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1

Controlled CO2 injection into heterogeneous geologic formations for improved solubility and residual trapping  

NASA Astrophysics Data System (ADS)

Geologic CO2 storage (GCS) has been proposed as a potentially viable climate change mitigation option. Among the trapping mechanisms known for permanent CO2 storage in saline aquifers, solubility and residual trapping are important for safe short-term entrapment. These storage mechanisms are hampered by density-driven upward CO2 movement that inhibits the lateral migration of the plume, leaving a large portion of the aquifer volume unexposed to CO2 and unavailable for storage. Heterogeneity of aquifer hydraulic properties and high horizontal/vertical hydraulic conductivity ratio of geologic formations are two competing mechanisms that can hinder upward CO2 migration. Postinjection displacement of free-phase CO2 is somewhat controlled by the heterogeneity in rock permeability and porosity distributions. In particular, low permeability shale layers that act as vertical flow barrier and high-permeability horizontal channels that form flow conduits can spread the CO2 plume laterally in the aquifer. In this paper, we consider CO2 storage in heterogeneous saline aquifers and propose controlled CO2 injection, based on existing knowledge of heterogeneity, to increase CO2 contact with brine and improve the solubility and residual trapping and the overall aquifer storage potential. We examine two optimization methods: directly maximizing the total stored gas in the aquifer, and maximizing the sweep efficiency of the CO2 flood to promote uniform displacement in all directions. We consider the effect of geologic uncertainty on the performance of the controlled injection schemes by using an ensemble of model realizations to represent the uncertainty in aquifer property distribution. We also show how a controlled injection can be used to mitigate the risk of leakage from potential pathways, such as an abandoned well, by restricting CO2 movement toward the leakage zone. Our results suggest that controlled injection can lead to substantial improvements in residual and dissolution trapping and can be used to divert a CO2 plume from approaching sensitive zones or leakage pathways.

Shamshiri, Hossein; Jafarpour, Behnam

2012-02-01

2

Quantifying geological uncertainty for flow and transport modeling in multi-modal heterogeneous formations  

Microsoft Academic Search

In this work, we address the problem of characterizing the heterogeneity and uncertainty of hydraulic properties for complex geological settings. Hereby, we distinguish between two scales of heterogeneity, namely the hydrofacies structure and the intrafacies variability of the hydraulic properties. We employ multiple-point geostatistics to characterize the hydrofacies architecture. The multiple-point statistics are borrowed from a training image that is

Luc Feyen; Jef Caers

2006-01-01

3

Quantifying geological uncertainty for flow and transport modeling in multi-modal heterogeneous formations  

NASA Astrophysics Data System (ADS)

In this work, we address the problem of characterizing the heterogeneity and uncertainty of hydraulic properties for complex geological settings. Hereby, we distinguish between two scales of heterogeneity, namely the hydrofacies structure and the intrafacies variability of the hydraulic properties. We employ multiple-point geostatistics to characterize the hydrofacies architecture. The multiple-point statistics are borrowed from a training image that is designed to reflect the prior geological conceptualization. The intrafacies variability of the hydraulic properties is represented using conventional two-point correlation methods, more precisely, spatial covariance models under a multi-Gaussian spatial law. We address the different levels and sources of uncertainty in characterizing the subsurface heterogeneity, and explore their effect on groundwater flow and transport predictions. Typically, uncertainty is assessed by way of many images, termed realizations, of a fixed statistical model. However, in many cases, sampling from a fixed stochastic model does not adequately represent the space of uncertainty. It neglects the uncertainty related to the selection of the stochastic model and the estimation of its input parameters. We acknowledge the uncertainty inherent in the definition of the prior conceptual model of aquifer architecture and in the estimation of global statistics, anisotropy, and correlation scales. Spatial bootstrap is used to assess the uncertainty of the unknown statistical parameters. As an illustrative example, we employ a synthetic field that represents a fluvial setting consisting of an interconnected network of channel sands embedded within finer-grained floodplain material. For this highly non-stationary setting we quantify the groundwater flow and transport model prediction uncertainty for various levels of hydrogeological uncertainty. Results indicate the importance of accurately describing the facies geometry, especially for transport predictions.

Feyen, Luc; Caers, Jef

2006-06-01

4

Formation evaluation: Geological procedures  

SciTech Connect

This volume goes beyond a discussion of petroleum geology and the techniques of hydrocarbon (oil and gas) logging as a reservoir evaluation tool. It provides the logging geologist with a review of geological techniques and classification systems that will ensure the maximum development of communicable geological information. Contents include: 1. Introduction--cuttings recovery, cutting sampling, core sampling, rock classification; 2. Detrital rocks--classification, description; 3. Carbonate rocks--classification, description; 4. Chemical rocks-introduction, siliceous rocks, ferruginous rocks, aluminous rocks, phosphatic rocks, aluminous rocks, carbonaceous rocks; 5. Igneous and metamorpbic rocks; Appendix; References and Index.

Whittaker, A.

1985-01-01

5

Geologic Puzzles: Morrison Formation  

NSDL National Science Digital Library

Images of faulted strata, tilted turbidites, and beach rocks bring the field into the classroom, giving students practice in doing what geoscientists do. These images are examples of geologic puzzles.

Macdonald, Heather

6

Heterogeneity and Scaling in Geologic Media  

SciTech Connect

The accurate characterization and remediation of contaminated subsurface environments requires the detailed knowledge of subsurface structures and flow paths. Enormous resources are invested in scoping and characterizing sites using core sampling, 3-D geophysical surveys, well tests, etc.... Unfortunately, much of the information acquired is lost to compromises and simplifications made in constructing numerical grids for the simulators used to predict flow and transport from the contaminated area to the accessible environment. In rocks and soils, the bulk geophysical and transport properties of the matrix and of fracture systems are determined by the juxtaposition of geometric features at many length scales. In the interest of computational efficiency, recognized heterogeneities are simplified, averaged out, or entirely ignored in spite of recent studies that recognize that: (1) Structural and lithologic heterogeneities exist on all scales in rocks. (2) Small heterogeneities influence, and can control the physical and chemical properties of rocks. In this work we propose a physically based approach for the description and treatment of heterogeneities, that highlights the use of laboratory equipment designed to measure the effect on physical properties of fine scale heterogeneities observed in rocks and soils. We then discuss the development of an integration methodology that uses these measurements to develop and upscale flow and transport models. Predictive simulations are 'calibrated' to the measured heterogeneity data, and subsequently upscaled in a way that is consistent with the transport physics and the efficient use of environmental geophysics. This methodology provides a more accurate interpretation and representation of the subsurface for both environmental engineering and remediation. We show through examples, (i) the important influence of even subtle heterogeneity in the interpreting of geophysical data, and (ii) how physically based upscaling can lead to a different and more accurate description of a heterogeneous system, when compared to a more traditional upscaling approach that combines averaging and the application of core-based models. This may be of particular significance in bio-remediation studies where the link between microorganism activity and mesoscale flow through geologic structures, resides in the integration of multiscale processes.

Gregory N. Boitnott; Gilles Y. Bussod; Paul N. Hagin; Stephen R. Brown

2005-04-18

7

Numerical Modelling of Geological Heterogeneity - Implications for CO2 Geological Storage  

NASA Astrophysics Data System (ADS)

CO2 geological storage is a proposed mitigation strategy currently being considered to reduce atmospheric greenhouse gas emissions. One factor often limiting the implementation of CO2 geological storage is the uncertainty associated with geological heterogeneities within storage reservoirs and how these heterogeneities will impact CO2 partitioning into the various storage mechanisms. Numerical models are a useful tool for integrating field and laboratory data to generate predictions on the extent of CO2 storage at larger spatial and temporal scales than experimental work is capable of undertaking alone. Numerical models use governing equations to simulate physical and chemical processes, such as the flow and transport of CO2 within the subsurface. Governing equations require the specification of a number of input parameters inherent to the porous medium. In nature, parameters such as porosity and permeability vary within and between different rock types, according to variations in factors such as grain size, sorting, cementation and structure. These variations lead to geological heterogeneity at a number of scales. However, geological heterogeneity is often oversimplified in numerical models, either due to a lack of geological data or to increase computational efficiency. Grid spacing is often coarse, leading to faster simulation times but a decrease in numerical accuracy. Further work is required to investigate how simplifying geological heterogeneity within numerical models affects short and long term CO2 storage predictions. To quantify the impact of geological heterogeneity, TOUGH2, a multiphase flow and transport code, is used to construct a series of simulations with increasing degrees of geological complexity. Comparisons are made between numerous scenarios, including discrete versus gradual progression into areas of heterogeneous rock types, continuous versus discontinuous layering, internal structures and anisotropy. Input parameters associated with different rock types are varied within reasonable ranges and grid spacing is refined to determine the sensitivity of the models to grid size. Variations between simulations are used to determine the differences in the partitioning of CO2 between its various storage mechanisms, and whether the differences are reflective of heterogeneities in the real system or attributed to numerical error. Initial results indicate that variations in certain parameters are more significant than others in terms of the movement and partitioning of CO2 into its various storage mechanisms. Variations in horizontal to vertical permeability contrasts, and residual liquid and gas saturation have significant impacts on the flow path of CO2 through the system, and therefore the amount of CO2 that becomes trapped residually within the pore spaces or dissolves into the formation brine. Gradual changes in heterogeneity do not seem to alter the results significantly in comparison to discrete changes, indicating that modelling heterogeneities as discrete bodies is an adequate assumption. Results imply that certain geological heterogeneities and associated parameters require more accurate representation then others when considering how CO2 will be stored within the subsurface. Although finer grid sizes increases the numerical accuracy of simulations, acute grid refinement may not be required for all purposes.

Hermanson, J. L.; Kirste, D. M.

2012-12-01

8

Anomalous transport in weakly heterogeneous geological porous media  

NASA Astrophysics Data System (ADS)

Anomalous transport is found to be ubiquitous in complex geological formations and it has a paramount impact on petroleum engineering and groundwater sciences. This process can be well described by the continuous time random walk (CTRW) model, in which the probability density function w(t) of a particle's transition time t follows a power law for large t: w(t)˜t-1-? (0geological porous media with weakly heterogeneous microstructures.

Wang, Yan

2013-03-01

9

Intermediate-Scale Investigation of Capillary and Dissolution Trapping during CO2 Injection and Post-Injection in Heterogeneous Geological Formations  

NASA Astrophysics Data System (ADS)

The capillary and dissolution trapping processes are believed to be major trapping mechanisms during CO2 injection and post-injection in heterogeneous subsurface environments. These processes are important at relatively shorter time periods compared to mineralization and have a strong impact on storage capacity and leakage risks, and they are suitable to investigate at reasonable times in the laboratory. The objectives of the research presented is to investigate the effect of the texture transitions and variability in heterogeneous field formations on the effective capillary and dissolution trapping at the field scale through multistage analysis comprising of experimental and modeling studies. A series of controlled experiments in intermediate-scale test tanks are proposed to investigate the key processes involving (1) viscous fingering of free-phase CO2 along high-permeability (or high-K) fast flow pathways, (2) dynamic intrusion of CO2 from high-K zones into low-K zones by capillarity (as well as buoyancy), (3) diffusive transport of dissolved CO2 into low-K zones across large interface areas, and (4) density-driven convective mass transfer into CO2-free regions. The test tanks contain liquid sampling ports to measure spatial and temporal changes in concentration of dissolved fluid as the injected fluid migrates. In addition to visualization and capturing images through digital photography, X-ray and gamma attenuation methods are used to measure phase saturations. Heterogeneous packing configurations are created with tightly packed sands ranging from very fine to medium fine to mimic sedimentary rocks at potential storage formations. Effect of formation type, injection pressure and injection rate on trapped fluid fraction are quantified. Macroscopic variables such as saturation, pressure and concentration that are measured will be used for testing the existing macroscopic models. The applicability of multiphase flow theories will be evaluated by comparing with the experimental data. Existing upscaling methodologies will be tested using experimental data for accurately estimating parameters of the large-scale heterogeneous porous media. This paper presents preliminary results from the initial-stage experiments and the modeling analysis. In the future, we will design and conduct a comprehensive set of experiments for improving the fundamental understanding of the processes, and refine and calibrate the models simulating the effective capillary and dissolution trapping with an ultimate goal to design efficient and safe storage schemes.

Cihan, A.; Illangasekare, T. H.; Zhou, Q.; Birkholzer, J. T.; Rodriguez, D.

2010-12-01

10

Method of fracturing a geological formation  

DOEpatents

An improved method of fracturing a geological formation surrounding a well bore is disclosed. A relatively small explosive charge is emplaced in a well bore and the bore is subsequently hydraulically pressurized to a pressure less than the formation breakdown pressure and preferably greater than the fracture propagation pressure of the formation. The charge is denoted while the bore is so pressurized, resulting in the formation of multiple fractures in the surrounding formation with little or no accompanying formation damage. Subsequent hydraulic pressurization can be used to propagate and extend the fractures in a conventional manner. The method is useful for stimulating production of oil, gas and possibly water from suitable geologic formations.

Johnson, James O. (2679-B Walnut, Los Alamos, NM 87544)

1990-01-01

11

Improved Subsurface Model Calibration Using Soft Data on Geologic Heterogeneity  

NASA Astrophysics Data System (ADS)

Calibration of numerical models for groundwater flow and transport uses available field data from observation wells that may be limited in number and located non-optimally. A series of data sets generated in a three- dimensional synthetic aquifer were used to explore the relationship between accuracy of estimated model parameters and increasing quantities of soft data. The synthetic aquifer consisted of five well-characterized sands carefully packed in a tank 208 cm long, 117 cm wide, and 57 cm tall. The sands were packed to represent a stationary spatially correlated random field with a moderate heterogeneity. A lens-like layer of fine sand embedded into the stationary field, resulting in a non-stationary composite aquifer heterogeneity. The presence of a single layer of fine sand was treated as soft data gathered through geophysical characterization. Pressure distribution within the aquifer was measured at 92 monitoring locations using an automated measuring system. Constituent transport data was generated using a new, automated, fluorimetry-based plume monitoring system consisting of 20 channels with optical fibers. The data generated were used to conduct a number studies related to the use of soft and hard data for model calibration. The first study, using the flow simulator MODFLOW and inversion code UCODE, confirmed that the accuracy in parameter estimation improves with increasing quantities of soft data especially information on heterogeneity. This supports the inclusion of a model designed to capture geological complexity to improve the accuracy of parameter estimation. Similar studies are underway and will be compared.

Howington, S. E.; Sakaki, T.; Hallberg, J.; Illangasekare, T. H.

2006-12-01

12

Simulation of Seismic Tunnel Detection Experiments in Heterogeneous Geological Media  

NASA Astrophysics Data System (ADS)

Detecting covert tunnels and other underground openings is an important yet challenging problem for geophysicists, especially where geological heterogeneity is pronounced. A number of geophysical methods have been employed to solve this problem, each with varying degrees of success. We focus on the near-surface seismic techniques of surface wave backscattering, surface wave attenuation tomography, body wave diffraction imaging, and resonant imaging. We use the elastodynamic wave propagation code E3D to simulate tunnel detection experiments completed at this site for a range of synthetic fractal velocity models. The Black Diamond mine, located near Pittsburg California, is used for the field test of our analysis. Our results show that for the relatively low-frequency surface wave attenuation and backscattering methods, the maximum detectable tunnel depth in a homogenous medium is approximately equal to the wavelength of the probing Rayleigh wave. The higher-frequency body wave diffraction and resonant imaging techniques are able to locate tunnels at greater depths, but require more sophisticated analysis and are prone to greater attenuation losses. As is expected, for large values of heterogeneity amplitude, ?, the percent standard deviation from the mean velocity model, the average observed surface wave attenuation signal decreases and the maximum detectable tunnel depth decreases. However, for moderate values of heterogeneity amplitude (? < 3%), the average surface wave attenuation signal increases and the maximum detectable tunnel depth increases. For the body wave diffraction and resonant imaging experiments, as ? increases the complexity of the observed signal increases, resulting in more difficult processing and interpretation. The additional scattering attenuation tends to degrade the signals significantly due to their reliance on lower amplitude and higher frequency waves.

Sherman, C. S.; Glaser, S. D.; Rector, J.

2013-12-01

13

Constructing Hydraulic Barriers in Deep Geologic Formations  

SciTech Connect

Many construction methods have been developed to create hydraulic barriers to depths of 30 to 50 meters, but few have been proposed for depths on the order of 500 meters. For these deep hydraulic barriers, most methods are potentially feasible for soil but not for hard rock. In the course of researching methods of isolating large subterranean blocks of oil shale, the authors have developed a wax thermal permeation method for constructing hydraulic barriers in rock to depths of over 500 meters in competent or even fractured rock as well as soil. The technology is similar to freeze wall methods, but produces a permanent barrier; and is potentially applicable in both dry and water saturated formations. Like freeze wall barriers, the wax thermal permeation method utilizes a large number of vertical or horizontal boreholes around the perimeter to be contained. However, instead of cooling the boreholes, they are heated. After heating these boreholes, a specially formulated molten wax based grout is pumped into the boreholes where it seals fractures and also permeates radially outward to form a series of columns of wax-impregnated rock. Rows of overlapping columns can then form a durable hydraulic barrier. These barriers can also be angled above a geologic repository to help prevent influx of water due to atypical rainfall events. Applications of the technique to constructing containment structures around existing shallow waste burial sites and water shutoff for mining are also described. (authors)

Carter, E.E.; Carter, P.E. [Technologies Co, Texas (United States); Cooper, D.C. [Ph.D. Idaho National Laboratory, Idaho Falls, ID (United States)

2008-07-01

14

Sparse Geologic Dictionaries for Identification of Subsurface Heterogeneity: A New Inverse Modeling Perspective  

NASA Astrophysics Data System (ADS)

Identification of heterogeneous hydraulic rock properties from flow data presents a challenging problem in modeling and prediction of fluid flow displacement in subsurface environments. Inference of these properties from limited dynamic flow measurements typically leads to a severely underdetermined nonlinear inverse problem that can have many non-unique solutions. The problem is usually regularized by incorporating implicit or explicit prior information in the search for an acceptable solution. Reducing the number of unknown parameters and/or constraining the solution space by imposing an appropriate structural assumption on the solution are common approaches for stabilizing the solution of ill-posed inverse problems. In geosciences inverse problems, a valid structural assumption must be supported by the physics of the problem, by the available information about the geologic history of the formation, and by other sources of information such as outcrop, well logs and seismic data. In this paper, we present a geologically-motivated regularization approach for representation and estimation of subsurface hydraulic properties. The approach is based on construction of a field-specific diverse geologic dictionary from a collection of prior model realizations. The main property of the constructed dictionary is that it can sparsely represent any individual realization in the collection of prior models; that is, only a small subset of the geologic dictionary elements is needed to accurately approximate each individual model in the prior library. Inspired by recent development in sparse signal processing, we formulate the inverse modeling as a sparse reconstruction problem and find its solution by searching for a sparse combination of model elements in the geologic dictionary that can reproduce the dynamic flow data. To identify these relevant components in the large geologic dictionary and to estimate their contribution (weight), we implement an efficient iteratively reweighted least-squares reconstruction algorithm that minimizes a data misfit objective function augmented with a sparsity regularization term over the dictionary. We illustrate the effectiveness and suitability of this new inversion approach and compare it with alternative prior-based methods using a series of numerical experiments in two-phase fluid flow problems.

Jafarpour, B.; M. Khaninezhad, M. R.

2011-12-01

15

Geological\\/Stochastic Mapping of Heterogeneity in a Carbonate Reservoir  

Microsoft Academic Search

Two major problems in estimating interwell porosity and permeability patterns are estimating permeability profiles in uncored wells and interpolating wellbore information between wells. This paper reports on a technique combining core analysis, rock fabrics, and wireline logs used to estimate permeability values at 1-ft intervals in 32 wells in Section 15 of the Dune field. Stochastic geologic interpolation was generated

F. J. Lucia; Graham Fogg

1990-01-01

16

A Laboratory Study of Heterogeneity and Scaling in Geologic Media  

NASA Astrophysics Data System (ADS)

In rocks and soils, the bulk geophysical and transport properties of the matrix and of fracture systems are determined by the juxtaposition of geometric features at many length scales. For sedimentary materials the length scales are: the pore scale (irregularities in grain surface roughness and cementation), the scale of grain packing faults (and the resulting correlated porosity structures), the scale dominated by sorting or winnowing due to depositional processes, and the scale of geomorphology at the time of deposition. We are studying the heterogeneity and anisotropy in geometry, permeability, and geophysical response from the pore (microscopic), laboratory (mesoscopic), and backyard field (macroscopic) scales. In turn these data are being described and synthesized for development of mathematical models. Eventually, we will perform parameter studies to explore these models in the context of transport in the vadose and saturated zones. We have developed a multi-probe physical properties scanner which allows for the mapping of geophysical properties on a slabbed sample or core. This device allows for detailed study of heterogeneity at those length scales most difficult to quantify using standard field and laboratory practices. The measurement head consists of a variety of probes designed to make local measurements of various properties, including: gas permeability, acoustic velocities (compressional and shear), complex electrical impedance (4 electrode, wide frequency coverage), and ultrasonic reflection (ultrasonic impedance and permeability). We can thus routinely generate detailed geophysical maps of a particular sample. We are testing and modifying these probes as necessary for use on soil samples. As a baseline study we have been characterizing the heterogeneity of a bench-size Berea sandstone block. Berea Sandstone has long been regarded as a laboratory standard in rock properties studies, owing to its uniformity and ``typical'' physical properties. We find that both permeability and velocity exhibit complex heterogeneity at the centimeter scale. While some correlation with the outcropping of the bedding is apparent, much of the heterogeneity is not clearly associated with visual features. For the study of soil heterogeneity at a wide range of scales, we are focusing on a local glacial deposit. This deposit is a glacial kame terrace of fluvial origin with multi-scale sedimentary structures comprised of unconsolidated sands, clays, and gravels. There are also many joints and faults in the unconsolidated sediments, allowing study of these as potential fluid flow conduits or barriers. We have obtained undisturbed soil samples from this site, allowing detailed laboratory study using similar methods to those described for the sandstone block.

Brown, S.; Boitnott, G.; Bussod, G.; Hagan, P.

2004-05-01

17

A Laboratory Study of Heterogeneity and Scaling in Geologic Media  

NASA Astrophysics Data System (ADS)

In rocks and soils, the bulk geophysical and transport properties of the matrix and of fracture systems are determined by the juxtaposition of geometric features at many length scales. For sedimentary materials the length scales are: the pore scale (irregularities in grain surface roughness and cementation), the scale of grain packing faults (and the resulting correlated porosity structures), the scale dominated by sorting or winnowing due to depositional processes, and the scale of geomorphology at the time of deposition. We are studying the heterogeneity and anisotropy in geometry, permeability, and geophysical response from the pore (microscopic), laboratory (mesoscopic), and backyard field (macroscopic) scales. In turn these data are being described and synthesized for development of mathematical models. Eventually, we will perform parameter studies to explore these models in the context of transport in the vadose and saturated zones. We have developed a multi-probe physical properties scanner which allows for the mapping of geophysical properties on a slabbed sample or core. This device allows for detailed study of heterogeneity at those length scales most difficult to quantify using standard field and laboratory practices. The measurement head consists of a variety of probes designed to make local measurements of various properties, including: gas permeability, acoustic velocities (compressional and shear), complex electrical impedance (4 electrode, wide frequency coverage), and ultrasonic reflection (ultrasonic impedance and permeability). We can thus routinely generate detailed geophysical maps of a particular sample. With the exception of the acoustic velocity, we are testing and modifying these probes as necessary for use on soil samples. As a baseline study we have been characterizing the heterogeneity of a bench-size Berea sandstone block. Berea Sandstone has long been regarded as a laboratory standard in rock properties studies, owing to its uniformity and ``typical'' physical properties. We find that both permeability and velocity exhibit complex heterogeneity at the centimeter scale. While some correlation with the outcropping of the bedding is apparent, much of the heterogeneity is not clearly associated with visual features. For the study of soil heterogeneity at a wide range of scales, we are focusing on a local glacial deposit. This deposit is a glacial kame terrace of fluvial origin with multi-scale sedimentary structures comprised of unconsolidated sands, clays, and gravels. There are also many joints and faults in the unconsolidated sediments, allowing study of these as potential fluid flow conduits or barriers. We have obtained undisturbed soil samples from this site, allowing detailed laboratory study using similar methods to those described for the sandstone block.

Brown, S.; Boitnott, G.; Smith, M.

2003-12-01

18

Geology of Montgomery Creek formation, Klamath Mountains, Shasta County, California  

SciTech Connect

Sediments of the Montgomery Creek formation record the early Tertiary tectonic history of the Klamath Mountains and the birth of the Cascade Range. Detailed field and laboratory investigations in this sedimentary unit reveal the stratigraphic sequence, thicknesses, contact relationships, depositional environments, and ages of the strata. Mineralogical patterns and heavy mineral distribution in the sandstones as well as sediment transport directions, the location and lithology of the source areas, and the relationships of the strata of this formation to the geologic history of the Klamath Mountains and Cascade Range have also been determined. The paper describes the regional geology, lithology, paleoenvironment, and geologic history.

Higinbotham, L.

1987-06-01

19

Integration of Seismic and SkyTEM in a Heterogeneous Geological Setting  

Microsoft Academic Search

The topic of this presentation is to show the benefits of integrating seismic and SkyTEM data acquired in an area with a highly heterogeneous geological setting. The study area is situated close to the town of Oelgod in western Denmark and covers 14 square kilometres. In this area SkyTEM lines with a spacing of approximately 100 meters have been measured,

A. H. Christensen; H. Lykke-Andersen; F. Jorgensen; E. Nørmark; E. Auken

2009-01-01

20

Electromagnetic instruments for imaging structure in geologic formations  

SciTech Connect

An apparatus is described for the detection and analysis of anomalies within geological formations comprising: a down hole transmitter set comprising a tuned-loop antenna for orienting vertically within a geological formation, the antenna electrically coupled to a transmitter and mechanically coupled to a drive means whereby the antenna may be rotated about a vertical axis; a down hole receiving set comprising a tuned-loop antenna of orienting vertically within the formation; a computer aided processing means for receiving, processing and interpreting the recorded data, the recorded data being stored on a magnetic storage medium by the surface analysis and control equipment for later analysis by the computer aided processing means.

Stolarczyk, L.G.

1987-09-01

21

Coalition formation with uncertain heterogeneous information  

Microsoft Academic Search

Coalition formation methods allow agents to join together and are thus necessary in cases where tasks can only be performed cooperatively by groups. This is the case in the Request For Proposal (RFP) domain, where some requester business agent issues an RFP - a complex task comprised of sub-tasks - and several service provider agents need to join together to

Sarit Kraus; Onn Shehory; Gilad Taase

2003-01-01

22

Combining geologic-process models and geostatistics for conditional simulation of 3-D subsurface heterogeneity  

NASA Astrophysics Data System (ADS)

The goal of simulation of aquifer heterogeneity is to produce a spatial model of the subsurface that represents a system such that it can be used to understand or predict flow and transport processes. Spatial simulation requires incorporation of data and geologic knowledge, as well as representation of uncertainty. Classical geostatistical techniques allow for the conditioning of data and uncertainty assessment, but models often lack geologic realism. Simulation of physical geologic processes of sedimentary deposition and erosion (process-based modeling) produces detailed, geologically realistic models, but conditioning to local data is limited at best. We present an aquifer modeling methodology that combines geologic-process models with object-based, multiple-point, and variogram-based geostatistics to produce geologically realistic realizations that incorporate geostatistical uncertainty and can be conditioned to data. First, the geologic features of grain size, or facies, distributions simulated by a process-based model are analyzed, and the statistics of feature geometry are extracted. Second, the statistics are used to generate multiple realizations of reduced-dimensional features using an object-based technique. Third, these realizations are used as multiple alternative training images in multiple-point geostatistical simulation, a step that can incorporate local data. Last, a variogram-based geostatistical technique is used to produce conditioned maps of depositional thickness and erosion. Successive realizations of individual strata are generated in depositional order, each dependent on previously simulated geometry, and stacked to produce a fully conditioned three-dimensional facies model that mimics the architecture of the process-based model. We demonstrate the approach for a typical subsea depositional complex.

Michael, H. A.; Li, H.; Boucher, A.; Sun, T.; Caers, J.; Gorelick, S. M.

2010-05-01

23

Integration of Seismic and SkyTEM in a Heterogeneous Geological Setting  

NASA Astrophysics Data System (ADS)

The topic of this presentation is to show the benefits of integrating seismic and SkyTEM data acquired in an area with a highly heterogeneous geological setting. The study area is situated close to the town of Oelgod in western Denmark and covers 14 square kilometres. In this area SkyTEM lines with a spacing of approximately 100 meters have been measured, and in addition to this 80 kilometres seismic profiling has been acquired in and in the vicinity of the study area. This dense data coverage of a geologically complex area is unique, and provides an optimal basis for assessment of the benefits from integrating the two methods. The SkyTEM method is currently the most widely used geophysical method for groundwater mapping in Denmark. SkyTEM is an airborne transient electromagnetic method with which data are collected continuously along parallel lines. The method is especially good at mapping the distribution of conductive layers at depths to about 250 meters. By undertaking airborne SkyTEM surveys it is possible to collect dense data grids over large survey areas. Such data sets often form the basis for three-dimensional geological interpretations. In order to obtain a larger degree of detail and thereby improved reliability of geological interpretations we find it advantageous to combine SkyTEM results with high-resolution seismic profiling. Seismic profiles may contribute with important information on the specific structural setting. The SkyTEM data show a highly complex setting with ridges, valleys, depressions and hummocks. These structures are found at depths down to about 200 meters. The structures are laterally well resolved due to the close line spacing. Resistivity levels and lithological information available from few, scattered groundwater wells suggest clay-sand lithologies. Detailed characterisation of the structural features in the sediments are not revealed in the SkyTEM data, but can be provided by the seismic data. Thus, combined application of the two methods will allow for construction of more exact geological models. High-resolution seismic surveying offers useful and detailed information along 2D sections, but as compared to the SkyTEM method it is expensive in use and difficult to carry out in areas of limited access. In order to resolve heterogeneous geology, dense areal data coverage is needed in combination with detailed insight in geological key features. The first demand is met by the SkyTEM method, and the second by the seismic method. An investigation strategy starting with SkyTEM, and followed by seismics along profiles located on lines selected from SkyTEM interpretations, therefore, provides a strong cost-effective approach when dealing with complex geology.

Christensen, A. H.; Lykke-Andersen, H.; Jorgensen, F.; Nørmark, E.; Auken, E.

2009-12-01

24

Upscaling of hydraulic conductivity in partially saturated heterogeneous porous formation  

Microsoft Academic Search

This paper describes a procedure to upscale unsaturated hydraulic conductivity from the scale at which it is measured to a scale more amenable to actual flow simulations in partially saturated heterogeneous porous formations. In the approach adopted here the block conductivity is defined as the ratio of volume-averaged flux to the volume-averaged head gradient. The “point” values of the underlying

David Russo

1992-01-01

25

Geological pattern formation by growth and dissolution in aqueous systems  

SciTech Connect

Although many geological processes take place on time scales that are very long compared with the human experience, essentially all geological processes, fast or slow, are far from equilibrium processes. Surprisingly often, geological processes lead to the formation of quite simple and distinctive patterns, which hint at an underlying simplicity in many complex geological systems.. The ability to predict the seasons was critically important to early human society, and Halley’s prediction of the return of the comet that bears his name is still considered to be a scientific milestone. Spatial patterns have also attracted attention because of their aesthetic appeal, which depends in subtle ways on a combination of regularity and irregularity. In recent decades, rapid growth in the capabilities of digital computers has facilitated the simulation of pattern formation processes, and computer simulations have become an important tool for evaluating theoretical concepts and for scientific discovery. Computer technology in combination with other technologies such as high resolution digital cameras, scanning microprobes (atomic force microscopy AFM), confocal microscopy, and scanning tunneling microscopy (STM), for example) has facilitated the quantitative characterization of patterns over a wide range of scales and has enabled rapid advances in our ability to understand the links between large scale pattern formation and microscopic processes. The ability to quantitatively characterize patterns is important because it enables a more rigorous comparison between the predictions of computer models and real world patterns and their formation.In some cases, the idea that patterns with a high degree of regularity have simple origins appears to be justified, but in other cases, such as the formation of almost perfectly circular stone rings due to freeze-thaw cycles simple patterns appear to be the consequence of quite complex processes. In other cases, it has been shown that very simple non-linear processes can lead to extremely complicated patterns, and that some apparently complex disordered systems can be described quantitatively in terms of simple fractal models.

Paul Meakin

2010-03-01

26

Flow in fractured geological media: the influence of fracture scale heterogeneity  

NASA Astrophysics Data System (ADS)

Flow channeling and permeability scaling in fractured geological media are usually adressed either at the fracture- or at the network- scales. In the latter case they are linked to the topological structure of the network, while at the fracture scale they are controlled by the variability of the local aperture distribution inside individual fractures. We combine these two effects and investigate how flow localization below the scale of individual fractures impacts that at the network scale and the resulting medium permeability. This is addressed with a highly-resolved 3D discrete fracture network model that accounts both for the typical topology of geological fracture networks and for the spatially-correlated roughness of fracture walls. At the fracture scale, accounting for aperture heterogeneities leads to a reduction of the equivalent fracture transmissivity of up to a factor of 6 as compared to the parallel plate of identical mean aperture, depending on the fractures' closure. At the network scale significant coupling is observed in most cases between flow heterogeneities at the fracture scale and those observed for the complete network, provided that the size of the medium be less than 20 times larger than the typical correlation length between the two matching walls of an individual fracture [1]. One single scalar parameter accounts for the deviation of the medium permeability from that of a network of identical topology and consisting of parallel plate fractures of mean apertures identical to those of the heterogeneous fractures in our medium. [1] de Dreuzy, J.-R., Méheust, Y. and Pichot, G. (2012), Influence of fracture scale heterogeneity on the flow properties of three-dimensional Discrete Fracture Networks (DFN), J. Geophys. Res.-Earth Surf. 117(B11207), 21 pp. Local fluid fluxes inside a discrete fracture network consisting of fractures with spatially-varying apertures.

Meheust, Y.; De Dreuzy, J.; Pichot, G.

2013-12-01

27

Heterogeneity and subjectivity in binary-state opinion formation systems  

NASA Astrophysics Data System (ADS)

In society, there is heterogeneous interaction and randomness in human decision making. In order to unfold the roles and the competition of the two factors mentioned above in opinion formation, we propose a toy model, which follows a majority rule with a Fermi function, on scale-free networks with degree exponent ?. The heterogeneous interaction is related to the connectivity of a person with the interactive parameter ?, and the randomness of human decision making is quantified by the interaction noise T. We find that a system with heterogeneity of network topology and interaction shows robustness perturbed by the interaction noise T according to the theoretical analysis and numerical simulation. Then, when T ? 0, the homogeneous interaction (? ? 0) has a powerful implication for the emergence of a consensus state. Furthermore, the emergence of the two extreme values shows the competition of the heterogeneity of interaction and the subjectivity of human decision making in opinion formation. Our present work provides some perspective on and tools for understanding the diversity of opinion in our society.

Guo, Long; Luo, Zhongjie; Zhu, Yueying

2013-11-01

28

Dispersion measurement as a method of quantifying geologic characterization and defining reservoir heterogeneity. Final report  

SciTech Connect

The main objective of this research project is to investigate dispersion as a method of quantifying geological characterization and defining reservoir heterogeneity in order to enhance crude oil recovery. The dispersion of flow of a reservoir rock (dispersion coefficient and dispersivity) was identified as one of the physical properties of a reservoir rock by measuring the mixing of two miscible fluids, one displacing the other in a porous medium. A rock was 100% saturated with a resident fluid and displaced by a miscible fluid of equal viscosity and equal density. Some specific experiments were performed with unequal densities. Produced fluid was analyzed by refractometer, nuclear reaction, electrical conductivity and X-ray scan. Several physical and flow characteristics were measured on the sand rock sample in order to establish correlations with the measured dispersion property. Absolute permeability, effective porosity, relative permeability, capillary pressure, the heterogeneity factor and electrical conductivity were used to better understand the flow system. Linear, transverse, 2-D and 3-D dispersions were measured and used to characterize the rock heterogeneity of the flow system. A new system of measuring dispersion was developed using a gas displacing gas system in a porous medium. An attempt was also made to determine the dispersion property of an actual reservoir from present day well log data on a producing well. 275 refs., 102 figs., 17 tabs.

Menzie, D.E.

1995-05-01

29

Estimation of hydrologic properties of heterogeneous geologic media with an inverse method based on iterated function systems  

SciTech Connect

The hydrologic properties of heterogeneous geologic media are estimated by simultaneously inverting multiple observations from well-test data. A set of pressure transients observed during one or more interference tests is compared to the corresponding values obtained by numerically simulating the tests using a mathematical model. The parameters of the mathematical model are varied and the simulation repeated until a satisfactory match to the observed pressure transients is obtained, at which point the model parameters are accepted as providing a possible representation of the hydrologic property distribution. Restricting the search to parameters that represent fractal hydrologic property distributions can improve the inversion process. Far fewer parameters are needed to describe heterogeneity with a fractal geometry, improving the efficiency and robustness of the inversion. Additionally, each parameter set produces a hydrologic property distribution with a hierarchical structure, which mimics the multiple scales of heterogeneity often seen in natural geological media. Application of the IFS inverse method to synthetic interference-test data shows that the method reproduces the synthetic heterogeneity successfully for idealized heterogeneities, for geologically-realistic heterogeneities, and when the pressure data includes noise.

Doughty, C.A.

1996-05-01

30

Modeling fine-scale geological heterogeneity--examples of sand lenses in tills.  

