRB) in southwestern Wyoming. The ultimate objective of the local analysis is to apply the techniques developed and demonstrated during earlier phases of the project in the Rulison Field area of the Piceance basin for sweet-spot delineation. The primary goal of this work is to focus in on the Table Rock field area in the northern Washakie basin of the Greater Green River basin in support of Union Pacific Resources and DOE planned horizontal drilling efforts. The work plan for the quarter of April 1, 1998--June 30, 1998 consisted of three tasks: (1) Acquire necessary seismic data and depth-convert, (2) Map major fault geometry and analyze displacement vectors, (3) Develop and initiate a natural fracture prediction study.

  7. Simulation of gas condensate reservoir performance

    SciTech Connect

    Coast, K.H.

    1982-01-01

    Generalized phase density and component fugacity equations are presented which represent several of the widely used cubic equations-of-state. A component pseudoization procedure is described which preserves densities and viscosities of the pseudo components and original mixture as functions of pressure and temperature. The full compositional simulation necessary for below-dewpoint cycling is performed for the near-critical condensate using a wide range of component pseudoizations. Results show the well-known necessity of splitting the C7+fraction and indicate a minimum set of about 7 total components necessary for acceptable accuracy. 21 refs.

  8. Naturally fractured tight gas reservoir detection optimization

    SciTech Connect

    NONE

    1996-09-30

    The focus of this report was on preparing data and modules for Piceance Basin-wide fracture prediction. A review of the geological data input and automated history reconstruction approach was made. Fluid pressure data analysis and preliminary basin simulations were carried out. These activities are summarized briefly below and reviewed in more detail in Appendices A-E. Appendix D is a review of the fluid pressure data and its implications for compartmentation. Preliminary fracture prediction computations on generic basins are presented in Appendix E; these were carried out as part of our code testing activities. The results of these two Appendices are the beginning of what will be the basis of the model testing; fluid pressures are directly comparable with the model predictions and are a key element of fracture nucleation and presentation. We summarize the tectonic and sedimentary history of the Piceance Basin based on our automated history reconstruction and published interpretations. The narrative and figures provide the basic material we have quantified for our CIRF.B basin simulator input. This data supplements our existing well data interpretation approach. It provides an independent check of the automated sedimentary/subsidence history reconstruction module. Fluid pressure data was gathered and analyzed. This data serves two functions. Fluid pressure distribution across the basin provides a quantitative test as it is a direct prediction of CIRF.B. Furthermore, fluid pressure modifies effective stress. It thereby enters fracture nucleation criteria and fracture extension rate and aperture laws. The pressure data is presented in Appendix Din terms of overpressure maps and isosurfaces.

  9. Naturally fractured tight gas reservoir detection optimization

    SciTech Connect

    NONE

    1998-02-06

    The previous report provided a detailed summary of the work data on the project at the Rulison field. Key to this report was the finding that the regions where wells showed good EURs were spatially associated with faulting. Specifically, areas considered more permeable due to the presence of natural fractures are generally located in the high-side (footwall) of reverse faults. While this association seems to hold in the Rulison seismic data coverage, this association requires corroboration. Thus the work plan for the quarter of July 1, 1997--September 30, 1997 consisted of three tasks: (1) perform detailed fault mapping of Rulison 3-D seismic data with Barrett Resources; (2) review SOCO 2-D seismic fault mapping and structural interpretations; and (3) initial work into developing a predictive method for locating fault-related natural fractures. The first two tasks were initiated and completed during this reporting period. The work involved required at the collaborative effort between the field operators and ARI staff. The third task marks the beginning of quantitative fracture mechanics analysis of the geologic processes that are involved for the development of fault-related natural fractures. The goal of this work is to develop a predictive capability of locating natural fractures prior to drilling.

  10. Reservoir Simulation and Evaluation of the Upper Jurassic Smackover Microbial Carbonate and Grainstone-Packstone Reservoirs in Little Cedar Creek Field, Conecuh County, Alabama 

    E-print Network

    Mostafa, Moetaz Y

    2013-04-25

    This thesis presents an integrated study of mature carbonate oil reservoirs (Upper Jurassic Smackover Formation) undergoing gas injection in the Little Cedar Creek Field located in Conecuh County, Alabama. This field ...

  11. Interpretation of tests in fissured and multilayered reservoirs with double-porosity behavior: Theory and practice

    SciTech Connect

    Gringarten, A.C.

    1984-04-01

    This paper summarizes current knowledge of reservoirs with double-porosity behavior. These include both naturally fissured reservoirs and multilayered reservoirs with high permeability contrast between layers. The first part presents available solutions to the direct problem (i.e., solutions to the diffusivity equation) that have appeared in the oil and ground water literature over the past 20 years. The second part discusses methods for solving the inverse problem--i.e., identifying a double-porosity behavior and evaluating all corresponding well and reservoir parameters. Several field examples demonstrate various aspects of double-porosity behavior and illustrate how additional knowledge of the reservoir (e.g., fissured vs. multilayered, gas saturation, etc.) can be obtained from numerical values of the reservoir parameters. Practical considerations for planning tests in double-porosity reservoirs also are included.

  12. Sediment pass-through, an alternative to reservoir dredging

    SciTech Connect

    Harrison, L.L.; Lee, W.H. [Pacific Gas and Electric Co., San Francisco, CA (United States); Tu, S. [Pacific and Gas Electric Co., San Ramon, CA (United States)

    1995-12-31

    Pacific Gas and Electric Company (PG&E) is studying an alternative {open_quotes}Sediment Management Plan{close_quotes} (SMP) to control sediments at Rock Creek Reservoir and the downstream Cresta Reservoir on the North Fork Feather River in Plumas County. The reservoirs are part of the 182,000 kW Rock Creek-Cresta Project hydroelectric development. Approximately 5.4 million cubic meters of sediments, deposited in the two reservoirs since they were placed in service in 1949 and 1950, partially obstruct the dams` low level outlets and pipe inlets supplying water for spillway gate operations. The sediments jeopardize the reliable and efficient operation of the dams and powerhouses. The SMP includes retrofitting Rock Creek and Cresta Dams with additional low-level gated outlets and modification of trash racks at the existing low level outlet pipes at each dam to improve sediment pass-through (SPT) capacity during high flows. Also, to enable construction of the dam modifications and to facilitate the initiation of SPT operation, dredging of approximately 46,000 cubic meters at Rock Creek Reservoir and 57,000 cubic meters at Cresta Reservoir can be accomplished using a new slurry pump dredging technology to minimize turbidity and re-suspension of solids during dredging. It is proposed to deposit the sediment on the reservoir bottoms, upstream of the areas to be dredged. The dredged sediments subsequently would be flushed from the reservoirs during SPT operations to ultimately be deposited in the dead storage volume of a large downstream reservoir, Lake Oroville. The SPT management plan supersedes more costly plans for major dredging, and may preclude the need for future maintenance dredging at the reservoirs.

  13. CASCADE RESERVOIR, IDAHO: LITERATURE SEARCH

    EPA Science Inventory

    Cascade Reservoir (17050123) is a shallow, dimictic, mesotrophic water body that is receiving nutrient and bacterial loading from its watershed. Sufficient data is available to indicate nonpoint source runoff as the most significant source of nutrient loading to the reservoir. ...