PubMed

Sand lenses at various spatial scales are recognized to add heterogeneity to glacial sediments. They have high hydraulic conductivities relative to the surrounding till matrix and may affect the advective transport of water and contaminants in clayey till settings. Sand lenses were investigated on till outcrops producing binary images of geological cross-sections capturing the size, shape and distribution of individual features. Sand lenses occur as elongated, anisotropic geobodies that vary in size and extent. Besides, sand lenses show strong non-stationary patterns on section images that hamper subsequent simulation. Transition probability (TP) and multiple-point statistics (MPS) were employed to simulate sand lens heterogeneity. We used one cross-section to parameterize the spatial correlation and a second, parallel section as a reference: it allowed testing the quality of the simulations as a function of the amount of conditioning data under realistic conditions. The performance of the simulations was evaluated on the faithful reproduction of the specific geological structure caused by sand lenses. Multiple-point statistics offer a better reproduction of sand lens geometry. However, two-dimensional training images acquired by outcrop mapping are of limited use to generate three-dimensional realizations with MPS. One can use a technique that consists in splitting the 3D domain into a set of slices in various directions that are sequentially simulated and reassembled into a 3D block. The identification of flow paths through a network of elongated sand lenses and the impact on the equivalent permeability in tills are essential to perform solute transport modeling in the low-permeability sediments. PMID:23252428

Kessler, Timo Christian; Comunian, Alessandro; Oriani, Fabio; Renard, Philippe; Nilsson, Bertel; Klint, Knud Erik; Bjerg, Poul Løgstrup

2013-01-01

31

Geology of the Biwabik Iron Formation and Duluth Complex.  

PubMed

The Biwabik Iron Formation is a approximately 1.9 billion year-old sequence of iron-rich sedimentary rocks that was metamorphosed at its eastern-most extent by approximately 1.1 billion year-old intrusions of the Duluth Complex. The metamorphic recrystallization of iron-formation locally produced iron-rich amphiboles and other fibrous iron-silicate minerals. The presence of these minerals in iron-formation along the eastern part of what is known as the Mesabi Iron Range, and their potential liberation by iron mining has raised environmental health concerns. We describe here the geologic setting and mineralogic composition of the Biwabik Iron Formation in and adjacent to the contact metamorphic aureole of the Duluth Complex. The effects of metamorphism are most pronounced within a few kilometers of the contact, and decrease progressively away from it. The contact aureole has been divided into four metamorphic zones-each characterized by the composition and crystal structure of the metamorphic minerals it contains. The recrystallization of iron-formation to iron-rich amphibole minerals (grunerite and cummingtonite) and iron-pyroxene minerals (hedenbergite and ferrohypersthene) is best developed in zones that are most proximal to the Duluth Complex contact. PMID:17997209

Jirsa, Mark A; Miller, James D; Morey, G B

2008-10-01

32

Role of particulate metals in heterogenous secondary sulfate formation  

NASA Astrophysics Data System (ADS)

A series of field sampling and controlled laboratory experiments were undertaken to quantify the role of trace metals found in ambient fine particulate matter and metal-rich primary sources in the heterogenous catalytic conversion of SO2 gas into sulfate particulate matter (PM) in the atmosphere. Analysis produced source profiles of three primary source materials, fluidized-bed catalytic cracking catalyst, coal-fired combustion fly ash, and paved road dust, featuring 33 elements including rare earth metals, which are not commonly reported in the literature. Subsequently three sets of experiments were conducted exposing 1) source materials, 2) ambient PM, and 3) ambient PM augmented with approximately an equal amount of source material to SO2 gas and measuring sulfate formation. Source material experiments revealed that the greatest extent of reaction was on the surface of coal fly ash with sulfate formation of 19 ± 5 mg sulfate g-1 material. Ambient fine particulate matter (PM) experiments showed sulfate formation ranging from negligible amounts to 180 ± 10 mg sulfate g-1 PM. It was much more difficult to quantify the sulfate formation on ambient filters augmented with the source materials. In these experiments, sulfate formation ranged from negligible amounts to 40 ± 8 mg sulfate g-1 of particles (ambient + augmented material). These three sets of experiments shows that heterogenous sulfate formation is often negligible but, under some conditions can contribute 10% or more to the total sulfate concentrations when exposed to high SO2 concentrations such as those found in plumes. Factor analysis of the source material experiments grouped metals into two categories, crustal components and anthropogenically emitted metals representative of catalyst material, with the former showing the strongest correlation with sulfate formation. Subsequent analysis of data collected from the ambient PM experiments showed a much weaker correlation of sulfate formation with the crustal components, including iron and titanium, remaining clustered with sulfate formation. Independent research has been previously reported in the literature establishing mechanisms for the iron and titanium catalyzed conversion of S(IV) to S(VI) suggesting there may be other metals within these crustal type metal components that behave similarly. Additional experiments spanning a wider range of variables including more sources, SO2 concentrations and exposure times, ambient PM locations, as well as more individual samples may be necessary to obtain more conclusive evidence into the role of various metals in catalyzing the conversion of S(IV) to S(VI).

Clements, Andrea L.; Buzcu-Guven, Birnur; Fraser, Matthew P.; Kulkarni, Pranav; Chellam, Shankararaman

2013-08-01

33

COMMENT ON 'AN ADVECTION-DIFFUSION CONCEPT FOR SOLUTE TRANSPORT IN HETEROGENEOUS UNCONSOLIDATED GEOLOGICAL DEPOSITS' BY GILLHAM ET AL  

EPA Science Inventory

The article is a technical commentary relating to the article, 'An Advection-Diffusion Concept for Solute Transport in Heterogenous Unconsolidated Geological Deposits,' by Gillham, et al, Water Resources Research 20(3):369-378, 1984. The authors principal comments relate to the c...

34

Heterogeneity and Scaling in Geologic Media: Applications to Transport in the Vadose and Saturated Zones  

SciTech Connect

Heterogeneity and Scaling in Geologic Media: Applications to Transport in the Vadose and Saturated Zones Stephen Brown, Gregory Boitnott, and Martin Smith New England Research In rocks and soils, the bulk geophysical and transport properties of the matrix and of fracture systems are determined by the juxtaposition of geometric features at many length scales. For sedimentary materials the length scales are: the pore scale (irregularities in grain surface roughness and cementation), the scale of grain packing faults (and the resulting correlated porosity structures), the scale dominated by sorting or winnowing due to depositional processes, and the scale of geomorphology at the time of deposition. We are studying the heterogeneity and anisotropy in geometry, permeability, and geophysical response from the pore (microscopic), laboratory (mesoscopic), and backyard field (macroscopic) scales. In turn these data are being described and synthesized for development of mathematical models. Eventually, we will perform parameter studies to explore these models in the context of transport in the vadose and saturated zones. We have developed a multi-probe physical properties scanner which allows for the mapping of geophysical properties on a slabbed sample or core. This device allows for detailed study of heterogeneity at those length scales most difficult to quantify using standard field and laboratory practices. The measurement head consists of a variety of probes designed to make local measurements of various properties, including: gas permeability, acoustic velocities (compressional and shear), complex electrical impedance (4 electrode, wide frequency coverage), and ultrasonic reflection (ultrasonic impedance and permeability). We can thus routinely generate detailed geophysical maps of a particular sample. With the exception of the acoustic velocity, we are testing and modifying these probes as necessary for use on soil samples. As a baseline study we have been characterizing the heterogeneity of a bench-size Berea Sandstone block. Berea Sandstone has long been regarded as a laboratory standard in rock properties studies, owing to its uniformity and ''typical'' physical properties. We find that both permeability and velocity exhibit complex heterogeneity at the centimeter scale. While some correlation with the outcropping of the bedding is apparent, much of the heterogeneity is not clearly associated with visual features. We are developing software tools to examine simultaneously pixel by pixel correlations among geophysical measurements, transport properties, and visual (photographic) texture and the dependence of these correlations on measurement scale. We find that certain pairs of physical quantities, such as P velocity and permeability for example, are distinctly correlated with one another at certain scales, but less obviously at other scales. Preliminary analyses of the Berea Sandstone data show that by simultaneous consideration of several physical properties the data can be separated into clusters of like properties which can be considered distinct facies. Apparently, identification of these facies, which could represent a limited range of fluid permeability, may be made by making joint geophysical measurements. Given various physical models for the dependence of the geophysical and transport properties on pore size, we expect that these observed correlations will provide conditioning and constraints to inversions for stochastic models of the internal structure of a specimen. For the study of soil heterogeneity at a wide range of scales, we are focusing on a local glacial deposit. This deposit is a glacial kame terrace of fluvial origin with multi-scale sedimentary structures comprised of unconsolidated sands, clays, and gravels. There are also many joints and faults in the unconsolidated sediments, allowing study of these as potential fluid flow conduits or barriers. We have obtained undisturbed soil samples from this site, allowing detailed laboratory study using similar methods to those described for the sandstone bl

Brown, Stephen R.

2003-06-01

35

Influence of tile-drainage on groundwater flow and nitrate transport in heterogeneous geological materials  

NASA Astrophysics Data System (ADS)

Subsurface drainage is a common agricultural practice in poorly drained production fields to guarantee the productivity of crops and to reduce flooding risks. The impact of shallow tile-drainage networks on groundwater flow patterns and associated nitrate transport from the surface needs to be quantified for adequate agricultural management. A challenge is to represent tile-drain networks in numerical models, at the field scale, while accounting for the influence of subsurface heterogeneities on flow and transport. A numerical model of a tile-drainage system has been developed with the fully integrated HydroGeoSphere model for the Lillebaek agricultural catchment, Denmark. The Lillebaek catchment is an experimental study area where hydraulic heads, stream and drain discharges, as well as groundwater and surface water nitrate concentrations are regularly measured. This catchment includes various tile-drainage networks that are monitored on a daily basis; the one we have been focusing on is about 5 ha within a 34 ha model domain. The Lillebaek catchment subsurface is made of about 30 m thick Quaternary deposits which consist of a local sandy aquifer with upper and lower clayey till units, confining the aquifer in the upper part. The main modelling objective is to assess the influence of tile drains on the water flow pattern within the confining clayey till unit with and on the nitrate reduction zone depth, also known as the redox-interface, while accounting for local geological heterogeneities. Using the national-scale geological model for Denmark combined with available local data, a hydrogeological model at field scale has been generated. A proper representation of the tile-drains geometry is essential to calibrate and validate the water flow model associated with nitrate transport. HydroGeoSphere can represent drains directly into a model as one-dimensional features, which however requires a very fine mesh discretization that limits the size of the simulation domain. Because of this limitation, we are testing an alternate approach where the tile-drain network and surrounding porous medium are represented by a dual-continuum formulation, similar to that used to represent fractured porous media, for example. Equivalent properties for the tile-drain network are defined from their geometry and spacing and the dual formulation allows for water and solute exchange between the drains and surrounding soil matrix. Validating this drain representation method in a model should allow us to work at larger scale in the future and thus to model tile-drained catchments without having to implement each and every drain, which would induce a very high number of model elements leading to time-consuming simulations. This contribution will focus on some preliminary simulations designed to validate the dual-continuum approach to represent tile-drained networks. These simulations are also designed to demonstrate the applicability of the approach for 3D variably-saturated flow and transport modelling at the field scale, accounting for local geological heterogeneities.

De Schepper, G.; Therrien, R.; Refsgaard, J.

2012-12-01

36

Acid-catalyzed Heterogeneous Reactions in SOA Formation  

NASA Astrophysics Data System (ADS)

The importance of heterogeneous reactions in secondary organic aerosol (SOA) formation has recently excited a great deal of interest in the aerosol community. Jang and Kamens (2001) showed enhanced aerosol yield from aldehydes, which can be produced by atmospheric photochemical reactions, in the presence of acidic seed. They suggest that the carbonyl functional groups of the aldehydes further react in the aerosol phase via hydration, polymerization, and hemiacetal/acetal formation with alcohols at an accelerated rate in the presence of acid. Jang et al. (2003) demonstrated similar results using a flow reactor and Czoschke et al. (in press) qualitatively showed increased yields for isoprene and alpha-pinene ozonolysis in the presence of acidic seed. While these findings are intriguing and important, the conditions under which the experiments were carried out were atmospherically unrealistic. A series of SOA formation experiments have been carried out in the Caltech Indoor Chamber Facility, which is comprised of dual 28 m3 FEP Teflon chambers, with the flexibility to carry out both dark ozonolysis and photochemical OH oxidation reactions. Cycloheptene and alpha-pinene were oxidized in the presence of neutral seed under dry (<10% RH) and humid (50% RH) conditions and in the presence of acidic seed under humid (50% RH) conditions. The SOA yields for these experiments will be presented, and the extent of the influence of acid-catalyzed reactions on SOA yield will be discussed. Reference List 1. Cocker, D. R. III. and R. C. Flagan and J. H. Seinfeld, State-of-the-art chamber facility for studying atmospheric aerosol chemistry, Environmental Science and Technology, 35, 2594-2601, 2001. 2. Czoschke, N. M., M. Jang, and R. M. Kamens, Effect of acid seed on biogenic sceondary organic aerosol growth, Atmospheric Environment, In press. 3. Jang, M., S. Lee, and R. M. Kamens, Organic aerosol growth by acid-catalyzed heterogeneous reactions of octanal in a flow reactor, Atmospheric Environment, 37, 2125-2138, 2003. 4. Jang, M. S. and R. M Kamens, Atmospheric secondary aerosol formation by heterogeneous reactions of aldehydes in the presence of a sulfuric acid aerosol catalyst. Environmental Science and Technology, 35, 4758-4766,2001.

Ng, N.; Keywood, M.; Varutbangkul, V.; Gao, S.; Loewer, E.; Surratt, J.; Richard, F. C.; John, S. H.

2003-12-01

37

In situ neutron capture spectroscopy of geological formations  

NASA Astrophysics Data System (ADS)

Neutron-capture-induced gamma-ray spectroscopy has been useful for determining the geological properties of porosity, lithology, and water salinity of the rock and fluid outside the iron casing which is cemented into most oil wells. This paper discusses such measurements using a pulsed source of 14-MeV neutrons and a NaI(T1) gamma-ray detector. The most difficult task in interpreting these measurements is to separate signals generated by elements in the formation rock and fluid from those due to elements inside the well bore. The physical properties at work here include fast-neutron thermalization times, thermal-neutron diffusion, competing neutron-capture cross sections, and gamma-ray transport to the detector. Results from studying the geophysical parameters which most affect these physical properties, porosity and water salinity, are presented here. Methods for enhancing the spectral contribution from the earth formation relative to that from the borehole are discussed. These include understanding the time dependence of the spectral shape, optimizing the source-to-detector spacing, and employing absorptive borehole fluid displacers.

Grau, J. A.; Antkiw, S.; Hertzog, R. C.; Marente, R. A.; Schweitzer, J. S.

1985-01-01

38

Investigating of the effects of target heterogeneities on terrestrial crater formation.  

NASA Astrophysics Data System (ADS)

The shape of terrestrial impact structures such as the Chesapeake or Ries crater indicate how important pre- existing target heterogeneities are even for fairly large impact structures. Both these craters possess an inverted sombrero structure as a result of a weaker sedimentary surface layer overlying a stronger crystalline basement. But beyond such horizontal layering, closer analyzes of the subsurface geology present in these and other terrestrial craters indicate that vertical heterogeneities in the strength and geochemistry of a target are also often present. These may influence the formation and subsequent modification of terrestrial craters. In deed, evidence indicates that at Meteor crater, for example, pre-existing vertical jointing of the target gives this crater its square appearance either by confining and re-directing the shock and subsequent rarefaction waves, or by allowing preferential weathering along zones of weakness at the joints. In this study, we present a series of 2 and 3 dimensional numerical investigations of crater formation in a conceptually simple but physical complex targets: a box of randomly distributed quartz spheres of identical size. These investigation should provide some constraints on how all types of target heterogeneities influence the cratering process at broad terrestrial scales. In this particular study, we analyze the formation of craters using a range of impact velocities, projectile sizes and strength of target components. We also consider a case where we immerse the spheres in a basaltic matrix. Our approach is to use the CTH code, that solves the equations of motion, while conserving mass, energy and momentum using a second order multi-material Eulerian methodology. The adaptive mesh refinement, a fairly new capability of CTH, is paramount to these studies, and allows investigating the effects of fine-scale target heterogeneity on the cratering process, through the use of a simple microscopic models with complex, but resolvable heterogeneous geometries, rather than a complex macroscopic model. Thus, the behavior of the impact shock traversing individual spheres in the target can be modeled, although slip between sphere is difficult for individual spheres separated by void; instead the material of each sphere merge and flow together. These calculations are not intended to exactly reproduce any given observations, but rather provide insights into what factors influence observed trends in shock propagation and excavation. Initial coupling between the projectile, initial distribution of the materials in the target and the presence of the matrix all influence the shape of resulting transient crater cavities. It is the subsequent collapse and modification of such transient craters that produce the structures seen on Earth.

Barnouin-Jha, O. S.; Crawford, D. A.; Cintala, M. J.; Wada, K.

2007-12-01

39

Heterogeneous and multiphase formation pathways of gypsum in the atmosphere.  

PubMed

Gypsum is a major sulphur-containing component of atmospheric particulate matter. To date, however, its formation pathways in the atmosphere are still not well known. In this study, several potentially important formation pathways of gypsum in atmospheric aerosols are proposed. We found that gypsum was formed in the humidifying-dehumidifying process of mixed sulphate and calcium salts. A deliquescent layer is crucial for the formation of gypsum from Ca(2+) and SO4(2-) ions. In particular, the presence of hygroscopic components, such as (NH4)2SO4 and Ca(NO3)2, is necessary for the conversion of calcium carbonate (CaCO3) upon heterogeneous reaction of either SO2 + O3 or SO2 + NO2 as well as anhydrous calcium sulphate (CaSO4) to form gypsum (CaSO4·2H2O) under ambient conditions. This study provides definitive evidence that synergistic effects in the physical and chemical processing of aerosol particles have a significant effect on their final chemical composition, mixing state and hygroscopic behaviour which dictates the environmental and climate impacts of the resulting aerosol. PMID:24107920

Ma, Qingxin; He, Hong; Liu, Yongchun; Liu, Chang; Grassian, Vicki H

2013-11-28

40

Sulfuric Acid Monohydrate: Formation and Heterogeneous Chemistry in the Stratosphere  

NASA Technical Reports Server (NTRS)

We have investigated some thermodynamic properties (i.e., freezing/melting points) and heterogeneous chemistry of sulfuric acid monohydrate (SAM, H2SO4.H2O), using a fast flow reactor coupled to a quadrupole mass spectrometer. The freezing point observations of thin liquid sulfuric acid films show that for acid contents between 75 and 85 wt % the monohydrate crystallizes readily at temperatures between 220 and 240 K on a glass substrate. Once formed, SAM can be thermodynamically stable in the H2O partial pressure range of (1-4) x 10(exp -4) torr and in the temperature range of 220-240 K. For a constant H2O partial pressure, lowering the temperature causes SAM to melt when the temperature and water partial pressure conditions are out of its stability regime. The reaction probability measurements indicate that the hydrolysis of N2O5 is significantly suppressed owing to the formation of crystalline SAM: The reaction probability on water-rich SAM (with higher relative humidity, or RH) is of the order of 10(exp -3) at 210 K and decreases by more than an order of magnitude for the acid-rich form (with lower RH). The hydrolysis rate of ClONO2 on water-rich SAM is even smaller, of the order of 10(exp -4) at 195 K. These reported values on crystalline SAM are much smaller than those on liquid solutions. No enhancement of these reactions is observed in the presence of HCl vapor at the stratospheric concentrations. In addition, Brunauer, Emmett, and Teller analysis of gas adsorption isotherms and photomicrography have been performed to characterize the surface roughness and porosities of the SAM substrate. The results suggest the possible formation of SAM in some regions of the middle- or low-latitude stratosphere and, consequently, much slower heterogeneous reactions on the frozen aerosols.

Zhang, Renyi; Leu, Ming-Taun; Keyser, Leon F.

1995-01-01

41

Contaminant Transport in the Highly Heterogeneous Sedimentary Formation at Canadian Forces Base Borden, Ontario, Canada  

NASA Astrophysics Data System (ADS)

Based on results of detailed geostatistical characterization of a sand quarry located two km from the Stanford-Waterloo site at Canadian Forces Base Borden, Ontario, Canada, and evaluation of material properties at this site, we show that the succession is highly heterogeneous with variance of log-conductivity as large as 17.9. The main goal of the present research is to identify key parameters that would impact solute plume transport, and especially tailing, through this formation. The identification, accomplished through modeling, is based on sensitivity analyses. The heterogeneity model adopted here is a special case of a general multi-indicator model, which has been extensively used in the past in stochastic modeling of plume transport and tailing in heterogeneous formations. The present model contains four types of randomly placed 3D oblate ellipsoidal inclusions (e.g. geological lenses) that represent different materials found at the site: gravel, lenticular sands, tabular sands, and clay. Inclusion sizes and volume fractions are determined through indicator geostatistical analysis. A constant hydraulic conductivity and linear sorption distribution coefficient are assigned to each type of inclusion for each simulation. Plume transport and tailing are quantified using break-through curves for a set of equally spaced control planes. Sensitivity analyses of the effect of inclusion sizes, volume fractions and properties on break-through curves are conducted to quantify contaminant tailing and to identify key parameters influencing the tailing. The preliminary results indicate that slow advection and diffusion through clay lenses are the main causes of the plume spreading and can produce plume tailing for several decades or longer.

Maghrebi, M.; Jankovic, I.; Allen-King, R. M.; Weissmann, G. S.; Rabideau, A. J.

2013-12-01

42

Comparison of Publically Available Methodologies for Development of Geologic Storage Estimates for Carbon Dioxide in Saline Formations  

NASA Astrophysics Data System (ADS)

High-level estimates of CO2 storage potential at the national, regional, and basin scale are required to assess the potential for carbon capture, utilization, and storage (CCUS) technologies to reduce CO2 emissions for application to saline formations. Both private and public entities worldwide rely on CO2 storage potential estimates for broad energy-related government policy and business decisions. High-level estimates of CO2 geologic storage potential, however, have a high degree of uncertainty because the assessments rely on simplifying assumptions due to the deficiency or absence of data from the subsurface associated with areas of potential storage in saline formations and the natural heterogeneity of geologic formations in general, resulting in undefined rock properties. As site characterization progresses to individual CO2 storage sites, additional site-specific data will likely be collected and analyzed that will allow for the refinement of high-level CO2 storage resource estimates and development of CO2 storage capacities. Until such detailed characterization can be documented, dependable high-level CO2 storage estimates are essential to ensure successful widespread deployment of CCUS technologies. Initiatives for assessing CO2 geologic storage potential have been conducted since 1993. Although dependable high-level CO2 storage estimates are essential to ensure successful deployment of CCUS technologies, it is difficult to assess the uncertainty of these estimates without knowing how the current methodologies targeted at high-level CO2 storage resource estimates for saline formations compare to one another. In this study, we compare high-level CO2 methodologies for development of geologic storage estimates for CO2 in saline formations to assess the uncertainty associated with various methodologies. The methodologies applied are listed as follows: (1) U.S. DOE Methodology: Development of Geologic Storage Potential for Carbon Dioxide at the National and Regional Scale, (2) Carbon Sequestration Leadership Forum: CO2 Storage Capacity Estimation: Methodology and Gaps, (3) U.S. Geologic Survey: A Probabilistic Assessment Methodology for the Evaluation of Geologic Carbon Dioxide Storage, (4) Szulczewski, M., MacMinn, C.W., Herzog, H.J., Juanes, R., 2012 Proc. Natl. Acad. Sci.: Lifetime of carbon capture and storage as a climate-change mitigation technology, and (5) Zhou, Q., Birkholzer, J.T., Tsang, C.-F., Rutqvist, J., 2008 Int. J. of Greenhouse Gas Control 2, 626-639: A method for quick assessment of CO2 storage capacity in closed and semi-closed saline formation. The methodologies are applied to formations throughout the United States.

Goodman, A.; Strazisar, B. R.; Guthrie, G. D.; Bromhal, G.

2012-12-01

43

Mesozoic marine tetrapod diversity: mass extinctions and temporal heterogeneity in geological megabiases affecting vertebrates.  

PubMed

The fossil record is our only direct means for evaluating shifts in biodiversity through Earth's history. However, analyses of fossil marine invertebrates have demonstrated that geological megabiases profoundly influence fossil preservation and discovery, obscuring true diversity signals. Comparable studies of vertebrate palaeodiversity patterns remain in their infancy. A new species-level dataset of Mesozoic marine tetrapod occurrences was compared with a proxy for temporal variation in the volume and facies diversity of fossiliferous rock (number of marine fossiliferous formations: FMF). A strong correlation between taxic diversity and FMF is present during the Cretaceous. Weak or no correlation of Jurassic data suggests a qualitatively different sampling regime resulting from five apparent peaks in Triassic-Jurassic diversity. These correspond to a small number of European formations that have been the subject of intensive collecting, and represent 'Lagerstätten effects'. Consideration of sampling biases allows re-evaluation of proposed mass extinction events. Marine tetrapod diversity declined during the Carnian or Norian. However, the proposed end-Triassic extinction event cannot be recognized with confidence. Some evidence supports an extinction event near the Jurassic/Cretaceous boundary, but the proposed end-Cenomanian extinction is probably an artefact of poor sampling. Marine tetrapod diversity underwent a long-term decline prior to the Cretaceous-Palaeogene extinction. PMID:19923126

Benson, Roger B J; Butler, Richard J; Lindgren, Johan; Smith, Adam S

2010-03-22

44

Mesozoic marine tetrapod diversity: mass extinctions and temporal heterogeneity in geological megabiases affecting vertebrates  

PubMed Central

The fossil record is our only direct means for evaluating shifts in biodiversity through Earth's history. However, analyses of fossil marine invertebrates have demonstrated that geological megabiases profoundly influence fossil preservation and discovery, obscuring true diversity signals. Comparable studies of vertebrate palaeodiversity patterns remain in their infancy. A new species-level dataset of Mesozoic marine tetrapod occurrences was compared with a proxy for temporal variation in the volume and facies diversity of fossiliferous rock (number of marine fossiliferous formations: FMF). A strong correlation between taxic diversity and FMF is present during the Cretaceous. Weak or no correlation of Jurassic data suggests a qualitatively different sampling regime resulting from five apparent peaks in Triassic–Jurassic diversity. These correspond to a small number of European formations that have been the subject of intensive collecting, and represent ‘Lagerstätten effects’. Consideration of sampling biases allows re-evaluation of proposed mass extinction events. Marine tetrapod diversity declined during the Carnian or Norian. However, the proposed end-Triassic extinction event cannot be recognized with confidence. Some evidence supports an extinction event near the Jurassic/Cretaceous boundary, but the proposed end-Cenomanian extinction is probably an artefact of poor sampling. Marine tetrapod diversity underwent a long-term decline prior to the Cretaceous–Palaeogene extinction.

Benson, Roger B. J.; Butler, Richard J.; Lindgren, Johan; Smith, Adam S.

2010-01-01

45

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

SciTech Connect

The objective of this project is to augment the National Reservoir Database (TORIS database), 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 resources that are producible at moderate cost. This objective will be achieved through detailed geological, geostatistical, and engineering characterization of typical Jurassic Smackover Formation hydrocarbon, and engineering 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 completion of Subtasks 1, 2, and 3 of this project. Work on Subtask 4 began in this quarter, and substantial additional work has been accomplished on Subtask 2. Subtask 1 included the survey and tabulation of available reservoir engineering and geological data. Subtask 2 comprises the geologic and engineering characterization of smackover reservoir lithofacies. Subtask 3 includes the geologic modeling of reservoir heterogeneities. Subtask 4 includes the development of reservoir exploitation methodologies for strategic infill drilling. 1 fig.

Mancini, E.A.

1990-01-01

46

A Formative Assessment of Geologic Time for High School Earth Science Students  

NSDL National Science Digital Library

Earth science courses typically include the concept of geological time. The authors of this study attempt to move past traditional assessment practices and develop a formative assessment of students' understanding of the construction of the geologic time scale and how it is interpreted. Through this approach students are challenged to conceptualize the geologic time scale by comparing it to a student-produced time scale for an older adult's life. This formative assessment allows the teacher to alter instruction based on students' feedback in order to maximize student understanding of geologic time.

2004-05-01

47

Statistical characterisation and stochastic parameterisation of sedimentary geological formations on their reaction capacity for sustainable groundwater quality management  

NASA Astrophysics Data System (ADS)

The fate of contaminants in groundwater aquifers is determined by the buffering capacity of those aquifers together with the composition of inflowing groundwater. A nationwide characterisation of the environmental geochemistry of the shallow subsurface (down to 30 m below surface) has been started in the Netherlands. This covers: 1. the reaction capacity of sediments as buffer for contamination, and 2. typical elemental composition of geological formations and the association between trace elements and major minerals. For this purpose, the Netherlands is subdivided into 27 so-called geotop regions each having a unique geological build-up of the shallow subsurface. Here, four types are recognised based on vertical hydrogeological build-up. The regions are statistically characterised on their geochemical composition using combinations of lithological class and geological formation as strata. The statistical data are subsequently coupled with a geological voxel model of the subsurface to stochastically parameterise the geological units on reaction capacity. This combined approach will be illustrated for the Dutch province Zeeland. Reaction capacity is considered as a series of geochemical characteristics that control acid/base condition, redox condition and sorption capacity. Five primary reaction capacity variables are characterised: 1. pyrite, 2. non-pyrite, reactive iron (oxides, siderite and glauconite), 3. clay fraction, 4. organic matter and 5. Ca-carbonate. Important reaction capacity variables that are determined by more than one solid compound are also deduced: 1. potential reduction capacity (PRC) by pyrite and organic matter, 2. cation-exchange capacity (CEC) by organic matter and clay content, 3. carbonate buffering upon pyrite oxidation (CPBO) by carbonate and pyrite. A statistical investigation of several hunderds of sediment analyses is performed that provides the geochemical properties of the sediments. Here, classification based on sedimentary facies may provide additional insight on spatial heterogeneity within lithological classes. A two-step stochastic algoritm is established for parameterisation of a geological voxel model. First, the cumulative frequency distribution (cfd) functions are calculated for the geochemical strata. Next, all voxels are classified into the geochemical strata and the cfd functions are used to put random reaction capacity variables into the geological voxel model. The result is a heterogeneous geochemical reaction capacity model of the subsurface having grid cells of 100x100x0.5 m. This model can be used in e.g. groundwater transport models or other instruments for groundwater quality management.

Griffioen, J.; Vermooten, S.; Keijzer, T.; Bakr, M.; Valstar, J.

2012-04-01

48

The digital geologic map of Wyoming in ARC/INFO format  

USGS Publications Warehouse

This geologic map was prepared as part of a study of digital methods and techniques as applied to complex geologic maps. The geologic map was digitized from the original scribe sheets used to prepare the published Geologic Map of Wyoming (Love and Christiansen, 1985). Consequently, the digital version is at 1:500,000 scale using the Lambert Conformal Conic map projection parameters of the State base map. Stable base contact prints of the scribe sheets were scanned on a Tektronix 4991 digital scanner. The scanner automatically converts the scanned image to an ASCII vector format. These vectors were transferred to a VAX minicomputer, where they were then loaded into ARC/INFO. Each vector and polygon was given attributes derived from the original 1985 geologic map. Descriptors: The Digital Geologic Map of Wyoming in ARC/INFO Format Open-File Report 94-0425

Green, G. N.; Drouillard, P. H.

1994-01-01

49

Capacity investigation of brine-bearing sands of the Fwwm formation for geologic sequestration of COâ  

Microsoft Academic Search

The capacity of fluvial brine-bearing formations to sequester COâ is investigated using numerical simulations of COâ injection and storage. Capacity is defined as the volume fraction of the subsurface available for COâ storage and is conceptualized as a product of factors that account for two-phase flow and transport processes, formation geometry, formation heterogeneity, and formation porosity. The space and time

Christine Doughty; Karsten Pruess; Sally M. Benson; Susan D. Hovorka; Paul R. Knox; Christopher T. Green

2001-01-01

50

Stochastic inversion of pneumatic cross-hole tests and barometric pressure fluctuations in heterogeneous unsaturated formations  

NASA Astrophysics Data System (ADS)

The distributions of permeability and porosity are key factors that control airflow and gas phase transport in unsaturated formations. To understand the behavior of flow and transport in such formations, characterization procedure is a typical approach that has been widely applied to laboratories and fields. As is recognized by most investigations, this approach relies on accurate measurements, and more importantly, an adequate tool to interpret those measurements from experiments. This study presents a pneumatic inverse model that is capable to estimate the distributions of permeability ( k) and porosity ( ?) with high resolution in heterogeneous unsaturated formations. Based on the concept of sequential successive linear estimator (SSLE), the developed model accounts for compressibility and density of air and estimates the geologic parameters using air pressure measurements from sequential cross-hole pneumatic pumping or injection tests. Four synthetic examples, including a one-dimensional well-posed, a horizontally two-dimensional, and two three-dimensional problems, are used to evaluate the developed model in estimating the distributions of permeability and porosity in unsaturated formations. Results of the numerical experiments are promising. The developed pneumatic inverse model can reconstruct the property (i.e., permeability and porosity) fields if the well-defined conditions are met. With a relatively small number of available measurements, the proposed model can accurately capture the patterns and the magnitudes of estimated properties for unsaturated formations. Results of two complex three-dimensional examples show that the proposed model can map the fracture connectivity using a small number of subsurface pressure measurements and estimate k and ? in shallow soil layers using spatial variations of barometric pressure.

Ni, Chuen-Fa; Yeh, Tian-Chyi Jim

2008-12-01

51

Stochastic Inversion of Pneumatic Cross-hole Tests and Barometric Pressure Fluctuations in Heterogeneous Unsaturated Formations  

NASA Astrophysics Data System (ADS)

The distributions of permeability and porosity are key factors that control airflow and gas phase transport in unsaturated formations. To understand the behavior of flow and transport in such formations, characterization procedure is a typical approach that has been widely applied to laboratories and fields. As is recognized by most investigations, this approach relies on accurate measurements, and more importantly, an adequate tool to interpret those measurements from experiments. This study presents a pneumatic inverse model that is capable to estimate the distributions of permeability (Ka) and porosity (n) with high resolution in heterogeneous unsaturated formations. Based on the concept of sequential successive linear estimator (SSLE), the developed model accounts for compressibility and density of air and estimates the geologic parameters using air pressure measurements from sequential cross-hole pneumatic pumping or injection tests. Four synthetic examples, including a one-dimensional well-posed, a horizontally two-dimensional, and two three-dimensional problems, are used to evaluate the developed model in estimating the distributions of permeability and porosity in unsaturated formations. Results of the numerical experiments are promising. The developed pneumatic inverse model can reconstruct the property (i.e., permeability and porosity) fields if the well-defined conditions are met. With relatively small number of available measurements, the proposed model can accurately capture the patterns and the magnitudes of estimated properties for unsaturated formations. Results of two complex three-dimensional examples show that the proposed model can map the fracture connectivity using relatively small number of subsurface pressure measurements and estimate and in shallow soil layers using spatial variations of barometric pressure.

Ni, C.-F.; Yeh, T.-C. J.; Hsu, H.-H.; Deng, Y.-T.

2009-04-01

52

Investigating of the effects of target heterogeneities on terrestrial crater formation  

Microsoft Academic Search

The shape of terrestrial impact structures such as the Chesapeake or Ries crater indicate how important pre- existing target heterogeneities are even for fairly large impact structures. Both these craters possess an inverted sombrero structure as a result of a weaker sedimentary surface layer overlying a stronger crystalline basement. But beyond such horizontal layering, closer analyzes of the subsurface geology

O. S. Barnouin-Jha; D. A. Crawford; M. J. Cintala; K. Wada

2007-01-01

53

Field geologist's training guide: An introduction to oilfield geology, mud logging and formation evaluation  

SciTech Connect

This handbook presents a basic overview of and introduction to petroleum geology, oilfield terminolgy and formation evaluation procedures. The chapters introduce many key concepts. Petroleum geology, oilfield fluids, rig types and their components, wellsite equipment and the environment in which field geologists work are presented in detail. Drilling and completing a well and formation evaluation procedures are examined from the logging geologist's perspective. The appendices contain a wide range of information such as general abbreviations, glossary, and bit classification.

Whittaker, A.

1985-01-01

54

Methods and apparatus for exploring geological formations utilizing strontium measurements  

US Patent & Trademark Office Database

Formation strontium concentrations are measured utilizing a borehole tool. A log may be provided as a function of depth or distance. The strontium measurements can be correlated chronostratigraphically to provide a depth to absolute time correlation. Measures of strontium made in the borehole can be correlated to information obtained via seismic exploration of the formation traversed by the borehole. Measures of strontium in multiple boreholes of a single formation can be correlated.

2009-12-22

55

River-aquifer interactions, geologic heterogeneity, and low-flow management  

USGS Publications Warehouse

Low river flows are commonly controlled by river-aquifer exchange, the magnitude of which is governed by hydraulic properties of both aquifer and aquitard materials beneath the river. Low flows are often important ecologically. Numerical simulations were used to assess how textural heterogeneity of an alluvial system influences river seepage and low flows. The Cosumnes River in California was used as a test case. Declining fall flows in the Cosumnes River have threatened Chinook salmon runs. A ground water-surface water model for the lower river basin was developed, which incorporates detailed geostatistical simulations of aquifer heterogeneity. Six different realizations of heterogeneity and a homogenous model were run for a 3-year period. Net annual seepage from the river was found to be similar among the models. However, spatial distribution of seepage along the channel, water table configuration and the level of local connection, and disconnection between the river and aquifer showed strong variations among the different heterogeneous models. Most importantly, the heterogeneous models suggest that river seepage losses can be reduced by local reconnections, even when the regional water table remains well below the riverbed. The percentage of river channel responsible for 50% of total river seepage ranged from 10% to 26% in the heterogeneous models as opposed to 23% in the homogeneous model. Differences in seepage between the models resulted in up to 13 d difference in the number of days the river was open for salmon migration during the critical fall months in one given year. Copyright ?? 2006 The Author(s).

Fleckenstein, J. H.; Niswonger, R. G.; Fogg, G. E.