  14. EXPLOITATION AND OPTIMIZATION OF RESERVOIR PERFORMANCE IN HUNTON FORMATION, OKLAHOMA

    SciTech Connect

    Mohan Kelkar

    2003-04-01

    West Carney Field produces from Hunton Formation. All the wells produce oil, water and gas. The main objective of this study is to understand the unique behavior observed in the field. This behavior includes: (1) Decrease in WOR over time; (2) Decrease in GOR at initial stages; (3) High decline rates of oil and gas; and (4) strong hydrodynamic connectivity between wells. This report specifically addresses two issues relevant to our understanding of the West Carney reservoir. By using core and log data as well as fluorescence information, we demonstrate that our hypothesis of how the reservoir is formed is consistent with these observations. Namely, oil migrated in water wet reservoir, over time, oil changed the wettability of some part of the reservoir, oil eventually leaked to upper formations prompting re-introduction of water into reservoir. Because of change in wettability, different pore size distributions responded differently to water influx. This hypothesis is consistent with fluorescence and porosity data, as we explain it in this quarterly report. The second issue deals with how to best calculate connected oil volume in the reservoir. The log data does not necessarily provide us with relevant information regarding oil in place. However, we have developed a new material balance technique to calculate the connected oil volume based on observed pressure and production data. By using the technique to four different fields producing from Hunton formation, we demonstrate that the technique can be successfully applied to calculate the connected oil in place.

  15. Studies reveal fractured reservoir perforating damage

    SciTech Connect

    Halleck, P. [Pennsylvania State Univ., University Park, PA (United States)

    1996-04-01

    Shock stresses resulting from detonation of the shaped explosive charges used in jet perforating cause deformation of the reservoir rock surrounding each perforation tunnel. Gas Research Institute (GRI) researchers have observed how this process seals a fracture where it intersects a perforation. Even an underbalance of 750 psi may not be sufficient to clear a performation of this debris or open the perforation fracture interface where deformation has closed the connection. Developing techniques to reduce skin in fractured gas reservoirs requires understanding the performation/fracture interface. Conventional engineering wisdom recognizes two causes for high skin values in fractured reservoirs; natural fractures may become plugged with cement or cement filtrate, or the performations may fail to intersect existing fractures. Fluid loss additives in the drilling and completion fluids and proper performation design can help alleviate these problems. However, a third possibility is that the connection between fracture and perforation may be plugged as a result of the performation process itself. Testing the hypothetical mechanism for such fracture plugging is the goal of this research effort.

  16. APPLICATION OF INTEGRATED RESERVOIR MANAGEMENT AND RESERVOIR CHARACTERIZATION

    SciTech Connect

    Jack Bergeron; Tom Blasingame; Louis Doublet; Mohan Kelkar; George Freeman; Jeff Callard; David Moore; David Davies; Richard Vessell; Brian Pregger; Bill Dixon; Bryce Bezant

    2000-03-01

    Reservoir performance and characterization are vital parameters during the development phase of a project. Infill drilling of wells on a uniform spacing, without regard to characterization does not optimize development because it fails to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, especially carbonate reservoirs. These reservoirs are typically characterized by: (1) large, discontinuous pay intervals; (2) vertical and lateral changes in reservoir properties; (3) low reservoir energy; (4) high residual oil saturation; and (5) low recovery efficiency. The operational problems they encounter in these types of reservoirs include: (1) poor or inadequate completions and stimulations; (2) early water breakthrough; (3) poor reservoir sweep efficiency in contacting oil throughout the reservoir as well as in the nearby well regions; (4) channeling of injected fluids due to preferential fracturing caused by excessive injection rates; and (5) limited data availability and poor data quality. Infill drilling operations only need target areas of the reservoir which will be economically successful. If the most productive areas of a reservoir can be accurately identified by combining the results of geological, petrophysical, reservoir performance, and pressure transient analyses, then this ''integrated'' approach can be used to optimize reservoir performance during secondary and tertiary recovery operations without resorting to ''blanket'' infill drilling methods. New and emerging technologies such as geostatistical modeling, rock typing, and rigorous decline type curve analysis can be used to quantify reservoir quality and the degree of interwell communication. These results can then be used to develop a 3-D simulation model for prediction of infill locations. The application of reservoir surveillance techniques to identify additional reservoir ''pay'' zones, and to monitor pressure and preferential fluid movement in the reservoir is demonstrated. These techniques are: long-term production and injection data analysis, pressure transient analysis, and advanced open and cased hole well log analysis. The major contribution of this project is to demonstrate the use of cost effective reservoir characterization and management tools that will be helpful to both independent and major operators for the optimal development of heterogeneous, low permeability carbonate reservoirs such as the North Robertson (Clearfork) Unit.

  17. Reservoir engineering evaluation of a hydraulic fracture treatment for Maxus Exploration Company and the Gas Research Institute, Ellis Ranch Field, Ochiltree County, Texas. HT Glasgow No. 2/Cleveland Sand. Topical report, September 1992

    SciTech Connect

    Not Available

    1992-09-01

    The fracture treatment pressure history match using FRACPRO(R) and the reservoir engineering evaluation of the production response of the well treated as part of an ongoing cooperative project are discussed. The predicted dimensions have been corroborated by history matching the production and bottomhole pressure responses with a reservoir simulator, using the RESPRO(TM) interface to FRACPRO(R). The results indicate that the predicted dimensions from FRACPRO(R) are consistent and that significant improvement in the treatment is possible. The report also includes recommendations relating to the design of a pressure transient test on the well.

  18. Dry hole or reservoir damage. What we need to know

    SciTech Connect

    Farina, J.R.

    1987-11-01

    Stories abound in the industry about the oil or gas field drilled and abandoned by one company, only to be discovered by a second company that evaluated the data from a different perspective. The Elmworth field (Canada), and Beeville, North Resenberg, and Running Duke fields (Texas) are all examples where the initial well penetrated the hydrocarbon column but was not completed, or was completed, tested, and abandoned. Numerous explanations exist as to why fields are abandoned and then rediscovered. Often contributing to this cycle is a lack of understanding of the reservoir's pore geometry, and of the effects of drilling or completion-induced damage on production or pressure performance measured by drill-stem tests, repeat formation testers, and well logs. Additionally, the inability to tell the difference between a low-permeability noncommercial reservoir and a damaged commercial reservoir results in a lot of missed field discoveries. In the author's lecture, he discusses the causes of formation damage, as well as factors that signal the reservoir's vulnerability to damage (e.g., small pore throats, authigenic clays, low reservoir pressure). He also includes case examples of conventional tests that, by routine analysis, show the zone to be noncommercial when, in fact, the well was completed and produced commercially. Understanding the type of reservoir system being tested and using all available tools and data are the key to determining reservoir behavior.

  19. Modelling evaporation from reservoirs

    Microsoft Academic Search

    B. HENDERSON-SELLERS

    It is shown that a numerical model for predicting the depth time variation of water temperature in a fresh water lake or reservoir can be used also for prediction of water losses due to evaporation. The seasonal change in peak evaporation from summer (in small lakes) to winter (in large lakes) is satisfactorily simulated.

  20. Reinjection into geothermal reservoirs

    SciTech Connect

    Bodvarsson, G.S.; Stefansson, V.

    1987-08-01

    Reinjection of geothermal wastewater is practiced as a means of disposal and for reservoir pressure support. Various aspects of reinjection are discussed, both in terms of theoretical studies as well as specific field examples. The discussion focuses on the major effects of reinjection, including pressure maintenance and chemical and thermal effects. (ACR)

  1. NMR properties of petroleum reservoir fluids.

    PubMed

    Hirasaki, George J; Lo, Sho-Wei; Zhang, Ying

    2003-01-01

    NMR well logging of petroleum reservoir require the measurement of the NMR response of water, oil, and gas in the pore space of rocks at elevated temperatures and pressures. The viscosity of the oil may range from less than 1 cp to greater than 10,000 cp. Also, the oil and gas are not a single component but rather a broad distribution of components. The log mean T1 and T2 relaxation time of dead (gas free) crude oils are correlated with viscosity/temperature and Larmor frequency. The relaxation time of live oils deviate from the correlation for dead crude oils. This deviation can be correlated with the methane content of the oil. Natural gas in the reservoir has components other than methane. Mixing rules are developed to accommodate components such as ethane, propane, carbon dioxide, and nitrogen. Interpretation of NMR logs uses both relaxation and diffusion to distinguish the different fluids present in the formation. Crude oils have a broad spectrum of components but the relaxation time distribution and diffusion coefficient distribution are correlated. This correlation is used to distinguish crude oil from the response of water in the pores of the rock. This correlation can also be used to estimate viscosity of the crude oil. PMID:12850718

  2. Impact of gas composition on natural gas storage by adsorption

    Microsoft Academic Search

    José P. B. Mota

    1999-01-01

    Adsorption storage is the most promising low-pressure alternative for storing natural gas, but some operational difficulties hinder the success of this technology. From a modeling perspective, this article addresses the impact of gas composition on the cyclic behavior of adsorptive natural gas storage systems. The cyclic operation of an onboard storage reservoir is modeled as a series of consecutive two-step

  3. Characterization and assessment of uncertainty in San Juan Reservoir Santa Rosa Field

    E-print Network

    Becerra, Ernesto Jose

    2005-02-17

    Venezuela..........................................................................................................3 Fig. 1.2 ? Structure map, top of San Juan Reservoir in Santa Rosa Field. .......................4 Fig. 1.3 ?Stratigraphic column, Santa................................6 Fig. 2.1 ? Material balance plot for San Juan reservoir. .................................................11 Fig. 3.1 ? Assumed probability density function for gas in place...................................19 Fig. 3.2 ? Likelihood probability...