2006-01-01

56

Modeling CO2 distribution in a heterogeneous sandstone reservoir: the Johansen Formation, northern North Sea  

NASA Astrophysics Data System (ADS)

The last few years there has been broad attention towards finding permanent storage options for CO2. The Norwegian continental margin holds great potential for storage in saline aquifers. Common for many of these reservoir candidates, however, is that geological data are sparse relative to thoroughly mapped hydrocarbon reservoirs in the region. Scenario modeling provides a method for estimating reservoir performances for potential CO2 storage sites and for testing injection strategies. This approach is particularly useful in the evaluation of uncertainties related to reservoir properties and geometry. In this study we have tested the effect of geological heterogeneities in the Johansen Formation, which is a laterally extensive sandstone and saline aquifer at burial depths of 2 - 4 km, proposed as a suitable candidate for CO2 storage by Norwegian authorities. The central parts of the Johansen Formation are underlying the operating hydrocarbon field Troll. In order not to interfere with ongoing gas production, a potential CO2 injection well should be located at a safe distance from the gas reservoir, which consequently implies areas presently without well control. From 3D seismic data, prediction of spatial extent of sandstone is possible to a certain degree, whereas intra-reservoir flow baffles such as draping mudstone beds and calcite cemented layers are below seismic resolution. The number and lateral extent of flow baffles, as well as porosity- and permeability distributions are dependent of sedimentary facies and diagenesis. The interpretation of depositional environment and burial history is thus of crucial importance. A suite of scenario models was established for a potential injection area south of the Troll field. The model grids where made in Petrel based on our interpretations of seismic data, wire line logs, core and cuttings samples. Using Eclipse 300 the distribution of CO2 is modeled for different geological settings; with and without the presence of pervasive low permeability draping mudstone layers, and with varying lateral extent of potential calcite cemented layers in 8 to 15 intra-reservoir depth levels. The modeled area covers 10 x 15.8 km, with a thickness of 110 m at the injection point. Simulations were run with an injection phase of 30 years plus 100 years of migration. The presence of meso-scale flow baffles causes a reduction in vertical permeability in addition to the facies related variation on the micro-scale. Scenarios including potential flow baffles as separate layers in the model grids were compared to scenarios in which the effect of flow baffles were included using harmonic mean average of vertical permeability. The subsequent differences in CO2 distribution are important in estimating the contact area between the plume front and reservoir brine. A heterogeneous reservoir with internal flow baffles is not necessarily a disadvantage as long as sufficient injectivity is maintained within individual sandstone bodies. In each scenario we aim to adapt a suitable injection strategy with respect to utilizing local effects such as the delimitation of gravitational flow, in order to increase reservoir sweep and maximize the effect of trapping mechanisms (i.e. residual, stratigraphic, mineral and dissolution).

Sundal, Anja; Miri, Rohaldin; Petter Nystuen, Johan; Dypvik, Henning; Aagaard, Per

2013-04-01

57

Fundamental Study on the Dynamics of Heterogeneity-Enhanced CO2 Gas Evolution in the Shallow Subsurface During Possible Leakage from Deep Geologic Storage Sites  

NASA Astrophysics Data System (ADS)

A concern for geologic carbon sequestration is the potential for CO2 stored in deep geologic formations to leak upward into shallow freshwater aquifers where it can have potentially detrimental impacts to the environment and human health. Understanding the mechanisms of CO2 exsolution, migration and accumulation (collectively referred to as 'gas evolution') in the shallow subsurface is critical to predict and mitigate the environmental impacts. During leakage, CO2 can move either as free-phase or as a dissolved component of formation brine. CO2 dissolved in brine may travel upward into shallow freshwater systems, and the gas may be released from solution. In the shallow aquifer, the exsolved gas may accumulate near interfaces between soil types, and/or create flow paths that allow the gas to escape through the vadose zone to the atmosphere. The process of gas evolution in the shallow subsurface is controlled by various factors, including temperature, dissolved CO2 concentration, water pressure, background water flow rate, and geologic heterogeneity. However, the conditions under which heterogeneity controls gas phase evolution have not yet been precisely defined and can therefore not yet be incorporated into models used for environmental risk assessment. The primary goal of this study is to conduct controlled laboratory experiments to help fill this knowledge gap. With this as a goal, a series of intermediate-scale laboratory experiments were conducted to observe CO2 gas evolution in porous media at multiple scales. Deionized water was saturated with dissolved CO2 gas under a specified pressure (the saturation pressure) before being injected at a constant volumetric flow rate into the bottom of a 1.7 meter-tall by 5.7 centimeter-diameter column or a 2.4 meter-tall by 40 centimeter-wide column that were both filled with sand in various heterogeneous packing configurations. Both test systems were initially saturated with fresh water and instrumented with soil moisture sensors to monitor the evolution of gas phase through time by measuring the average water content in small sampling volumes of soil. Tensiometers allowed for observation of water pressure through space and time in the test systems, and a computer-interfaced electronic scale continuously monitored the outflow of water from the top of the two test columns. Several packing configurations with five different types of sands were used in order to test the effects of various pore size contrasts and interface shapes on the evolution of the gas phase near soil texture transitions in the heterogeneous packings. Results indicate that: (1) heterogeneity affects gas phase evolution patterns within a predictable range of conditions quantified by the newly introduced term 'oversaturation,' (2) soil transition interfaces where less permeable material overlies more permeable material have a much more pronounced effect on gas evolution than interfaces with opposite orientations, and (3) anticlines (or stratigraphic traps) cause significantly greater gas accumulation than horizontal interfaces. Further work is underway to apply these findings to more realistic, two-dimensional scenarios, and to assess how well existing numerical models can capture these processes.

Plampin, M. R.; Lassen, R. N.; Sakaki, T.; Pawar, R.; Jensen, K.; Illangasekare, T. H.

2013-12-01

58

Geology  

NSDL National Science Digital Library

With three levels to choose from on each page - beginner, intermediate or advanced - this site provides information on the many different kinds of geological exploration. The elements that make up minerals and the different ways minerals are developed, The special characteristics of minerals, like physical properties, is explained. Earths tectonic plates, the reasons they move, and the effects of the shifting are also given. Also featured is fossils and how they are developed and are found, as well as why fossils are useful tools for scientists.

Bergman, Jennifer

2009-08-03

59

Transport in Heterogeneous Porous Formations: Spatial Moments, Ergodicity, and Effective Dispersion  

Microsoft Academic Search

Transport of inert solutes in natural porous formations is dominated by convection and by the large-scale heterogeneity of permeability. A solute body inserted in the formation spreads because of the variation of velocity among and along the stream tubes which cross the plume. With neglect of the slow effect of pore-scale dispersion the solute particles preserve their initial concentration, but

Gedeon Dagan

1990-01-01

60

Geology of the Grand Canyon: Interpreting its rock layers and formation  

NSDL National Science Digital Library

In this culminating activity, students will be assessed on what they have learned during the Geology unit of their Earth Science class. After conducting classroom and field studies on geology students will utilize this knowledge to interpret the rock layers and formation of the Grand Canyon. Outside of class students will read/review a website and complete a study guide to be reviewed by the teacher to assess students' learning. Following teacher review of study guides, the next class period(s) will be a discussion and questioning session(s) on the formation of the Grand Canyon.

61

Thermal state and complex geology of a heterogeneous salty crust of Jupiter's satellite, Europa  

NASA Astrophysics Data System (ADS)

The complex geology of Europa is evidenced by many tectonic and cryomagmatic resurfacing structures, some of which are "painted" into a more visible expression by exogenic alteration processes acting on the principal endogenic cryopetrology. The surface materials emplaced and affected by this activity are mainly composed of water ice in some areas, but in other places there are other minerals involved. Non-ice minerals are visually recognized by their low albedo and reddish color either when first emplaced or, more likely, after alteration by Europan weathering processes, especially sublimation and alteration by ionizing radiation. While red chromophoric material could be due to endogenic production of solid sulfur allotropes or other compounds, most likely the red substance is an impurity produced by radiation alteration of hydrated sulfate salts or sulphuric acid of mainly internal origin. If the non-ice red materials or their precursors have a source in the satellite interior, and if they are not merely trace contaminants, then they can play an important role in the evolution of the icy crust, including structural differentiation and the internal dynamics. Here we assume that these substances are major components of Europa's cryo/hydrosphere, as some models have predicted they should be. If this is an accurate assumption, then these substances should not be neglected in physical, chemical, and biological models of Europa, even if major uncertainties remain as to the exact identity, abundance, and distribution of the non-ice materials. The physical chemical properties of the ice-associated materials will contribute to the physical state of the crust today and in the geological past. In order to model the influence of them on the thermal state and the geology, we have determined the thermal properties of the hydrated salts. Our new lab data reveal very low thermal conductivities for hydrated salts compared to water ice. Lower conductivities of salty ice would produce steeper thermal gradients than in pure ice. If there are salt-rich layers inside the crust, forming salt beds over the seafloor or a briny eutectic crust, for instance, the high thermal gradients may promote endogenic geological activity. On the seafloor, bedded salt accumulations may exhibit high thermochemical gradients. Metamorphic and magmatic processes and possible niches for thermophilic life at shallow suboceanic depths result from the calculated thermal profiles, even if the ocean is very cold.

Prieto-Ballesteros, Olga; Kargel, Jeffrey S.

2005-01-01

62

Thermal state and complex geology of a heterogeneous salty crust of Jupiter's satellite, Europa  

USGS Publications Warehouse

The complex geology of Europa is evidenced by many tectonic and cryomagmatic resurfacing structures, some of which are "painted" into a more visible expression by exogenic alteration processes acting on the principal endogenic cryopetrology. The surface materials emplaced and affected by this activity are mainly composed of water ice in some areas, but in other places there are other minerals involved. Non-ice minerals are visually recognized by their low albedo and reddish color either when first emplaced or, more likely, after alteration by Europan weathering processes, especially sublimation and alteration by ionizing radiation. While red chromophoric material could be due to endogenic production of solid sulfur allotropes or other compounds, most likely the red substance is an impurity produced by radiation alteration of hydrated sulfate salts or sulphuric acid of mainly internal origin. If the non-ice red materials or their precursors have a source in the satellite interior, and if they are not merely trace contaminants, then they can play an important role in the evolution of the icy crust, including structural differentiation and the internal dynamics. Here we assume that these substances are major components of Europa's cryo/hydrosphere, as some models have predicted they should be. If this is an accurate assumption, then these substances should not be neglected in physical, chemical, and biological models of Europa, even if major uncertainties remain as to the exact identity, abundance, and distribution of the non-ice materials. The physical chemical properties of the ice-associated materials will contribute to the physical state of the crust today and in the geological past. In order to model the influence of them on the thermal state and the geology, we have determined the thermal properties of the hydrated salts. Our new lab data reveal very low thermal conductivities for hydrated salts compared to water ice. Lower conductivities of salty ice would produce steeper thermal gradients than in pure ice. If there are salt-rich layers inside the crust, forming salt beds over the seafloor or a briny eutectic crust, for instance, the high thermal gradients may promote endogenic geological activity. On the seafloor, bedded salt accumulations may exhibit high thermochemical gradients. Metamorphic and magmatic processes and possible niches for thermophilic life at shallow suboceanic depths result from the calculated thermal profiles, even if the ocean is very cold. ?? 2004 Elsevier Inc. All rights reserved.

Prieto-Ballesteros, O.; Kargel, J. S.

2005-01-01

63

Geology, compositional heterogeneities, and geochemical origin of the Yacheng gas field, Qiongdongnan Basin, South China Sea  

Microsoft Academic Search

The Yacheng gas field is located in the footwall of the No. 1 fault, the boundary fault between the Yinggehai and Qiongdongnan basins. All strata are normally pressured in the gas field except for the Meishan Formation. The Meishan Formation is overpressured near the No. 1 fault in the gas field and in the adjacent Yinggehai Basin. An obvious thermal

F. Hao; S. Li; Y. Sun; Q. Zhang

1998-01-01

64

Comparison of methods for geologic storage of carbon dioxide in saline formations  

SciTech Connect

Preliminary estimates of CO{sub 2} storage potential in geologic formations provide critical information related to Carbon Capture, Utilization, and Storage (CCUS) technologies to mitigate CO{sub 2} emissions. Currently multiple methods to estimate CO{sub 2} storage and multiple storage estimates for saline formations have been published, leading to potential uncertainty when comparing estimates from different studies. In this work, carbon dioxide storage estimates are compared by applying several commonly used methods to general saline formation data sets to assess the impact that the choice of method has on the results. Specifically, six CO{sub 2} storage methods were applied to thirteen saline formation data sets which were based on formations across the United States with adaptations to provide the geologic inputs required by each method. Methods applied include those by (1) international efforts – the Carbon Sequestration Leadership Forum (Bachu et al., 2007); (2) United States government agencies – U.S. Department of Energy – National Energy Technology Laboratory (US-DOE-NETL, 2012) and United States Geological Survey (Brennan et al., 2010); and (3) the peer-reviewed scientific community – Szulczewski et al. (2012) and Zhou et al. (2008). A statistical analysis of the estimates generated by multiple methods revealed that assessments of CO{sub 2} storage potential made at the prospective level were often statistically indistinguishable from each other, implying that the differences in methodologies are small with respect to the uncertainties in the geologic properties of storage rock in the absence of detailed site-specific characterization.

Goodman, Angela L. [U.S. DOE; Bromhal, Grant S. [U.S. DOE; Strazisar, Brian [U.S. DOE; Rodosta, Traci D. [U.S. DOE; Guthrie, William J. [U.S. DOE; Allen, Douglas E. [ORISE; Guthrie, George D. [U.S. DOE

2013-01-01

65

Numerical study on the impacts of heterogeneous reactions on ozone formation in the Beijing urban area  

NASA Astrophysics Data System (ADS)

The air quality model CMAQ-MADRID (Community Multiscale Air Quality-Model of Aerosol Dynamics, Reaction, Ionization and Dissolution) was employed to simulate summer O3 formation in Beijing China, in order to explore the impacts of four heterogeneous reactions on O3 formation in an urban area. The results showed that the impacts were obvious and exhibited the characteristics of a typical response of a VOC-limited regime in the urban area. For the four heterogeneous reactions considered, the NO2 and HO2 heterogeneous reactions have the most severe impacts on O3 formation. During the O3 formation period, the NO2 heterogeneous reaction increased new radical creation by 30%, raising the atmospheric activity as more NO?NO2 conversion occurred, thus causing the O3 to rise. The increase of O3 peak concentration reached a maximum value of 67 ppb in the urban area. In the morning hours, high NO titration reduced the effect of the photolysis of HONO, which was produced heterogeneously at night in the surface layer. The NO2 heterogeneous reaction in the daytime is likely one of the major reasons causing the O3 increase in the Beijing urban area. The HO2 heterogeneous reaction accelerated radical termination, resulting in a decrease of the radical concentration by 44% at the most. O3 peak concentration decreased by a maximum amount of 24 ppb in the urban area. The simulation results were improved when the heterogeneous reactions were included, with the O3 and HONO model results close to the observations.

Xu, Jun; Zhang, Yuanhang; Wang, Wei

2006-12-01

66

Outcrop analogs for mdoeling heterogeneous restricted platform reservoirs: Grayburg Formation (Guadalupian) of the Guadalupe Mountains and subsurface Permian basin  

SciTech Connect

Restricted platform deposits of the Permian basin have produced more than 10 billion bbl of oil, but because of complex internal facies architecture ultimate recovery rarely exceeds 30% of original oil in place. The first step in locating and exploiting the substantial unrecovered hydrocarbons in this play is developing improved development-oriented (as opposed to exploration-oriented) models of facies/permeability heterogeneity. Quantitative geologic/engineering analysis of outcrops analogous to reservoirs allows characterization of styles of variability and three-dimensional geometry at interwell, reservoir, and play scales beyond that possible using limited subsurface data. The Guadalupian Grayburg Formation is exposed in the northern Guadalupe Mountains less than 60 mi west of reservoir trends on the Northwest Shelf and Central Basin platform. These outcrops provide a test for the development of outcrop-based reservoir heterogeneity models. A 10-mi dip section of the mixed siliciclastic/carbonate Grayburg of the Guadalupes exhibits inner ramp (4-mi dip width), ramp-crest ooid shoal/tidal flat (4 mi dip width), and outer ramp fusulinid-peloid (2-mi dip width) facies tracts. Maximum facies heterogeneity occurs in upward-shallowing cycles of the ramp crest where porous ooid shoals pass laterally into tight peloid packstones in less than 1,000 ft. Siliciclastic sands are intercalated in all facies tracts typically as sheets. However, in the ramp crest they also occur as 15-ft-thick by 50-ft-wide channels dissecting ooid shoals. Grayburg reservoirs on the eastern side of the Central Basin platform contain facies tracts and styles of heterogeneity analogous to the outcrop. Production trends from these reservoirs similarly illustrate most variability in grainstone shoal complexes.

Kerans, C.; Nance, H.S.; Bebout, D.G. (Univ. of Texas, Austin (USA))

1990-05-01

67

Regional Geology of the McMurray Formation, Athabasca Bitumen Accumulation Region, Northeastern Alberta: A Synthesis  

Microsoft Academic Search

This study focused on the comprehension of deposition environments and regional geological history of the McMurray Formation from core-derived (90) information with the aim of improving prediction of reservoir quality trends within oil sands leases of the Athabasca Bitumen Accumulation Region. Four main lithofacies associations (LA) have been recognised. These are: fluvial channels (LA I); estuarine channels (LA II); tidal

Mark Caplan

68

Method and device with adjustable focusing for measuring the electric resistivity of geological formations  

SciTech Connect

The method of the invention comprises determining the variation of the electric potential on both sides of a central electrode in a borehole, detecting the two levels of the borehole where the potential gradient is zero, and measuring the electric resistivity of the geological formation between these two levels.

Desbrandes, R.

1983-10-25

69

Selection of areas for testing in the Eleana formation: Paleozoic geology of western Yucca Flat  

Microsoft Academic Search

The Paleozoic geology of NTS is reviewed to select an area for underground nuclear testing in shale. Constraints on possible areas, dictated by test program requirements and economics, are areas with topographic slope less than 5°, depths to working point less than 3000 ft., and working points above the water table. The rock formation selected is Unit J (argillite) of

Sweeney

1984-01-01

70

Petroleum geology of Woodbine Formation, Freestone County, Texas  

SciTech Connect

The Upper Cretaceous Woodbine Formation consists of clastics deposited in various southwestward-prograding environments on the margin of the subsiding East Texas basin. Depositional environments range from fluvial (in the north) to deltaic and a shelf strandplain (in the southwest). The Woodbine unconformably overlies the Lower Cretaceous Washita Group except in the basin axis and south of the Angelina-Caldwell flexure where deposition may have been continuous. Transgression by Eagle Ford seas closed the Woodbine deposition. Structural features in Freestone County include the East Texas basin, the Sabine uplift, the Mexia-Talco fault zone, and the East Texas salt province. Isopach thicknesses of the Woodbine range from 375 ft in the west to more than 900 ft in the east (basinward). Thickening on the downthrown side of the Mexia-Talco faults indicates syndepositional faulting, related to allochthonous rocks sliding over the Jurassic Louann Salt. Structural accumulations of petroleum have been discovered against faults and salt domes, but stratigraphic pinch-outs of the Woodbine's discontinuous lenticular sand bodies remain as excellent exploration opportunities.

Carden, M.

1986-05-01

71

Reservoir heterogeneity at West 76 field: An opportunity for increased oil recovery by geologically targeted infill drilling  

SciTech Connect

West 76 is a typical field of the Eocene Jackson-Yegua Barrier/Strandplain sandstone play in south Texas. Located in northwest Duval County, the field has produced 4.6 million barrels (MMbbl) as of 1988 and has an estimated 6 MMbbl of remaining mobile oil. The Jackson-Yegua play, which includes nearly 300 fields, has produced 624 MMbbl (as of 1988) and has estimated remaining mobile oil in excess of 1 billion barrels (Bbbl). Production at West 76 is from the Cole Sands of the uppermost Jackson Group at depths of 1,300 to 1,400 ft. The trapping mechanism is principally stratigraphic, but small normal faults influence production trends. Reservoir geometry is highly complex with numerous internal permeability barriers. The reservoir section was constructed by a progradational and overlying retrogradational barrier beach system that deposited discontinuous strike-oriented beach ridges, a strike-oriented tidal channel unit, and sand-poor lagoonal facies. Production trends mirror the strike-aligned beach-ridge and tidal-channel facies but also bear a minor dip-oriented component associated with the washover sand facies. Infill wells that produce from beach-ridge facies at rates an order of magnitude higher than existing, neighboring wells reflect the significant reservoir heterogeneity and highlight the considerable potential for untapped reservoir compartments. Identification of these compartments from detailed characterization of the reservoir provides targets for infill drilling and, ultimately, increased oil recovery. The geologic heterogeneity at West 76 has application to the entire Jackson-Yeuga Barrier/Strandplain sandstone play and increased recovery of the estimated 1 Bbbl of remaining mobile oil.

Hamilton, D.S. (Univ. of Texas, Austin (United States))

1991-03-01

72

Modeling Heterogeneous CINO2 Formation, Chloride Availability, and Chlorine Cycling in Southeast Texas  

EPA Science Inventory

Nitryl chloride (ClNO2) mixing ratios above 1 ppbv have been measured off the coast of Southeast Texas. ClNO2 formation, the result of heterogeneous N205 uptake on chloride-containing aerosols, has a significant impact on oxidant form...

73

Simulation of Dispersion in Heterogeneous Porous Formations: Statistics, First-Order Theories, Convergence of Computations  

Microsoft Academic Search

This paper discusses the results of numerical analysis of dispersion of passive solutes in two-dimensional heterogeneous porous formations. Statistics of flow and transport variables, the accuracy and the role of approximations implicit in existing first-order theories, and the convergence of computational results are investigated. The results suggest that quite different rates of convergence with Monte Carlo runs hold for different

Alberto Bellin; Paolo Salandin; Andrea Rinaldo

1992-01-01

74

The digital geologic map of Colorado in ARC/INFO format  

USGS Publications Warehouse

This geologic map was prepared as a part of a study of digital methods and techniques as applied to complex geologic maps. The geologic map was digitized from the original scribe sheets used to prepare the published Geologic Map of Colorado (Tweto 1979). Consequently the digital version is at 1:500,000 scale using the Lambert Conformal Conic map projection parameters of the state base map. Stable base contact prints of the scribe sheets were scanned on a Tektronix 4991 digital scanner. The scanner automatically converts the scanned image to an ASCII vector format. These vectors were transferred to a VAX minicomputer, where they were then loaded into ARC/INFO. Each vector and polygon was given attributes derived from the original 1979 geologic map. This database was developed on a MicroVAX computer system using VAX V 5.4 nd ARC/INFO 5.0 software. UPDATE: April 1995, The update was done solely for the purpose of adding the abilitly to plot to an HP650c plotter. Two new ARC/INFO plot AMLs along with a lineset and shadeset for the HP650C design jet printer have been included. These new files are COLORADO.650, INDEX.650, TWETOLIN.E00 and TWETOSHD.E00. These files were created on a UNIX platform with ARC/INFO 6.1.2. Updated versions of INDEX.E00, CONTACT.E00, LINE.E00, DECO.E00 and BORDER.E00 files that included the newly defined HP650c items are also included. * Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Descriptors: The Digital Geologic Map of Colorado in ARC/INFO Format Open-File Report 92-050

Green, Gregory N.

1992-01-01

75

The digital geologic map of Colorado in ARC/INFO format, Part A. Documentation  

USGS Publications Warehouse

This geologic map was prepared as a part of a study of digital methods and techniques as applied to complex geologic maps. The geologic map was digitized from the original scribe sheets used to prepare the published Geologic Map of Colorado (Tweto 1979). Consequently the digital version is at 1:500,000 scale using the Lambert Conformal Conic map projection parameters of the state base map. Stable base contact prints of the scribe sheets were scanned on a Tektronix 4991 digital scanner. The scanner automatically converts the scanned image to an ASCII vector format. These vectors were transferred to a VAX minicomputer, where they were then loaded into ARC/INFO. Each vector and polygon was given attributes derived from the original 1979 geologic map. This database was developed on a MicroVAX computer system using VAX V 5.4 nd ARC/INFO 5.0 software. UPDATE: April 1995, The update was done solely for the purpose of adding the abilitly to plot to an HP650c plotter. Two new ARC/INFO plot AMLs along with a lineset and shadeset for the HP650C design jet printer have been included. These new files are COLORADO.650, INDEX.650, TWETOLIN.E00 and TWETOSHD.E00. These files were created on a UNIX platform with ARC/INFO 6.1.2. Updated versions of INDEX.E00, CONTACT.E00, LINE.E00, DECO.E00 and BORDER.E00 files that included the newly defined HP650c items are also included. * Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Descriptors: The Digital Geologic Map of Colorado in ARC/INFO Format Open-File Report 92-050

Green, Gregory N.

1992-01-01

76

Sedimentological and Petrophysical Heterogeneity of Glaciogenic Paleovalley, Late Ordovician Sarah Formation, Central Saudi Arabia  

NASA Astrophysics Data System (ADS)

The Late Ordovician Sarah Formation deposited in glaciogenic environment, mainly dominated by braided river outwash system. Compared to the subsurface, the Sarah formation is considered as important tight gas sandstone reservoir at southern and northern parts of Saudi Arabia. Ten outcrops from Al-Ilb paleochannel were studied in detail to identify the heterogeneity in terms of the types and distribution of facies and related petrophysical properties. The Sarah Formation shows highly heterogeneous behavior at all scales. The main facies observed at Al-Ilb paleovalley are 64% trough-cross bedded sandstone, 23% horizontally stratified sandstone facies, and 2% massive conglomerates are observed at the proximal, medial and distal parts of the paleovalley. The remaining facies are trough-cross bedded sandstone facies that is laterally changes to horizontally stratified sandstone facies and in some cases to planner cross-bedded sandstone facies. The petrophysical analysis revealed good quality of porosity present in all parts of paleovalley. On the other hand the permeability values are high and ranging between 53mD to 5D. The descriptive statistics clearly indicate the normal distribution of porosity values for proximal, medial and distal parts of paleovalley and can be described as homogeneous. For permeability the distribution is heterogeneous as it is log-normally distributed. The scatter plots of porosity versus horizontal and vertical permeability shows very poor correlation for each part of paleochannel. This heterogeneity is attributed to depositional and post-depositional viabilities. These variables are grain size and shape distribution, sorting, packing, distribution of matrix and cementing material, and the presence of clays like kaolinite, smectite, and palygorskite. These observations further indicate that Sarah Formation is affected by shallow burial conditions during diagenesis. However, Sarah Formation shows highly heterogeneous behavior at outcrop scale that might be unpredictable and challenging in the subsurface.

Razzaq, Waseem; Abdullatif, Osman; Sahin, Ali; Hariri, Mustafa

2014-05-01

77

Experiences with the Application of Services Oriented Approaches to the Federation of Heterogeneous Geologic Data Resources  

NASA Astrophysics Data System (ADS)

The federation of databases is not a new endeavor. Great strides have been made e.g. in the health and astrophysics communities. Reviews of those successes indicate that they have been able to leverage off key cross-community core concepts. In its simplest implementation, a federation of databases with identical base schemas that can be extended to address individual efforts, is relatively easy to accomplish. Efforts of groups like the Open Geospatial Consortium have shown methods to geospatially relate data between different sources. We present here a summary of CHRONOS's (http://www.chronos.org) experience with highly heterogeneous data. Our experience with the federation of very diverse databases shows that the wide variety of encoding options for items like locality, time scale, taxon ID, and other key parameters makes it difficult to effectively join data across them. However, the response to this is not to develop one large, monolithic database, which will suffer growth pains due to social, national, and operational issues, but rather to systematically develop the architecture that will enable cross-resource (database, repository, tool, interface) interaction. CHRONOS has accomplished the major hurdle of federating small IT database efforts with service-oriented and XML-based approaches. The application of easy-to-use procedures that allow groups of all sizes to implement and experiment with searches across various databases and to use externally created tools is vital. We are sharing with the geoinformatics community the difficulties with application frameworks, user authentication, standards compliance, and data storage encountered in setting up web sites and portals for various science initiatives (e.g., ANDRILL, EARTHTIME). The ability to incorporate CHRONOS data, services, and tools into the existing framework of a group is crucial to the development of a model that supports and extends the vitality of the small- to medium-sized research effort that is essential for a vibrant scientific community. This presentation will directly address issues of portal development related to JSR-168 and other portal API's as well as issues related to both federated and local directory-based authentication. The application of service-oriented architecture in connection with ReST-based approaches is vital to facilitate service use by experienced and less experienced information technology groups. Application of these services with XML- based schemas allows for the connection to third party tools such a GIS-based tools and software designed to perform a specific scientific analysis. The connection of all these capabilities into a combined framework based on the standard XHTML Document object model and CSS 2.0 standards used in traditional web development will be demonstrated. CHRONOS also utilizes newer client techniques such as AJAX and cross- domain scripting along with traditional server-side database, application, and web servers. The combination of the various components of this architecture creates an environment based on open and free standards that allows for the discovery, retrieval, and integration of tools and data.

Cervato, C.; Fils, D.; Bohling, G.; Diver, P.; Greer, D.; Reed, J.; Tang, X.

2006-12-01

78

Estimation of Geologic Storage Capacity of Carbon Dioxide in the Bukpyeong Basin, Korea Using Integrated Three-Dimensional Geologic Formation Modeling and Thermo-Hydrological Numerical Modeling  

NASA Astrophysics Data System (ADS)

A conventional method, which was suggested by NETL (2007), has been widely used for estimating the geologic storage capacity of carbon dioxide in sedimentary basins. Because of its simple procedure, it has been straightforwardly applied to even spatially very complicate sedimentary basins. Thus, the results from the conventional method are often not accurate and reliable because it can not consider spatial distributions of fluid conditions and carbon dioxide properties, which are not uniform but variable within sedimentary basins. To overcome this limit of the conventional method, a new method, which can consider such spatially variable distributions of fluid conditions and carbon dioxide properties within sedimentary basins, is suggested and applied in this study. In this new method, a three-dimensional geologic formation model of a target sedimentary basin is first established and discretized into volume elements. The fluid conditions (i.e., pressure, temperature, and salt concentration) within each element are then obtained by performing thermo-hydrological numerical modeling. The carbon dioxide properties (i.e., phase, density, dynamic viscosity, and solubility to groundwater) within each element are then calculated from thermodynamic database under corresponding fluid conditions. Finally, the geologic storage capacity of carbon dioxide with in each element is estimated using the corresponding carbon dioxide properties as well as porosity and element volume, and that within the whole sedimentary basin is determined by summation over all elements. This new method is applied to the Bukpyeong Basin, which is one of the prospective offshore sedimentary basins for geologic storage of carbon dioxide in Korea. A three-dimensional geologic formation model of the Bukpyeong Basin is first established considering the elevation data of the boundaries between the geologic formations obtained from seismic survey and geologic maps at the sea floor surface. This geologic formation model is discretized into 170,808 hexahedral elements. Thermo-hydrological numerical modeling is then performed for the geologic formation model using TOUGH2 (Pruess et al., 1999). Finally, the geologic storage capacity of carbon dioxide in the Bukpyeong Basin is estimated to be about 345 Mton in the supercritical carbon dioxide region and about 1,883 Mton in both supercritical and liquid carbon dioxide regions. It is expected that the new method, which is suggested and applied in this study, can be utilized as reasonable and practical guidelines when more quantitative estimation of the geologic storage capacity of carbon dioxide in a sedimentary basin is required. This work was supported by the Energy Efficiency and Resources Program grant (No. 2010201020001A) funded by the Korea Institute of Energy Technology Evaluation and Planning (KETEP), Ministry of Knowledge Economy, Republic of Korea.

Kim, J.; Kihm, J.; Park, S.; SNU CO2 GEO-SEQ TEAM

2011-12-01

79

Methods and apparatus for measurement of the resistivity of geological formations from within cased boreholes  

DOEpatents

Methods and apparatus are disclosed which allow measurement of the resistivity of a geological formation through borehole casing which may be surrounded by brine saturated cement. A.C. current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. The A.C. voltage difference is measured between two additional vertically disposed electrodes on the interior of the casing which provides a measure of the resistivity of the geological formation. A calibration and nulling procedure is presented which minimizes the influence of variations in the thickness of the casing. The procedure also minimizes the influence of inaccurate placements of the additional vertically disposed electrodes. 3 figs.

Vail, W.B. III.

1989-04-11

80

Methods and apparatus for measurement of the resistivity of geological formations from within cased boreholes  

DOEpatents

Methods and apparatus are disclosed which allow measurement of the resistivity of a geological formation through borehole casing which may be surrounded by brine saturated cement. A.C. current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. The A.C. voltage difference is measured between two additional vertically disposed electrodes on the interior of the casing which provides a measure of the resistivity of the geological formation. A calibration and nulling procedure is presented which minimizes the influence of variations in the thickness of the casing. The procedure also minimizes the influence of inaccurate placements of the additional vertically disposed electrodes.

Vail, III, William B. (Bothell, WA)

1989-01-01

81

Evaluation of the geological relationships to gas hydrate formation and stability  

SciTech Connect

Although there are many publications pertaining to gas hydrates, their formation and stability in various geological conditions are poorly known. Therefore, for the same reasons and because of the very broad scope of our research, limited amount and extremely dispersed information, the study regions are very large. Moreover, almost without exception the geological environments controlling gas hydrates formation and stability of the studied regions are very complex. The regions studied (completed and partially completed - total 17 locations) during the reporting period, particularly the Gulf of Mexico and the Middle America Trench, are the most important in this entire research project. In the past, both of these regions have been extensively studied, the presence of gas hydrates confirmed and samples recovered. In our investigation it was necessary not only to review all previous data and interpretations, but to do a thorough analysis of the basins, and a critical evaluation of an previously reported and publicly available but not published information.

Not Available

1986-01-01

82

Methods and apparatus for measurement of electronic properties of geological formations through borehole casing  

DOEpatents

Methods and apparatus are provided for measuring electronic properties of geological formations and cement layers adjacent to cased boreholes including resistivities, polarization phenomena and dielectric constants. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. At least three voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of the differential current conducted into formation in the vicinity of those electrodes. These measurements facilitate calculation of the resistivities of the adjacent geological formations as well as an indication of whether cement is present. Measurements of the differential voltage response to transient currents provide a measurement of the polarization phenomena in formation as well as the capacitance of the casing in contact with the formation which is useful for determining whether oil and gas present. Lithological characteristics of the formation such as the pressence or absence of clay can also be determined. A calibration procedure is provided for minimizing errors induced by variations in the casing. The device also may be placed within the pipe attached to a drill bit while drilling open holes.

Vail, III, William B. (Bothell, WA)

1991-01-01

83

Methods and apparatus for measurement of electronic properties of geological formations through borehole casing  

DOEpatents

Methods and apparatus are provided for measuring electronic properties of geological formations and cement layers adjacent to cased boreholes including resistivities, polarization phenomena and dielectric constants. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. At least three voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of differential current conducted into formation in the vicinity of those electrodes. These measurements facilitate calculation of the resistivities of the adjacent geological formations as well as an indication of whether cement is present. Measurements of the differential voltage response to transient currents provide a measurement of the polarization phenomena in formation as well as the capacitance of the casing in contact with the formation which is useful for determining whether oil and gas are present. Lithological characteristics of the formation such as the presence or absence of clay can also be determined. A calibration procedure is provided for minimizing errors induced by variations in the casing. The device also may be placed within the pipe attached to a drill bit while drilling open holes.

Vail, III, William B. (Bothell, WA)

1989-01-01

84

Geologic Explorations  

NSDL National Science Digital Library

Geologic Explorations allows learners to explore a variety of unique geological formations of Utah using Quicktime Virtual Reality (QTVR) panoramas and digital still imagery. Spectacular panoramas and striking images capture Utah's unique geology and invite students to explore and learn interesting facts and concepts central to the study of geology.

Bodzin, Alec

2002-04-01

85

Heterogeneous formation of polar stratospheric clouds - Part 2: Nucleation of ice on synoptic scales  

NASA Astrophysics Data System (ADS)

This paper provides compelling evidence for the importance of heterogeneous nucleation, likely on solid particles of meteoritic origin, and of small-scale temperature fluctuations, for the formation of ice particles in the Arctic stratosphere. During January 2010, ice PSCs (polar stratospheric clouds) were shown by CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) to have occurred on a synoptic scale (~1000 km dimension). CALIPSO observations also showed widespread PSCs containing NAT (nitric acid trihydrate) particles in December 2009, prior to the occurrence of synoptic-scale regions of ice PSCs during mid-January 2010. We demonstrate by means of detailed microphysical modeling along air parcel trajectories that the formation of these PSCs is not readily reconciled with expectations from the conventional understanding of PSC nucleation mechanisms. The measurements are at odds with the previous laboratory-based understanding of PSC formation, which deemed direct heterogeneous nucleation of NAT and ice on preexisting solid particles unlikely. While a companion paper (Part 1) addresses the heterogeneous nucleation of NAT during December 2009, before the existence of ice PSCs, this paper shows that also the large-scale occurrence of stratospheric ice in January 2010 cannot be explained merely by homogeneous ice nucleation but requires the heterogeneous nucleation of ice, e.g. on meteoritic dust or preexisting NAT particles. The required efficiency of the ice nuclei is surprisingly high, namely comparable to that of known tropospheric ice nuclei such as mineral dust particles. To gain model agreement with the ice number densities inferred from observations, the presence of small-scale temperature fluctuations, with wavelengths unresolved by the numerical weather prediction models, is required. With the derived rate parameterization for heterogeneous ice nucleation we are able to explain and reproduce CALIPSO observations throughout the entire Arctic winter 2009/2010.

Engel, I.; Luo, B. P.; Pitts, M. C.; Poole, L. R.; Hoyle, C. R.; Grooß, J.-U.; Dörnbrack, A.; Peter, T.