  4. Environmental concerns and future oil and gas developments in Coastal Wetlands of Louisiana

    Microsoft Academic Search

    B. J. Harder; C. G. Groat

    1993-01-01

    Recent studies have confirmed that much oil and natural gas have been overlooked and increases in future recoverable reserves will come from drilling in these areas. Increased production will result from identifying unexploited compartmentalized reservoirs, new infield reservoirs, and bypassed reservoirs, and by using enhanced recovery technologies for hydrocarbon recovery in incompletely drained reservoirs previously left unproduced for economic reasons.

  5. Study on the Effect of Source-Contacting Gas Accumulations upon Abnormal Pressures in Western Sichuan Depression

    Microsoft Academic Search

    Jinchuan ZHANG; Lifang LIU; Xuan TANG; Xiaowei SONG; Shengling JIANG; Bo XU; Ruikang BIAN

    2008-01-01

    The migration and accumulation of typical source-contacting gas, also called basin-centered gas, follow the piston principle that it generates superpressures essentially. In the tight sand reservoir, the formation water cannot exchange sufficiently, which maintains higher pressure in gas reservoirs compared with conventional reservoirs during tectonic uplift or subsidences. The western Sichuan depression is one of the earliest basins in China

  6. A committee machine with intelligent systems for estimation of total organic carbon content from petrophysical data: An example from Kangan and Dalan reservoirs in South Pars Gas Field, Iran

    Microsoft Academic Search

    Ali Kadkhodaie-Ilkhchi; Hossain Rahimpour-Bonab; Mohammadreza Rezaee

    2009-01-01

    Total organic carbon (TOC) content present in reservoir rocks is one of the important parameters, which could be used for evaluation of residual production potential and geochemical characterization of hydrocarbon-bearing units. In general, organic-rich rocks are characterized by higher porosity, higher sonic transit time, lower density, higher ?-ray, and higher resistivity than other rocks. Current study suggests an improved and

  7. Compositional simulation of primary depletion for near critical reservoirs using the VIP simulator 

    E-print Network

    Ordonez, Roberto E

    1995-01-01

    Equations of state present computational problems predicting the behavior of near critical reservoirs. Around the critical point the properties of the liquid and the gas become the same and the equations of state often fail to converge, making...

  8. Model Calibration, Drainage Volume Calculation and Optimization in Heterogeneous Fractured Reservoirs 

    E-print Network

    Kang, Suk Sang 1975-

    2012-08-16

    We propose a rigorous approach for well drainage volume calculations in gas reservoirs based on the flux field derived from dual porosity finite-difference simulation and demonstrate its application to optimize well placement. Our approach relies...

  9. Application of Fast Marching Methods for Rapid Reservoir Forecast and Uncertainty Quantification 

    E-print Network

    Olalotiti-Lawal, Feyisayo

    2013-05-17

    Rapid economic evaluations of investment alternatives in the oil and gas industry are typically contingent on fast and credible evaluations of reservoir models to make future forecasts. It is often important to also quantify inherent risks...

  10. Model-Based Control and Optimization of Large Scale Physical Systems -Challenges in Reservoir Engineering

    E-print Network

    Van den Hof, Paul

    bearing layer - referred to as an aquifer - is present below the oil and gas-bearing layer that provides. The production life of a petroleum reservoir generally lasts a number of decades and usually two or three produc

  11. 30 CFR 250.1159 - May the Regional Supervisor limit my well or reservoir production rates?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Regional Supervisor limit my well or reservoir production rates? 250.1159 Section 250.1159 ...IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Requirements Production Rates § 250.1159 May the Regional...

  12. Characterization of Rodessa Formation Reservoir (Lower Cretaceous) in Van Field, Van Zandt County, Texas 

    E-print Network

    Triyana, Yanyan

    2004-09-30

    The Rodessa Formation is one of the major oil and gas reservoirs in the East Texas Basin. In Van Field, the upper Rodessa Formation consists of interbedded biotic and abiotic mudstones to grainstones. The lower Rodessa is ...

  13. Rock Physics-Based Carbonate Reservoir Pore Type Evaluation by Combining Geological, Petrophysical and Seismic Data 

    E-print Network

    Dou, Qifeng

    2012-07-16

    Pore type variations account for complex velocity-porosity relationship and intensive permeability heterogeneity and consequently low oil and gas recovery in carbonate reservoir. However, it is a challenge for geologist ...

  14. Reservoir Simulation with the Finite Element Method Using Biot Poroelastic Approach

    E-print Network

    Zheng, Yibing

    2003-01-01

    We are developing a finite element program for oil and gas reservoir simulation based on Biot's poroelastic theory, where a simultaneous solution is sought for both the pore pressure and strain in the solid phase. Several ...

  15. Model Calibration, Drainage Volume Calculation and Optimization in Heterogeneous Fractured Reservoirs

    E-print Network

    Kang, Suk Sang 1975-

    2012-08-16

    We propose a rigorous approach for well drainage volume calculations in gas reservoirs based on the flux field derived from dual porosity finite-difference simulation and demonstrate its application to optimize well placement. Our approach relies...

  16. Modeling and Analysis of Reservoir Response to Stimulation by Water Injection 

    E-print Network

    Ge, Jun

    2011-02-22

    The distributions of pore pressure and stresses around a fracture are of interest in conventional hydraulic fracturing operations, fracturing during water-flooding of petroleum reservoirs, shale gas, and injection/extraction ...

  17. Atlas of major Appalachian basin gas plays

    SciTech Connect

    Aminian, K.; Avary, K.L.; Baranoski, M.T.; Flaherty, K.; Humphreys, M.; Smosna, R.A.

    1995-06-01

    This regional study of gas reservoirs in the Appalachian basin has four main objectives: to organize all of the -as reservoirs in the Appalachian basin into unique plays based on common age, lithology, trap type and other geologic similarities; to write, illustrate and publish an atlas of major gas plays; to prepare and submit a digital data base of geologic, engineering and reservoir parameters for each gas field; and technology transfer to the oil and gas industry during the preparation of the atlas and data base.

  18. Gas geochemistry of the Geysers geothermal field

    SciTech Connect

    Truesdell, A.H.

    1993-04-01

    Increases in gas concentrations in Central and Southeast Geysers steam are related to the decreases in pressure caused by heavy exploitation in the 1980s. When reservoir pressures in the central parts of the field decreased, high-gas steam from undrilled reservoir margins (and possibly from underlying high-temperature zones) flowed into exploited central areas. The Northwest Geysers reservoir probably lacks high-gas marginal steam and a decline in pressure may not cause a significant increase of gas concentrations in produced steam.

  19. Methane hydrate gas production: evaluating and exploiting the solid gas resource

    SciTech Connect

    McGuire, P.L.

    1981-01-01

    Methane hydrate gas could be a tremendous energy resource if methods can be devised to produce this gas economically. This paper examines two methods of producing gas from hydrate deposits by the injection of hot water or steam, and also examines the feasibility of hydraulic fracturing and pressure reduction as a hydrate gas production technique. A hydraulic fracturing technique suitable for hydrate reservoirs and a system for coring hydrate reservoirs are also described.

  20. Reservoir systems optimization

    SciTech Connect

    Helweg, O.J. (Univ. of California, Davis); Hinks, R.W.; Ford, D.T.

    1982-06-01

    Although systems analysis tools have been available for over a decade, no major reservoir system presently uses optimization models for real-time operation. Of the many existing reservoir systems, the Central Valley Project in California, and the Tennessee Valley Authority project in Tennessee were examined as representative systems. Though the TVA is actively engaged in developing optimization models, the reasons neither is presently using optimization models are summarized as lack of upper management support, lack of qualified personnel in the development and use, inflexibility of many optimization models, and numerous associated problems such as hardware deficiencies. The potential net benefits of optimization are however, apparently quite large which should encourage such systems operators to utilize these tools.

  1. Geochemical analysis of reservoir continuity and connectivity, Arab-D and Hanifa Reservoirs, Abqaiq Field, Saudia Arabia

    SciTech Connect

    Mahdi, A.A.; Grover, G. [Saudi Aramco, Dhahran (Saudi Arabia); Hwang, R. [Chevron Petroleum Technology Co., La Habra, CA (United States)] [and others

    1995-08-01

    Organic geochemistry and its integration with geologic and reservoir engineering data is becoming increasingly utilized to assist geologists and petroleum engineers in solving production related problems. In Abqaiq Field of eastern Saudi Arabia, gas chromatographic analysis (FSCOT) of produced oils from the Arab-D and Hanifa reservoirs was used to evaluate vertical and lateral continuity within and between these reservoirs. Bulk and molecular properties of produced Arab-D oils do not vary significantly over the 70 km length and 10 km width of the reservoir. Hanifa oils, however, do reflect two compositionally distinct populations that are hot in lateral communication, compatible with the occurrence of a large oil pool in the southern part of the field, and a separate, and smaller northern accumulation. The Arab-D and underlying Hanifa oil pools are separated by over 450 feet of impermeable carbonates of the Jubaila Formation, yet the Southern Hanifa pool and the Arab-D have been in pressure communication since onset of Hanifa production in 1954. Recent borehole imaging and core data from horizontal Hanifa wells confirmed the long suspected occurrence of fractures responsible for fluid transmissibility within the porous (up to 35%) but tight (<10md matrix K) Hanifa reservoir, and between the Hanifa and Arab-D. The nearly identical hydrocarbon composition of oils from the Arab-D and southern Hanifa pool provided the final confirmation of fluid communication between the two reservoirs, and extension of a Hanifa fracture-fault network via the Jubaila Formation. This work lead to acquisition of 3-D seismic to image and map the fracture-fault system. The molecular fingerprinting approach demonstrated that produced oils can be used to evaluate vertical and lateral reservoir continuity, and at Abqaiq Field confirmed, in part, the need to produce the Hanifa reservoir via horizontal wells to arrest the reservoir communication that occurs with existing vertical wells.

  2. Work reservoirs in thermodynamics

    NASA Astrophysics Data System (ADS)

    Anacleto, Joaquim

    2010-05-01

    We stress the usefulness of the work reservoir in the formalism of thermodynamics, in particular in the context of the first law. To elucidate its usefulness, the formalism is then applied to the Joule expansion and other peculiar and instructive experimental situations, clarifying the concepts of configuration and dissipative work. The ideas and discussions presented in this study are primarily intended for undergraduate students, but they might also be useful to graduate students, researchers and teachers.

  3. Recent Development of HFR Geothermal Reservoir System in Australia

    Microsoft Academic Search

    H. Xing; D. Wyborn; H. Xu; C. Yin; P. Mora

    2006-01-01

    Since the 1970's, a number of research programmes have worked towards developing Hot Dry Rock technology (HDR) for geothermal energy which has been renamed as Hot Fractured Rock (HFR) in Australia. The HFR energy resource has the potential to supply base-load power with no greenhouse gas emissions. This paper will introduce the recent development of HFR geothermal reservoir system in

  4. EXPLOITATION AND OPTIMIZATION OF RESERVOIR PERFORMANCE IN HUNTON FORMATION, OKLAHOMA

    SciTech Connect

    Mohan Kelkar

    2005-02-01

    Hunton formation in Oklahoma has displayed some unique production characteristics. These include high initial water-oil and gas-oil ratios, decline in those ratios over time and temporary increase in gas-oil ratio during pressure build up. The formation also displays highly complex geology, but surprising hydrodynamic continuity. This report addresses three key issues related specifically to West Carney Hunton field and, in general, to any other Hunton formation exhibiting similar behavior: (1) What is the primary mechanism by which oil and gas is produced from the field? (2) How can the knowledge gained from studying the existing fields can be extended to other fields which have the potential to produce? (3) What can be done to improve the performance of this reservoir? We have developed a comprehensive model to explain the behavior of the reservoir. By using available production, geological, core and log data, we are able to develop a reservoir model which explains the production behavior in the reservoir. Using easily available information, such as log data, we have established the parameters needed for a field to be economically successful. We provide guidelines in terms of what to look for in a new field and how to develop it. Finally, through laboratory experiments, we show that surfactants can be used to improve the hydrocarbons recovery from the field. In addition, injection of CO{sub 2} or natural gas also will help us recover additional oil from the field.

  5. Integration of seismic methods with reservoir simulation, Pikes Peak heavy oil field, Saskatchewan

    NASA Astrophysics Data System (ADS)

    Zou, Ying

    The Pikes Peak heavy oil field has been operated by Husky Energy Ltd since 1981. Steam injection has been successfully employed to increase production. Efforts in geophysics and reservoir engineering have been made to improve interpretations in the mapping of reservoir conditions. This dissertation developed tools and a working flow for integrating the analysis of time-lapse seismic surveys with reservoir simulation, and applied them to the Pikes Peak field. Two time-lapse 2D seismic lines acquired in February 1991 and March 2000 in the eastern part of the field were carefully processed to produce wavelet and structure matched final sections. Reservoir simulation based on the field reservoir production history was carried out. It provided independent complementary information for the time-lapse seismic analysis. A rock physics procedure based on Gassmann's equation and Batzle and Wang's empirical relationship successfully linked the reservoir engineering to the seismic method. Based on the resultant seismic models, synthetic seismic sections were generated as the analogy of field seismic sections. The integrated interpretation for the Pikes Peak reservoir drew the following conclusions: The areas with a gas saturation difference, between two compared time steps, have seismic differences. Thicker gas zones correspond with large reflectivity changes on the top of the reservoir and larger traveltime delays in the seismic section. The thin gas zones only induce large reflectivity changes on the top of the reservoir, and do not have large time delays below the reservoir zone. High temperature regions also correlate with areas having large seismic energy differences. High temperature with thick gas (steam and methane) zones may be evidence for steam existence. The seismic differences at locations far from the production zone are due to the lower pressure that causes solution gas to evolve from the oil. Pressure changes propagate much faster (˜20 m in one month) than temperature changes (˜8 m in a year) based on the reservoir simulation results. The pressure dependence of the seismic data is due to its influences on gas saturation. The bypassed oil area and steam fronts (high temperature front) can be estimated from the temperature and oil saturation distributions from the reservoir simulation. AVO results show a steam and gas zone pattern similar to the one produced by reservoir simulation.