2013-11-01

86

Heterogeneous formation of polar stratospheric clouds - Part 2: Nucleation of ice on synoptic scales  

NASA Astrophysics Data System (ADS)

This paper provides unprecedented evidence for the importance of heterogeneous nucleation, likely on solid particles of meteoritic origin, and of small-scale temperature fluctuations, for the formation of ice particles in the Arctic stratosphere. During January 2010, ice PSCs (Polar Stratospheric Clouds) were shown by CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) to have occurred on a synoptic scale (~ 1000 km dimension). CALIPSO observations also showed widespread PSCs containing nitric acid trihydrate (NAT) particles in December 2009, prior to the occurrence of synoptic-scale regions of ice PSCs during mid-January 2010. We demonstrate by means of detailed microphysical modeling along air parcel trajectories that the formation of these PSCs is not readily reconciled with expectations from the conventional understanding of PSC nucleation mechanisms. The measurements are at odds with the previous laboratory-based understanding of PSC formation, which deemed direct heterogeneous nucleation of NAT and ice on preexisting solid particles unlikely. While a companion paper (Part 1) addresses the heterogeneous nucleation of NAT during December 2009, before the existence of ice PSCs, this paper shows that also the large-scale occurrence of stratospheric ice in January 2010 cannot be explained merely by homogeneous ice nucleation but requires the heterogeneous nucleation of ice, e.g. on meteoritic dust or preexisting NAT particles. The required efficiency of the ice nuclei is surprisingly high, namely comparable to that of known tropospheric ice nuclei such as mineral dust particles. To gain model agreement with the ice number densities inferred from observations, the presence of small-scale temperature fluctuations, with wavelengths unresolved by the numerical weather prediction models, is required. With the derived rate parameterization for heterogeneous ice nucleation we are able to explain and reproduce CALIPSO observations throughout the entire Arctic winter 2009/2010.

Engel, I.; Luo, B. P.; Pitts, M. C.; Poole, L. R.; Hoyle, C. R.; Grooß, J.-U.; Dörnbrack, A.; Peter, T.

2013-04-01

87

Multiple scale physical and numerical modeling for improved understanding of mechanisms of trapping and leakage of CO2 in deep geologic formations  

NASA Astrophysics Data System (ADS)

The fundamental processes associated with trapping and leakage of CO2 in deep geologic formations are complex. Formation heterogeneity manifested at all scales is expected to affect capillary and dissolution trapping and leakage of gaseous CO2 to the shallow subsurface. Research is underway to improve our fundamental understanding of trapping and leakage. This research involves experimentation in multiple scales and modeling focusing on effects of formation heterogeneity. The primary hypothesis that drives this research is that when the effects of heterogeneity on entrapment and leakage are understood, it will be possible to design more effective and safe storage schemes. Even though field investigations have some value in understanding issues related to large scale behavior and performance assessment, a fundamental understanding of how the heterogeneity affects trapping is difficult or impossible to obtain in field settings. Factors that contribute to these difficulties are the inability to fully characterize the formation heterogeneity at all scales of interest and lack of experimental control at very high depths. Intermediate scale physical model testing provides an attractive alternative to investigate these processes in the laboratory. Heterogeneities can be designed using soils with known properties in test tanks and the experiments can be conducted under controlled conditions to obtain accurate data. Conducting laboratory experiments under ambient pressure and temperature conditions to understand the processes that occur in deep formations poses many challenges. This research attempts to address such challenges and demonstrates how this testing approach could be used to generate useful data. The experiments involve the use of test systems of hierarchy of scales from small to intermediate scale tanks (~ 5 m) and long columns (~ 4.5 m). These experiments use surrogate fluids to investigate both capillary and solubility trapping in homogeneous and heterogeneous systems. A traversing x-ray scanning system is used to monitor the advancement of the plume during and after injection and to measure the residual (trapped) CO2 saturation. Dissolution of a surrogate non-wetting fluid in a surrogate wetting fluid is analyzed in small and large tanks. We test the numerical models that are capable of simulating two-phase flow and density driven flow as a result of dissolution by using the experimental data. Verified models are used to further evaluate the effect of capillary and solubility trapping in complex heterogeneous environments. During leakage, under different pressure and temperature conditions, dissolved CO2 may come back out of solution (exsolve), but the fundamental triggering mechanisms of this process in porous media are not yet well understood. An extensive series of column experiments has been conducted to investigate the factors that control the rates of CO2 gas bubble nucleation, growth, and migration. Results indicate that the saturation pressure (i.e. the amount of CO2 dissolved into the injected water) and heterogeneity both significantly affect the gas formation and migration, whereas the injection rate has less of an effect. These column experiments will soon be upscaled to an intermediate-scale two-dimensional tank to investigate the behaviour of the CO2 gas-water-soil system in more complex geological environments.

Illangasekare, T.; Plampin, M.; Trevisan, L.; Agartan, E.; Mori, H.; Sakaki, T.; Cihan, A.; Birkholzer, J.; Zhou, Q.; Pawar, R.; Zyvoloski, G.

2012-04-01

88

Geologic factors controlling CO2 storage capacity and permanence: case studies based on experience with heterogeneity in oil and gas reservoirs applied to CO2 storage  

NASA Astrophysics Data System (ADS)

A variety of structural and stratigraphic factors control geological heterogeneity, inferred to influence both sequestration capacity and effectiveness, as well as seal capacity. Structural heterogeneity factors include faults, folds, and fracture intensity. Stratigraphic heterogeneity is primarily controlled by the geometry of depositional facies and sandbody continuity, which controls permeability structure. The permeability structure, in turn, has implications for CO2 injectivity and near-term migration pathways, whereas the long-term sequestration capacity can be inferred from the production history. Examples of Gulf Coast oil and gas reservoirs with differing styles of stratigraphic heterogeneity demonstrate the impact of facies variability on fluid flow and CO2 sequestration potential. Beach and barrier-island deposits in West Ranch field in southeast Texas are homogeneous and continuous. In contrast, Seeligson and Stratton fields in south Texas, examples of major heterogeneity in fluvial systems, are composed of discontinuous, channel-fill sandstones confined to narrow, sinuous belts. These heterogeneous deposits contain limited compartments for potential CO2 storage, although CO2 sequestration effectiveness may be enhanced by the high number of intraformational shale beds. These field examples demonstrate that areas for CO2 storage can be optimized by assessing sites for enhanced oil and gas recovery in mature hydrocarbon provinces.

Ambrose, W. A.; Lakshminarasimhan, S.; Holtz, M. H.; Núñez-López, V.; Hovorka, S. D.; Duncan, I.

2008-06-01

89

Geologic Mapping Applications Using THEMIS Data for the Medusae Fossae Formation, Mars  

NASA Technical Reports Server (NTRS)

The Medusae Fossae Formation (MFF) is a regionally extensive deposit located along the equator of Mars between roughly 130 and 240 E longitude, the origin of which has stimulated a host of published hypotheses. A volcanic or aeolian origin appear most consistent with Viking and MGS data, but other hypotheses remain viable and new data, as from the Mars Odyssey spacecraft, is likely to stimulate additional hypotheses of origin. NASA is supporting geologic mapping of portions of the MFF deposits, but it is now quite clear that this on-going mapping will need considerable revision as data from the Thermal Emission Imaging System (THEMIS) on Mars Odyssey become available. The daytime IR THEMIS images hold particularly strong potential for providing a new base on which geologic mapping can be carried out, as illustrated by the examples discussed.

Zimbelman, J. R.; Bender, K. C.; Harris, J. C.

2003-01-01

90

The geological setting of the ultramafic-hosted Logatchev hydrothermal field (14°45?N, Mid-Atlantic Ridge) and its influence on massive sulfide formation  

NASA Astrophysics Data System (ADS)

The Logatchev hydrothermal field (14°45'N on the MAR) is one of a few submarine hydrothermal systems associated with ultramafic rocks. It is situated on the eastern inner flank of the rift valley wall, 7 km away from the spreading axis and its formation has previously been linked to detachment faulting and core complex formation. Geological mapping during various ROV dives, geological sampling, and shallow drilling reveal a structural control of hydrothermal activity as well as its location in a debris flow consisting of heterogeneous ultramafic and mafic intrusive rocks. The mixed mafic/ultramafic host rock lithology is in agreement with published vent fluid and gas chemical data showing characteristics for interaction with mafic as well as with ultramafic rocks. Massive sulfide formation is more focused than previously thought and likely limited to a thin veneer at the seafloor. The Logatchev hydrothermal field shows a number of peculiarities that are unusual for most other hydrothermal systems. One of these are so-called ,,smoking craters", seafloor depressions that are several meters wide, characterized by an elevated crater rim made up partly of sulfide talus but also of abundant wall rock material. At these smoking craters hydrothermal venting occurs directly from holes within the craters and from small, cm to dm high, Cu-rich chimneys occurring at the crater rim. Based on geological mapping and sampling we suggest that these smoking craters are the product of processes related to the regional and local geological setting in an ultramafic-hosted, off-axis location with abundant landslides, as well as off-axis gabbroic intrusions providing the heat for the hydrothermal convection cell.

Petersen, S.; Kuhn, K.; Kuhn, T.; Augustin, N.; Hékinian, R.; Franz, L.; Borowski, C.

2009-09-01

91

Modulation format identification in heterogeneous fiber-optic networks using artificial neural networks.  

PubMed

We propose a simple and cost-effective technique for modulation format identification (MFI) in next-generation heterogeneous fiber-optic networks using an artificial neural network (ANN) trained with the features extracted from the asynchronous amplitude histograms (AAHs). Results of numerical simulations conducted for six different widely-used modulation formats at various data rates demonstrate that the proposed technique can effectively classify all these modulation formats with an overall estimation accuracy of 99.6% and also in the presence of various link impairments. The proposed technique employs extremely simple hardware and digital signal processing (DSP) to enable MFI and can also be applied for the identification of other modulation formats at different data rates without necessitating hardware changes. PMID:22714229

Khan, Faisal Nadeem; Zhou, Yudi; Lau, Alan Pak Tao; Lu, Chao

2012-05-21

92

R And D Program on Radioactive Waste Disposal into Geological Formations (Study of a Clay Formation).  

National Technical Information Service (NTIS)

This report deals with the R and D activities performed by the Belgian Nuclear Research Establishment (SCK/CEN) and its subcontractors concerning the disposal of high-level and long-life conditioned wastes in a deep clay formation, the Boom clay. The stud...

M. Centre d'Etude de l'Energie Nucleai

1987-01-01

93

Role of geomechanically grown fractures on dispersive transport in heterogeneous geological formations.  

PubMed

A second order in space accurate implicit scheme for time-dependent advection-dispersion equations and a discrete fracture propagation model are employed to model solute transport in porous media. We study the impact of the fractures on mass transport and dispersion. To model flow and transport, pressure and transport equations are integrated using a finite-element, node-centered finite-volume approach. Fracture geometries are incrementally developed from a random distributions of material flaws using an adoptive geomechanical finite-element model that also produces fracture aperture distributions. This quasistatic propagation assumes a linear elastic rock matrix, and crack propagation is governed by a subcritical crack growth failure criterion. Fracture propagation, intersection, and closure are handled geometrically. The flow and transport simulations are separately conducted for a range of fracture densities that are generated by the geomechanical finite-element model. These computations show that the most influential parameters for solute transport in fractured porous media are as follows: fracture density and fracture-matrix flux ratio that is influenced by matrix permeability. Using an equivalent fracture aperture size, computed on the basis of equivalent permeability of the system, we also obtain an acceptable prediction of the macrodispersion of poorly interconnected fracture networks. The results hold for fractures at relatively low density. PMID:22181492

Nick, H M; Paluszny, A; Blunt, M J; Matthai, S K

2011-11-01

94

Geologic setting, petrophysical characteristics, and regional heterogeneity patterns of the Smackover in southwest Alabama. Draft topical report on Subtasks 2 and 3  

SciTech Connect

This is the draft topical report on Subtasks 2 and 3 of DOE contract number DE-FG22-89BC14425, entitled ``Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity.`` This volume constitutes the final report on Subtask 3, which had as its primary goal the geological modeling of reservoir heterogeneity in Smackover reservoirs of southwest Alabama. This goal was interpreted to include a thorough analysis of Smackover reservoirs, which was required for an understanding of Smackover reservoir heterogeneity. This report is divided into six sections (including this brief introduction). Section two, entitled ``Geologic setting,`` presents a concise summary of Jurassic paleogeography, structural setting, and stratigraphy in southwest Alabama. This section also includes a brief review of sedimentologic characteristics and stratigraphic framework of the Smackover, and a summary of the diagenetic processes that strongly affected Smackover reservoirs in Alabama. Section three, entitled ``Analytical methods,`` summarizes all nonroutine aspects of the analytical procedures used in this project. The major topics are thin-section description, analysis of commercial porosity and permeability data, capillary-pressure analysis, and field characterization. ``Smackover reservoir characteristics`` are described in section four, which begins with a general summary of the petrographic characteristics of porous and permeable Smackover strata. This is followed by a more-detailed petrophysical description of Smackover reservoirs.

Kopaska-Merkel, D.C.; Mann, S.D.; Tew, B.H.

1992-06-01

95

3-D geologic modeling and its applications for the Clearwater formation Reservoir, Cold Lake, Alberta, Canada  

SciTech Connect

Three-dimensional models were built to mimic the geology of the Clearwater Formation reservoir at Esso Resources Canada Limited Cold Lake production operations. Each model consists of 3.9 million cells, covers an area of 376 km{sup 2} (144 mi{sup 2}), and encompasses the Esso in-situ development area. The models, facies, bitumen saturation, and sand quality were built using stratigraphic surfaces (nonparallel surfaces) to guide the interwell data interpolation process. The Lower Cretaceous Clearwater Formation in the Cold Lake area contains 11.3 billion m{sup 3} in place (71 billion bbl) of bitumen requiring in-situ thermal stimulation processes for recovery. Within the development area, the facies are dominantly deltaic and include clean, rich, outer stream mouth bar; shaleprone inner stream mouth bar; and offshore transition sands. Sand quality affects resource distribution and reservoir performance. Erosional and downlap surfaces make the modeling process more complex than simple layer-cake, parallel surface modeling. The procedure for building the three-dimensional geologic model included (1) data gathering, (2) data editing, (3) data preparation, (4) geologic horizon gridding, (5) well modeling, (6) data interpolation, and (7) verification. Each of the models can be merged with the other. Various cutoffs with any combination of the three modeled reservoir parameters can be applied in information retrieval. These merge and search capabilities are very useful for sensitivity studies, resources distribution calculation, reservoir quality displays, production problem solving, and various statistical analyses. Moreover, the three-dimensional models can be input directly into the Exxon reservoir engineering simulator.

Leung, S.K.; Belanger, C.E.; Sheptycki, R.J. (Esso Resources Canada Ltd., Calgary, Alberta (Canada))

1990-05-01

96

Formation of HCN+ in Heterogeneous Reactions of N2+ and N+ with Surface Hydrocarbons  

NASA Astrophysics Data System (ADS)

A significant increase of the ion yield at m/z 27 in collisions of low-energy ions of N2+ and N+ with hydrocarbon-covered room-temperature or heated surfaces of tungsten, carbon-fiber composite, and beryllium, not observed in analogous collisions of Ar+, is ascribed to the formation of HCN+ in heterogeneous reactions between N2+ or N+ and surface hydrocarbons. The formation of HCN+ in the reaction with N+ indicated an exothermic reaction with no activation barrier, likely to occur even at very low collision energies. In the reaction with N2+, the formation of HCN+ was observed to a different degree on these room-temperature and heated (150 and 300 °C) surfaces at incident energies above about 50 eV. This finding suggested an activation barrier or reaction endothermicity of the heterogeneous reaction of about 3-3.5 eV. The main process in N2+ or N+ interaction with the surfaces is ion neutralization; the probability of forming the reaction product HCN+ was very roughly estimated for both N2+ and N+ ions to about one in 104 collisions with the surfaces.

Harnisch, Martina; Keim, Alan; Scheier, Paul; Herman, Zdenek

2013-10-01

97

Formation of HCN+ in Heterogeneous Reactions of N2+ and N+ with Surface Hydrocarbons  

PubMed Central

A significant increase of the ion yield at m/z 27 in collisions of low-energy ions of N2+ and N+ with hydrocarbon-covered room-temperature or heated surfaces of tungsten, carbon-fiber composite, and beryllium, not observed in analogous collisions of Ar+, is ascribed to the formation of HCN+ in heterogeneous reactions between N2+ or N+ and surface hydrocarbons. The formation of HCN+ in the reaction with N+ indicated an exothermic reaction with no activation barrier, likely to occur even at very low collision energies. In the reaction with N2+, the formation of HCN+ was observed to a different degree on these room-temperature and heated (150 and 300 °C) surfaces at incident energies above about 50 eV. This finding suggested an activation barrier or reaction endothermicity of the heterogeneous reaction of about 3–3.5 eV. The main process in N2+ or N+ interaction with the surfaces is ion neutralization; the probability of forming the reaction product HCN+ was very roughly estimated for both N2+ and N+ ions to about one in 104 collisions with the surfaces.

2013-01-01

98

BIGFLOW: A numerical code for simulating flow in variably saturated, heterogeneous geologic media. Theory and user`s manaual, Version 1.1  

SciTech Connect

This report documents BIGFLOW 1.1, a numerical code for simulating flow in variably saturated heterogeneous geologic media. It contains the underlying mathematical and numerical models, test problems, benchmarks, and applications of the BIGFLOW code. The BIGFLOW software package is composed of a simulation and an interactive data processing code (DATAFLOW). The simulation code solves linear and nonlinear porous media flow equations based on Darcy`s law, appropriately generalized to account for 3D, deterministic, or random heterogeneity. A modified Picard Scheme is used for linearizing unsaturated flow equations, and preconditioned iterative methods are used for solving the resulting matrix systems. The data processor (DATAFLOW) allows interactive data entry, manipulation, and analysis of 3D datasets. The report contains analyses of computational performance carried out using Cray-2 and Cray-Y/MP8 supercomputers. Benchmark tests include comparisons with other independently developed codes, such as PORFLOW and CMVSFS, and with analytical or semi-analytical solutions.

Ababou, R. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Bagtzoglou, A.C. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

1993-06-01

99

Sr isotopes of the Seoguipo Formation (Korea) and their application to geologic age  

NASA Astrophysics Data System (ADS)

The Seoguipo Formation, Cheju Island, Korea is a shallow-marine to nonmarine sedimentary formation formed by the earliest stage of volcanism and simultaneous volcanogenic sedimentation of the island. The formation contains signatures of glacioeustasy, providing an opportunity to study Neogene paleoceanographic changes in the northwestern Pacific. The proposed geologic age of the formation varies widely from Pliocene to Pleistocene in spite of an abundance of biostratigraphic and paleomagnetic data. This situation has hampered establishment of a time framework on which paleoenvironmental interpretations can be based. In this study, strontium isotopic ratios were measured from diverse macrofossils obtained from the fossiliferous lower part of the formation to constrain the carbonate ages. All macrofossils retain the original mineralogy and microstructures, negating the possibility of postdepositional diagenesis. The stable oxygen and carbon isotopic compositions of the specimens also show little sign of alteration. 87Sr/ 86Sr ratios of the shells display a wide range of values (0.70863-0.70919), categorized into two groups; calcitic pectenids, brachiopods, and an aragonitic bivalve showing high 87Sr/ 86Sr values (greater than 0.70909), and the rest of bivalves and an aragonitic gastropod showing unusually low values. The low 87Sr/ 86Sr ratios of the latter group are interpreted to be due to the local variation of the paleoseawater condition in which the organisms grew, probably caused by contemporaneous volcanic activities and weathering of volcaniclastic materials in a restricted environment. The average 87Sr/ 86Sr ratio of the heavy group yields a carbonate age of 0.86 (+0.40/-0.57) Ma by the LOWESS fit to the marine Sr-isotope curve of Howarth and McArthur (J. Geol., 105 (1997) 441). The Sr isotope age, in conjunction with radiometric and biostratigraphic ages, suggests that the deposition of the Seoguipo Formation began since the early Pleistocene, and the surface exposure of the formation belongs mostly to the middle Pleistocene (˜0.86-0.4 Ma).

Khim, B. K.; Woo, K. S.; Sohn, Y. K.

2001-10-01

100

Carbon Dioxide Capture and Storage: An Overview With Emphasis on Capture and Storage in Deep Geological Formations  

Microsoft Academic Search

A transition to a low-carbon economy can be facilitated by CO2 capture and storage. This paper begins with an overview of CO2 capture and storage in the terrestrial biosphere, oceans, and deep geologic systems. The remainder focuses on what now appears to be the most promising option for large-scale deployment-capture and storage in deep geologic formations. A detailed description of

Sally M. Benson; Terry Surles

2006-01-01

101

Role of initial heterogeneities on wormhole formation during CO2 rich-brine injection: upscaling of permeability - porosity relationships  

NASA Astrophysics Data System (ADS)

CO2 sequestration in deep geological formation seems to be a good solution for minimizing CO2 emissions in the atmosphere. In the vicinity of the injection well, scCO2 will dissolve in the brine and produce low pH solution favouring dissolution of carbonate and to a less extent silicate minerals. Consequently, important modifications of the rock properties (hydrodynamical and mechanical) are expected. Characterizing and modelling these mechanisms is essential for predicting short- and long-term behaviour. Here, we present results of six percolation experiments which reproduced in situ CO2 injection into two types of oolithic limestone (one with macro-porosity and an only percolating cluster (experiments D1, D2 and D3) and the other one composed of micro- and macro-porosity without an initial percolating cluster (experiences Port1, Port2 and Port3)) for different value of Damköhler number (ie. different partial pressure of CO2). X-ray microtomography (XMT), using ID19 at ESRF, is used to characterize, from pore scale to Darcy scale, the changes in the structural properties induced by the percolation of the CO2-rich brine. Coupling imaging techniques with sample scale measurements of the time-resolved permeability and chemical fluxes, allows determining i) the change in the chemical and physical parameters of the sample (porosity, reactive surface area, tortuosity) induced by the dissolution processes and ii) the role of each phase in the formation of the observed preferential flow path (or wormhole like structures). All experiments show that the sample porosity and permeability increases. For all experiments on samples initially composed of micro- and macro-porosity we observe that the macro-porosity extended at the expense of the micro-porosity (73% and 27% of total porosity respectively). XMT data show that the initial heterogeneity controls the wormhole formations together with the composition of the inlet fluid (at constant flow rate). For a same chemical forcing (D3 and Port1) we characterized different dissolution processes (homogeneous dissolution for D3 and wormhole formation for Port1) depending on the different structure of the two limestone rocks. Moreover, we demonstrated that for the same chemical forcing (D3 and Port1), the permeability-porosity relationships are identical depending only on the chemical forcing and not the flow-path formations.

Mangane, P.; Luquot, L.; Gouze, P.

2011-12-01

102

On the accuracy of classic numerical schemes for modeling flow in saturated heterogeneous formations  

NASA Astrophysics Data System (ADS)

Quantitative hydrogeology often relies on numerical modeling of flow and transport processes in the earth subsurface. Despite the richness of numerical schemes proposed in the literature most applications are performed by using a few very popular codes based on classical finite volume or finite element techniques. An important limitation of these numerical schemes is that they lead to solutions that do not satisfy the refraction law of streamlines at element (or volume) edges. This is not of great concern when the hydraulic conductivity K is spatially homogeneous, or varies smoothly within the computational domain. However, the solution may deteriorate in heterogeneous formations with high contrast between the hydraulic conductivity of adjacent computational cells. We analyze the performance of four widely used classic numerical schemes for solving the flow equation when they are applied to heterogeneous porous media. We first analyze the convergence of the numerical schemes to a known analytical solution in a simple heterogeneous field composed by 4 blocks with contrasting hydraulic conductivities. Then we compare the numerical solutions obtained in both Gaussian and exponential weakly heterogeneous logconductivity fields with existing analytical first- and second-order solutions in the variance of the logconductivity field, ?Y2. Our analysis highlights that postprocessing the velocity field to enforce a posteriori the refraction law leads to biased results and that the performance of the numerical scheme depends on how mass conservation is discretized on the computational grid. Numerical schemes using inter-block conductivities, based for example on the harmonic mean, modify the spatial structure of the conductivity, with a negative impact on the structure of the velocity field.

Cainelli, Oscar; Bellin, Alberto; Putti, Mario

2012-10-01

103

Abiotic Mechanisms for the Formation of Greenhouse Gases from Heterogeneous Atmospheric Chemistry and Photochemistry  

NASA Astrophysics Data System (ADS)

Atmospheric aerosol particles such as mineral dust can undergo interfacial, heterogeneous reactions that can be involved in both the formation and destruction of important greenhouse gases. This talk will provide an overview of some of these reactions and will focus on the formation of atmospheric nitrous oxide from ammonium nitrate coated dust particles that can be initiated with simulated solar radiation. Although nitrous oxide is an important greenhouse gas and a primary cause of stratospheric ozone destruction, there remain missing sources in the nitrous oxide budget. Nitrous oxide production by the abiotic mechanism discussed here is expected globally from both megacities and agricultural areas and may become more important under future projected changes in anthropogenic emissions.

Grassian, V. H.

2012-12-01

104

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

The objective of this project is to augment the National Reservoir Database (TORIS database), 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 resources that are producible at moderate cost. This objective will be achieved through detailed geological, geostatistical, and engineering characterization of

Mancini

1990-01-01

105

Heterogeneous formation of polar stratospheric clouds - Part 1: Nucleation of nitric acid trihydrate (NAT)  

NASA Astrophysics Data System (ADS)

Satellite based observations during the Arctic winter of 2009/2010 provide firm evidence that, in contrast to the current understanding, the nucleation of nitric acid trihydrate (NAT) in the polar stratosphere does not only occur on preexisting ice particles. In order to explain the NAT clouds observed over the Arctic in mid December 2009, a heterogeneous nucleation mechanism is required, occurring via immersion freezing on the surface of solid particles, likely of meteoritic origin. For the first time, a detailed microphysical modelling of this NAT formation pathway has been carried out. Heterogeneous NAT formation was calculated along more than sixty thousand trajectories, ending at Cloud Aerosol Lidar with Orthogonal Polarisation (CALIOP) observation points. Comparing the optical properties of the modelled NAT with these observations enabled the thorough validation of a newly developed NAT nucleation parameterisation, which has been built into the Zurich Optical and Microphysical box Model (ZOMM). The parameterisation is based on active site theory, is simple to implement in models and provides substantial advantages over previous approaches which involved a constant rate of NAT nucleation in a given volume of air. It is shown that the new method is capable of reproducing observed PSCs very well, despite the varied conditions experienced by air parcels travelling along the different trajectories. In a companion paper, ZOMM is applied to a later period of the winter, when ice PSCs are also present, and it is shown that the observed PSCs are also represented extremely well under these conditions.

Hoyle, C. R.; Engel, I.; Luo, B. P.; Pitts, M. C.; Poole, L. R.; Grooß, J.-U.; Peter, T.

2013-03-01

106

Heterogeneous chemistry of butanol and decanol with sulfuric acid: implications for secondary organic aerosol formation.  

PubMed

Recent environmental chamber studies suggest that acid-catalyzed reactions between alcohols and aldehydes in the condensed phase lead to the formation of hemiacetals and acetals, enhancing secondary organic aerosol (SOA) growth. We report measurements of heterogeneous uptake of butanol and decanol on liquid H2SO4 in the range of 62-84 wt % and between 273 and 296 K. Both alcohols exhibit two distinct types of uptake behaviors (partially irreversible vs totally irreversible uptake), depending on the acid concentration and temperature. For the partially irreversible uptake, a fraction of the alcohol was physically absorbed while the other fraction underwent irreversible reaction. For the totally irreversible uptake, the alcohols were completely lost onto the sulfuric acid. The Henry's law solubility constant (H*) was determined from the time-dependent uptake, while the reactive uptake coefficients were calculated from the time-independent irreversible loss. Coexistence of butanol or decanol with octanal or decanal did not show enhanced uptake of the aldehydes in the sulfuric acid. Protonation and dissolution likely account for the reversible uptake, while formation of alkyl sulfate or dialkyl sulfate explains irreversible uptake of the alcohols. The results suggest that heterogeneous uptake of larger alcohols is unlikely of significant importance in the lower atmosphere except in the case of freshly nucleated aerosols that may have high acid concentrations. PMID:17149836

Levitt, Nicholas P; Zhao, Jun; Zhang, Renyi

2006-12-14

107

Contrasting the impact of aerosols at northern and southern midlatitudes on heterogeneous ice formation  

NASA Astrophysics Data System (ADS)

Three cloud data sets, each covering four months of observations, were recently recorded with a lidar at Punta Arenas (53°S), Chile, at Stellenbosch (34°S, near Cape Town), South Africa, and aboard the research vessel Polarstern during three north-south cruises. By comparing these observations with an 11-year cloud data set measured with a lidar at Leipzig (51°N), Germany, the occurrence of heterogeneous ice formation (as a function of cloud top temperature) for very different aerosol conditions in the northern and southern hemisphere is investigated. Large differences in the heterogeneous freezing behavior in the mostly layered clouds are found. For example, <20%, 30%-40% and around 70% of the cloud layers with cloud top temperatures from -15°C to -20°C, showed ice formation over Punta Arenas, Stellenbosch, and Leipzig, respectively. The observed strong contrast reflects the differences in the free tropospheric aerosol conditions at northern midlatitudes, that are controlled by anthropogenic pollution, mineral dust, forest fire smoke, terrestrial biological material and high southern midlatitudes with clean marine conditions.

Kanitz, T.; Seifert, P.; Ansmann, A.; Engelmann, R.; Althausen, D.; Casiccia, C.; Rohwer, E. G.

2011-09-01

108

Heterogeneous Formation of Polar Stratospheric Clouds- Part 1: Nucleation of Nitric Acid Trihydrate (NAT)  

NASA Technical Reports Server (NTRS)

Satellite-based observations during the Arctic winter of 2009/2010 provide firm evidence that, in contrast to the current understanding, the nucleation of nitric acid trihydrate (NAT) in the polar stratosphere does not only occur on preexisting ice particles. In order to explain the NAT clouds observed over the Arctic in mid-December 2009, a heterogeneous nucleation mechanism is required, occurring via immersion freezing on the surface of solid particles, likely of meteoritic origin. For the first time, a detailed microphysical modelling of this NAT formation pathway has been carried out. Heterogeneous NAT formation was calculated along more than sixty thousand trajectories, ending at Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) observation points. Comparing the optical properties of the modelled NAT with these observations enabled a thorough validation of a newly developed NAT nucleation parameterisation, which has been built into the Zurich Optical and Microphysical box Model (ZOMM). The parameterisation is based on active site theory, is simple to implement in models and provides substantial advantages over previous approaches which involved a constant rate of NAT nucleation in a given volume of air. It is shown that the new method is capable of reproducing observed polar stratospheric clouds (PSCs) very well, despite the varied conditions experienced by air parcels travelling along the different trajectories. In a companion paper, ZOMM is applied to a later period of the winter, when ice PSCs are also present, and it is shown that the observed PSCs are also represented extremely well under these conditions.

Hoyle, C. R.; Engel, I.; Luo, B. P.; Pitts, M. C.; Poole, L. R.; Grooss, J.-U.; Peter, T.

2013-01-01

109

Structured development of a petrophysics laboratory computer system to aid in formation evaluation and geologic interpretation  

SciTech Connect

Problem solving, data collection, and analysis in geology require diverse tools and methods. Computers must be convenient and versatile to be useful as laboratory apparatus and as tools for use in formation evaluation and geologic interpretation. Networking and distributed intelligence provide a laboratory with flexibility and power for cost-effective real-time data collection, management, and analysis. Networking facilities toolbox-style programming; improves data compilation, management, and comparison; and increases peripheral effectiveness. Distributed intelligence enhances local instrumentation, uninterrupted real-time data collector, and data analysis. The system presented includes facilities for instrumentation, data collection and management, and interpretation, analysis, and presentation for such systems as mercury injection, rock electrical properties, gas slippage, Klinkenberg correction, gamma-ray logging, cation exchange capacity, thermal neutron capture cross section, and permeability/porosity measurements. The individual systems share central text and graphic hard-copy devices and high-speed mass storage and backup facilities. Modifying the central system updates many of the remote system facilities such as user interfaces and graphic facilities. Individual system configurations include instrumentation, high-resolution color graphics, analog to digital conversion, and variation in computing power.

Hoyt, B.R.; Skopec, R.A. (Gearhart Industries, Inc., Fort Worth, TX (USA))

1987-02-01

110

Probability density function of non-reactive solute concentration in heterogeneous porous formations.  

PubMed

Available models of solute transport in heterogeneous formations lack in providing complete characterization of the predicted concentration. This is a serious drawback especially in risk analysis where confidence intervals and probability of exceeding threshold values are required. Our contribution to fill this gap of knowledge is a probability distribution model for the local concentration of conservative tracers migrating in heterogeneous aquifers. Our model accounts for dilution, mechanical mixing within the sampling volume and spreading due to formation heterogeneity. It is developed by modeling local concentration dynamics with an Ito Stochastic Differential Equation (SDE) that under the hypothesis of statistical stationarity leads to the Beta probability distribution function (pdf) for the solute concentration. This model shows large flexibility in capturing the smoothing effect of the sampling volume and the associated reduction of the probability of exceeding large concentrations. Furthermore, it is fully characterized by the first two moments of the solute concentration, and these are the same pieces of information required for standard geostatistical techniques employing Normal or Log-Normal distributions. Additionally, we show that in the absence of pore-scale dispersion and for point concentrations the pdf model converges to the binary distribution of [Dagan, G., 1982. Stochastic modeling of groundwater flow by unconditional and conditional probabilities, 2, The solute transport. Water Resour. Res. 18 (4), 835-848.], while it approaches the Normal distribution for sampling volumes much larger than the characteristic scale of the aquifer heterogeneity. Furthermore, we demonstrate that the same model with the spatial moments replacing the statistical moments can be applied to estimate the proportion of the plume volume where solute concentrations are above or below critical thresholds. Application of this model to point and vertically averaged bromide concentrations from the first Cape Cod tracer test and to a set of numerical simulations confirms the above findings and for the first time it shows the superiority of the Beta model to both Normal and Log-Normal models in interpreting field data. Furthermore, we show that assuming a-priori that local concentrations are normally or log-normally distributed may result in a severe underestimate of the probability of exceeding large concentrations. PMID:17628204

Bellin, Alberto; Tonina, Daniele

2007-10-30

111

Integration of local–global upscaling and grid adaptivity for simulation of subsurface flow in heterogeneous formations  

Microsoft Academic Search

We propose a methodology, called multilevel local–global (MLLG) upscaling, for generating accurate upscaled models of permeabilities\\u000a or transmissibilities for flow simulation on adapted grids in heterogeneous subsurface formations. The method generates an\\u000a initial adapted grid based on the given fine-scale reservoir heterogeneity and potential flow paths. It then applies local–global\\u000a (LG) upscaling for permeability or transmissibility [7], along with adaptivity,

M. Gerritsen; J. V. Lambers

2008-01-01

112

Travel time approach to kinetically sorbing solute by diverging radial flows through heterogeneous porous formations  

NASA Astrophysics Data System (ADS)

Diverging radial flow takes place in a heterogeneous porous medium where the log conductivity Y = ln K is modeled as a stationary random space function (RSF). The flow is steady, and is generated by a fully penetrating well. A linearly sorbing solute is injected through the well envelope, and we aim at computing the average flux concentration (breakthrough curve). A relatively simple solution for this difficult problem is achieved by adopting, similar to Indelman and Dagan (1999), a few simplifying assumptions: (i) a thick aquifer of large horizontal extent, (ii) mildly heterogeneous medium, (iii) strongly anisotropic formation, and (iv) large Peclet number. By introducing an appropriate Lagrangian framework, three-dimensional transport is mapped onto a one-dimensional domain (?, t) where ? and t represent the fluid travel and current time, respectively. Central for this approach is the probability density function of the RSF ?that is derived consistently with the adopted assumptions stated above. Based on this, it is shown that the travel time can be regarded as a Gaussian random variable only in the far field. The breakthrough curves are analyzed to assess the impact of the hydraulic as well as reactive parameters. Finally, the travel time approach is tested against a forced-gradient transport experiment and shows good agreement.

Severino, Gerardo; de Bartolo, Samuele; Toraldo, Gerardo; Srinivasan, Gowri; Viswanathan, Hari

2012-12-01

113

Reactive Tracer Techniques to Quantitatively Monitor Carbon Dioxide Storage in Geologic Formations  

NASA Astrophysics Data System (ADS)

Injection of CO2 into geologic storage reservoirs induces fluid-rock reactions that may lead to the mineralization of the injected CO2. The long-term safety of geologic CO2 storage is, therefore, determined by in situ CO2-fluid-rock reactions. Currently existing monitoring and verification techniques for CO2 storage are insufficient to characterize the solubility and reactivity of the injected CO2, and to establish a mass balance of the stored CO2. Dissolved and chemically transformed CO2 thus avoid detection. We developed and are testing a new reactive tracer technique for quantitative monitoring and detection of dissolved and chemically transformed CO2 in geologic storage reservoirs. The technique involves tagging the injected carbon with radiocarbon (14C). Carbon-14 is a naturally occurring radioisotope produced by cosmic radiation and made artificially by 14N neutron capture. The ambient concentration is very low with a 14C/12C ratio of 10-12. The concentration of 14C in deep geologic formations and fossil fuels is at least two orders of magnitude lower. This makes 14C an ideal quantitative tracer for tagging underground injections of anthropogenic CO2. We are testing the feasibility of this tracer technique at the CarbFix pilot injection site in Iceland, where approximately 2,000 tons of CO2 dissolved in water are currently injected into a deep basalt aquifer. The injected CO2 is tagged with 14C by dynamically adding calibrated amounts of H14CO3 solution to the injection stream. The target concentration is 12 Bq/kg of injected water, which results in a 14C activity that is 5 times enriched compared to the 1850 background. In addition to 14C as a reactive tracer, trifluormethylsulphur pentafluoride (SF5CF3) and sulfurhexafluoride (SF6) are used as conservative tracers to monitor the transport of the injected CO2 in the subsurface. Fluid samples are collected for tracer analysis from the injection and monitoring wells on a regular basis. Results show a fast reaction of the injected CO2 with the ambient reservoir fluid and rocks. Mixing and in situ CO2-water-rock reactions are detected by changes in the different tracer ratios. The feasibility of 14C as a reactive tracer for geologic CO2 storage also depends on the analytical technique used to measure 14C activities. Currently, 14C is analyzed using Accelerator Mass Spectrometery (AMS), which is expensive and requires centralized facilities. To enable real time online monitoring and verification, we are developing an alternative detection method for radiocarbon. The IntraCavity OptoGalvanic Spectroscopy (ICOGS) system is using a CO2 laser to detect carbon isotope ratios at environmental levels. Results from our prototype of this bench-top technology demonstrate that an ICOGS system can be used in a continuous mode with analysis times of the order of minutes, and can deliver data of similar quality as AMS.