  6. Pressure-transient analysis for a slanted well in a reservoir with vertical pressure support

    SciTech Connect

    Abbaszadeh, M. (Arco Oil and Gas Co., Plano, TX (US)); Hegeman, P.S. (Schlumberger Well Services, Ventura, CA (US))

    1990-09-01

    Analytical solutions are presented for the pressure response of a slanted limited-entry well in an infinite reservoir subject to pressure support from a gas cap, bottomwater drive, or a combination of both. The well's inclination angle ranges from 0 to 90{degrees}, covering vertical and horizontal wells as limiting cases. An interpretation method based on nonlinear regression provides a useful analysis procedure for well tests from such reservoirs. The pressure support from the gas cap or bottomwater often masks the late-time reservoir features, making conventional semilog analysis difficult. Field tests are interpreted to illustrate the applicability and limitations of the regression method.

  7. Evaluation of fractal models to describe reservoir heterogeneity and performance

    SciTech Connect

    Perez, G.; Chopra, A.K. [Arco E and P Technology, Plano, TX (United States)

    1997-03-01

    This work uses fractals to characterize the spatial correlation structures of porosity and permeability of vertical and horizontal logs in a braided-fluvial sandstone reservoir. The data comprise cores and logs of adjacent vertical wells and logs of horizontal wells. Small-scale realizations of interwell heterogeneity were generated with successive random additions (SRA) technique for new observed fractal models. A deterministic description is also developed. Effects of fractal and deterministic reservoir heterogeneity on reservoir performance were studied for waterflood and water-alternating-gas (WAG) injection processes. The effects of scale up on spatial correlation of porosity was investigated. The fractal model of fractional Brownian motion (FBM) in the horizontal direction, having same intermittency exponent as for fractional Gaussian noise (FGN) in the vertical direction, is not supported by log observations in horizontal wells. Fractal character of core and log data of vertical wells is similar. The incremental WAG recovery response compared to waterflooding response is more sensitive to reservoir heterogeneity. Scale-up experiments indicate that spatial correlation structure of reservoir properties may be different at different scales. Results of this paper will be useful for evaluation of infill drilling, and design, selection, and optimization of an EOR process. The proposed techniques also provide a framework to quantify uncertainty in reservoir performance.

  8. High potential recovery -- Gas repressurization

    SciTech Connect

    Madden, M.P.

    1998-05-01

    The objective of this project was to demonstrate that small independent oil producers can use existing gas injection technologies, scaled to their operations, to repressurize petroleum reservoirs and increase their economic oil production. This report gives background information for gas repressurization technologies, the results of workshops held to inform small independent producers about gas repressurization, and the results of four gas repressurization field demonstration projects. Much of the material in this report is based on annual reports (BDM-Oklahoma 1995, BDM-Oklahoma 1996, BDM-Oklahoma 1997), a report describing the results of the workshops (Olsen 1995), and the four final reports for the field demonstration projects which are reproduced in the Appendix. This project was designed to demonstrate that repressurization of reservoirs with gas (natural gas, enriched gas, nitrogen, flue gas, or air) can be used by small independent operators in selected reservoirs to increase production and/or decrease premature abandonment of the resource. The project excluded carbon dioxide because of other DOE-sponsored projects that address carbon dioxide processes directly. Two of the demonstration projects, one using flue gas and the other involving natural gas from a deeper coal zone, were both technical and economic successes. The two major lessons learned from the projects are the importance of (1) adequate infrastructure (piping, wells, compressors, etc.) and (2) adequate planning including testing compatibility between injected gases and fluids, and reservoir gases, fluids, and rocks.

  9. Genesis Analysis of High-Gamma Ray Sandstone Reservoir and Its Log Evaluation Techniques: A Case Study from the Junggar Basin, Northwest China

    PubMed Central

    Wang, Liang; Mao, Zhiqiang; Sun, Zhongchun; Luo, Xingping; Song, Yong; Liu, Zhen

    2013-01-01

    In the Junggar basin, northwest China, many high gamma-ray (GR) sandstone reservoirs are found and routinely interpreted as mudstone non-reservoirs, with negative implications for the exploration and exploitation of oil and gas. Then, the high GR sandstone reservoirs' recognition principles, genesis, and log evaluation techniques are systematically studied. Studies show that the sandstone reservoirs with apparent shale content greater than 50% and GR value higher than 110API can be regarded as high GR sandstone reservoir. The high GR sandstone reservoir is mainly and directly caused by abnormally high uranium enrichment, but not the tuff, feldspar or clay mineral. Affected by formation's high water sensitivity and poor borehole quality, the conventional logs can not recognize reservoir and evaluate the physical property of reservoirs. Then, the nuclear magnetic resonance (NMR) logs is proposed and proved to be useful in reservoir recognition and physical property evaluation. PMID:24078797

  10. Hydrodynamic modeling of petroleum reservoirs using simulator MUFITS

    NASA Astrophysics Data System (ADS)

    Afanasyev, Andrey

    2015-04-01

    MUFITS is new noncommercial software for numerical modeling of subsurface processes in various applications (www.mufits.imec.msu.ru). To this point, the simulator was used for modeling nonisothermal flows in geothermal reservoirs and for modeling underground carbon dioxide storage. In this work, we present recent extension of the code to petroleum reservoirs. The simulator can be applied in conventional black oil modeling, but it also utilizes a more complicated models for volatile oil and gas condensate reservoirs as well as for oil rim fields. We give a brief overview of the code by providing the description of internal representation of reservoir models, which are constructed of grid blocks, interfaces, stock tanks as well as of pipe segments and pipe junctions for modeling wells and surface networks. For conventional black oil approach, we present the simulation results for SPE comparative tests. We propose an accelerated compositional modeling method for sub- and supercritical flows subjected to various phase equilibria, particularly to three-phase equilibria of vapour-liquid-liquid type. The method is based on the calculation of the thermodynamic potential of reservoir fluid as a function of pressure, total enthalpy and total composition and storing its values as a spline table, which is used in hydrodynamic simulation for accelerated PVT properties prediction. We provide the description of both the spline calculation procedure and the flashing algorithm. We evaluate the thermodynamic potential for a mixture of two pseudo-components modeling the heavy and light hydrocarbon fractions. We develop a technique for converting black oil PVT tables to the potential, which can be used for in-situ hydrocarbons multiphase equilibria prediction under sub- and supercritical conditions, particularly, in gas condensate and volatile oil reservoirs. We simulate recovery from a reservoir subject to near-critical initial conditions for hydrocarbon mixture. We acknowledge financial support by a Grant from the president of the Russian Federation (SP-2222.2012.5) and by Russian foundation for basic research (RFBR 15-31-20585).

  11. All-optical Reservoir Computing

    E-print Network

    Duport, François; Smerieri, Anteo; Haelterman, Marc; Massar, Serge

    2012-01-01

    Reservoir Computing is a novel computing paradigm which uses a nonlinear recurrent dynamical system to carry out information processing. Recent electronic and optoelectronic Reservoir Computers based on an architecture with a single nonlinear node and a delay loop have shown performance on standardized tasks comparable to state-of-the-art digital implementations. Here we report an all-optical implementation of a Reservoir Computer, made of off-the-shelf components for optical telecommunications. It uses the saturation of a semiconductor optical amplifier as nonlinearity. The present work shows that, within the Reservoir Computing paradigm, all-optical computing with state-of-the-art performance is possible.

  12. Laser with bypass gas deflector

    SciTech Connect

    Jones, R.E.; Peterson, R.D.

    1987-09-15

    This patent describes a gas laser which consists of: a laser tube having a longitudinal discharge bore therethrough, the tube containing a gas capable of lasing action, cathode and anode means at opposite ends of the tube for sustaining a gas discharge in the discharge bore, a resonant optical cavity aligned with the tube, a gas reservoir joined in sealing relation to an end of the tube, the cathode means being within the gas reservoir, the laser tube having at least one bypass bore with an opening into the gas reservoir and a first bypass gas deflector mounted in the reservoir and having a deflector interior region, the first deflector having an open end and an opposite aperture end, the first deflector surrounding at least a portion of the cathode means, the aperture end having an aperture, the first deflector being connected to the tube with the aperture aligned with the discharge bore, the bypass bore opening into the reservoir outside of the deflector interior region, the bypass bore being in fluid communication with the discharge bore via the open end of the first detector.