Matter, J. M.; Carson, C.; Stute, M.; Broecker, W. S.

2012-12-01

114

Domain formation in membranes with quenched protein obstacles: Lateral heterogeneity and the connection to universality classes  

NASA Astrophysics Data System (ADS)

We show that lateral fluidity in membranes containing quenched protein obstacles belongs to the universality class of the two-dimensional random-field Ising model. The main feature of this class is the absence of a phase transition: there is no critical point and macroscopic domain formation does not occur. Instead there is only one phase. This phase is highly heterogeneous with a structure consisting of microdomains. The presence of quenched protein obstacles thus provides a mechanism to stabilize lipid rafts in equilibrium. Crucial for two-dimensional random-field Ising universality is that the obstacles are randomly distributed and have a preferred affinity to one of the lipid species. When these conditions are not met standard Ising or diluted Ising universality applies. In these cases a critical point does exist which then marks the onset toward macroscopic demixing.

Fischer, T.; Vink, R. L. C.

2011-02-01

115

Microbial and Chemical Enhancement of In-Situ Carbon Mineralization in Geological Formation  

SciTech Connect

Predictions of global energy usage suggest a continued increase in carbon emissions and rising concentrations of CO2 in the atmosphere unless major changes are made to the way energy is produced and used. Various carbon capture and storage (CCS) technologies are currently being developed, but unfortunately little is known regarding the fundamental characteristics of CO2-mineral reactions to allow a viable in-situ carbon mineralization that would provide the most permanent and safe storage of geologically-injected CO2. The ultimate goal of this research project was to develop a microbial and chemical enhancement scheme for in-situ carbon mineralization in geologic formations in order to achieve long-term stability of injected CO2. Thermodynamic and kinetic studies of CO2-mineral-brine systems were systematically performed to develop the in-situ mineral carbonation process that utilizes organic acids produced by a microbial reactor. The major participants in the project are three faculty members and their graduate and undergraduate students at the School of Engineering and Applied Science and at the Lamont-Doherty Earth Observatory at Columbia University: Alissa Park in Earth and Environmental Engineering & Chemical Engineering (PI), Juerg Matter in Earth and Environmental Science (Co-PI), and Kartik Chandran in Earth and Environmental Engineering (Co-PI). Two graduate students, Huangjing Zhao and Edris Taher, were trained as a part of this project as well as a number of graduate students and undergraduate students who participated part-time. Edris Taher received his MS degree in 2012 and Huangjing Zhao will defend his PhD on Jan. 15th, 2014. The interdisciplinary training provided by this project was valuable to those students who are entering into the workforce in the United States. Furthermore, the findings from this study were and will be published in referred journals to disseminate the results. The list of the papers is given at the end of the report for reference.

Matter, J.; Chandran, K.

2013-05-31

116

Process and device for injecting a liquid agent used for treating a geological formation in the vicinity of a well bore traversing this formation  

SciTech Connect

A technique is disclosed for liquid treating a geological formation. It comprises spraying the liquid with a pressurized carrier gas, using a spraying pipe whose length and diameter are adjusted as a function of the pressure prevailing at the level of the formation and of the characteristics of the injected liquid and the pressurized carrier gas, so that the size of the liquid droplets at the outlet of the spraying pipe has a narrow range of distribution about a single preselected value.

Colonna, J.; Fitremann, Jm.; Genin, R.; Sarda, Jp.

1984-02-14

117

A dynamic flow simulation code benchmark study addressing the highly heterogeneous properties of the Stuttgart formation at the Ketzin pilot site  

NASA Astrophysics Data System (ADS)

CO2 injection at the Ketzin pilot site located in Eastern Germany (Brandenburg) about 25 km west of Berlin is undertaken since June 2008 with a scheduled total amount of about 70,000 t CO2 to be injected into the saline aquifer represented by the Stuttgart Formation at a depth of 630 m to 650 m until the end of August 2013. The Stuttgart Formation is of fluvial origin determined by high-permeablity sandstone channels embedded in a floodplain facies of low permeability indicating a highly heterogeneous distribution of reservoir properties as facies distribution, porosity and permeability relevant for dynamic flow simulations. Following the dynamic modelling activities discussed by Kempka et al. (2010), a revised geological model allowed us to history match CO2 arrival times in the observation wells and reservoir pressure with a good agreement (Martens et al., 2012). Consequently, the validated reservoir model of the Stuttgart Formation at the Ketzin pilot site enabled us to predict the development of reservoir pressure and the CO2 plume migration in the storage formation by dynamic flow simulations. A benchmark study of industrial (ECLIPSE 100 as well as ECLIPSE 300 CO2STORE and GASWAT) and scientific dynamic flow simulations codes (TOUGH2-MP/ECO2N, OpenGeoSys and DuMuX) was initiated to address and compare the simulator capabilities considering a highly complex reservoir model. Hence, our dynamic flow simulations take into account different properties of the geological model such as significant variation of porosity and permeability in the Stuttgart Formation as well as structural geological features implemented in the geological model such as seven major faults located at the top of the Ketzin anticline. Integration of the geological model into reservoir models suitable for the different dynamic flow simulators applied demonstrated that a direct conversion of reservoir model discretization between Finite Volume and Finite Element flow simulators is not feasible. Hence, the initial hexahedron meshes as applied for the ECLIPSE 100 and TOUGH2-MP/ECO2N simulations had to be converted into tetrahedron meshes to meet the convergence criteria of the Finite Element simulators DuMuX and OpenGeoSys. Our simulation results show a good agreement of reservoir pressure between all simulators, while CO2 arrival times at the observation wells strongly depend on the chosen discretization. In summary, all simulators applied are capable to address the highly complex reservoir properties present in the Stuttgart Formation at the Ketzin pilot site by dynamic flow simulations providing results of sufficient quality for prediction of future site behaviour. References Kempka, T.; Kühn, M.; Class, H.; Frykman, P.; Kopp, A.; Nielsen, C.M.; Probst, P. (2010) Modelling of CO2 arrival time at Ketzin - Part I. International Journal of Greenhouse Gas Control, Special Issue Geological CO2 Storage 4(6):1007-1015. Martens, S.; Kempka, T.; Liebscher, A.; Lüth, S.; Möller, F.; Myrttinen, A.; Norden, B.; Schmidt-Hattenberger, C.; Zimmer, M.; Kühn, M. (2012): Europe's longest-operating on-shore CO2 storage site at Ketzin, Germany: a progress report after three years of injection. Environmental Earth Sciences. 10.1007/s12665-012-1672-5.

Kempka, Thomas; Class, Holger; Görke, Uwe-Jens; Norden, Ben; Kolditz, Olaf; Kühn, Michael; Walter, Lena; Wang, Wenqing; Zehner, Björn

2013-04-01

118

Kinetics of the heterogeneously catalyzed formation of tert-amyl ethyl ether  

SciTech Connect

In this work, the kinetics and equilibrium of the heterogeneously catalyzed liquid-phase formation of tert-amyl ethyl ether (TAEE) were studied. The catalyst used was a commercial sulfonic acid ion-exchange resin (Amberlyst 16W). The experiments were carried out in a continuous stirred-tank reactor, measuring stationary reaction rates. The measured reaction rates were fitted to three kinetic models; homogeneous, Eley-Rideal type, and Langmuir-Hinshelwood type. Of these, the Langmuir-Hinshelwood type model described the experimental results best. This model is based on single-site adsorption of every component, with the surface reaction being the rate-limiting step. The activation energies for the formation of tert-amyl ethyl ether from 2-methyl-1-butene were 90 and from 2-methyl-2-butene 108 kJ/mol. For the isomerization of 2-methyl-1-butene to 2-methyl-2-butene, an activation energy of 82 kJ/mol was obtained.

Linnekoski, J.A.; Krause, A.O. [Helsinki Univ. of Technology, Espoo (Finland). Lab. of Industrial Chemistry] [Helsinki Univ. of Technology, Espoo (Finland). Lab. of Industrial Chemistry; Rihko, L.K. [Neste Oy, Porvoo (Finland). Technology Center] [Neste Oy, Porvoo (Finland). Technology Center

1997-02-01

119

Nuclear Waste Disposal in Deep Geological Formations: What are the Major Remaining Scientific Issues?  

SciTech Connect

For more than thirty years, considerable efforts have been carried out in order to evaluate the possibility of disposing of high level wastes in deep geological formations. Different rock types have been examined, such as water-under-saturated tuffs (USA), granites or crystalline rocks (Canada, Sweden, and Finland), clays (France, Belgium, and Switzerland), rock-salt (Germany). Deep clays and granites, (provided that the most fractured zones are avoided in the second case) are considered to fulfill most allocated functions, either on short term (reversibility) or long term. Chemically reducing conditions favor the immobilization of actinides and most fission products by precipitation, co-precipitation and sorption. If oxidizing conditions prevail, the safety demonstration will mostly rely on the performance of artificial confinement systems. Rock-salt offers limited performance considering the issue of reversibility, which is now perceived as essential, mostly for ethical and sociological reasons. However, several issues would deserve additional research programs, and as a first priority, a clear description of time/space succession of processes during the evolution of the repository. This will allow a better representation of coupled processes in performance assessment, such as the influence of gases (H{sub 2}) generated by corrosion, on the long term dynamics of the re-saturation. Geochemical interactions between the host formation and the engineered systems (packages + barriers) are still insufficiently described. Additional gains in performance could be obtained when taking into account processes such as isotopic exchange. Imaginative solutions, employing ceramic- carbon composite materials could be proposed to replace heavy and gas-generating overpacks, or to accommodate the small but probably significant amount of 'ultimate' wastes that will be inevitably produced by Generation IV reactor systems. (author)

Toulhoat, Pierre [Institut des Sciences Analytiques, Universite de Lyon, 43 avenue du 11 novembre 1918, Villeurbanne, 69622 (France); Scientific Direction, INERIS, Parc Technologique ALATA, BP2, Verneuil-en-Halatte, 60550, (France)

2007-07-01

120

Upscaling of flow in heterogeneous porous formations: Critical examination and issues of principle  

NASA Astrophysics Data System (ADS)

We consider heterogeneous media whose properties vary in space and particularly aquifers whose hydraulic conductivity K may change by orders of magnitude in the same formation. Upscaling of conductivity in models of aquifer flow is needed in order to reduce the numerical burden, especially when modeling flow in heterogeneous aquifers of 3D random structure. Also, in many applications the interest is in average values of the dependent variables over scales larger or comparable to the conductivity length scales. Assigning values of the conductivity Kb to averaging domains, or computational blocks, is the topic of a large body of literature, the problem being of wide interest in various branches of physics and engineering. It is clear that upscaling causes loss of information and at best it can render a good approximation of the fine scale solution after averaging it over the blocks. The present article focuses on upscaling approaches dealing with random media. It is not meant to be a review paper, its main scope being to elucidate a few issues of principle and to briefly discuss open questions. We show that upscaling can be usually achieved only approximately, and the result may depend on the particular upscaling scheme adopted. The typically scarce information on the statistical structure of the fine-scale conductivity imposes a strong limitation to the upscaling problem. Also, local upscaling is not possible in nonuniform mean flows, for which the upscaled conductivity tensor is generally nonlocal and it depends on the domain geometry and the boundary conditions. These and other limitations are discussed, as well as other open topics deserving further investigation.

Dagan, G.; Fiori, A.; Jankovic, I.

2013-01-01

121

The effects of geological heterogeneities and piezometric fluctuations on groundwater flow and chemistry in a hard-rock aquifer, southern India  

NASA Astrophysics Data System (ADS)

Crystalline aquifers of semi-arid southern India represent a vital water resource for farming communities. A field study is described that characterizes the hydrodynamic functioning of intensively exploited crystalline aquifers at local scale based on detailed well monitoring during one hydrological year. The main results show large water-table fluctuations caused by monsoon recharge and pumping, high spatial variability in well discharges, and a decrease of well yields as the water table decreases. Groundwater chemistry is also spatially variable with the existence of aquifer compartments within which mixing occurs. The observed variability and compartmentalization is explained by geological heterogeneities which play a major role in controlling groundwater flow and connectivity in the aquifer. The position of the water table within the fracture network will determine the degree of connectivity between aquifer compartments and well discharge. The presented aquifer conceptual model suggests several consequences: (1) over-exploitation leads to a drop in well discharge, (2) intensive pumping may contribute to the hydraulic containment of contaminants, (3) groundwater quality is highly variable even at local scale, (4) geological discontinuities may be used to assist in the location of drinking-supply wells, (5) modeling should integrate threshold effects due to water-table fluctuations.

Perrin, Jerome; Ahmed, Shakeel; Hunkeler, Daniel

2011-09-01

122

Evaluation of the Effect of Geological Heterogeneity on the Surfactant Transport by Performing Push-Pull Test in a Physical Aquifer Model (PAM)  

NASA Astrophysics Data System (ADS)

A surfactant flushing process is commonly used to remove light non-aqueous phase liquids (LNAPLs) such as benzene, toluene, ethylbenzene, and xylene (BTEX) by enhancing solubility of the contaminants. Since the surfactant flushing process is significantly affected by the degree of geological heterogeneity, push-pull tests in a physical aquifer model (PAM) was performed to evaluate the surfactant transport and toluene removal efficiency in a lab-scale three layered aquifer. Push-pull tests showed that maximum bromide concentration detected at a sampling port located 15 cm downgradient from an injection port was approximately 95% of average injected bromide concentration in two permeable layers (0.22±0.02 cm/min of hydraulic conductivity) and only 40% in lower permeable layers (0.05±0.02 cm/min of hydraulic conductivity). Through the push-pull tests, we also found the different mass recovery of bromide (58%), toluene (47%) and surfactant (17%) in the PAM, confirming higher absorption characteristics of the surfactant on the soil particle than other solutes. Interestingly, toluene mass recovery in the presence of excessive surfactant decreased, possibly because of adsorption of toluene mass on the surfactant attached to soil particle. Through this work, we proved soil permeability, adsorption rate of surfactant, and amount of injected surfactant should be considered to remove the LNAPL contaminants efficiently by surfactant flushing process from the heterogeneous aquifer.

Kim, Y.; Lim, D.; Park, S.; Hong, U.; Lim, J.; Lee, W.; Kwon, S.

2009-12-01

123

3rd hand smoking; heterogeneous oxidation of nicotine and secondary aerosol formation in the indoor environment  

NASA Astrophysics Data System (ADS)

Tobacco smoking is well known as a significant source of primary indoor air pollutants. However, only recently has it been recognized that the impact of Tobacco smoking may continue even after the cigarette has been extinguished (i.e., third hand smoke) due to the effect of indoor surfaces. These surfaces may affect the fate of tobacco smoke in the form of secondary reactions and pollutants, including secondary organic aerosol (SOA) formation. Fourier Transform Infrared spectrometry with Attenuated Total Reflection (FTIR-ATR) in tandem with a Scanning Mobility Particle Sizing (SMPS) system was used to monitor the ozonation of cellulose sorbed nicotine and resulting SOA formation. SOA formation began at onset of ozone introduction ([O3] = 60 ± 5 ppb) with a size distribution of dp ? 25 nm, and was determined to be a result of heterogeneous reaction (opposed to homogeneous). SOA yield from reacted surface nicotine was on the order of 10 %. Simultaneous to SOA monitoring, FTIR-ATR spectra showed surface changes in the nicotine film as the reaction progressed, revealing a pseudo first-order surface reaction rate of 0.0026 ± 0.0008 min-1. Identified surface oxidation products included: cotinine, myosmine, methylnicotinamide and nicotyrine. Surface reaction rate was found to be partially inhibited at high relative humidity. Given the toxicity of some of the identified products (e.g., cotinine has shown potential mutagenicity and teratogenicity) and that small particles may contribute to adverse health effects, the present study indicates that exposure to 3rd hand smoke ozonation products may pose additional health risks.

Petrick, Lauren; Dubowski, Yael

2010-05-01

124

Spontaneous formation of heterogeneous patches on polymer-lipid core-shell particle surfaces during self-assembly.  

PubMed

Spontaneous formation of heterogeneous patches on the surface of lipid-based nanoparticles (NPs) and microparticles (MPs) due to the segregation of two different functional groups. Patch formation is observed when tracing the functional groups with quantum dots, gold nanoparticles, and fluorescent dyes. This discovery could have important implications for the future design of self-assembled NPs and MPs for different biomedical applications. PMID:23109494

Salvador-Morales, Carolina; Valencia, Pedro M; Gao, Weiwei; Karnik, Rohit; Farokhzad, Omid C

2013-02-25

125

Source/Sink Matching for U.S. Ethanol Plants and Candidate Deep Geologic Carbon Dioxide Storage Formations  

SciTech Connect

This report presents data on the 140 existing and 74 planned ethanol production facilities and their proximity to candidate deep geologic storage formations. Half of the existing ethanol plants and 64% of the planned units sit directly atop a candidate geologic storage reservoir. While 70% of the existing and 97% of the planned units are within 100 miles of at least one candidate deep geologic storage reservoir. As a percent of the total CO2 emissions from these facilities, 92% of the exiting units CO2 and 97% of the planned units CO2 emissions are accounted for by facilities that are within 100 miles of at least one potential CO2 storage reservoir.

Dahowski, Robert T.; Dooley, James J.

2008-09-18

126

The Oil Game: Problem-based learning exercise in an Environmental Geology lecture-format class  

NSDL National Science Digital Library

This is an active engagement exercise as a capstone exercise in a unit on energy in an Environmental Geology class of non-science majors combining a 'field-based' simulation and 'office-based' geological modeling. It uses readily available supplies and easily constructed equipment that can take 1 or 2 class meetings.

Voorhees, David

127

Heterogeneous diagenetic patterns in the Pleistocene Ironshore Formation of Grand Cayman, British West Indies  

NASA Astrophysics Data System (ADS)

The Ironshore Formation on Grand Cayman consists of six unconformity-bounded units (A to F) that developed in response to repeated transgressive-regressive cycles during the Middle to Late Pleistocene. Corals and matrices in limestones from the Rogers Wreck Point (RWP), offshore George Town (GT), and western onshore (WO) areas are characterized by complex diagenetic fabrics that reflect marine (bioerosion, micrite envelopes, internal sediments, fibrous high-Mg calcite, acicular aragonite, isopachous prismatic calcite cements), freshwater phreatic (circumgranular cements, even/random blocky calcite cements), and vadose (meniscus calcite cements, blocky calcite cements) diagenesis. Throughout these limestones, the matrices have undergone more meteoric diagenetic alteration than the corals. Overall, however, no systematic stratigraphic patterns exist to the distribution of these diagenetic fabrics and it is generally impossible to link the different phases of diagenesis with specific unconformities that cap each unit. These heterogenous patterns of diagenetic features can be attributed to many intrinsic and extrinsic factors, including the original compositions of the different components in the limestones, the porosity and permeability of the substrate, the nature of the diagenetic fluids, climate, and the duration of exposure during each lowstand. Integration of available data, however, indicates that maximum diagenesis took place during the lowstands denoted by the unconformities at the top of Unit C (Marine Isotope Stage 7) and Unit D (Marine Isotope Stage 5e) when long periods of exposure were accompanied by wet climates with high annual rainfalls.

Li, Rong; Jones, Brian

2013-08-01

128

The Carancas meteorite impact crater, Peru: Geologic surveying and modeling of crater formation and atmospheric passage  

NASA Astrophysics Data System (ADS)

The recent Carancas meteorite impact event caused a worldwide sensation. An H4-5 chondrite struck the Earth south of Lake Titicaca in Peru on September 15, 2007, and formed a crater 14.2 m across. It is the smallest, youngest, and one of two eye-witnessed impact crater events on Earth. The impact violated the hitherto existing view that stony meteorites below a size of 100 m undergo major disruption and deceleration during their passage through the atmosphere and are not capable of producing craters. Fragmentation occurs if the strength of the meteoroid is less than the aerodynamic stresses that occur in flight. The small fragments that result from a breakup rain down at terminal velocity and are not capable of producing impact craters. The Carancas cratering event, however, demonstrates that meter-sized stony meteoroids indeed can survive the atmospheric passage under specific circumstances. We present results of a detailed geologic survey of the crater and its ejecta. To constrain the possible range of impact parameters we carried out numerical models of crater formation with the iSALE hydrocode in two and three dimensions. Depending on the strength properties of the target, the impact energies range between approximately 100-1000 MJ (0.024- 0.24 t TNT). By modeling the atmospheric traverse we demonstrate that low cosmic velocities (12- 14 kms-1) and shallow entry angles (<20°) are prerequisites to keep aerodynamic stresses low (<10 MPa) and thus to prevent fragmentation of stony meteoroids with standard strength properties. This scenario results in a strong meteoroid deceleration, a deflection of the trajectory to a steeper impact angle (40-60°), and an impact velocity of 350-600 ms-1, which is insufficient to produce a shock wave and significant shock effects in target minerals. Aerodynamic and crater modeling are consistent with field data and our microscopic inspection. However, these data are in conflict with trajectories inferred from the analysis of infrasound signals.

Kenkmann, T.; Artemieva, N. A.; Wünnemann, K.; Poelchau, M. H.; Elbeshausen, D.; Núñez Del Prado, H.

2009-08-01

129

Formation and evolution of the midlands of Venus: Geological features and structures, stratigraphic relationships and geologic history of the Fredegonde area (V-57)  

NASA Astrophysics Data System (ADS)

The topographic midlands on Venus comprise about 80% of the surface and an understanding of their mode of formation is essential to unraveling the geologic and geodynamic history of the planet. We explore this question by undertaking a comprehensive geological mapping of the Fredegonde Quadrangle (V-57, 50-75°S, 60-120°E, 1:5M scale) that represents the transition zone from the midlands to the lowlands at the edge of Lada Terra. We report on the geologic units and structures and the sequence of events and, thus, the major stages in the evolution of this region of the midlands. At earlier stages of evolution of the long-wavelength topography, broad (hundreds of kilometers wide) and relatively low (1-1.5 km high) topographic ridges formed due to sequential development of deformation zones, first of contractional ridge belts (NW orientation) and then crosscut by extensional groove belts (NE orientation). Arcuate swarms of graben within groove belts often form the rims of coronae and represent their tectonic component. This suggests that groove belts and coronae within the quadrangle formed simultaneously. Intersections of these deformation zones caused separation of the topography of the region into a series of broad, shallow equidimensional basins many hundreds of kilometers across and currently hundreds of meters up to a kilometer deep. Thus, the principal topographic features within the quadrangle were established near the beginning of its observable geological record. The basins then remained sites of accumulation of successive volcanic plains units such as shield plains (psh) and the lower unit of regional plains (rp1). The flows of the younger plains, such as upper unit of regional plains (rp2) and lobate plains (pl), are less voluminous, and flow down the current topographic gradients. This implies that the major topographic pattern of the Fredegonde quadrangle has been stable since its establishment. Further evidence for this is that the vast volcanic plains units (psh and rp1) that postdate the heavily tectonized units of the deformation zones are only mildly deformed. This suggests that since the emplacement of shield plains, volcanism has been the primary geologic process and that the time of formation of unit psh corresponds to a major change from the earlier regime dominated by tectonics to the later volcanically dominated regime. Consistent age relationships among the main volcanic units within the quadrangle from older shield plains, through regional plains, to lobate plains, documents an evolution in volcanic style. Shield plains were formed from small eruptions from ubiquitous small shield volcanoes and are interpreted to be derived from broadly distributed and shallow magmatic sources. The lower unit of regional plains is widely distributed but vents and flow fronts are rare; this unit is interpreted to represent massive and probably short-lived flood basalts-like eruptions that filled in the lowlands basins. The upper unit of regional plains (rp2) and lobate plains (pl) are associated with localized and distinctive sources, such as late-stage volcanic activity at coronae. Thus, the tectonic stage of evolution of coronae (formation of the rims) and the volcanic stage when coronae served as magmatic centers and sourced lava flows, were separated in time by the emplacement of the shield and lower regional plains. How and when did the major components of Venus midland topography form? Clearly, in the Fredegonde quadrangle, regional deformation produced the deformation belts and groove belts/coronae in the earliest phases, and this topography formed the basis for the next, volcanic stage of emplacement (filling of the basins), with coronae-associated volcanism following this phase. The broad topography resulting from this early phase has persisted until the present. We compare this tectonic-volcanic sequence and history of topography in the Fredegonde quadrangle with other areas on Venus and find that the sequence has widespread application globally, and that the history of topography may be similar planet-w

Ivanov, Mikhail A.; Head, James W.

2012-12-01

130

Effects of geologic heterogeneity on waterflood efficiency at Jordan field, University lands, Ector and Crane Counties, Texas  

Microsoft Academic Search

Jordan field produces oil from the Permian (Guadalupian) San Andres Formation at a depth of approximately 3500 ft on the east flank of a low, broad anticline located on the eastern side of the Central Basin platform in the Permian basin of west Texas. Since discovery in 1937, the portion of the field on university lands has produced 68 million

R. P. Major; M. H. Holtz

1989-01-01

131

Capacity investigation of brine-bearing sands of the Fwwm formation for geologic sequestration of CO{sub 2}  

SciTech Connect

The capacity of fluvial brine-bearing formations to sequester CO{sub 2} is investigated using numerical simulations of CO{sub 2} injection and storage. Capacity is defined as the volume fraction of the subsurface available for CO{sub 2} storage and is conceptualized as a product of factors that account for two-phase flow and transport processes, formation geometry, formation heterogeneity, and formation porosity. The space and time domains used to define capacity must be chosen with care to obtain meaningful results, especially when comparing different authors' work. Physical factors that impact capacity include permeability anisotropy and relative permeability to CO{sub 2}, brine/CO{sub 2} density and viscosity ratios, the shape of the trapping structure, formation porosity and the presence of low-permeability layering.

Doughty, Christine; Pruess, Karsten; Benson, Sally M.; Hovorka, Susan D.; Knox, Paul R.; Green, Christopher T.

2001-05-01

132

FOREWORD: Heterogenous nucleation and microstructure formation---a scale- and system-bridging approach Heterogenous nucleation and microstructure formation---a scale- and system-bridging approach  

Microsoft Academic Search

Scope and aim of this volume. Nucleation and initial microstructure formation play an important role in almost all aspects of materials science [1-5]. The relevance of the prediction and control of nucleation and the subsequent microstructure formation is fully accepted across many areas of modern surface and materials science and technology. One reason is that a large range of material

H. Emmerich

2009-01-01

133

Block-effective macrodispersion for numerical simulations of sorbing solute transport in heterogeneous porous formations  

Microsoft Academic Search

Heterogeneity is prevalent in aquifers and has an enormous impact on contaminant transport in groundwater. Numerical simulations are an effective way to deal with heterogeneity directly by assigning different hydraulic property values to each numerical grid block. Because hydraulic properties vary on different scales, but they cannot be sampled exhaustively and the number of numerical grid blocks is limited by

Alison E. Lawrence; Yoram Rubin

2007-01-01

134

Numerical Simulation of Behavior of Carbon Dioxide Injected into Target Geologic Formations in the Bukpyeong Basin, Korea  

NASA Astrophysics Data System (ADS)

A series of thermo-hydrological numerical simulations was performed to predict and analyze behavior of carbon dioxide injected into target geologic formations in the Bukpyeong Basin, which is one of the prospective offshore basins for geologic carbon dioxide storage in Korea. The results of the numerical simulations for the two areas in the basin show that the spatial distribution, structure (layered structure), and hydrological properties (anisotropy of intrinsic permeability) of the target geologic formations have significant impacts on three-dimensional behavior of carbon dioxide injected. The horizontal movement of carbon dioxide along the spatial distribution of a target geologic formation (Unit C-4) is more dominant than the vertical movement. As the injection amount of carbon dioxide increases, carbon dioxide plume expands furthermore and reaches to the shallower depth region from the mean sea level. Even in case of the maximum injection amount of carbon dioxide, carbon dioxide does not leak through the top boundary (sea floor) of the modeling domain for both areas. It indicates that carbon dioxide can be stored in the two areas up to their effective storage capacities of free fluid phase carbon dioxide, which was estimated in authors' previous study. As time progresses, carbon dioxide stored by hydrodynamic trapping decreases, while carbon dioxide stored by solubility trapping increases. The total mass of carbon dioxide stored by solubility trapping evaluated in this study is significantly greater than that estimated in authors' previous study. It indicates that the storage efficiency of aqueous phase carbon dioxide is greater than that of free fluid phase carbon dioxide. Therefore, this difference in the storage efficiencies of the free fluid and aqueous phases of carbon dioxide must be properly considered when more rigorous effective storage capacities of carbon dioxide are to be estimated on basin and even site scales. This work was supported by the Energy Efficiency and Resources Program funded by the Korea Institute of Energy Technology Evaluation and Planning (KETEP), Ministry of Trade, Industry and Energy, Republic of Korea.

Kihm, J.; Park, S.; Kim, J.

2013-12-01

135

Integration of Sedimentology,Petrophysics and Statistics for Characterizing the Reservoir Heterogeneity of the Late Ordovician Sarah Formation, Central Saudi Arabia  

NASA Astrophysics Data System (ADS)

The first glaciogenic event in the Arabian Peninsula is represented by the Late Ordovician Sarah Formation. Sarah Formation is outcropping in areas of central and northern Arabia bordering the Arabian Shield, while it occupies several sub-basinal areas in the subsurface. The glacio-fluvial Sarah Formation is considered as an important tight gas reservoir target. This study uses the outcrop analog of the Sarah Formation to characterize the reservoir heterogeneity of the paleovalleys based on sedimentological, petrophysical, and statistical approaches. Facies types and architectural elements were identified within several paleovalleys of the Sarah Formation. The study indicated variability in texture, composition, sandstone type, facies, geometry and architecture at outcrop scale. Outcrop relationships also showed vertical and lateral facies change with other Paleozoic formations. The integration of field and laboratory data helped identifying the heterogeneity within Sarah paleovalleys. The reservoir quality trends in the Sarah Formation show variations that might be due to the controls of facies, depositional environments, and paleogeography. Three measures of heterogeneity were applied on the petrophysical data for various paleovalleys of the Sarah Formation. Those measures are: the coefficient of variation, Dykstra-Parsons, and Lorenz coefficients.The coefficient of variation values indicate extremely heterogeneous distribution. Dykstra-Parsons coefficient values suggest very to extremely heterogeneous reservoirs. Lorenz coefficients show good correlation with Dykstra-Parsons coefficient for Sarah paleovalleys. The studied heterogeneity measures indicate that Sarah paleovalleys represent very to extremely heterogeneous reservoirs.

El-Deek, Islam; Abdullatif, Osman; Korvin, Gabor; Al-Ramadan, Khalid

2014-05-01

136

Effect of pattern formation on C and N turnover heterogeneity in initial soils  

NASA Astrophysics Data System (ADS)

The formation of vegetation patterns and hydrological processes, among others, result in soil heterogeneity in newly exposed land surfaces. We studied the effect of these developling structures on carbon and nitrogen trunover in soils of the artificial catchment Chicken Creek (Schaaf et al. 2011, 2012). Substrates with different physical and geochemical properties in combination with different labelled plant litter materials were studied in a microcosm experiment over a period of 80 weeks. Main objectives of the microcosm experiment were to determine the transformation processes of C and N from litter decomposition within the gaseous, liquid and solid phase, the interaction with mineral surfaces and its role for the establishment of biogeochemical cycles. The microcosm experiments were established in a climate chamber at constant 10 °C. In total, 48 soil columns (diameter: 14.4 cm; height: 30 cm) were filled with two different quaternary substrates (sand and loamy sand) representing the textural variation within the catchment at a bulk density of 1.4-1.5 g cm-3. The columns were automatically irrigated with artificial rainwater four times a day with 6.6 ml each (corresponding to 600 mm yr-1). The gaseous phase in the headspace of the microcosms was analyzed continuously for CO2 and N2O concentrations. C and N transformation processes were studied using 13C and 15N labelled litter of two different plant species occurring at the catchment (Lotus corniculatus, Calamagrostis epigejos) that was incorporated into the microcosm surface. By including litter from species with wide distribution within the catchment and soil substrates representing the main variation types of the sediments used for catchment construction we were able to characterize the general function of these sub-patches within the catchment with respect to litter decomposition, soil solution composition, DOC and nutrient leaching, and impact on the mineral soil phase. The results suggest that initial differences in substrate composition in combination with invading vegetation leads to the development of patterns with different biogeochemical process intensities within the catchment. These patterns are not mere additive effects of substrates plus litter, but reflect differences in element cycling. Schaaf, W., Bens, O., Fischer, A., Gerke, H.H., Gerwin, W., Grünewald, U., Holländer, H.M., Kögel-Knabner, I., Mutz, M., Schloter, M., Schulin, R., Veste, M., Winter, S. & Hüttl, R.F. (2011): Patterns and processes of initial terrestrial ecosystem development. J Plant Nutr Soil Sci, 174, 229-239. Schaaf, W., Elmer, M., Fischer, A., Gerwin, W., Nenov, R., Pretzsch, H., Seifert, S., Winter, S., Zaplata, M. (2012): Monitoring the formation of structures and patterns during initial development of an artificial catchment. Environmental Monitoring and Assessment. doi: 10.1007/s10661-012-2998-x.

Schaaf, Wolfgang; Zimmermann, Claudia

2013-04-01

137

Saharan dust and heterogeneous ice formation: Eleven years of cloud observations at a central European EARLINET site  

Microsoft Academic Search

More than 2300 observed cloud layers were analyzed to investigate the impact of aged Saharan dust on heterogeneous ice formation. The observations were performed with a polarization\\/Raman lidar at the European Aerosol Research Lidar Network site of Leipzig, Germany (51.3°N, 12.4°E) from February 1997 to June 2008. The statistical analysis is based on lidar-derived information on cloud phase (liquid water,

P. Seifert; A. Ansmann; I. Mattis; U. Wandinger; M. Tesche; R. Engelmann; D. Müller; C. Pérez; K. Haustein

2010-01-01

138

Investigation of the geologic setting and geomorphic processes that control the formation and preservation of precarious rock zones  

NASA Astrophysics Data System (ADS)

Zones of precariously balanced rocks have been used as negative indicators of previous strong ground motion in seismically active regions of Southern California and Nevada (e.g. Brune 1996). Understanding the geologic context and the geomorphic framework that control the formation and preservation of precarious rocks is essential to testing their fidelity for extreme ground motion analyses. In this study we assess the geologic settings and the geomorphic processes nested within them using precarious rock zones (Granite Dells, Texas Canyon, and Granite Pediment) in low-seismicity regions of Arizona and Southern California. The Granite Dells locality is a ~20 km2 Proterozoic granite field that is ~5 km from the Prescott Valley graben faults (<0.2 mm/yr of Quaternary slip). The Texas Canyon locality is a ~132 km2 Mesozoic granite field that is ~23 km from the Little Rincon Mountains fault (<0.2 mm/yr of Quaternary slip). The Granite Pediment locality is a ~12 km2 Mesozoic granite pediment located ~96 km from the eastern section of the Garlock fault (<5 mm/yr of Quaternary slip). Characterization of the geologic context of each site included assembling a digital geologic database for Arizona, Southern California, and southern Nevada. The geologic database was queried for granitic bodies and Quaternary deposits. Active faults were categorized by their Quaternary slip rates, and a 20 km zone of no precarious rocks was created around each active fault based on the field surveys of Brune (1996). Aerial photographs were used to map the spatial distribution and geometry of joint sets within each site. Ground surveys using hand-held GPS units and digital photography were conducted to document the characteristics (lithology, size, fragility, weathering characteristics) and spatial density of precariously balanced rocks. Morphometric analyses of digital elevation data may indicate if there is a slope or relief range which the precarious rocks are optimally produced and/or preserved.

Haddad, D.; Arrowsmith, R.

2008-12-01

139

Assessment of the Geologic Carbon Dioxide Storage Resources of the Clinton, Medina, and Tuscarora Formations in the Appalachian Basin  

NASA Astrophysics Data System (ADS)

The U.S. Geological Survey (USGS) has completed an assessment of the geologic carbon dioxide (CO2) storage potential within the Appalachian Basin. This assessment was performed as part of the USGS national assessment of geologic CO2 storage resources in which individual sedimentary basins are divided into storage assessment units (SAUs) based on geologic characteristics such as lithology, porosity, permeability, reservoir depth, formation water salinity, and the presence of a regional sealing formation. This study focuses on the assessment of the Clinton, Medina and Tuscarora Formations storage assessment unit (SAU) that covers an area of 48.9 million acres in eastern Kentucky and Ohio, West Virginia, northern and western Pennsylvania, and southwestern New York. The areal extent of the SAU is defined on the western boundary by the 100 foot isopach contour of the combined Rochester and Rose Hill Shales that acts as the regional sealing formation and is defined by the 3,000 foot depth to top contour of the Clinton and Tuscarora Formations elsewhere. Depth-to-top and isopach contours were derived from IHS Energy Group, 2011 data for over 25,000 unique boreholes located throughout the area of the SAU. The Clinton, Medina and Tuscarora Formations SAU is composed of the porous intervals of the Lower to Middle Silurian strata that is bounded by the underlying Ordovician age Queenston Shale, and the overlying Silurian age Rochester and Rose Hill Shales. Porous intervals were deposited in a variety of wave and tidal dominated environments as a result of a Lower Silurian shoreline that prograded southeast to northwest. Porous units in the Tuscarora Formation in southwestern and central Pennsylvania and West Virginia are predominantly fine to medium grained sands of alluvial plain facies and those of the Clinton and Medina Formations in southwestern New York, northeastern Pennsylvania, eastern Ohio and northeastern Kentucky are typically fine grained quartzarenites deposited in littoral, deltaic, and offshore marine environments. The mean total thickness and thickness of the net porous interval, determined from geophysical logs, are 200 and 100 feet respectively at depths between 3,000 and 13,000 feet. Input parameters used to calculate the volume of technically available storage resources in the Clinton, Medina and Tuscarora Formations SAU include the area and net porous thickness of the SAU, a mean porosity of 9% for the net porous interval, and a permeability of 13 millidarcys for the net porous interval. Both the mean porosity and permeability used as input parameters for the SAU were determined by examining reported porosity and permeability values for petroleum reservoirs throughout the study area. Buoyant trapping pore volumes were determined by examining reported pore volumes of known petroleum plays within the SAU and extrapolating into areas where CO2 storage potential may exist in the absence of petroleum resources. The Clinton, Medina and Tuscarora Formations SAU has geologic storage resources to hold a mean of 32.1 megatons (Mt) of CO2, with 31Mt as buoyant trapping storage resources and 1.1 Mt as residual trapping storage resources.