  13. Downhole fluid analysis and asphaltene science for petroleum reservoir evaluation.

    PubMed

    Mullins, Oliver C; Pomerantz, Andrew E; Zuo, Julian Y; Dong, Chengli

    2014-01-01

    Petroleum reservoirs are enshrouded in mysteries associated with all manner of geologic and fluid complexities that Mother Nature can inspire. Efficient exploitation of petroleum reservoirs mandates elucidation of these complexities; downhole fluid analysis (DFA) has proven to be indispensable for understanding both fluids and reservoir architecture. Crude oil consists of dissolved gases, liquids, and dissolved solids, known as the asphaltenes. These different fluid components exhibit fluid gradients vertically and laterally, which are best revealed by DFA, with its excellent precision and accuracy. Compositional gradient analysis falls within the purview of thermodynamics. Gas-liquid equilibria can be treated with a cubic equation of state (EoS), such as the Peng-Robinson EoS, a modified van der Waals EoS. In contrast, the first EoS for asphaltene gradients, the Flory-Huggins-Zuo (FHZ) EoS, was developed only recently. The resolution of the asphaltene molecular and nanocolloidal species in crude oil, which is codified in the Yen-Mullins model of asphaltenes, enabled the development of this EoS. The combination of DFA characterization of gradients of reservoir crude oil with the cubic EoS and FHZ EoS analyses brings into view wide-ranging reservoir concerns, such as reservoir connectivity, fault-block migration, heavy oil gradients, tar mat formation, huge disequilibrium fluid gradients, and even stochastic variations of reservoir fluids. New petroleum science and DFA technology are helping to offset the increasing costs and technical difficulties of exploiting ever-more-remote petroleum reservoirs. PMID:24702298

  14. Squeezed-reservoir lasers

    SciTech Connect

    Marte, M.A.M.; Ritsch, H.; Walls, D.F.

    1988-10-01

    The effects of squeezing the reservoir coupled to the atoms of a laser are compared with the effects of squeezing the electromagnetic vacuum modes entering the laser cavity. The analysis includes the semiclassical theory, a calculation of the phase diffusion rate and the laser linewidth in the rotating-wave van der Pol model of the laser, and squeezing spectra calculated from a linearized theory without adiabatic elimination of the atoms. It is demonstrated that good squeezing is achievable in the laser output if an appropriate classical field driving the atoms is added.

  15. Using Chemicals to Optimize Conformance Control in Fractured Reservoirs

    SciTech Connect

    Seright, Randall S.; Liang, Jenn-Tai; Schrader, Richard; Hagstrom II, John; Wang, Ying; Kumar, Ananad; Wavrik, Kathryn

    2001-10-29

    This report describes work performed during the third and final year of the project, Using Chemicals to Optimize Conformance Control in Fractured Reservoirs. This research project had three objectives. The first objective was to develop a capability to predict and optimize the ability of gels to reduce permeability to water more than that to oil or gas. The second objective was to develop procedures for optimizing blocking agent placement in wells where hydraulic fractures cause channeling problems. The third objective was to develop procedures to optimize blocking agent placement in naturally fractured reservoirs.

  16. Application of cased-hole logs to reservoir management

    SciTech Connect

    Olarunsola, A.O.; Ekpo, E.U.

    1984-04-01

    Cased-hole electric wireline logs can be useful for diagnosing well problems as well as assuring optimum application of clearly defined remedial work. These logs are carefully run directly opposite points of fluid entry into the borehole. When used appropriately, interpretation is facilitated, and their subsequent application to well problems often yield positive results. The data obtained offer more definitive and more complete understanding of the production trends and the reservoir behavior. This work illustrates the interpretation and the appropriate use of various logs for identifying gas and water production problems in oil reservoirs. Examples as encountered in the Niger Delta are discussed.

  17. ‘A reservoir within a reservoir’ – An unusual complication associated with a defunctioned inflatable penile prosthesis reservoir

    PubMed Central

    Abboudi, Hamid; Bolgeri, Marco; Nair, Rajesh; Chetwood, Andrew; Symes, Andrew; Thomas, Philip

    2014-01-01

    INTRODUCTION Inflatable penile prostheses (IPP) have been a successful method of treating men with erectile dysfunction since the early 1970s. IPP are comprised of two intracorporal cylinders, a scrotal pump and a fluid reservoir. PRESENTATION OF CASE We present a case of a retained reservoir in a sixty eight year old gentlemen presenting with a cystic abdominal mass and bothersome LUTS, 15 years after the removal of the penile components of a three-piece penile prosthesis. Percutaneous drainage of the cyst was performed, with four litres of purulent fluid evacuated. A midline laparotomy was required to remove the reservoir and drain the collection completely. DISCUSSION Inflammatory reaction and subsequent erosion of an IPP reservoir is an infrequent but severe complication of IPP insertion, replacement or infection. Infection remains the primary indication for penile prosthesis removal and in this setting removal of the reservoir is routine. A thorough literature search has identified that in the non-infective setting, the routine removal of the original reservoir is not standard practice during three-component IPP replacement. In patients with a history of IPP presenting with new LUTS, reservoir erosion should be considered in the differential diagnosis and investigation with cystoscopy and computed tomography included early in the investigatory armament of the urologist. CONCLUSION It is our belief that a defunctionalized reservoir serves no purpose; rather it can only cause trouble in the future. Consequently, at our institution we do not leave defunctionalized reservoirs in situ. PMID:25247874

  18. Gas-operated motor systems

    SciTech Connect

    Rilett, J.W.

    1980-09-30

    A gas-operated motor system of the stored energy type-as disclosed in U.S. Pat. No. 4,092,830-in which the gas exhausted from the motor is ducted to a chamber during operation of the motor and thereafter compressed back into the gas reservoir vessel. Recompression may be achieved, e.g., by providing the exhaust gas chamber with a movable piston, or by running the motor in the reverse mode as a compressor.

  19. Collapsible sheath fluid reservoirs for flow cytometers

    DOEpatents

    Mark, Graham A. (Los Alamos, NM)

    2000-01-01

    The present invention is a container in the form of a single housing for holding fluid, including a first collapsible reservoir having a first valve. The first reservoir initially contains a volume of fluid. The container also includes a second reservoir, initially empty (or substantially empty), expandable to a second volume. The second reservoir has a second valve. As the volume of said first reservoir decreases, the volume of the second reservoir proportionally increases.

  20. Water resources review: Ocoee reservoirs, 1990

    SciTech Connect

    Cox, J.P.

    1990-08-01

    Tennessee Valley Authority (TVA) is preparing a series of reports to make technical information on individual TVA reservoirs readily accessible. These reports provide a summary of reservoir purpose and operation; physical characteristics of the reservoir and watershed; water quality conditions; aquatic biological conditions; and designated, actual and potential uses of the reservoir and impairments of those use. This reservoir status report addressed the three Ocoee Reservoirs in Polk County, Tennessee.

  1. Analysis of error in using fractured gas well type curves for constant pressure production 

    E-print Network

    Schkade, David Wayne

    1987-01-01

    /xf for Case 4 r e 8 Effect of Gas Specific Gravity 9 Effect of Reservoir Temperature 10 Effect of Porosity 11 Effect of Reservoir Thickness 12 Effect of Permeability 13 Effect of Fracture Half-Length 14 Effect of Normalized Time 15 Comparison...) Constant fluid viscosity; 4) Reservoir initially at uniform pressure, p. ; 1 5) Negligible gravity forces; and 6) Small pressure gradients in the reservoir, In applying type curves to gas wells, a number of these assumptions are v io lated...