Doolan, C.

2013-12-01

140

Heterogeneous Catalysis.  

ERIC Educational Resources Information Center

Described is a heterogeneous catalysis course which has elements of materials processing embedded in the classical format of catalytic mechanisms and surface chemistry. A course outline and list of examples of recent review papers written by students are provided. (MVL)

Miranda, R.

1989-01-01

141

High-temperature seafloor hydrothermal circulation over geologic time and archean banded iron formations  

Microsoft Academic Search

Under the assumption of simple plate tectonics with a range of continental growth scenarios, we construct models of global lithospheric heat loss, hydrothermal heat loss and hydrothermal iron flux to the ocean as functions of geologic time from 4.0 Ga to present. The models show that lithospheric heat loss scales with the square root of the plate creation rate, whereas

Robert P. Lowell; Susan M. Keller

2003-01-01

142

Nanoparticles and their influence on radionuclide mobility in deep geological formations  

Microsoft Academic Search

This article gives an overview of the current status of knowledge concerning the role of nanoparticles (inorganic and organic) in deep geological host rocks and the potential influence of these nanoparticles on radionuclide migration in far-field systems. The manuscript is not intended to be a full review paper or overview paper concerning nanoparticles, here the intention is to refer to

Thorsten Schäfer; Florian Huber; Holger Seher; Tiziana Missana; Ursula Alonso; Michael Kumke; Sascha Eidner; Francis Claret; Frieder Enzmann

143

Comparison between a vertical equilibrium model and a three-dimensional multiphase flow model for CO2 sequestration in geologic formations  

NASA Astrophysics Data System (ADS)

The vertical equilibrium (VE) approach, assuming pore fluid pressure equilibrium in a vertical direction, becomes more popular within the CO2 geosequestration research community due to its computational efficiency compared to three-dimensional multiphase flow models. However, the accuracy of this simplified pseudo 3-D numerical method has not fully verified for basin-scale geologic CO2 storage applications. To address this problem, we have compared CO2 plume migration in a homogeneous aquifer for benchmarking, calculated by both VE approach and 3-D model implemented by TOUGH2/ECO2N code. Then further comparison on injected fluid pressure and CO2 transport was performed using a more complicated numerical grid having a realistic reservoir topology. Preliminary results show that the VE model is generally in good agreement with the 3-D model in terms of overpressure ratio, whose values are similar and reach ~60% at the injection well installed in the reservoir with permeability of 4.0 x 10-14m2 and porosity of 15%. The migration distance of CO2 plume estimated by both models also matched closely, showing ~10 km dispersion along with flow path after 0.5 MtCO2/year injection for 50 years. The results also suggest that the VE approach can be an efficient alternative method for CO2 storage modeling, especially when reservoir formations have relatively small vertical heterogeneity.

Jung, Byeongju; Tian, Liang; Niemi, Auli

2014-05-01

144

The Enigmatic Longevity of Granular Materials on Mars: The Case for Geologically Episodic Dune Formation  

NASA Technical Reports Server (NTRS)

Martian sand dunes are concentrated in vast sand seas in the circumpolar belt of the planet's northern hemisphere, but they are also pervasive over the whole planet. Their occurrence is to be expected on a super-arid planetary surface subjected to boundary layer drag from a continually active atmosphere. Whilst their occurrence is to be expected, their survival is enigmatic. But the enigma only arises if the martian system is considered similar to Earth's --where sand is moved highly frequently, more or less on a seasonal basis. Experimentally it is readily demonstrated that active sand will soon wear down to small grains and eventually diminish to below the critical sand size required to sustain dune formation. According to conventional wisdom, sand moves at higher speeds on Mars than on Earth, and if it were to move as frequently as it does on Earth, then the dune-forming sand population should have long since disappeared, given the great longevity of the martian aeolian system (Sagan coined the term "kamikaze" grains to express this disappearance). No supply of sand could keep pace with this depletion, especially in light of the fact that Mars does not have very active weathering, nor significant crustal differentiation. On Earth, plate tectonics, magmatic activity, and general crustal differentiation over geological time have produced great concentrations of quartz crystals in the continental crustal masses. Not only are these quartz grains chemically and mechanically resilient, they are about the right size for being transported by either wind or water. Add to this, the geologically recent contribution of glacial grinding, and it is easy to see why there are dune field on Earth. So what are the martian dunes composed of, and how does the material survive the eons of attrition? In addition to experimental demonstrations of sand comminution in laboratory aeolian simulations, the problem can be approached from first principles. Sagan showed that by simple considerations of material strength versus mechanical work applied to the material, comminution to sub-sand size would be inevitable. Another semi-analytical approach might be taken by considering that the archetypal aeolian sand surface texture is an irregularly pitted ("frosted") surface composed of chipping hollows approximately 10 microns in diameter, 5 microns deep. Their volume = about 250 cubic microns, or about 1/25000 of the volume of a 100 micron diameter dune grain. Because a saltating grain always strikes another grain, then two surfaces are impacted. Thus each grain undergoes two impacts for every one saltation leap, when the impact statistics are considered for a closed dune system (it can be calculated that a grain can never undergo <1 impact, and never >2 per saltation leap). Hence, if we conservatively assume that there is damage to a grain each time it bounces, but with the minimum damage of only 2 microscopic craters per impact, then approximately 12,500 impacts are required to completely eliminate the grain. Of course, it would require only a fraction of this amount to reduce the grain to below sand size. A grain will make only several tens of saltation leaps on the stoss side of a dune before becoming buried on the lee slope. The dune then has to move its full length before the grain is exhumed again for abrasion. Even with this hiatus in transport, it is easy to see that terrestrial dunes need resupplying with sand in order to survive. In recent theoretical work it has been shown that martian aeolian transport may be initiated with high-speed grains, but this converts to a lower energy dynamic transport equilibrium in which a reptation population dominates grain transport (on Earth, at least half of the flux is by reptation and creep). On Mars, therefore, average grain speeds may be lower than those on Earth, or at least comparable. This would permit greater longevity for martian sands, but it would not go far enough to solve the survival problem. It may, however, explain why martian dunes are about the same size as terr

Marshall, J.

1999-01-01

145

Numerical Study of Artificial Seal Formation to Remedy Leakage from Geological CO2 Storage Reservoirs  

NASA Astrophysics Data System (ADS)

In the Carbon dioxide Capture and Storage (CCS), the CO2 is captured from emission source and stored into geological reservoirs at a depth below 800 m. The injected CO2 is less dense than water, and as a result, it tends to migrate upward. For trapping to inhibit the upward migration of CO2, the reservoirs should be covered with a sufficiently impermeable seal, i.e. caprock. However, the caprock may contain imperfections such as faults and fractures which will play a role of a high permeability path to arise leakage of the injected CO2 from the reservoirs. Pressurization with the injected CO2 can create fissures that may transmit CO2 through the caprock (Zoback and Zinke, 2002). Preparing for such risk of CO2 leakage through pre-existing and/or induced fractures, the International Energy Agency (IEA) has pointed out the importance of establishing a ready-to-use strategy for remediation of leakage from CO2 storage reservoirs (IEA, 2007). As one possibility to realize the strategy, we have proposed a concept to use an aqueous solution (Ito et al., 2006). The solution will have a sufficiently-low viscosity for passing through even small aperture, and it will not impact formation permeability as long as the solution is left as it is. When the solution encounters dissolved CO2, precipitation will occur due to chemical reaction. As a result, the permeability will be reduced by filling the pores and fractures in the rocks with the precipitates. In the present study, we demonstrated first this idea through laboratory experiments simulating subsurface condition at 1000 m deep, i.e. 10 MPa and 40 deg. C, and using a silicate solution reacting with CO2. In this case, the solution - CO2 reaction will produce precipitates of amorphous silica. The results of laboratory experiments show that the present method led to a 99 % permeability reduction in a glass-bead artificial rock even its initially-high permeability of few darcy. Such reduction of permeability was reproduced successfully by the non-isothermal reactive geochemical transport program TOUGHREACT (Xu and Pruess, 2001; Xu et al., 2006). Based upon these success, the present method was applied by numerical modelling to a 2-D caprock-aquifer system under field physical and chemical conditions. Then we considered typical two cases to remedy CO2 leakage from a reservoir, in which the silica solution are injected after and before the occurrence of CO2 leakage respectively. For both the cases, the silica precipitates were produced and they filled up pores around outlet of the leakage path so sufficiently that the CO2 migration was blocked, and the condition was confirmed stable over a long time.

Ito, T.; Tanaka, H.; Xu, T.

2011-12-01

146

Reservoir geology and paleoenvironmental reconstruction of Yates Formation, Central Basin Platform, West Texas  

Microsoft Academic Search

Computer slice maps and proprietary three-dimensional interactive graphics were used to reconstruct the paleodeposition and to map reservoir variations within the Yates Formation of west Texas. The prolific Yates Formation is a major reservoir in the North Ward Estes field, Ward County, Texas. The Upper Permian (Guadalupian) Yates Formation is an overall regressive shallowing-upward package containing variable sequences of subtidal,

R. R. Casavant

1988-01-01

147

A Comparative Study on Uncertainty Quantification for Flow in Randomly Heterogeneous Media Using Monte Carlo Simulations and Conventional and KL-Based Moment-Equation Approaches  

Microsoft Academic Search

Geological formations are ubiquitously heterogeneous, and the equations that govern flow and transport in such formations can be treated as stochastic partial differential equations. The Monte Carlo method is a straightforward approach for simulating flow in heterogeneous porous media; an alternative based on the moment-equation approach has been developed in the last two decades to reduce the high computational expense

Zhiming Lu; Dongxiao Zhang

2004-01-01

148

Combined isotope and enantiomer analysis to assess the fate of phenoxy acids in a heterogeneous geologic setting at an old landfill.  

PubMed

Phenoxy acid herbicides and their potential metabolites represent industrial or agricultural waste that impacts groundwater and surface waters through leaching from old landfills throughout the world. Fate assessment of dichlorprop and its putative metabolite 4-CPP (2-(4-chlorophenoxy)propionic acid) is frequently obstructed by inconclusive evidence from redox conditions, heterogeneous geologic settings (e.g. clay till) and ambiguous parent-daughter relationships (i.e. 4-CPP may be daughter product or impurity of dichlorprop). For the first time, a combination of four methods was tested to assess transformation of phenoxy acids at a contaminated landfill (Risby site): analysis of (i) parent and daughter compound concentrations, (ii) enantiomer ratios (iii) compound-specific isotope analysis and (iv) enantiomer-specific isotope analysis. Additionally, water isotopes and chloride were used as conservative tracers to delineate two distinct groundwater flow paths in the clay till. Metabolite concentrations and isotope ratios of chlorinated ethenes demonstrated dechlorination activity in the area with highest leachate concentrations (hotspot) indicating favorable conditions also for dechlorination of dichlorprop to 4-CPP and further to phenoxypropionic acid. Combined evidence from concentrations, enantiomer ratios and isotope ratios of dichlorprop and 4-CPP confirmed their dechlorination in the hotspot and gave evidence for further degradation of 4-CPP downgradient of the hotspot. A combination of 4-CPP enantiomer and isotope analysis indicated different enantioselectivity and isotope fractionation, i.e. different modes of 4-CPP degradation, at different locations. This combined information was beyond the reach of any of the methods applied alone demonstrating the power of the new combined approach. PMID:23168311

Milosevic, N; Qiu, S; Elsner, M; Einsiedl, F; Maier, M P; Bensch, H K V; Albrechtsen, H-J; Bjerg, P L

2013-02-01

149

Time-related capture zones for contaminants in randomly heterogeneous formations  

Microsoft Academic Search

Prediction of solute travel distance based on homogeneous and isotropic hydraulic conductivity may lead to substantial differences in the actual travel distance in a heterogeneous system. The effect of randomly varying hydraulic conductivity on the spatial location of time-related well capture zones for a nonreactive tracer in a confined aquifer with uniform base flow is considered. A numerical Monte Carlo

Alberto Guadagnini; Silvio Franzetti

1999-01-01

150

Stochastic analysis of unsaturated steady state flow through bounded heterogeneous formations  

Microsoft Academic Search

The effort of heterogeneity in saturated hydraulic conductivity (Ks) and in a pore-scale distribution parameter (alpha) on unsaturated steady state flow in bounded domains is studied. The properties are assumed to be random space functions having stationary means and covariances. An analytic model based on small-perturbation approximation in Ks and alpha for predicting the spatial moments of the pressure head

Peter Indelman; Dani; Yoram Rubin

1993-01-01

151

Geologic Assessment of Undiscovered Oil and Gas Resources-Oligocene Frio and Anahuac Formations, United States Gulf of Mexico Coastal Plain and State Waters.  

National Technical Information Service (NTIS)

The Oligocene Frio and Anahuac Formations were assessed as part of the 2007 U.S. Geological Survey (USGS) assessment of Tertiary strata of the U.S. Gulf of Mexico Basin onshore and State waters. The Frio Formation, which consists of sand-rich fluvio-delta...

A. W. Karlsen B. J. Valentine S. M. Swanson

2013-01-01

152

Geological and geochemical model of formation of oil and gas accumulations in the South Caspian basin  

SciTech Connect

The South Caspian Sea, Azerbaijan, has been a major petroleum producer since 1848 and is still one of the premier prospective areas for oil and gas in the Soviet Union. Many years of research studies suggest oil and gas in the Soviet Union. Many years of research studies suggest an area of increased prospectivity in the deeper part of the Caspian Sea. Geologic history recorded that a trough developed during the Mesozoic through the Tertiary. The sedimentary sequence is up to 23 km thick. The Pliocene sequence is the major proven productive and prospective interval. Multiple stages of active sedimentation and tectonism took place starting in the early Pliocene and ending in the late Pliocene. Traps were formed and destroyed during the early to late Pliocene. The final tectonic events during the late Pliocene trapped the remigrated oil. Gas and gas condensate probably are within the lower reaches of the basin. Because of the rapid deposition, mud volcanoes were also active. Many are still active today and can be noted in proximity to hydrocarbon deposits. Rapid subsidence and deposition, and anomalously low geothermal regime, and a low maturity of sampled organic matter from the Pliocene section leads to the hypothesis of hydrocarbon generation at depth from older sedimentary rocks. With this proposed geological and geochemical model, the prospectivity for oil and gas deposits is greatly enhanced in aerial extent and possibly to a depth of 9 km.

Narimanov, A.A.

1991-08-01

153

The effect of random recharge on uniform steady free-surface flow in heterogeneous porous formations  

Microsoft Academic Search

The effect of parametric uncertainty in recharge rate and spatial variability of hydraulic conductivity upon free-surface flow is investigated in a stochastic framework. We examine the three-dimensional free-surface gravitational flow problem for sloped mean uniform flow in a randomly heterogeneous porous medium under the influence of random recharge. We develop analytic solutions for the variance of free-surface position, head, and

O. Amir

2004-01-01

154

Heterogeneities of a low permeability exhumed petroleum reservoir, El Abra Formation, Sierra el Abra, NE Mexico  

Microsoft Academic Search

Characterization of heterogeneities in low-permeability petroleum reservoirs is typically problematic, mostly due to the lack of research on three dimensional reservoir analogs. In the Sierra el Abra of northeastern Mexico there is an exhumed petroleum reservoir exposing mid-Cretaceous Abra Limestone. This unit is the reservoir for the famous Golden Lane fields of northeast Mexico. This study focused on three-dimensional exposures

Sean T. Brennan

1996-01-01

155

Formation of double glass in binary mixtures of anisotropic particles: dynamic heterogeneities in rotations and displacements.  

PubMed

We study glass behavior in a mixture of elliptic and circular particles in two dimensions at low temperatures using an orientation-dependent Lennard-Jones potential. The ellipses have a mild aspect ratio (?1.2) and tend to align at low temperatures, while the circular particles play the role of impurities disturbing the ellipse orientations at a concentration of 20%. These impurities have a size smaller than that of the ellipses and attract them in the homeotropic alignment. As a result, the coordination number around each impurity is mostly 5 or 4 in glassy states. We realize double glass, where both the orientations and the positions are disordered but still hold mesoscopic order. We find a strong heterogeneity in the flip motions of the ellipses, which sensitively depends on the impurity clustering. In our model, a small fraction of the ellipses still undergo flip motions relatively rapidly even at low temperatures. In contrast, the nonflip rotations (with angle changes not close to ±?) are mainly caused by the cooperative configuration changes involving many particles. Then, there arises a long-time heterogeneity in the nonflip rotations closely correlated with the dynamic heterogeneity in displacements. PMID:24229182

Takae, Kyohei; Onuki, Akira

2013-10-01

156

Formation of double glass in binary mixtures of anisotropic particles: Dynamic heterogeneities in rotations and displacements  

NASA Astrophysics Data System (ADS)

We study glass behavior in a mixture of elliptic and circular particles in two dimensions at low temperatures using an orientation-dependent Lennard-Jones potential. The ellipses have a mild aspect ratio (˜1.2) and tend to align at low temperatures, while the circular particles play the role of impurities disturbing the ellipse orientations at a concentration of 20%. These impurities have a size smaller than that of the ellipses and attract them in the homeotropic alignment. As a result, the coordination number around each impurity is mostly 5 or 4 in glassy states. We realize double glass, where both the orientations and the positions are disordered but still hold mesoscopic order. We find a strong heterogeneity in the flip motions of the ellipses, which sensitively depends on the impurity clustering. In our model, a small fraction of the ellipses still undergo flip motions relatively rapidly even at low temperatures. In contrast, the nonflip rotations (with angle changes not close to ±?) are mainly caused by the cooperative configuration changes involving many particles. Then, there arises a long-time heterogeneity in the nonflip rotations closely correlated with the dynamic heterogeneity in displacements.

Takae, Kyohei; Onuki, Akira

2013-10-01

157

GEODYN2: A Bottom Hole Assembly. Geological Formation Dynamic Interaction Computer Program.  

National Technical Information Service (NTIS)

This paper describes the current development of a three-dimensional transient dynamic finite element computer program, GEODYN2, capable of simulating the behavior of a rotating bottom hole assembly (BHA) interacting with a non-uniform formation. The GEODY...

J. A. Baird B. C. Caskey D. N. Wormley C. M. Stone

1985-01-01

158

The geology and geochemistry of the Maru Banded Iron-Formation, northwestern Nigeria  

Microsoft Academic Search

Narrow units (< 1–30 m thick) of banded iron-formation (BIF) occur in the low-grade schist belt of the Maru district, northwest Nigeria. The schist belt consists of a deformed sequence of pelitic to semi-pelitic phyllites with subordinate iron-formation and quartiztes, and also amphibolites of inferred tholeiitic volcanic origin. The Maru BIF is commonly interlayered with phyllites within an antiformal fold.

J. A. Adekoya

1998-01-01

159

The impact of mantle heterogeneity on oceanic core complex formation, 12-16°N, Mid-Atlantic Ridge  

NASA Astrophysics Data System (ADS)

The 12-16°N segment of the Mid-Atlantic Ridge has two fundamentally different modes of seafloor spreading: symmetric and asymmetric. The central part of this segment (~14°N) is characterized by continuous axial rift valleys flanked by normal faults with high length/displacement ratios. In contrast, crust that has spread asymmetrically within this segment features shorter fault scarp lengths, outward tilted surfaces, nodal basins, discontinuous neovolcanic zones and has a more irregular bathymetric character. Asymmetric spreading is a result of amagmatic tectonic extension and is accommodated by very-large-offset low-angle normal faults. These faults expose a complete section through the mafic crust to serpentinized mantle on the seafloor. Collectively, tectonic, magmatic and hydrothermal processes lead to the formation and character of oceanic core complexes. Dredged peridotites from this region are predominantly harzburgites. Electron microprobe analyses of accessory chromian spinel suggest at least 16 to 20% melt extraction preceded their exposure. However, it is difficult to reconcile the high melt volumes implied by the peridotite with thin, absent, and asymmetrically spreading crust. This evidence supports our prior suggestions that magma supply, and oceanic core complex formation, within these ridge segments is controlled by mantle heterogeneities. Heterogeneities may include, but are not limited to, garnet-pyroxenite sources that produce high volume melts and ultra-depleted mantle that produce little melt. Large segments of the mantle are likely receiving a free ride to the surface without significant melting in the region.

Barnard, A.; Casey, J. F.; Chang, T.; Murton, B. J.

2012-12-01

160

Geology and ground-water resources of the Cockfield Formation in western Tennessee  

USGS Publications Warehouse

The Cockfield Formation of the Claiborne Group of Tertiary age underlies approximately 4,000 sq mi in western Tennessee. The formation consists primarily of lenticular beds of very fine to coarse sand, silt, clay, and lignite. The Cockfield Formation has been extensively eroded, and the original thickness is preserved only in a few areas where the formation ranges from 235 to 270 ft in thickness. Recharge to the Cockfield aquifer is from precipitation on sparse outcrops or by downward infiltration of water from the overlying fluvial deposits of Tertiary and Quaternary age and alluvium of Quaternary age or, where present, the overlying Jackson Formation of Tertiary age. Data from two observation wells indicate that water levels have risen at average rates of about 0.5 and 0.7 ft/year during the period 1980-85. Water from the Cockfield aquifer is a calcium bicarbonate type that contains low concentrations of most major constituents, and generally is suitable for most uses. Dissolved-solids concentrations range from 44 to 218 mg/L. Data from two aquifer tests indicate transmissivities of 2,500 and 6 ,000 sq ft/day and storage coefficients of 0.0003 and 0.0007, respectively. The Cockfield aquifer presently provides small to moderate quantities of water for several public and industrial water supplies and small quantities to numerous domestic and farm wells. Withdrawals for public and industrial supplies in 1983 averaged about 3.3 million gal/day. (USGS)

Parks, W. S.; Carmichael, J. K.

1990-01-01

161

Effects on the mobility of metals from acidification caused by possible CO? leakage from sub-seabed geological formations.  

PubMed

Carbon dioxide capture and storage (CCS) in submarine geological formations has been proposed as a mitigation measure for the prevention of global warming. However, leakage of CO2 to overlying sediments may occur over time, leading to various effects on ecosystems. Laboratory-scale experiments were performed, involving direct release of carbon dioxide into sediment, inside non-pressurized chambers, in order to provide data on the possible effects of CO2 leakage from geological storage sites on the fate of several metals. Marine sediments from three sites with different levels of contamination were sampled and submitted to acidification by means of CO2 injection. The experiment lasted 10 days and sediment samples were collected at the beginning and end of the experiment and pore water was extracted for metal analysis. The results revealed that mobility of metals from sediment to pore water depends on the site, metal and length of time exposed. Mobilization of the metals Al, Fe, Zn, Co, Pb and Cu increases with acidification, and this response generally increases with time of exposure to CO2 injection. The geochemical model applied suggests that acidification also influences the speciation of metals, transforming metals and metalloids, like As, into species much more toxic to biota. The data obtained from this study will be useful for calculating the potential risk of CCS activities to the marine environment. PMID:24144940

de Orte, Manoela Romanó; Sarmiento, Aguasanta M; Basallote, Maria Dolores; Rodríguez-Romero, Araceli; Riba, Inmaculada; Delvalls, Angel

2014-02-01

162

Modeling the composition of the pore water in a clay-rock geological formation (Callovo-Oxfordian, France)  

NASA Astrophysics Data System (ADS)

The interstitial water contained in the microporosity of highly compact clay-rich media does not obey the classical condition usually used to derive the ionic composition of a solution. This is because the requirement for global electroneutrality of a charged microporous body (one having a significant fraction of pores with dimensions of the same order of size as the diffuse double layer) implies that the net charge density of the pore water must balance the deficiency (or the excess) of electrical charge carried by the solid matrix. In order to determine the solution composition in the micropores of a clay-rock, we first generalize the Donnan equilibrium conditions for the case of a multi-ionic electrolyte, with partitioning of the charge compensating counterions between the Stern and the diffuse layers A material-specific geochemical equilibrium model, incorporating an electrical triple layer model for adsorption reactions, is used to calculate the partition coefficient for the compensating ion charge (i.e., the fraction of charge in the Stern layer). This is then used to calculate the osmotic pressure and ionic composition of the pore water in the micropores. The material considered in this study is the argillite clay-rock sampled from the Callovo-Oxfordian geological formation under consideration in France for a deep geological disposal facility for radioactive waste.

Leroy, P.; Revil, A.; Altmann, S.; Tournassat, C.

2007-03-01

163

Geologic structure and altitude of the top of the Minnelusa Formation, northeastern Black Hills, South Dakota  

USGS Publications Warehouse

This map shows the altitude of the top of the Permian--and Pennsylvanian age Minnelusa Formation, the deepest aquifer in the northeastern Black Hills for which there is sufficient data available to construct a structural map. The Minnelusa Formation outcrops in the western part of the map area and is more than 3 ,600 ft below land surface in the northeastern corner of the area. The formation consists of interbedded sandstone, sandy dolomite and limestone, shale, siltstone, gypsum, and anhydrite. The upper beds are an aquifer and the lower beds are a confining or semi-confining unit. Small anticlines and synclines parallel the Minnelusa outcrop. Domal structures and peaks in the study area are the result of Tertiary-age intrusions. (USGS)

Peter, Kathy D.; Kyllonen, David P.; Mills, Kathy R.

1988-01-01

164

Inventory of Shale Formations in the US, Including Geologic, Hydrological, and Mechanical Characteristics  

SciTech Connect

The objective of this report is to build upon previous compilations of shale formations within many of the major sedimentary basins in the US by developing GIS data delineating isopach and structural depth maps for many of these units. These data are being incorporated into the LANL digital GIS database being developed for determining host rock distribution and depth/thickness parameters consistent with repository design. Methods were developed to assess hydrological and geomechanical properties and conditions for shale formations based on sonic velocity measurements.

Dobson, Patrick; Houseworth, James

2013-11-22

165

The Use of Photo-projects and Term Projects in Large-Format (200+ Students) Introductory Geology Courses.  

NASA Astrophysics Data System (ADS)

Photo-projects have long been utilized as a way of getting students in introductory geology courses to apply what they have learned in lecture to the outcrop and landscape. While the projects have many benefits, we have found that with large-format classes of 200+ students, where a mandatory field trip is logistically impossible, many problems can arise. One problem has been that of consistent and timely grading, which can be addressed by a project that can be turned in throughout the course of the semester and by utilizing a grading rubric. Also, in many cases, students simply take photographs of "scenery" and then try to identify features/processes with little thought as to whether that particular feature/process can occur in that geologic setting (such as identifying features as having a glacial origin in a non-glaciated terrain.) These types of problem can be attributed to the student's lack of knowledge of the geology of the area within which the photographs were taken and having little to no field instruction. Many of these problems can be addressed by utilizing a term project that combines elements of both research and the traditional photo project. The student chooses a specific area/region (i.e. a national park) that the student will/has actually visit(ed) and is then required to do background research before attempting to identify features and processes in photographs they have taken from the area. Here we present details of such a project that involves students performing research activities in three stages: The history/geologic setting of the area, the specific lithology of the area, and then the hydrology of the area, with each being completed at specified times throughout the semester. The final stage is the photo project component where the student identifies and interprets the features/processes in photographs from the area. The research provides the student with a framework within which they can identify and interpret the features/processes that are likely to be seen in their area.

Giles, A. N.; Wilkie, K. M.

2008-12-01

166

The upper Bow Island (Blackleaf) Formation of southwestern Alberta: Geological aspects and exploration approaches  

Microsoft Academic Search

The upper parts of the Bow Island Formation (Albian) of southwestern Alberta are significant gas reservoirs. The main westernmost reservoir zone is part of a complex package of interbedded lenticular sandstones, mudstones, and localized chert pebble conglomerates. The depositional setting for these sediments comprised a wave-dominated shoreline with conglomerates found proximal to drowned river mouths. The coarse nature of the

P. E. Putnam; S. L. Christensen

1991-01-01

167

Geological formation - drill string dynamic interaction finite-element program (GEODYN). Phase 1. Theoretical description  

SciTech Connect

The Theoretical Description for the GEODYN interactive finite-element computer program is presented. The program is capable of performing the analysis of the three-dimensional transient dynamic response of a Polycrystalline Diamond Compact Bit-Bit Sub arising from the intermittent contact of the bit with the downhole rock formations. The program accommodates nonlinear, time-dependent, loading and boundary conditions.

Baird, J.A.; Apostal, M.C.; Rotelli, R.L. Jr.; Tinianow, M.A.; Wormley, D.N.

1984-06-01

168

Leveraging Regional Exploration to Develop Geologic Framework for CO2 Storage in Deep Formations in Midwestern United States  

SciTech Connect

Obtaining subsurface data for developing a regional framework for geologic storage of CO{sub 2} can require drilling and characterization in a large number of deep wells, especially in areas with limited pre-existing data. One approach for achieving this objective, without the prohibitive costs of drilling costly standalone test wells, is to collaborate with the oil and gas drilling efforts in a piggyback approach that can provide substantial cost savings and help fill data gaps in areas that may not otherwise get characterized. This leveraging with oil/gas drilling also mitigates some of the risk involved in standalone wells. This collaborative approach has been used for characterizing in a number of locations in the midwestern USA between 2005 and 2009 with funding from U.S. Department of Energy's National Energy Technology Laboratory (DOE award: DE-FC26-05NT42434) and in-kind contributions from a number of oil and gas operators. The results are presented in this final technical report. In addition to data collected under current award, selected data from related projects such as the Midwestern Regional Carbon Sequestration Partnership (MRCSP), the Ohio River Valley CO{sub 2} storage project at and near the Mountaineer Plant, and the drilling of the Ohio Stratigraphic well in Eastern Ohio are discussed and used in the report. Data from this effort are also being incorporated into the MRCSP geologic mapping. The project activities were organized into tracking and evaluation of characterization opportunities; participation in the incremental drilling, basic and advanced logging in selected wells; and data analysis and reporting. Although a large number of opportunities were identified and evaluated, only a small subset was carried into the field stage. Typical selection factors included reaching an acceptable agreement with the operator, drilling and logging risks, and extent of pre-existing data near the candidate wells. The region of study is primarily along the Ohio River Valley corridor in the Appalachian Basin, which underlies large concentrations of CO{sub 2} emission sources. In addition, some wells in the Michigan basin are included. Assessment of the geologic and petrophysical properties of zones of interest has been conducted. Although a large number of formations have been evaluated across the geologic column, the primary focus has been on evaluating the Cambrian sandstones (Mt. Simon, Rose Run, Kerbel) and carbonates layers (Knox Dolomite) as well as on the Silurian-Devonian carbonates (Bass Island, Salina) and sandstones (Clinton, Oriskany, Berea). Factors controlling the development of porosity and permeability, such as the depositional setting have been explored. In northern Michigan the Bass Islands Dolomite appears to have favorable reservoir development. In west central Michigan the St. Peter sandstone exhibits excellent porosity in the Hart and Feuring well and looks promising. In Southeastern Kentucky in the Appalachian Basin, the Batten and Baird well provided valuable data on sequestration potential in organic shales through adsorption. In central and eastern Ohio and western West Virginia, the majority of the wells provided an insight to the complex geologic framework of the relatively little known Precambrian through Silurian potential injection targets. Although valuable data was acquired and a number of critical data gaps were filled through this effort, there are still many challenges ahead and questions that need answered. The lateral extent to which favorable potential injection conditions exist in most reservoirs is still generally uncertain. The prolongation of the characterization of regional geologic framework through partnership would continue to build confidence and greatly benefit the overall CO{sub 2} sequestration effort.

Neeraj Gupta

2009-09-30

169

Pore-space alteration induced by brine acidification in subsurface geologic formations  

NASA Astrophysics Data System (ADS)

A new Lagrangian particle-based method is presented to simulate reactive transport in natural porous media. This technique is based on Modified Moving Particle Semi-implicit (MMPS) and takes as input high-resolution voxel images of natural porous media. The flow field in the medium is computed by solving the incompressible Navier-Stokes equations. Moreover, a multicomponent ion transport model is coupled with a homogeneous and heterogeneous reactions module to handle pore-space alteration (i.e., pore-wall dissolution). The model is first successfully validated against the experimental data available in the literature. Subsequently, X-ray microtomographic images of two naturally occurring porous media are used to investigate the impact of reaction kinetics and pore-space topology on pore-space alteration induced by brine acidification in subsurface conditions. We observed that at the normal rates of reactions no significant change in porosity and permeability takes place in the short term. Whereas, higher reaction rates caused major changes in the macroscopic properties (e.g., porosity and permeability) of the rocks. We also show that these changes are strongly affected by the rocks' pore-scale topologies.

Ovaysi, Saeed; Piri, Mohammad

2014-01-01

170

Microbial growth and biofilm formation in geologic media is detected with complex conductivity measurements  

NASA Astrophysics Data System (ADS)

Complex conductivity measurements (0.1-1000 Hz) were obtained from biostimulated sand-packed columns to investigate the effect of microbial growth and biofilm formation on the electrical properties of porous media. Microbial growth was verified by direct microbial counts, pH measurements, and environmental scanning electron microscope imaging. Peaks in imaginary (interfacial) conductivity in the biostimulated columns were coincident with peaks in the microbial cell concentrations extracted from sands. However, the real conductivity component showed no discernible relationship to microbial cell concentration. We suggest that the observed dynamic changes in the imaginary conductivity (??) arise from the growth and attachment of microbial cells and biofilms to sand surfaces. We conclude that complex conductivity techniques, specifically imaginary conductivity measurements are a proxy indicator for microbial growth and biofilm formation in porous media. Our results have implications for microbial enhanced oil recovery, CO2 sequestration, bioremediation, and astrobiology studies.

Davis, Caroline A.; Atekwana, Estella; Atekwana, Eliot; Slater, Lee D.; Rossbach, Silvia; Mormile, Melanie R.

2006-09-01

171

The formation and functional consequences of heterogeneous mitochondrial distributions in skeletal muscle  

PubMed Central

SUMMARY Diffusion plays a prominent role in governing both rates of aerobic metabolic fluxes and mitochondrial organization in muscle fibers. However, there is no mechanism to explain how the non-homogeneous mitochondrial distributions that are prevalent in skeletal muscle arise. We propose that spatially variable degradation with dependence on O2 concentration, and spatially uniform signals for biogenesis, can account for observed distributions of mitochondria in a diversity of skeletal muscle. We used light and transmission electron microscopy and stereology to examine fiber size, capillarity and mitochondrial distribution in fish red and white muscle, fish white muscle that undergoes extreme hypertrophic growth, and four fiber types in mouse muscle. The observed distributions were compared with those generated using a coupled reaction-diffusion/cellular automata (CA) mathematical model of mitochondrial function. Reaction-diffusion analysis of metabolites such as oxygen, ATP, ADP and PCr involved in energy metabolism and mitochondrial function were considered. Coupled to the reaction-diffusion approach was a CA approach governing mitochondrial life cycles in response to the metabolic state of the fiber. The model results were consistent with the experimental observations and showed higher mitochondrial densities near the capillaries because of the sometimes steep gradients in oxygen. The present study found that selective removal of mitochondria in the presence of low prevailing local oxygen concentrations is likely the primary factor dictating the spatial heterogeneity of mitochondria in a diversity of fibers. The model results also suggest decreased diffusional constraints corresponding to the heterogeneous mitochondrial distribution assessed using the effectiveness factor, defined as the ratio of the reaction rate in the system with finite rates of diffusion to that in the absence of any diffusion limitation. Thus, the non-uniform distribution benefits the muscle fiber by increasing the energy status and increasing sustainable metabolic rates.

Pathi, B.; Kinsey, S. T.; Howdeshell, M. E.; Priester, C.; McNeill, R. S.; Locke, B. R.

2012-01-01

172

Microbial growth and biofilm formation in geologic media is detected with complex conductivity measurements  

Microsoft Academic Search

Complex conductivity measurements (0.1–1000 Hz) were obtained from biostimulated sand-packed columns to investigate the effect of microbial growth and biofilm formation on the electrical properties of porous media. Microbial growth was verified by direct microbial counts, pH measurements, and environmental scanning electron microscope imaging. Peaks in imaginary (interfacial) conductivity in the biostimulated columns were coincident with peaks in the microbial

Caroline A. Davis; Estella Atekwana; Eliot Atekwana; Lee D. Slater; Silvia Rossbach; Melanie R. Mormile

2006-01-01

173

Petroleum geology of MC3 member, Mississippian Mission Canyon Formation, Pierson area, southwestern Manitoba  

Microsoft Academic Search

Mississippian beds in the Manitoba portion of the Williston basin produce oil from a series of stratigraphic units where porous cyclic carbonates are truncated by pre-Mesozoic erosion and sealed by Amaranth (Watrous\\/Spearfish) strata. In the Pierson area of southwest Manitoba, oil is trapped within the MC-3 member of the Mission Canyon Formation, correlative with the Alida beds of Saskatchewan. Production

M. Husain; S. P. Halabura

1988-01-01

174

Geologic and metallogenic aspects concerning the Nahuelbuta mountains banded iron formation, Chile  

Microsoft Academic Search

Paleozoic banded-iron-formation (BIF) deposits occur within the Nahuelbuta-Queule Complex (south central Chile) which hosts the following stratigraphic units: Cabo Tirúa (green schists, mica schists, and metacherts), Lleu-Lleu (iron-bearing metacherts, mica schists, and serpentinites), and Colcura (metagraywackes and metapelites). The lithological, structural, and geochemical characteristics of the Lleu-Lleu and Cabo Tirúa units indicate that they were part of a tectonic mélange

R. Oyarzún; H. Clemmey; S. Collao

1986-01-01

175

The geology and mineralogy of Ritchey crater, Mars: Evidence for post-Noachian clay formation  

NASA Astrophysics Data System (ADS)

detection of phyllosilicates (clay minerals) in Noachian (>3.5 Ga) terrains on Mars and their paucity in younger terrains have led to the hypothesis that Noachian conditions were more clement than the colder, drier conditions that have since followed. However, recent clay detections in several Hesperian impact craters suggest that fluvial transport and alteration were possible after the posited early era of phyllosilicate formation. Here we present evidence that rocks within Hesperian age Ritchey crater (28.5°S, 51°W) record a period of post-Noachian fluvial transport and in situ alteration. This resulted in the transport of clays from the crater wall to the crater floor and the formation of hydrated silica and Fe/Mg smectite in Ritchey's central uplift. Clay minerals associated with central uplifts are commonly interpreted to represent preexisting clays excavated from depth, potentially providing insight into older crustal clay-forming processes. Here we present detailed geomorphic and mineralogic maps and show that the clays in Ritchey's central peak formed after or as a direct result of the impact and are thus Hesperian or younger. Clays on the crater wall were either preexisting clays exposed by the impact or formed in situ through postimpact water-rock interaction. In either scenario, some of these clays were likely subsequently transported to the crater floor by fluvial-alluvial processes in a source-to-sink system. In this context, the hydrated phases in Ritchey indicate several different formation and transport mechanisms and provide further evidence that near-surface clay mineral formation, and thus habitable conditions, existed on Mars after the Noachian.

Sun, Vivian Z.; Milliken, Ralph E.

2014-04-01

176

The geology and mechanics of formation of the Fort Rock Dome, Yavapai County, Arizona  

USGS Publications Warehouse

The Fort Rock Dome, a craterlike structure in northern Arizona, is the erosional product of a circular domal uplift associated with a Precambrian shear zone exposed within the crater and with Tertiary volcanism. A section of Precambrian to Quaternary rocks is described, and two Tertiary units, the Crater Pasture Formation and the Fort Rock Creek Rhyodacite, are named. A mathematical model of the doming process is developed that is consistent with the history of the Fort Rock Dome.

Fuis, Gary S.

1996-01-01

177

Multi-Scale Modeling of CO2 and Brine Flow in Geologic Formations Containing Faults  

NASA Astrophysics Data System (ADS)

Basins being considered for geologic storage of CO2 contain faults that can act as conduits for flow. The flow of CO2 and brine in and around faults involves relatively small-scale processes, when compared to typical grid-cell sizes in basin-scale numerical models. A computationally efficient approach to multi-phase flow modeling of basins containing faults can be developed based on embedding analytical solutions to represent small-scale features (like faults) within larger-scale numerical models. This approach is analogous to the use of analytical solutions for flow around wells as sub-scale corrections in numerical models (e.g. Peaceman (1978), Gasda et al. (2009)). However, the modeling approach for faults departs from wells due to the possibility of the fault extending beyond one numerical grid block, and its underlying Cartesian, rather than cylindrical, geometry. The combined analytical-numerical multi-scale (CAN-MS) model for faults is composed of (1) numerical approximation for the basin-scale flow system, (2) analytical solutions for the small-scale flow regimes for a given fault, and (3) the coupling between basin and small-scale flow systems. Following the approach of Nordbotten and Celia (2006) given in radial coordinates, analytical solutions representing different flow conditions in and around faults are derived in Cartesian coordinates for a stationary problem with a finite outer boundary. The solutions are based on mass conservation equations, Darcy's Law, and structured vertical flow to represent vertical non-equilibrium. These solutions are used to determine the fluxes along the fault and to derive pressure corrections that relate pressure at a given fault to the (average) pressure in the numerical grid blocks. The flow and pressure solutions are solved simultaneously to describe the small-scale effects of the fault and produce an output in a form that is compatible with the coarse-scale numerical model. Model test results will be presented to facilitate future application of the CAN-MS model to real basins such as the Illinois Basin.

Kang, M.; Nordbotten, J. M.; Celia, M. A.

2011-12-01

178

Geologic study and engineering review of Jurassic Smackover Formation of Thomasville field, Rankin County, Mississippi  

SciTech Connect

The Jurassic (Oxfordian) Smackover Formation in Thomasville field, Rankin County, Mississippi, produces sour gas from deep (19,000 + ft), geopressured (> 0.88 psi/ft) siliciclastics that are interbedded with nonreservoir carbonates. The siliciclastics are moderately to moderately well-sorted, fine to medium-grained subarkosic sandstones. They are characterized by low average porosities (7.0%) and permeabilities (0.35 md) resulting from both diagenetic and primary textural controls. Secondary and altered primary porosity are present. Permeability is reduced by several diagenetic events, including the formation of anthraxolite and authigenic fibrous illite. Smackover carbonate ramp deposition was interrupted in Thomasville by the periodic influx of siliciclastics. Siliciclastics were delivered to the basin of deposition by ancestral drainage systems and distributed on the ramp by current and storm processes. They are interpreted to be shallow marine (beach and bar), inner shelf (sand waves and storm deposits), and outer shelf to upper basinal (storm and turbidite channels) deposits based on sedimentary structures, trace fossils, and lateral and vertical facies association with the interbedded carbonates. The carbonates indicate a shoaling-upward sequence, with outer shelf and upper basinal mudstones and wackestones at the base grading upward through shelf packstones, high-energy ooid grainstone shoals, and asphalt intertidal mudstones to grainstones. Rock properties and interpretations of the depositional environments were based on core and drill-cutting analyses. These analyses supplemented the use of computer-enhanced wireline logs to establish rock-log calibrations, correlation markers, structural growth, and reservoir continuity.

Shew, R.D.; Garner, M.M.

1986-09-01

179

Effect of deformation conditions of fibre-formation in spinning from heterogeneous mixtures of polymers  

Microsoft Academic Search

Capillary diameter, shear stress, and jet stretch all affect the phenomenon of specific fibre formation in extrudates of the mixtures POM-copolyamide 548, POM-polystyrene, POM-ethylene-vinyl acetate copolymer, POM-polyvinyl alcohol, and low-pressure polyethylene-copolyamide 548.

M. V. Tsebrenko

1984-01-01

180

The upper Bow Island (Blackleaf) Formation of southwestern Alberta: Geological aspects and exploration approaches  

SciTech Connect

The upper parts of the Bow Island Formation (Albian) of southwestern Alberta are significant gas reservoirs. The main westernmost reservoir zone is part of a complex package of interbedded lenticular sandstones, mudstones, and localized chert pebble conglomerates. The depositional setting for these sediments comprised a wave-dominated shoreline with conglomerates found proximal to drowned river mouths. The coarse nature of the upper Bow Island is related to tectonic movements associated with Crowsnest (Vaughn) volcanism. Conglomerates form the most impressive Bow Island reservoirs because of their thickness (up to 25 m) and petrophysical properties (17% porosity, 24 d permeability). Diagenesis dominantly comprises compaction features within grain-supported conglomerates. Increasing quartz content is related to decreasing grain size and is associated with porosity occlusion by quartz overgrowths. Bow Island reservoirs in southwestern Alberta are cool (under 50C) and significantly underpressured (0.2 psi). The high permeabilities and low pressures at depths of 1,000 to 1,500 m suggest the potential for formation damage is high, and many wells in the region were targeted for deeper, high-pressure zones. In spite of the low pressures, however, many Bow Island wells are capable of excellent gas deliveries with individual well recoveries of up to 10 bcf. All significant Bow Island porosity in the deepest, undisturbed parts of southwestern Alberta is gas saturated with updip aquifers flanking the gas. Seismic definition of the thickest Bow Island targets is feasible but has been hampered, in part, by difficult surface conditions and a prior emphasis on deeper targets.

Putnam, P.E.; Christensen, S.L. (Petrel Robertson Ltd., Calgary, Alberta (Canada))

1991-06-01

181

Studies of the formation, chemical reactivity, and properties of small clusters: Application to an understanding of aerosol formation and heterogeneous chemistry  

SciTech Connect

The small cluster program involves (1) studies of reactions related to formation and growth of heteromolecular clusters and their thermochemical properties, (2) studies of photoinitiated processes in clusters, (3) investigations related to heterogeneous reactions including the influence of reaction centers on the interconversion, and (4) theoretical calculations of properties, dynamics, and structure. A major thrust of the work during the past year has been devoted to a study of the role of ionization and the presence of ions on reactions and energetics. During the past few months, particular attention has been paid to systems having varying proton affinities. From the data, we can determine the influence of these values on the nature of the reactions and ascertain the ultimate chemical nature of the ionization center formed as a result of the reactions. 83 refs., 12 figs., 2 tabs.

Castleman, A.W. Jr.

1990-01-01

182

Monitoring of Water and Thermic Transfers in the Vadose Zone of a Geological Carbonate Formation : Example of and Underground Quarry, Gironde, France  

Microsoft Academic Search

The aim of this study is the monitoring of water and thermic transfers in vadose zone of a geological carbonate formation during three hydrological cycles (August 2001- November 2004). The application of the Time Domain Reflectometry (TDR) and Self-Potential (SP) methods to determine the water content of porous rock has been widely investigated. More than 285 studied point measurements of

A. Cerepi; C. Loisy; R. Burlot; L. Mao

2007-01-01

183

Preservation of Fe isotope heterogeneities during diagenesis and metamorphism of banded iron formation  

Microsoft Academic Search

We present the iron isotope composition of primary, diagenetic and metamorphic minerals in five samples from the contact metamorphosed\\u000a Biwabik Iron Formation. These samples attained peak metamorphic temperatures of <200, <340, ?500, <550, and <740°C respectively.\\u000a ?56Fe of bulk layers ranges from ?0.8 to +0.8‰; in some samples the layers may differ by >1‰ on the millimeter scale. Minerals\\u000a in

C. D. Frost; F. von Blanckenburg; R. Schoenberg; B. R. Frost; S. M. Swapp

2007-01-01

184

Stratigraphic hierarchy and cycle stacking, facies distribution, and Interwell-Scale heterogeneity: Grayburg Formation, New Mexico  

Microsoft Academic Search

The Grayburg Formation (middle Guadaluplan) of southeastern New Mexico is a mixed carbonate-siliciclastic succession that represents predominantly shallow water sedimentation on the Northwest Shelf of the Delaware Basin. Exceptional Grayburg outcrops in the Brokeoff Mountains permit high-resolution correlation and mapping of interwell-scale facies complexity both along depositional dip and across strike. Three orders of stratigraphic hierarchy are recognized using vertical

R. J. Barnaby; W. B. Ward

1996-01-01

185

Preservation of Fe isotope heterogeneities during diagenesis and metamorphism of banded iron formation  

Microsoft Academic Search

We present the iron isotope composition of primary, diagenetic and metamorphic minerals in five samples from the contact metamorphosed Biwabik Iron Formation. These samples attained peak metamorphic temperatures of <200, <340, ˜500, <550, and <740°C respectively. delta56Fe of bulk layers ranges from -0.8 to +0.80\\/00; in some samples the layers may differ by >10\\/00 on the millimeter scale. Minerals in

C. D. Frost; F. von Blanckenburg; R. Schoenberg; B. R. Frost; S. M. Swapp

2007-01-01

186

Influence of iron and copper oxides on polychlorinated diphenyl ether formation in heterogeneous reactions.  

PubMed

Polychlorinated diphenyl ether (PCDE) has attracted great attention recently as an important type of environmental pollutant. The influence of iron and copper oxides on formation of PCDEs was investigated using laboratory-scale flow reactors under air and under nitrogen at 350 °C, a temperature corresponding to the post-combustion zone of a municipal solid waste incinerator. The results show that the 2,2',3,4,4',5,5',6-otachlorodiphenyl ether (OCDE) formed from the condensation of pentachlorophenol (PCP) and 1,2,4,5-tetrachlorobenzene (Cl4Bz) is the predominant congener formed on the SiO2/Fe2O3 surface with and without oxygen. This indicated that HCl elimination between PCP and 1,2,4,5-Cl4Bz molecules formed 2,2',3,4,4',5,5',6-OCDE in the presence of Fe2O3. On the other hand, decachlorodiphenyl ether, nonachlorodiphenyl ether, and OCDE were the dominant products on the SiO2/CuO surface without oxygen, although the 2,2',3,4,4',5,5',6-OCDE was the dominant product on the SiO2/CuO surface with oxygen. Therefore, the presence of Fe2O3 and CuO influences the formation and homologue distribution of PCDEs, which shifted towards the lower chlorinated species. Fe2O3 can promote both the condensation and dechlorination reaction without oxygen. On the contrary, with oxygen, Fe2O3 suppresses the condensation of chlorobenzene and chlorophenol to form PCDEs and polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). CuO can increase the formation of lower chlorinated PCDEs and PCDDs without oxygen. In conclusion, the different fly ash components have a major influence on PCDE emissions. PMID:23440438

Liu, Wenxia; Shen, Lianfeng; Zhang, Fawen; Liu, Wenbin; Zheng, Minghui; Yang, Xitian

2013-08-01

187

Relationship between Mineralogy and Porosity in Subsurface Formations Relevant to Geologic CO2 Sequestration  

NASA Astrophysics Data System (ADS)

Porosity and permeability are the key variables that link the thermal, hydrological, geochemical and geomechanical processes that redistribute mass and energy in response to injection of CO2 into the subsurface. The size, shape, distribution and connectivity of rock pores dictate how fluids migrate into and through these micro- and nanoenvironments, wet and react with the solid. The link between pore size distribution and connectivity and pore-wall mineralogy is still poorly constrained for both reservoir and caprocks.. The objectives of this effort are to characterize the nano- to macropore features, quantify mineral-specific reactive surface areas in both pore and fracture networks, and determine how pores and fractures evolve in reacted systems at temperature-pressure-composition conditions relevant to CO2 injection. Representative caprocks and reservoir rocks associated with CO2 injection activities (e.g. shallow buried quartz arenites from the St. Peter Sandstone and the deeper Mt. Simon sandstone in Ohio as well as the Eau Claire Formation shale and mudrocks) are being interrogated with an array of complementary methods - e.g. SEM, TEM, neutron scattering, X-ray CT, neutron tomography as well as conventional petrophysics. (Ultra)small-angle neutron scattering and autocorrelations derived from BSE imaging provide a powerful method of quantifying pore structures in a statistically significant manner from the nanometer to the centimeter scale. Results will be described comparing shale and mudrocks that indicate there are significant variations not only in terms of total nano- to micro-porosity and pore interconnectivity, but also in terms of pore surface fractal (roughness) and mass fractal (pore distributions) dimensions as well as size distributions. For tight formations we have observed that: (a) total porosity exhibiting bimodality may be typical of shale and mudstones, (b) connected porosity exhibiting bimodal tendencies may not be uncommon in shale and mudstone caprocks, (c) as expected, fissile shale contains far greater abundance of nanopores than do mudstones, (d) connected porosity also mimics the bimodal total porosity trends with connected nanopores observed below about 400 nm and connected micropores between 50 and 100 microns, (e) pore mineralogy (hence potential reactive surface area) is generally very different than the bulk mineralogy, especially for mudstones where phases present in minor abundances in the bulk may contribute more to the connected pore network. The data on sandstones suggest that nano- and microporosity are more prevalent in nominally coarse-grained lithologies and may play a more important role than previously thought in fluid/rock interactions. Information from imaging and scattering are being used to constrain computer-generated, random, three-dimensional porous structures. The results integrate various sources of experimental information and are statistically compatible with the real rock. These computerized porous matrices will then be used in CO2 sorption MD simulations.

Cole, D. R.; Swift, A.; Sheets, J.; Welch, S.; Anovitz, L. M.; Rother, G.; Vlcek, L.

2013-12-01

188

Petroleum geology of MC-3 member, Mississippian Mission Canyon Formation, Pierson area, southwestern Manitoba  

SciTech Connect

Mississippian beds in the Manitoba portion of the Williston basin produce oil from a series of stratigraphic units where porous cyclic carbonates are truncated by pre-Mesozoic erosion and sealed by Amaranth (Watrous/Spearfish) strata. In the Pierson area of southwest Manitoba, oil is trapped within the MC-3 member of the Mission Canyon Formation, correlative with the Alida beds of Saskatchewan. Production was first obtained in 1954 and subsequent exploration has led to the discovery of 11 pools of various sizes. As of December 31, 1987, 2.4 million bbl (375,510 m/sup 3/) of 36/degrees/ API gravity oil had been produced from the area, and currently eight pools are producing. In Manitoba, the Mission Canyon is subdivided into three members: MC-1, MC-2, and MC-3, in ascending order. The MC-3 is further subdivided by the MC-3 marker into lower MC-3a and upper MC-3b units. Oil, in the Pierson area, occurs in these two units. The MC-3 member consists of a cyclic sequence of lithofacies deposited in a shallow-water, moderate to high-energy, carbonate-dominated inner shelf environment that was present over much of southwest Manitoba. Five lithofacies have been recognized in core, but oil is found largely within the more porous shoal and backshoal facies (average porosity 14% and permeability 12 md). The cap rock, in most places, is a secondary, dense dolomite and anhydrite zone (altered zone) directly below the pre-Mesozoic erosion surface. Where the altered zone is thin or absent, lower Amaranth shales (red beds) form the cap rock. Entrapment is primarily stratigraphic, resulting from regional truncation of the MC-3 beds with accumulation localized and controlled by (1) local paleotopographic highs, (2) porosity and permeability pinch-out due to primary lithofacies variations, and (3) porosity closure resulting from variation in the thickness of the altered zone.

Husain, M.; Halabura, S.P.

1988-07-01

189

Neoproterozoic Cana Brava chrysotile deposit (Goiás, Brazil): Geology and geochemistry of chrysotile vein formation  

NASA Astrophysics Data System (ADS)

The Cana Brava chrysotile asbestos deposit of Goiás, Brazil, contains approximately 150 Mt of ore with an average of 3.5 wt.% of cross-fiber chrysotile and lies in the differentiated, mafic-ultramafic Neoproterozoic Cana Brava complex. This complex was formed at approximately 0.79 Ga and metamorphosed at 0.77 to 0.76 and 0.63 Ga. The 0.77 to 0.76 Ga metamorphic event was a high-grade one that transformed the mafic and ultramafic rocks into meta-peridotites and meta-pyroxenites. The low-grade 0.63 Ga metamorphism allowed the formation of black, red and brown serpentinite, graphitic, magnesite-rich talc serpentinite, and rodingite, which became folded and foliated. At the end of the 0.63 Ga metamorphism, black serpentinites were oxidized to form red serpentinites, the main type of serpentinite that outcrops today at the Cana Brava mineralized region. Post-metamorphic fluids reactivated the process of serpentinization, thereby generating massive green serpentinite from the red. Green formed on the most fractured zones, and double red and green reaction rims formed on the sides of the veins located outside the green serpentinite zones. This process did not cause significant variation in the volume of the rocks and resulted in a strongly reducing system thanks to the loss of Fe2O3 and iron and the subsequent crystallization of magnetite within veinlets and altered rocks. Low angle shear, developed under brittle conditions, caused hydraulic fracturing and the generation of oversaturated, oxidizing fluids that crystallized the cross-fiber chrysotile inside open fractures. Very densely fractured zones with fractures filled with cross-fiber chrysotile constitute the ore that is mined at present.

Biondi, João Carlos

2014-01-01

190

Method of Analysis at the U.S. Geological Survey California Water Science Center, Sacramento Laboratory: Determination of Haloacetic Acid Formation Potential, Method Validation, and Quality-Control Practices.  

National Technical Information Service (NTIS)

An analytical method for the determination of haloacetic acid formation potential of water samples has been developed by the U.S. Geological Survey California Water Science Center, Sacramento Laboratory. The haloacetic acid formation potential is measured...

B. C. Zazzi K. L. Crepeau M. S. Fram B. A. Bergamaschi

2005-01-01

191

Phased Array Approach To Retrieve Gases, Liquids, Or Solids From Subsurface And Subaqueous Geologic Or Man-Made Formations  

DOEpatents

A method of enhancing the remediation of contaminated soils and ground water, production of oil and gas, and production of any solid, gas, and/or liquid from subsurface geologic and man-made formations including the steps of estimating the geometric boundaries of the region containing the material to be recovered, drilling a recovery well(s) into subsurface in a strategic location to recover the material of interest, establishing multiple sources of acoustical power in an array about and spaced-apart from the surface or at various depths below the surface in a borehole(s) and/or well(s), directing a volume of acoustical excitation from the sources into the region containing the material to be recovered, the excitation in the form of either controllable sinusoidal, square, pulsed, or various combinations of these three waveforms, and controlling the phasing, frequency, power, duration, and direction of these waveforms from the sources to increase and control the intensity of acoustical excitation in the region of the material to be recovered to enhance. the recovery of said material from the recovery well(s). The invention will augment any technology affecting the removal of materials from the subsurface.

Rynne, Timothy M. (Long Beach, CA); Spadaro, John F. (Huntington Beach, CA); Iovenitti, Joe L. (Pleasant Hill, CA); Dering, John P. (Lakewood, CA); Hill, Donald G. (Walnut Creek, CA)

1998-10-27

192

Preliminary modeling of the long-term fate of CO2 following injection into deep geological formations  

SciTech Connect

The injection of CO2 into deep saline aquifers is a potential option for greenhouse gas mitigation. However, several key issues, such as underground storage time and the fate of the injected CO2, must be studied before this option becomes economically and socially acceptable. In the current study, a one-dimensional reactive mass-transport model was used to predict the long-term chemical behavior of a deep saline aquifer following CO2 injection, far away from the injection site and representative of basin-scale migration and long-term fate. The dissolution of the injected CO2 into brine causes a sharp drop in pH, and consequently, the acidic brine aggressively reacts with aquifer minerals. Our model also predicts the dissolution of aluminosilicate minerals with the formation of secondary minerals and the precipitation and dissolution of carbonate minerals and is consistent with laboratory-scale CO2 core-flooding experiments. However, the extent and development of reaction fronts depend on the reaction rates used. For example, our modeling results indicate that the transport of carbon can be significantly retarded with respect to the flow of the brine itself, and a significant amount of injected CO2 is immobilized because of mineral trapping. The precise locations and patterns of the carbon reactive transport are sensitive to the reaction rates used, illustrating the need for improved knowledge of reaction kinetics, particularly the in-situ rates of dissolution and precipitation of aluminosilicate minerals, in evaluating mineral trapping of CO2 in deep geological formations.

Strazisar, B.R.; Shu, C.; Hedges, S.W.

2006-03-01

193

High-resolution photo geologic mapping of the Tuscan Formation cliffs in the BCCER and Upper Bidwell Park, Chico CA  

NASA Astrophysics Data System (ADS)

The Tuscan Formation rocks make up the uppermost cliffs of the Big Chico Creek Ecological Reserve (BCCER) and Upper Bidwell Park. These rocks are composed of 3.2 to 1.8 million year old tuffs, conglomerate and sandstone dominated by volcanic clasts, as well as siltstone and mudstone mostly derived from the ancient Mt. Yana volcanic complex near Lake Almanor. This study attempts to investigate stratal geometries of Tuscan deposits in the BCCER and Upper Bidwell Park by mapping stratigraphic sections and using high resolution aerial geologic photomosaics of the Tuscan rocks. In order to obtain the best perspective of the rocks, the photos have been taken directly perpendicular to the cliff face using a helicopter and high resolution photography. With these photos, detailed layering and features of the Tuscan, both in the breccia units and the interbedded fluvial units, can be detected. These 'head on' photos are the best way to see erosional surfaces, pinch-outs, and individual flow units. They can also be used to document how well these features correlate down-canyon. Additionally, aerial photos provide a foundation for recognizing larger scale features and trends which would otherwise go unnoticed (channel flow direction, cross-cutting flows). One example of these larger scale features are two larger debris flows at the top of the unit that are best seen by the aerial photos. By foot, these debris flows can be difficult to access because of steep terrain and vegetation cover. These photos will not only aid in the study of the Tuscan deposits, but will potentially benefit other research focused on the hydrology, ecology, or archeology of Upper Bidwell Park and the BCCER. The Tuscan Formation. Debris Flow layers can easily be mapped from high-resolution photos

gonzalez, M.; Greene, T.

2013-12-01

194

Geologic and climatic controls on the formation of the Permian coal measures in the Sohagpur coal field, Madhya Pradesh, India  

SciTech Connect

The U.S. Geological Survey (USGS) and the Geological Survey of India (GSI) are concluding a cooperative study of the coking coal deposits in the Sohagpur coal field in central India. Because of the importance of coal in India's economy, the Coal Wing of the Geological Survey of India has studied the area intensely since the early 1980's. This report summarizes the overall stratigraphic, tectonic, and sedimentologic framework of the Sohagpur coal field area, and the interpretations of the geologic and climatic environments required for the accumulation of the thick Gondwana coal deposits, both coking and non-coking.

Milici, R.C.; Warwick, P.D.; Mukhopadhyah, A.; Adhikari, S.; Roy, S.P.; Bhattacharyya, S.

1999-07-01

195

Thermal decomposition of gaseous ammonium nitrate at low pressure: kinetic modeling of product formation and heterogeneous decomposition of nitric acid.  

PubMed

The thermal decomposition of ammonium nitrate, NH(4)NO(3) (AN), in the gas phase has been studied at 423-56 K by pyrolysis/mass spectrometry under low-pressure conditions using a Saalfeld reactor coated with boric acid. The sublimation of NH(4)NO(3) at 423 K was proposed to produce equal amounts of NH(3) and HNO(3), followed by the decomposition reaction of HNO(3), HNO(3) + M --> OH + NO(2) + M (where M = third-body and reactor surface). The absolute yields of N(2), N(2)O, H(2)O, and NH(3), which can be unambiguously measured and quantitatively calibrated under a constant pressure at 5-6.2 torr He are kinetically modeled using the detailed [H,N,O]-mechanism established earlier for the simulation of NH(3)-NO(2) (Park, J.; Lin, M. C. Technologies and Combustion for a Clean Environment. Proc. 4th Int. Conf. 1997, 34-1, 1-5) and ADN decomposition reactions (Park, J.; Chakraborty, D.; Lin, M. C. Proc. Combust. Inst. 1998, 27, 2351-2357). Since the homogeneous decomposition reaction of HNO(3) itself was found to be too slow to account for the consumption of reactants and the formation of products, we also introduced the heterogeneous decomposition of HNO(3) in our kinetic modeling. The heterogeneous decomposition rate of HNO(3), HNO(3) + (B(2)O(3)/SiO(2)) --> OH + NO(2) + (B(2)O(3)/SiO(2)), was determined by varying its rate to match the modeled result to the measured concentrations of NH(3) and H(2)O; the rate could be represented by k(2b) = 7.91 x 10(7) exp(-12 600/T) s(-1), which appears to be consistent with those reported by Johnston and co-workers (Johnston, H. S.; Foering, L.; Tao, Y.-S.; Messerly, G. H. J. Am. Chem. Soc. 1951, 73, 2319-2321) for HNO(3) decomposition on glass reactors at higher temperatures. Notably, the concentration profiles of all species measured could be satisfactorily predicted by the existing [H,N,O]-mechanism with the heterogeneous initiation process. PMID:19845384

Park, J; Lin, M C

2009-12-01

196

Architecture, internal heterogeneity, and resulting drainage efficiency of Upper Oligocene Frio Formation inner-shelf sandstone reservoirs in West Fulton Beach Field, Aransas County, Texas  

Microsoft Academic Search

The architecture, internal heterogeneity, and production history of selected reservoirs in West Fulton Beach field, Copano Bay, Aransas County, Texas, were examined as part of a project to identify additional oil and gas reserves on Texas state lands. Upper Oligocene Frio Formation reservoirs in this field have yielded more than 146 bcf of gas and 8 MMbbl of oil. A

Paul R. Knox

1994-01-01

197

Heterogeneous immunoassays in microfluidic format using fluorescence detection with integrated amorphous silicon photodiodes  

PubMed Central

Miniaturization of immunoassays through microfluidic technology has the potential to decrease the time and the quantity of reactants required for analysis, together with the potential of achieving multiplexing and portability. A lab-on-chip system incorporating a thin-film amorphous silicon (a-Si:H) photodiode microfabricated on a glass substrate with a thin-film amorphous silicon-carbon alloy directly deposited above the photodiode and acting as a fluorescence filter is integrated with a polydimethylsiloxane-based microfluidic network for the direct detection of antibody-antigen molecular recognition reactions using fluorescence. The model immunoassay used consists of primary antibody adsorption to the microchannel walls followed by its recognition by a secondary antibody labeled with a fluorescent quantum-dot tag. The conditions for the flow-through analysis in the microfluidic format were defined and the total assay time was 30 min. Specific molecular recognition was quantitatively detected. The measurements made with the a-Si:H photodiode are consistent with that obtained with a fluorescence microscope and both show a linear dependence on the antibody concentration in the nanomolar-micromolar range.

Pereira, A. T.; Novo, P.; Prazeres, D. M. F.; Chu, V.; Conde, J. P.

2011-01-01

198

Geological evolution and analysis of confirmed or suspected gas hydrate localities: Volume 2, basin analysis, formation and stability of gas hydrates in the Black Sea  

SciTech Connect

This document is Volume 11 of a series of reports entitled ''Geological Evolution and Analysis Confirmed or Suspected Gas Hydrate Localities.'' Volume 11 provides an analysis of the Black Sea region. The report presents a geological description of the Black Sea region, including regional and local structural settings, geomorphology, geological history, stratigraphy, and physical properties. Included also is a discussion of bottom simulating acoustic reflectors, sediment acoustic properties, distribution of hydrates within the sediments, and the relation of hydrate distribution to other features such as salt dispirism. The formation and stabilization of gas hydrates in sediments are discussed in terms of phase relations, nucleation, and crystallization constraints, gas solubility, pore fluid chemistry, inorganic diagenesis, and sediment organic content. A depositional analysis of the areas is discussed in order to better understand the thermal evolution of the locality and to assess the potential for thermogenic hydrocarbon generation. 80 refs., 27 figs., 16 tabs.

Ciesnik, M.S.; Krason, J.

1987-05-01

199

Geological evolution and analysis of confirmed or suspected gas hydrate localities: Volume 6, Basin analysis, formation and stability of gas hydrates in the Panama Basin  

SciTech Connect

This report presents a geological description of the Panama Basin, including regional and local structural settings, geomorphology, geological history, stratigraphy, and physical properties. It provides the necessary regional and geological background for more in-depth research of the area. Detailed discussion of bottom simulating acoustic reflectors, sediment acoustic properties, distribution of hydrates within the sediments, and the relation of hydrate distribution to other features such as salt diapirism are also included. The formation and stabilization of gas hydrates in sediments are considered in terms of phase relations, nucleation, and crystallization constraints, gas solubility, pore fluid chemistry, inorganic diagenesis, and sediment organic content. Together with a depositional analysis of the area, this report is a better understanding of the thermal evolution of the locality. It should lead to an assessment of the potential for both biogenic and thermogenic hydrocarbon generation. 63 refs., 38 figs., 7 tabs.

Krason, J.; Ciesnik, M.

1986-03-01

200

STOCHASTIC ANALYSIS OF EFFECTIVE CONDUCTIVITY FOR BOUNDED, RANDOMLY HETEROGENEOUS AQUIFERS Proceedings of the 5th Annual Conference of the International Association for Mathematical Geology (IAMG99), Trondheim, Norway, August 6-11, Vol. II, 760-766, 1999  

Microsoft Academic Search

SUMMARY We explore the concept of effective hydraulic conductivity for a bounded randomly heterogeneous formation under steady-state flow regime. The novelty of our study consists of establishing a tensorial nature of the effective conductivity. This occurs even for locally isotropic conductivity fields. Neuman and Orr (1) have demonstrated that stochastically averaged flow equations are non-local and non-Darcian, so that effective

D. M. Tartakovsky; A. Guadagnini; M. Riva

201

Geologic Maps  

NSDL National Science Digital Library

This web site provides an introduction to geologic maps. Topics covered include what is a geologic map, unique features of geologic maps, letter symbols, faults, and strike and dip. Users may click to view colored geologic maps, the geologic map of the United States and the geologic relief map of the United States.

Graymer, Russell

202

Electrochemical formation mechanism for the controlled synthesis of heterogeneous MnO2/Poly(3,4-ethylenedioxythiophene) nanowires.  

PubMed

The formation mechanism of a coaxial manganese oxide/poly(3,4-ethylenedioxythiophene) (MnO(2)/PEDOT) nanowire is elucidated herein by performing electrodeposition of MnO(2) and PEDOT on Au-sputtered nanoelectrodes with different shapes (ring and flat-top, respectively) within the 200 nm diameter pores of an anodized aluminum oxide (AAO) template. It is found that PEDOT prefers to grow on the sharp edge of the ring-shaped electrode, while MnO(2) is more likely to deposit on the flat-top electrode due to its smooth surface. The formation of coaxial nanowires is shown to be a result of simultaneous growth of core MnO(2) and shell PEDOT by an analysis of the current density resulting from electrochemical deposition. Furthermore, the structures of the MnO(2)/PEDOT coaxial nanowires were studied for their application as supercapacitors by modifying their coelectrodeposition potential. A potential of 0.70 V is found to be the most favorable condition for synthesis of MnO(2)/PEDOT coaxial nanowires, resulting in a high specific capacitance of 270 F/g. Additionally, other heterogeneous MnO(2)/PEDOT nanostructures are produced, such as nanowires consisting of MnO(2) nanodomes with PEDOT crowns as well as segmented MnO(2)/PEDOT nanowires. This is accomplished by simply adjusting the parameters of the electrochemical deposition. Finally, in smaller diameter (50 nm) AAO channels, MnO(2) and PEDOT are found to be partially assembled into coaxial nanowires due to the alternative depletion of Mn(II) ions and EDOT monomers in the smaller diameter pores. PMID:21661749

Liu, Ran; Duay, Jonathon; Lee, Sang Bok

2011-07-26

203

Regional geology of the low-permeability, gas-bearing Cleveland Formation, western Anadarko Basin, Texas Panhandle: Lithologic and depositional facies, structure, and sequence stratigraphy  

NASA Astrophysics Data System (ADS)

The Upper Pennsylvania (lower Missourian) Cleveland formation produces gas from low-permeability ('tight') sandstone reservoirs in the western Anadarko Basin of the northeastern Texas Panhandle. In the six-county region, these reservoirs had produced more than 412 Bcf of natural gas through December 31, 1989. Because of their typically low permeability, the Cleveland sandstones require acidizing and hydraulic fracture treatment to produce gas at economic rates. Since 1982, the Gas Research Institute has supported geological investigations throughout the United States to develop the scientific and technological knowledge for producing from low-permeability, gas-bearing sandstones. As part of the program and the GRI Tight Gas Sands project, the Bureau of Economic Geology has been conducting research on low-permeability sandstones in the Cleveland formation and on several other sandstone units of similar character in Texas and Wyoming.

Hentz, Tucker F.

1992-09-01

204

Evaluation of the geological relationships to gas hydrate formation and stability. Second annual technical progress report, October 1, 1985--September 30, 1986  

SciTech Connect

Although there are many publications pertaining to gas hydrates, their formation and stability in various geological conditions are poorly known. Therefore, for the same reasons and because of the very broad scope of our research, limited amount and extremely dispersed information, the study regions are very large. Moreover, almost without exception the geological environments controlling gas hydrates formation and stability of the studied regions are very complex. The regions studied (completed and partially completed - total 17 locations) during the reporting period, particularly the Gulf of Mexico and the Middle America Trench, are the most important in this entire research project. In the past, both of these regions have been extensively studied, the presence of gas hydrates confirmed and samples recovered. In our investigation it was necessary not only to review all previous data and interpretations, but to do a thorough analysis of the basins, and a critical evaluation of an previously reported and publicly available but not published information.

Not Available

1986-12-31

205

Amazonis Planitia: The role of geologically recent volcanism and sedimentation in the formation of the smoothest plains on Mars  

NASA Astrophysics Data System (ADS)

Amazonis Planitia, located between the two main volcanic provinces on Mars (Tharsis and Elysium), is characterized by extremely smooth topography at several scale lengths, as smooth as oceanic abyssal plains topography on Earth. We use Mars Global Surveyor (MGS) data (primarily very high resolution Mars Orbiter Laser Altimeter (MOLA) topography and derivative slope maps, gradient maps, and detrended maps) to examine the surface morphology of Amazonis Planitia and the stratigraphic relationships among previously mapped and newly defined units. These new data reveal the presence of a 1300 km diameter Noachian impact basin in northwest Amazonis Planitia and an extensive Late Hesperian lava flow unit that appears to have originated from the Olympus Mons source area prior to aureole formation. The presence of this previously unrecognized flow unit strongly suggests that Olympus Mons activity dates back to at least the Hesperian, as did activity on the Tharsis Montes. Emplacement of this ~100 meter thick flow unit formed a barrier along the northern margin of Amazonis Planitia which had a profound influence on the subsequent geologic history of the region. Formation of Olympus Mons aureole deposits created an eastern topographic barrier, and subsequent Tharsis Montes lava flows entered the basin from the south, flowing around the aureole. These three barriers (degraded Noachian crater rim, proto-Olympus Mons flow unit, and Olympus Mons aureole) caused subsequent lava flows and outflow channel effluents, primarily from the Elysium region to the west, to pond on the floor of Amazonis Planitia, preferentially smoothing the terrain there. Mars Orbiter Camera (MOC) images substantiate that at least two very fluid lava flows alternated with fluvial episodes from Elysium Planitia, flowing through Marte Valles onto the floor of the Amazonis Planitia basin. Within Amazonis Planitia, MOC images show flow-like textures heavily mantled by sediments, and radar data reveal the presence of rough lava flow surfaces underlying the sedimentary debris. These data thus suggest that the unique smoothness of Amazonis Planitia is the result of deposition of thin fluid lava flows and fluvial sediments in an enclosed basin. Crater counts suggest that the most recent resurfacing may have occurred in the latest Amazonian Period, in the last 1% of the history of Mars. In light of its unique history, it is somewhat ironic to note that Amazonis Planitia was originally thought to be a typical young Martian surface and therefore used to name the Amazonian era.