  2. Computer Classification of Reservoir Sandstones

    Microsoft Academic Search

    R. M. Haralick; K. Shanmugam

    1973-01-01

    A procedure is developed to extract numerical features which characterize the pore structure of reservoir rocks. The procedure is based on a set of descriptors which give a statistical description of porous media. These features are evaluated from digitized photomicrographs of reservoir rocks and they characterize the rock grain structure in term of (1) the linear dependency of grey tones

  3. LIMNOLOGICAL SURVEY OF LAFAYETTE RESERVOIR

    EPA Science Inventory

    Lafayette Reservoir is located in Lafayette, California, approximately 20 miles east of San Francisco. The reservoir is an emergency standby water supply and recreational facility. The purpose of the project was to monitor selected chemical and biological characteristics of the r...

  4. Do reservoirs need ecological management?

    Microsoft Academic Search

    D. R. H. Price

    1999-01-01

    Eastern England, the driest part of England, has the fastest population growth and water demand in the UK. Existing supplies taken from groundwater have to be supported by surface water, in pumped storage reservoirs supplied from highly eutrophic rivers. These reservoirs are managed primarily by technical means to produce high quality drinking water but there is recognition that intensive recreational

  5. EXPLOITATION AND OPTIMIZATION OF RESERVOIR PERFORMANCE IN HUNTON FORMATION, OKLAHOMA

    SciTech Connect

    Mohan Kelkar

    2004-10-01

    West Carney field--one of the newest fields discovered in Oklahoma--exhibits many unique production characteristics. These characteristics include: (1) decreasing water-oil ratio; (2) decreasing gas-oil ratio followed by an increase; (3) poor prediction capability of the reserves based on the log data; and (4) low geological connectivity but high hydrodynamic connectivity. The purpose of this investigation is to understand the principal mechanisms affecting the production, and propose methods by which we can extend the phenomenon to other fields with similar characteristics. In our experimental investigation section, we present the data on surfactant injection in near well bore region. We demonstrate that by injecting the surfactant, the relative permeability of water could be decreased, and that of gas could be increased. This should result in improved gas recovery from the reservoir. Our geological analysis of the reservoir develops the detailed stratigraphic description of the reservoir. Two new stratigraphic units, previously unrecognized, are identified. Additional lithofacies are recognized in new core descriptions. Our engineering analysis has determined that well density is an important parameter in optimally producing Hunton reservoirs. It appears that 160 acre is an optimal spacing. The reservoir pressure appears to decline over time; however, recovery per well is only weakly influenced by the pressure. This indicates that additional opportunity to drill wells exists in relatively depleted fields. A simple material balance technique is developed to validate the recovery of gas, oil and water. This technique can be used to further extrapolate recoveries from other fields with similar field characteristics.

  6. Data requirements and acquisition for reservoir characterization

    SciTech Connect

    Jackson, S.; Chang, Ming Ming; Tham, Min.

    1993-03-01

    This report outlines the types of data, data sources and measurement tools required for effective reservoir characterization, the data required for specific enhanced oil recovery (EOR) processes, and a discussion on the determination of the optimum data density for reservoir characterization and reservoir modeling. The two basic sources of data for reservoir characterization are data from the specific reservoir and data from analog reservoirs, outcrops, and modern environments. Reservoir data can be divided into three broad categories: (1) rock properties (the container) and (2) fluid properties (the contents) and (3)interaction between reservoir rock and fluid. Both static and dynamic measurements are required.

  7. Stochastic thermodynamics with information reservoirs.

    PubMed

    Barato, Andre C; Seifert, Udo

    2014-10-01

    We generalize stochastic thermodynamics to include information reservoirs. Such information reservoirs, which can be modeled as a sequence of bits, modify the second law. For example, work extraction from a system in contact with a single heat bath becomes possible if the system also interacts with an information reservoir. We obtain an inequality, and the corresponding fluctuation theorem, generalizing the standard entropy production of stochastic thermodynamics. From this inequality we can derive an information processing entropy production, which gives the second law in the presence of information reservoirs. We also develop a systematic linear response theory for information processing machines. For a unicyclic machine powered by an information reservoir, the efficiency at maximum power can deviate from the standard value of 1/2. For the case where energy is consumed to erase the tape, the efficiency at maximum erasure rate is found to be 1/2. PMID:25375481

  8. Gas Hydrates: It's a Gas

    NSDL National Science Digital Library

    In this activity, students will discover the importance of carbon, where carbon is stored on Earth, and that the largest reservoir of carbon is in the form of gas hydrates where methane and other hydrocarbon gases are trapped in a lattice of water molecules in deep sea sediments. Students will learn how climate change is related to the greenhouse effect. They will also learn about the potential of hydrates as a major new energy resource, and explore the conditions under which hydrates form. In addition, students will understand the use of acoustics for mapping the sea floor and sub-sea floor.

  9. A New Global Unconventional Natural Gas Resource Assessment 

    E-print Network

    Dong, Zhenzhen

    2012-10-19

    In 1997, Rogner published a paper containing an estimate of the natural gas in place in unconventional reservoirs for 11 world regions. Rogner's work was assessing the unconventional gas resource base, and is now considered to be very conservative...

  10. A New Global Unconventional Natural Gas Resource Assessment

    E-print Network

    Dong, Zhenzhen

    2012-10-19

    In 1997, Rogner published a paper containing an estimate of the natural gas in place in unconventional reservoirs for 11 world regions. Rogner's work was assessing the unconventional gas resource base, and is now considered to be very conservative...

  11. EXPLOITATION AND OPTIMIZATION OF RESERVOIR PERFORMANCE IN HUNTON FORMATION, OKLAHOMA

    SciTech Connect

    Mohan Kelkar

    2002-03-31

    The West Carney Field in Lincoln County, Oklahoma is one of few newly discovered oil fields in Oklahoma. Although profitable, the field exhibits several unusual characteristics. These include decreasing water-oil ratios, decreasing gas-oil ratios, decreasing bottomhole pressures during shut-ins in some wells, and transient behavior for water production in many wells. This report explains the unusual characteristics of West Carney Field based on detailed geological and engineering analyses. We propose a geological history that explains the presence of mobile water and oil in the reservoir. The combination of matrix and fractures in the reservoir explains the reservoir's flow behavior. We confirm our hypothesis by matching observed performance with a simulated model and develop procedures for correlating core data to log data so that the analysis can be extended to other, similar fields where the core coverage may be limited.

  12. Induced stresses due to fluid extraction from axisymmetric reservoirs

    USGS Publications Warehouse

    Segall, P.

    1992-01-01

    Earthquakes can be induced by fluid extraction, as well as by fluid injection. Segall (1989) proposed that poroelastic stresses are responsible for inducing earthquakes associated with fluid extraction. Here, I present methods for computing poroelastic stress changes due to fluid extraction for general axisymmetric reservoir geometries. The results of Geertsma (1973) for a thin disk reservoir with uniform pressure drop are recovered as a special case. Predicted surface subsidence agrees very well with measured leveling changes over the deep Lacq gas field in southwestern France. The induced stresses are finite if the reservoir pressure changes are continuous. Computed stress changes are on the order of several bars, suggesting that the preexisting stress states in regions of extraction induced seismicity are very close to frictional instability prior to production. ?? 1992 Birkha??user Verlag.

  13. Compressor solves solution gas bottleneck

    SciTech Connect

    Vargas, K.J. [Falcon EDF Ltd., Calgary, Alberta (Canada); Lowe, F. [Gulf Canada Resources Ltd., Calgary, Alberta (Canada)

    1996-08-05

    A new turbine-driven, centrifugal compressor installation increased gas handling capacity in the Westerose D-3 oil reservoir, about 100 km south of Edmonton. Gulf Canada Resources Ltd.`s Westerose D-3 oil reservoir has prolifically produced oil for the last 3 decades. Produced gas has been reinjected into the gas cap to maintain heterogeneity and reservoir fluid interfaces. As oil production continues, increased quantities of solution gas must be handled by the Westerose facility. The cost-effective design of the new compressor installation was based on Gulf`s aggressive drilling program for recovering oil as quickly and economically as possible to reach full blowdown. The paper describes the design considerations, auxiliary equipment, costs, process flow, construction contracts, equipment and systems, and startup.

  14. Interfacial interactions of the crude oil-reservoir brine-reservoir rock systems with dissolution of carbon dioxide under reservoir conditions

    Microsoft Academic Search

    Daoyong Yang

    2005-01-01

    CO2 flooding is considered as one of the most promising enhanced oil recovery (EOR) techniques because it not only effectively enhances oil recovery due to the dissolution of CO2 into the crude oil but also considerably reduces greenhouse gas emissions by sequestrating CO2 in a depleted oil reservoir. Successful CO2 EOR and CO2 sequestration processes are strongly affected by the

  15. Seismic characterization of naturally fractured reservoirs

    NASA Astrophysics Data System (ADS)

    Bansal, Reeshidev

    Many hydrocarbon reservoirs have sufficient porosity but low permeability (for example, tight gas sands and coal beds). However, such reservoirs are often naturally fractured. The fracture patterns in these reservoirs can control flow and transport properties, and therefore, play an important role in drilling production wells. On the scale of seismic wavelengths, closely spaced parallel fractures behave like an anisotropic media, which precludes the response of individual fractures in the seismic data. There are a number of fracture parameters which are needed to fully characterize a fractured reservoir. However, seismic data may reveal only certain fracture parameters and those are fracture orientation, crack density and fracture infill. Most of the widely used fracture characterization methods such as S-wave splitting analysis or amplitude vs. offset and azimuth (AVOA) analysis fail to render desired results in laterally varying media. I have conducted a systematic study of the response of fractured reservoirs with laterally varying elastic and fracture properties, and I have developed a scheme to invert for the fracture parameters. I have implemented a 3D finite-difference method to generate multicomponent synthetic seismic data in general anisotropic media. I applied the finite-difference algorithm in both Standard and Rotated Staggered grids. Standard Staggered grid is used for media having symmetry up to orthorhombic (isotropic, transversely isotropic, and orthorhombic), whereas Rotated Staggered grid is implemented for monoclinic and triclinic media. I have also developed an efficient and accurate ray-bending algorithm to compute seismic traveltimes in 3D anisotropic media. AVOA analysis is equivalent to the first-order Born approximation. However, AVOA analysis can be applied only in a laterally uniform medium, whereas the Born-approximation does not pose any restriction on the subsurface structure. I have developed an inversion scheme based on a ray-Born approximation to invert for the fracture parameters. Best results are achieved when both vertical and horizontal components of the seismic data are inverted simultaneously. I have also developed an efficient positivity constraint which forbids the inverted fracture parameters to be negative in value. I have implemented the inversion scheme in the frequency domain and I show, using various numerical examples, that all frequency samples up to the Nyquist are not required to achieve desired inversion results.

  16. Analytical solution of the Boltzmann transient line sink for an oil reservoir with pressure-dependent formation properties

    Microsoft Academic Search

    Bernt Sigve Aadnoy; Jan Finjord

    1996-01-01

    This paper gives an analytical solution for the transient line sink for oil reservoirs assuming that the porosity, permeability, viscosity, rock compressibility and reservoir height (bulk compressibility) are pressure dependent. The solution is obtained by a perturbation method, improving a procedure initially proposed for real gas flow. Traditionally, these parameters have been assumed constant in the Boltzmann solution for the

  17. Application of hydrology to evaluation of coalbed methane reservoirs. Topical report, January 1987-December 1988

    SciTech Connect

    Koenig, R.A.; Bumb, A.C.; McKee, C.R.; Murphy, C.L.; Ramesh, M.S.

    1989-03-01

    Coal seams have unique properties that make conventional production methods for gas-sand reservoirs ineffective. A systematic approach to selecting and developing a site using hydrologic concepts and well-testing techniques is presented. The most significant factors influencing methane production include adsorption, dewatering, gas desorption, two-phase flow of gas and water, and optimal wellfield patterns. New techniques are described for situations outside the realm of conventional reservoir engineering methods. The principal methods have been incorporated in PC software. The three stages of fluid flow from a coal seam to a well-bore are analyzed as 'windows' for determining critical reservoir properties. The most important parameters controlling production in a coal seam with adequate gas content are gas desorption pressure, permeability-thickness, and static reservoir pressure. Gas content and seam thickness are readily derived from drilling and core samples, and desorption pressure can be derived simply from a controlled drawdown test. A low-cost, easily applied procedure called a STEP Test was devised to determine permeability and static-reservoir pressure along with the condition of the wellbore.

  18. A vapor-dominated reservoir exceeding 600{degrees}F at the Geysers, Sonoma County, California

    SciTech Connect

    Walters, M.A.; Sternfeld, J.N.; Haizlip, J.R.; Drenick, A.F.; Combs, Jim

    1988-01-01

    A high-temperature vapor-dominated reservoir underlies a portion of the Northwest Geysers area, Sonoma County, California. The high-temperature reservoir (HTR) is defined by flowing fluid temperatures exceeding 500º F, rock temperatures apparently exceeding 600º F and steam enthalpies of about 1320 BTU/lb. Steam from existing wells drilled in the Northwest Geysers is produced from both a “typical” Geysers reservoir and the HTR. In all cases, the HTR is in the lower portion of the wells and is overlain by a “typical” Geysers reservoir. Depth to the high-temperature reservoir is relatively uniform at about -5900 ft subsea. There are no identified lithologic or mineralogic conditions that separate the HTR from the “typical” reservoir, although the two reservoirs are vertically distinct and can be located in most wells to within about 200 ft by the use of downhole temperature-depth measurements. Gas concentrations in steam from the HTR are higher (6 to 9 wt %) than from the “typical” Geysers reservoir (0.85 to 2.6 wt %). Steam from the HTR is enriched in chloride and the heavy isotopes of water relative to the “typical” reservoir. Available static and dynamic measurements show pressures are subhydrostatic in both reservoirs with no anomalous differences between the two: the HTR pressure being near 520 psia at sea level datum. The small observed differences in pressure between the reservoirs appear to vary along a steam density gradient. It is postulated that the Northwest Geysers area evolved more slowly toward vapor-dominated conditions than other parts of The Geysers field because of its poor connection with the surface. In this paper, a model is presented in which the boundary between the HTR and “typical” reservoir is a thermodynamic feature only, resulting from recent deep venting of a liquid-dominated system in which conduction is still an important component of heat transfer.

  19. TRITIUM RESERVOIR STRUCTURAL PERFORMANCE PREDICTION

    SciTech Connect

    Lam, P.S.; Morgan, M.J

    2005-11-10

    The burst test is used to assess the material performance of tritium reservoirs in the surveillance program in which reservoirs have been in service for extended periods of time. A materials system model and finite element procedure were developed under a Savannah River Site Plant-Directed Research and Development (PDRD) program to predict the structural response under a full range of loading and aged material conditions of the reservoir. The results show that the predicted burst pressure and volume ductility are in good agreement with the actual burst test results for the unexposed units. The material tensile properties used in the calculations were obtained from a curved tensile specimen harvested from a companion reservoir by Electric Discharge Machining (EDM). In the absence of exposed and aged material tensile data, literature data were used for demonstrating the methodology in terms of the helium-3 concentration in the metal and the depth of penetration in the reservoir sidewall. It can be shown that the volume ductility decreases significantly with the presence of tritium and its decay product, helium-3, in the metal, as was observed in the laboratory-controlled burst tests. The model and analytical procedure provides a predictive tool for reservoir structural integrity under aging conditions. It is recommended that benchmark tests and analysis for aged materials be performed. The methodology can be augmented to predict performance for reservoir with flaws.

  20. US crude oil, natural gas, and natural gas liquids reserves

    SciTech Connect

    Not Available

    1990-10-05

    This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1989, and production volumes for the year 1989 for the total United States and for selected states and state sub-divisions. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), its two major components (nonassociated and associated-dissolved gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, two components of natural gas liquids, lease condensate and natural gas plant liquids, have their reserves and production reported separately. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. 28 refs., 9 figs., 15 tabs.