Fuller, Elizabeth R.; Head, James W.

2002-10-01

206

A Study of the Geology of the Rocks of the Huntington Formation in the Izee and Olds Ferry Terrains of the Blue Mountains Region  

NSDL National Science Digital Library

This winning entry in the museum's Young Naturalist Awards 1999 by Matthew, a 17 year old student from Idaho, takes a look at the geology of the rocks of the Huntington Formation. His essay discusses the hypothetical series of events that explains how the Izee and Olds Ferry terrains were formed over hundreds of millions of years, the 10 rock specimens he collected there and the metamorphoses they have each undergone.

207

Identification of discharge zones and quantification of contaminant mass discharges into a local stream from a landfill in a heterogeneous geologic setting  

NASA Astrophysics Data System (ADS)

SummaryContaminants from Risby Landfill (Denmark) are expected to leach through the underlying geologic strata and eventually reach the local Risby Stream. Identification of the groundwater discharge zone was conducted systematically by an array of methods including studies on site geology and hydrogeology, ground- and surface water flows and landfill leachate tracing from April 2009 to December 2010. Chemical profiling by driven wells and gradients in streambed temperatures was an efficient method to identify the contaminant discharge area. A considerable variation of leachate indicators, redox parameters and xenobiotic organic compounds were revealed in this area because of a complex geological setting with clay till (interbedded sand lenses) and deposits of sand and peat. Concentrations of leachate indicators decreased from the landfill to the stream, implying attenuation processes. Xenobiotic organic compounds were mainly phenoxy acid herbicides, while petroleum hydrocarbons and chlorinated solvents were found at very few boreholes. Findings of putative metabolites of phenoxy acid herbicides suggest degradation under the anaerobic conditions, which dominated inside and beneath the landfill. The groundwater discharge was quantified by two methods: direct collection of discharged groundwater by seepage meters and calculations from measurement of streambed temperature gradients. The landfill impacted the stream seasonally during dry periods when concentrations in the stream reached groundwater concentration levels. A comparison between mass balance for selected stream stretches and upscaled measurements of the contaminant discharge from groundwater into the stream indicated that only a small part of the actual contaminant discharge of the stream could be explained by the inflowing contaminant discharge from groundwater. Surface runoff and seepage from ponds along the stream impacted by landfill interflow may be important pathways as well. The placement of Risby Landfill near a stream and the complex source and geology causing a large spatial variability of leachate compounds are typical for landfill sites so the approaches and findings from Risby Landfill can be applied to other landfill sites. The study highlights that landfills may pose a risk to surface waters and future studies should be directed towards evaluation of both chemical and ecological risk.

Milosevic, N.; Thomsen, N. I.; Juhler, R. K.; Albrechtsen, H.-J.; Bjerg, P. L.

2012-06-01

208

INTEGRATED GEOLOGIC-ENGINEERING MODEL FOR REEF AND CARBONATE SHOAL RESERVOIRS ASSOCIATED WITH PALEOHIGHS: UPPER JURASSIC SMACKOVER FORMATION, NORTHEASTERN GULF OF MEXICO  

SciTech Connect

The University of Alabama in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company are undertaking an integrated, interdisciplinary geoscientific and engineering research project. The project is designed to characterize and model reservoir architecture, pore systems and rock-fluid interactions at the pore to field scale in Upper Jurassic Smackover reef and carbonate shoal reservoirs associated with varying degrees of relief on pre-Mesozoic basement paleohighs in the northeastern Gulf of Mexico. The project effort includes the prediction of fluid flow in carbonate reservoirs through reservoir simulation modeling which utilizes geologic reservoir characterization and modeling and the prediction of carbonate reservoir architecture, heterogeneity and quality through seismic imaging. The primary objective of the project is to increase the profitability, producibility and efficiency of recovery of oil from existing and undiscovered Upper Jurassic fields characterized by reef and carbonate shoals associated with pre-Mesozoic basement paleohighs. The principal research effort for Year 1 of the project has been reservoir description and characterization. This effort has included four tasks: (1) geoscientific reservoir characterization, (2) the study of rock-fluid interactions, (3) petrophysical and engineering characterization and (4) data integration. This work was scheduled for completion in Year 1. Overall, the project work is on schedule. Geoscientific reservoir characterization is essentially completed. The architecture, porosity types and heterogeneity of the reef and shoal reservoirs at Appleton and Vocation Fields have been characterized using geological and geophysical data. The study of rock-fluid interactions has been initiated. Observations regarding the diagenetic processes influencing pore system development and heterogeneity in these reef and shoal reservoirs have been made. Petrophysical and engineering property characterization is progressing. Data on reservoir production rate and pressure history at Appleton and Vocation Fields have been tabulated, and porosity data from core analysis has been correlated with porosity as observed from well log response. Data integration is on schedule, in that, the geological, geophysical, petrophysical and engineering data collected to date for Appleton and Vocation Fields have been compiled into a fieldwide digital database for reservoir characterization, modeling and simulation for the reef and carbonate shoal reservoirs for each of these fields.

Ernest A. Mancini

2001-09-14

209

Geology and Radiometry of Chalkidiki.  

National Technical Information Service (NTIS)

A brief geological description of Chalkidiki (Greece) is given followed by car-borne-scintillometer (CBS) survey results showing that granitic rocks in Central and Eastern Chalkidiki constitute the most promising geological formations for uranium minerali...

D. G. Minatidis

1980-01-01

210

Geological Investigation of Uranium Resources.  

National Technical Information Service (NTIS)

A geologic investigation of the Ogcheon uraniferous black shale has been carried out at the northeast of Miweon. Geology of the study area consists of following stratigraphic sequences in ascending order pebbly phyllitic rock formation, lower black slate ...

1983-01-01

211

Dispersion measurement as a method of quantifying geologic characterization and defining reservoir heterogeneity. [Quarterly] report, July 12, 1993--October 12, 1993  

SciTech Connect

Dispersion of fluids flowing through porous media is an important phenomenon in miscible displacement. Much of the research involving dispersion and dispersivity as a property of reservoir rock has focused on miscible liquid-liquid displacement processes. This study addresses the measurement of dispersion in a gas-gas displacement system. The objectives of this study are: (1) to develop a method and set up an experimental apparatus to measure gas-gas dispersion in consolidated rocks.(2) to study the effect of displacement velocity and pressure on gas-gas dispersion and dispersivity; and (3) to study the heterogeneity of reservoir rocks and investigate the relationship between dispersivity and rock properties to characterize the flow system using gas-gas dispersion measurements. New experimental methods and apparatus for gas-gas dispersion were developed in this study. Twenty eight gas-gas miscible displacement measurements under different flowrates and pressures were conducted on three Berea sandstone cores of varying lengths and physical properties. A gas chromatograph was utilized and modified to measure the concentration of gas at the outlet of the cores. Nitrogen was used as the displacing gas, while helium was used as the displaced gas. The experimental results were illustrated using S-shaped effluent breakthrough curves. The effect of flowrate and pressure on gas-gas dispersion, dispersion coefficient, dispersivity, and dispersion factor were determined from these curves. Gas effective diffusion coefficients were obtained by graphical methods using the dispersion coefficients under low velocities. The heterogeneity of reservoir rock can be studied by this method.

Menzie, D.E.

1993-12-31

212

Distribution of mineralized groundwaters in a deep aquifer due to geological heterogeneities and paleogeographic conditions: the Eocene aquifer in the Aquitaine Basin (France)  

NASA Astrophysics Data System (ADS)

In the sedimentary Nord Aquitaine Basin (south-west of France), the Eocene aquifer, mostly confined, is one of the main resources for irrigation, thermo-mineral water, and moreover for drinking water in the Bordeaux region. In this aquifer, a large saline area has been identified, where the groundwaters show high values of mineralization and anomalous levels of critical elements, such as sulfates and fluoride, leading to difficulties of resource exploitation for drinking water supply (i.e. the Entre-deux-Mers area). This study focused on the geochemical, multi-isotopic and hydrogeological characterization of these mineralized groundwaters with the aims to improve the understanding of the origin of the salinity in this mineralized area and how these waters circulate in the Eocene aquifer system. Compared to existing data, many new analysis including both major and trace elements, and several isotope systematics show a common origin for the mineralized groundwaters. These data are completed by a detailed geochemical modeling which determines the chemical processes that led to the acquisition of this mineralization, notwithstanding that the spatial distribution of the mineralization is very heterogeneous. The vertical and lateral localization of the mineralization in the aquifer was scrutinized through with an important paleogeographic reconstruction. This was undertaken to locate horizons which can be source and origin of this mineralization. Following a reinterpretation of existing data and acquisition of new ones (logs, mineralogical analysis of cuttings), several levels have been identified in the Eocene aquifer containing either evaporates, or fluorine. Their geographical organization was designed and the spatial distribution is consistent with geochemical analysis. The extreme lateral variability of the mineralization appears to be rooted in the complexity of the overlapping layers of low permeability within the Eocene aquifer system. A hydrodynamic and geochemical modeling can be run at local scale, in accordance with the regional hydrodynamic model. Both have validated hypotheses on groundwaters circulation within the heterogeneous Eocene aquifer system.

Malcuit, E.; Négrel, Ph.; Atteia, O.; Petelet-Giraud, E.; Franceschi, M.; Dupuy, A.

2012-04-01

213

Marine Geological Discoveries  

NSDL National Science Digital Library

This site by a Norwegian researcher features descriptions of marine geological formations: pockmarks, mud volcanoes, deep-water coral reefs, and gas hydrates. Using ROV technology, he has taken photos of these deep seafloor features, and compares them to geological structures seen on land, and even on the moon.

Hovland, Martin

2010-12-28

214

Geologic Time Online Edition  

NSDL National Science Digital Library

This tutorial will help students learn and understand the concepts of geologic time and the age of the Earth. They will investigate the geologic time scale and learn about the use of index fossils and radiometric dating to determine the age of rock formations and fossils.

215

Flow and transport in highly heterogeneous formations: 1. Conceptual framework and validity of first-order approximations  

NASA Astrophysics Data System (ADS)

Flow of uniform mean velocity U takes place in a formation of spatially variable, random conductivity K(x). Advective transport of a plume of an inert solute is investigated by the Lagrangean approach. The aim of the study is to determine the spatial moments of the plume, i.e., of fluid particle trajectories, for highly heterogeneous aquifers, for which ?Y > 1, where Y = ln K. A multi-indicator model of the permeability structure, which is different from the common multi-Gaussian one, is proposed: the formation is modeled as a collection of N blocks of different K(j). The structure is defined by the distribution of K(j), the blocks' shape, and the coordinates of their centroids. The following simplifications are adopted: the blocks are inclusions of a regular shape (circles, spheres for isotropic media investigated here) defined by the radius A, and the inclusions are not overlapping, and their centroids are distributed uniformly and independently in space. At the continuous limit the model is characterized by the joint pdf f(Y, A). The model is shown to be quite general and to comprise binary, bimodal, indicator variograms and unimodal distributions of Y as particular cases. The study is focused on the latter case, with Y normal N [, ?Y2] and stationary covariance of given integral scale IY; these are the parameters commonly estimated for sedimentary formations. This leaves still freedom in selecting the pdf f(A). The simple model selected for semianalytical and numerical analysis is that of inclusions of radius R and volume fraction n, submerged in a matrix of effective conductivity Kef. The latter represents the effect of inclusions of much smaller radius, which appear as a nugget in the log conductivity two-point covariance. An approximate analytical solution of the flow is obtained by using a self-consistent approximation, while a fully numerical one is derived in part 3 [, 2003a]. Transport is solved by particle tracking, and the time-dependent spatial moments (trajectories variance, skewness, kurtosis) are presented in part 2 [, 2003]. In the self-consistent approximation the asymptotic longitudinal macrodispersivity ?L, which is a function of Y, shows strong nonlinear effects: inclusions of large positive Y lead to a finite ?L, whereas ?L grows unbounded for those of negative Y. This effect is not captured by the common first-order approximation in ?Y, which is symmetrical and overestimates ?L for Y > 0 and underestimates it for Y < 0. As a result, the second spatial moment is predicted accurately by the first-order approximation, by cancellation of errors, provided that f(Y) is symmetrical. However, the transient regime and higher-order moments are not captured by the first-order approximation.

Dagan, G.; Fiori, A.; Jankovi?, I.

2003-09-01

216

Computer Technology on Geological Modeling on the Upper Second Member of Shahejie Formation in the Eastern Pucheng Oilfield  

Microsoft Academic Search

Facies are important in reservoir modeling because the petrophysical properties of interest are highly correlated with facies type. The knowledge of facies constrains the range of variability in porosity and permeability. This paper presents a stochastic modeling for characteristics of petroleum reservoirs constrained by facies to yield results coincided with real geological setting. The facies acting as the constraint are

Shujuan Xu; Jinliang Zhang; Xin Zhang; Xueping Ma

2008-01-01

217

Geology, geochemistry, and age of volcanites of the Tunguda Volcanic Formation: The problem of the Archean-Proterozoic boundary in North Karelia  

NASA Astrophysics Data System (ADS)

The geological, geochemical, and isotopic-geochronological data obtained for Sumian moderate-basic metavolcanites of Shombozero and Lekhta structures of the Panayarvi-Vygozero belt shows that the Tunguda Formation is confined to the Paleoproterozoic structural and material complex. This formation is represented by the complex of weakly differentiated andesitobasalts and andesites of calc-alkaline series with higher contents of MgO and moderate contents of Al2O3 and rare earth elements. The rocks of the Tunguda Formation are different from the Late Archean basic rocks of the Hiziyarvi Formation represented mainly by tholeiitic basalts with low REE contents and undifferentiated spectrum of REE distribution. The age of volcanites of the Tunguda Formation was determined to be 2439 ± 21 Ma. The xenogenic zircons from metaandesites of the Tunguda Formation have Neoarchean age according to the 207Pb/206Pb ratio (from 2536 ± 4 to 2825 ± 7 Ma). The Neoarchean zircons, a negative value of ?Nd (-3.8), and indicative geochemical parameters are evidence that the crustal component took part in formation of the protolith of the studied rocks.

Myskova, T. A.; Ivanov, N. M.; Korsakova, M. A.; Mil'kevich, R. I.; Berezhnaya, N. G.; Presnyakov, S. L.

2013-07-01

218

Devil's Tower Geology  

NSDL National Science Digital Library

This site from the National Park Service briefly addresses the geology of Devil's Tower. The evolution of various theories on the formation of the tower are discussed. A slide show of the emplacement of the tower is also available.

National Park Service (NPS)

219

A model of the Quaternary geological deposits of Bucharest City  

NASA Astrophysics Data System (ADS)

Bucharest city is located in the central part of the Moesic Platform, in the Romanian Plain with micro-relief resulting from erosion and sedimentary processes which extended along the valleys of the Dambovita River to the south and the Colentina River to the north. The city is located in the axial area of a syncline where the thickness of the sedimentary deposits is up to 1000 m. The area lies on a rigid base is made of metamorphites, and various igneous intrusions (granodiorite, granite). The sedimentary deposits covering this rigid base are made by different phases of erosion and sedimentary processes of marine, lacustrian or continental sediments ending with Quaternary sediments. As a result, different alluvial deposits (such as piedmont, deltaic, alluvial cones, terrace, waterside and lacustrine deposits) can be met. Furthermore one also can find loess deposits which in turn cover totally the older deposits where rivers dug the present relief. To highlight the spatial extent of these geological structures, a geological model of Bucharest city is developed. A set of information coming from different sources as geological and geotechnical boreholes showing a detailed geological and lithological description, geological and topographical maps, geological and hydrogeological reports have been used to develop the 3D geological model of this region. 33 geological cross sections were defined and interpreted by using lithological and sedimentological criteria. Using these geological cross sections and prior geological knowledge, the Quaternary deposits have been described and classified into 6 structural units given from top to down as follows: (1) Superficial deposits represented by loess and anthropogenic materials. The geological model indicates that these deposits show a sporadic development becoming more concentrated in the central west part of the city. (2) Colentina Formations composed by of poorly sorted, cross-stratified sand and gravel with clayey lens indicating a high energy deposition environment. The geological model indicates more accentuate vertical lithological heterogeneity than a horizontal one as well as a decrease of the Colentina Formation thickness. (3) Intermediary deposits represented by silty-clay with fine sand intercalation indicating a mixed regime with limited lakes and dry lands. (4) Mostistea Formation made of sediments with a variety of grain size, from fine sand to coarse sand with small intercalations of gravels and scrap of woods. It was found that areas where the Intermediary deposits are less developed making the Colentina Formation in direct connection to Mostistea Formation. (5) Marly Complex composed by a succession of marls and clays with lenticular sandy intercalations indicating a fluvial-lacustrine environment. (6) Fratesti Strata made of sand and gravel which includes A, B and C Fratesti levels.

Serpescu, Irina; Radu, Emil; Radu Gogu, Constantin; Amine Boukhemacha, Mohamed; Gaitanaru, Dragos; Bica, Ioan

2013-04-01

220

Geoscience/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian Basin, West Texas and New Mexico-stratigraphic hierarchy and cycle stacking facies distribution, and interwell-scale heterogeneity: Grayburg Formation, New Mexico. Final report  

SciTech Connect

The Grayburg Formation (middle Guadalupian) is a major producing interval in the Permian Basin and has yielded more than 2.5 billion barrels of oil in West Texas. Grayburg reservoirs have produced, on average, less than 30 percent of their original oil in place and are undergoing secondary and tertiary recovery. Efficient design of such enhanced recovery programs dictates improved geological models to better understand and predict reservoir heterogeneity imposed by depositional and diagenetic controls. The Grayburg records mixed carbonate-siliciclastic sedimentation on shallow-water platforms that rimmed the Delaware and Midland Basins. Grayburg outcrops in the Guadalupe and Brokeoff Mountains region on the northwest margin of the Delaware Basin present an opportunity to construct a detailed, three-dimensional image of the stratigraphic and facies architecture. This model can be applied towards improved description and characterization of heterogeneity in analogous Grayburg reservoirs. Four orders of stratigraphic hierarchy are recognized in the Grayburg Formation. The Grayburg represents a long-term composite sequence composed of four high-frequency sequences (HFS 1-4). Each HFS contains several composite cycles comprising two or more cycles that define intermediate-scale transgressive-regressive successions. Cycles are the smallest scale upward-shoaling vertical facies successions that can be recognized and correlated across various facies tracts. Cycles thus form the basis for establishing the detailed chronostratigraphic correlations needed to delineate facies heterogeneity.

Barnaby, R.J.; Ward, W.B.; Jennings, J.W. Jr.

1997-06-01

221

Two-phase mechanism of the formation of platinum-metal basites of the Fedorova Tundra intrusion on the Kola Peninsula: New data on geology and isotope geochronology  

NASA Astrophysics Data System (ADS)

This report contains the results of the authors’ studies on geology and isotope geochronology, which allowed them to formulate the thesis of a two-phase mechanism of the formation of rock associations in the Fedorova Tundra massif. During the former phase (2526-2507 My), a laminated series of the massif was formed, with shows of platinum-metal mineralization of reef type. During the later phase (2493-2485 My), a taxitic zone of the massif appeared, with a highly developed basal platinum-metal mineralization.

Groshev, N. Yu.; Nitkina, E. A.; Mitrofanov, F. P.

2009-08-01

222

On the formation of breakthrough curves tailing during convergent flow tracer tests in three-dimensional heterogeneous aquifers  

NASA Astrophysics Data System (ADS)

Anomalous transport in advection-dominated convergent flow tracer tests can occurs due to small-scale heterogeneities in aquifer hydraulic properties. These result in fluctuations of the groundwater velocity field and complex connectivity patterns between injection and extraction wells. While detailed characterization of heterogeneity is often not possible in practice, a proper understanding of what fundamental physical mechanisms can give rise to macroscopic behaviors that are measurable is essential for proper upscaling of solute transport processes. We analyze here how heavy-tailed breakthrough curves can arise in radially convergent flow to a well. The permeability fields are three-dimensional multi-Gaussian fields with varying statistical geometry and degrees of heterogeneity. We consider transport of conservative tracers from multiple injection locations by varying distance and angle from the extraction well. Anomalous power law tailing in breakthrough curves is attributed to a variety of features including the initial vertical stratification of the solute that arises due to a flux-weighted injection, the injection distance to the well relative to the depth of the aquifer, and the statistics of the heterogeneity field as defined by the correlation length and variance of the permeability. When certain conditions cooccur for a given injection, such as strong connectivity contrasts between aquifer layers, injection distances comparable to the horizontal heterogeneity integral scales, and large global variances, breakthrough curves tend to scale as a PL with unit slope at late time. These findings offer new insights to understand what physical processes must be understood to develop and choose appropriate upscaling approaches that might reproduce such anomalous transport in heterogeneous advection-dominated systems.

Pedretti, D.; Fernã Ndez-Garcia, D.; Bolster, D.; Sanchez-Vila, X.

2013-07-01

223

Methods and apparatus for measurement of the resistivity of geological formations from within cased wells in presence of acoustic and magnetic energy sources  

DOEpatents

Methods and apparatus are provided for measuring the acoustically modulated electronic properties of geological formations and cement layers adjacent to cased boreholes. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. Voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of the leakage current conducted into formation in the vicinity of those electrodes. Simultaneously subjecting the casing and formation to an acoustic source acoustically modulates the leakage current measured thereby providing a measure of the acoustically modulated electronic properties of the adjacent formation. Similarly, methods and apparatus are also described which measure the leakage current into formation while simultaneously subjecting the casing to an applied magnetic field which therefore allows measurement of the magnetically modulated electronic properties of the casing and the adjacent formation.

Vail, III, William B. (Bothell, WA)

1991-01-01

224

Dispersion measurement as a method of quantifying geologic characterization and defining reservoir heterogeneity. Annual report, July 12, 1992--July 12, 1993  

SciTech Connect

Dispersion of fluids flowing through porous media is an important phenomenon in miscible displacement. Much of the research involving dispersion and dispersivity as a property of reservoir rock has focused on miscible liquid-liquid displacement processes. This study addresses the measurement of dispersion in a gas-gas displacement system. It will enlarge the understanding of the characteristics of dispersivity and flow systems of reservoir rocks. New experimental methods and apparatus for gas-gas dispersion were developed in this study. Twenty eight gas-gas miscible displacement measurements under different flowrates and pressures were conducted on three Berea sandstone cores of varying lengths and physical properties. A gas chromatograph was utilized and modified to measure the concentration of gas at the outlet of the cores. Nitrogen was used as the displacing gas, while helium was used as the displaced gas. The experimental results were illustrated using S-shaped effluent breakthrough curves. The effect of flowrate and pressure on gas-gas dispersion, dispersion coefficient, dispersivity, and dispersion factor were determined from these curves. Gas effective diffusion coefficients were obtained by graphical methods using the dispersion coefficients under low velocities. A new method to determine the total flowing pore volume by dispersion measurement was proposed in this study. The heterogeneity of reservoir rock can be studied by this method. An increase in displacing velocity was found to decrease the mixing or dispersion of gases in porous media under low pressure (15, 30 and 40 psig). The presumption was made that a critical velocity exists for a given displacement, below which the increase of velocity results in a decrease in dispersion, and above which an increase in dispersion occurs. An increase in pressure will decrease the mixing of gases when the displacement velocity remains constant.

Menzie, D.E.

1994-01-01

225

Geologic Maps  

NSDL National Science Digital Library

Geologic Maps are unique in that they show the distribution of geologic features on a landscape through specific symbols and colors. The United States Geological Survey's (USGS) site Geologic Maps provides visitors with a good introduction to these concepts, which include the unique features of a geologic map; the meaning of their lines, colors, and symbols; the location of faults; and more. Anyone working with geologic maps or just interested in learning a little about cartography or geology will find this site easy to explore and full of good information.

2000-01-01

226

Geologic Map of New Jersey  

NSDL National Science Digital Library

This map displays the sedimentary rocks of the Cenozoic, Mesozoic, and Paleozoic eras as well as the igneous and metamorphic rocks of the Mesozoic and Precambrian eras. There is a pagesize copy of the geologic map, a brief description of the geology and physiographic provinces of New Jersey, and information on bedrock geologic maps of New Jersey (in CD-ROM format).

227

Inversion of synthetic geodetic data for dip-slip faults: clues to the effects of lateral heterogeneities and data distribution in geological environments typical of the Apennines (Italy)  

NASA Astrophysics Data System (ADS)

The inversion of geodetic data to obtain earthquake parameters is often performed by assuming that the medium is isotropic, elastic and either homogeneous or layered. The layered medium often offers the best estimate of the structure of the crust; however, predicted displacements and observed data may differ beyond the measurement errors. The slip distribution on the fault plane is usually obtained by dividing the best uniform slipping fault into an arbitrarily large number of subfaults and minimizing a cost function that includes a smoothness (Laplacian) term and a data misfit term. The smoothing factor controls the trade-off between the smoothness and the goodness-of-fit. The main focus of this work is the determination and effect of the smoothing parameter. We conducted several inversion tests of noiseless synthetic surface displacement due to faults embedded in media with properties consistent with the geology of the Central Apennines (Italy), where the 2009 April 6, L'Aquila earthquake occurred. We used the following three-step procedure: (i) global optimization with no smoothness constraint for a fault divided into a small number of equally sized equal-rake subfaults; (ii) selection of the best fault parameters using information criteria and (iii) evaluation of the slip amplitude distribution on an expanded fault after choosing the smoothing factor from trade-off curves or from cross-validation for different numbers of subfaults. We show that all of the fault features obtained by the inversion procedure, including the slip distribution, agree with those (`true') used in the forward modelling when the data cover the majority of the displacement field. Notable departures from the true slip distribution occur when a suboptimal smoothing factor (obtained from the trade-off curves or cross-validation) is used. If different crustal stratifications are used in the inversions, the best results are obtained for the stratification that is the closest to the true crustal structure. When we use more realistic GPS distributions, prominent spurious slip patches can be obtained. Modellers should use synthetic tests and sensitivity analyses as an initial step in the data inversion for source parameters.

Amoruso, A.; Barba, S.; Crescentini, L.; Megna, A.

2013-02-01

228

Formation of nitro-PAHs from the heterogeneous reaction of ambient particle-bound PAHs with NO3/N2O5  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbons (PAHs) and their nitrated derivatives (nitro-PAHs) have been shown to be mutagenic in bacterial and mammalian assays and are classified as probable human carcinogens. Semi-volatile PAHs partition between the gas and particulate phases, depending on their liquid-phase vapor pressures and ambient temperatures. These PAHs have been extensively measured in ambient particulate matter and can ultimately undergo long-range transport from source regions (e.g., China to the western USA) (1). During transport these particle-bound PAHs may undergo reaction with NO3/N2O5 to form nitro-PAH derivatives. Previous studies of heterogeneous nitration of PAHs have used particles composed of graphite, diesel soot, and wood smoke (2-4). This study investigates the heterogeneous formation of nitro-PAHs from ambient particle-bound PAHs from Beijing, China and sites located within the Los Angeles air basin. These ambient particle samples, along with filters coated with isotopically labeled PAHs, were exposed to a mix of NO2/NO3/N2O5 in a 7000 L Teflon chamber, with analysis focused on the heterogeneous formation of molecular weight 247 and 273 nitro-PAHs. The heterogeneous formation of certain nitro-PAHs (including1-nitropyrene and 1- and 2-nitrotriphenylene) was observed for some, but not all, ambient samples. Formation of nitro-PAHs typically formed through gas-phase reactions (2-nitrofluoranthene and 2-nitropyrene) was not observed. The effect of particle age and local photochemical conditions during sampling on the degree of nitration in environmental chamber reactions, as well as ambient implications, will be presented. 1. Primbs, T.; Simonich, S.; Schmedding, D.; Wilson, G.; Jaffe, D.; Takami, A.; Kato, S.; Hatakeyama, S.; Kajii, Y. Environ. Sci. Technol. 2007, 41, 3551-3558. 2. Esteve, W.; Budzinski, H.; Villenave, E. Atmospheric Environment 2004, 38, 6063-6072. 3. Nguyen, M.; Bedjanian, Y.; Guilloteau, A. Journal of Atmospheric Chemistry 2009, 62, 139-150. 4. Kamens, R. M.; Zhi-Hua, F.; Yao, Y.; Chen, D.; Chen, S.; Vartiainen, M. Chemosphere 1994, 28, 1623-1632.

Zimmermann, K.; Jariyasopit, N.; Simonich, S. L.; Atkinson, R.; Arey, J.

2012-12-01

229

Modeling heterogeneous interaction during SHS in the NiAl system: A phase-formation-mechanism map  

Microsoft Academic Search

Heterogeneous reaction Ni + Al ? NiAl in strongly non-isothermal conditions typical of SHS has been modeled for planar geometry\\u000a (unit bilayer Ni\\/Al film). The model used for simulation is based on the traditional quasi-equilibrium concept of the diffusion-controlled\\u000a growth of a continuous solid product layer, NiAl, between molten Al and solid (or liquid) Ni-based solution. The basic idea\\u000a is

B. B. Khina; B. Formanek

2007-01-01

230

Travel time distributions under convergent radial flow in heterogeneous formations: Insight from the analytical solution of a stratified model  

NASA Astrophysics Data System (ADS)

We analyze conservative solute transport under convergent flow to a well in perfectly stratified porous media, in which the hydraulic conductivity is treated as a random spatial function along the vertical direction (K(z)). The stratified model provides a rare exception of an exact analytical solution of travel time distributions in the proximity of pumping wells, and it is used here to obtain insights about ergodic and nonergodic transport conditions under nonuniform flow conditions. In addition, it provides a benchmark for numerical models aiming to correctly reproduce convergent flow transport in heterogeneous media, such as indicating the minimum number of layers required to obtain ergodic travel time distributions using only one model realization. The model provides important insights about the shape of the depth-integrated concentrations over time measured at the well (breakthrough curves, BTCs), which are usually applied to obtain transport parameters of the subsurface. It can be applied to any degree of system's heterogeneity and using either resident or flux-weighted injection modes. It can be built using different probabilistic distributions of K. In our analysis, we consider a log-normal K distribution, and the results indicate that, especially for highly heterogeneous systems, described by the log-K variance (?Y2), the minimum number of layers required for from one model simulation to reproduce ergodic travel time distributions can be prohibitively high, e.g., above 106 for ?Y2=8 considering flux-weighted injections. This issue poses serious concerns for numerical applications aiming to simulate transport in the proximity of pumping wells. In addition, this simple solution confirms that stratification can lead BTCs to display strong preferential flow and persistent, power-law-like late-time tailing. Since the latter are common phenomenological macroscale evidences of other microscale hydrodynamic processes than pure advection (e.g., mass-transfer), caution must be taken when inferring aquifer properties controlling the anomalous transport dynamics in heterogeneous media from BTCs fitting.

Pedretti, Daniele; Fiori, Aldo

2013-10-01

231

Geologic assessment of undiscovered oil and gas resources: Oligocene Frio and Anahuac Formations, United States Gulf of Mexico coastal plain and State waters  

USGS Publications Warehouse

The Oligocene Frio and Anahuac Formations were assessed as part of the 2007 U.S. Geological Survey (USGS) assessment of Tertiary strata of the U.S. Gulf of Mexico Basin onshore and State waters. The Frio Formation, which consists of sand-rich fluvio-deltaic systems, has been one of the largest hydrocarbon producers from the Paleogene in the Gulf of Mexico. The Anahuac Formation, an extensive transgressive marine shale overlying the Frio Formation, contains deltaic and slope sandstones in Louisiana and Texas and carbonate rocks in the eastern Gulf of Mexico. In downdip areas of the Frio and Anahuac Formations, traps associated with faulted, rollover anticlines are common. Structural traps commonly occur in combination with stratigraphic traps. Faulted salt domes in the Frio and Anahuac Formations are present in the Houston embayment of Texas and in south Louisiana. In the Frio Formation, stratigraphic traps are found in fluvial, deltaic, barrier-bar, shelf, and strandplain systems. The USGS Tertiary Assessment Team defined a single, Upper Jurassic-Cretaceous-Tertiary Composite Total Petroleum System (TPS) for the Gulf Coast basin, based on previous studies and geochemical analysis of oils in the Gulf Coast basin. The primary source rocks for oil and gas within Cenozoic petroleum systems, including Frio Formation reservoirs, in the northern, onshore Gulf Coastal region consist of coal and shale rich in organic matter within the Wilcox Group (Paleocene–Eocene), with some contributions from the Sparta Sand of the Claiborne Group (Eocene). The Jurassic Smackover Formation and Cretaceous Eagle Ford Formation also may have contributed substantial petroleum to Cenozoic reservoirs. Modeling studies of thermal maturity by the USGS Tertiary Assessment Team indicate that downdip portions of the basal Wilcox Group reached sufficient thermal maturity to generate hydrocarbons by early Eocene; this early maturation is the result of rapid sediment accumulation in the early Tertiary, combined with the reaction kinetic parameters used in the models. A number of studies indicate that the migration of oil and gas in the Cenozoic Gulf of Mexico basin is primarily vertical, occurring along abundant growth faults associated with sediment deposition or along faults associated with salt domes. The USGS Tertiary assessment team developed a geologic model based on recurring regional-scale structural and depositional features in Paleogene strata to define assessment units (AUs). Three general areas, as described in the model, are found in each of the Paleogene stratigraphic intervals assessed: “Stable Shelf,” “Expanded Fault,” and “Slope and Basin Floor” zones. On the basis of this model, three AUs for the Frio Formation were defined: (1) the Frio Stable Shelf Oil and Gas AU, containing reservoirs with a mean depth of about 4,800 feet in normally pressured intervals; (2) the Frio Expanded Fault Zone Oil and Gas AU, containing reservoirs with a mean depth of about 9,000 feet in primarily overpressured intervals; and (3) the Frio Slope and Basin Floor Gas AU, which currently has no production but has potential for deep gas resources (>15,000 feet). AUs also were defined for the Hackberry trend, which consists of a slope facies stratigraphically in the middle part of the Frio Formation, and the Anahuac Formation. The Frio Basin Margin AU, an assessment unit extending to the outcrop of the Frio (or basal Miocene), was not quantitatively assessed because of its low potential for production. Two proprietary, commercially available databases containing field and well production information were used in the assessment. Estimates of undiscovered resources for the five AUs were based on a total of 1,734 reservoirs and 586,500 wells producing from the Frio and Anahuac Formations. Estimated total mean values of technically recoverable, undiscovered resources are 172 million barrels of oil (MMBO), 9.4 trillion cubic feet of natural gas (TCFG), and 542 million barrels of natural gas liquids for all of the Frio and Anahuac AUs. Of the five units asse

Swanson, Sharon M.; Karlsen, Alexander W.; Valentine, Brett J.

2013-01-01

232

Late Quaternary Normal Faulting and Hanging Wall Basin Evolution of the Southwestern Rift Margin From Gravity and Geology, B.C.S., MX and Exploring the Influence of Text-Figure Format on Introductory Geology Learning  

NASA Astrophysics Data System (ADS)

An array of north-striking, left-stepping, active normal faults is situated along the southwestern margin of the Gulf of California. This normal fault system is the marginal fault system of the oblique-divergent plate boundary within the Gulf of California. To better understand the role of upper-crustal processes during development of an obliquely rifted plate margin, gravity surveys were conducted across the normal-fault-bounded basins within the gulf-margin array and, along with optically stimulated luminescence dating of offset surfaces, fault-slip rates were estimated and fault patterns across basins were assessed, providing insight into sedimentary basin evolution. Additionally, detailed geologic and geomorphic maps were constructed along two faults within the system, leading to a more complete understanding of the role of individual normal faults within a larger array. These faults slip at a low rate (0.1--1 mm/yr) and have relatively shallow hanging wall basins (˜500--3000 m). Overall, the gulf-margin faults accommodate protracted, distributed deformation at a low rate and provide a minor contribution to overall rifting. Integrating figures with text can lead to greater science learning than when either medium is presented alone. Textbooks, composed of text and graphics, are a primary source of content in most geology classes. It is essential to understand how students approach learning from text and figures in textbook-style learning materials and how the arrangement of the text and figures influences their learning approach. Introductory geology students were eye tracked while learning from textbook-style materials composed of text and graphics. Eye fixation data showed that students spent less time examining the figure than the text, but the students who more frequently examined the figure tended to improve more from the pretest to the posttest. In general, students tended to examine the figure at natural breaks in the reading. Textbook-style materials should, therefore, be formatted to include a number of natural breaks so that learners can pause to inspect the figure without the risk of losing their place in the reading and to provide a chance to process the material in small chunks. Multimedia instructional materials should be designed to support the cognitive processes of the learner.

Busch, Melanie M. D.

233

Geological images  

NSDL National Science Digital Library

This site from Marli Bryant Miller, a professor at the University of Oregon, presents images of geological features from around the world. Photographs of glacial features, igneous and metamorphic rocks and processes, and structural geology are featured.

Miller, Marli B.; Oregon, University O.

234

Comment on “Formation of chenier plain of the Doñana marshland (SW Spain): Observations and geomorphic model” by A. Rodríguez-Ramírez and C.M. Yáñez-Camacho [Marine Geology 254 (2008) 187–196  

Microsoft Academic Search

The speculative method and data suggested by Lario et al. [J. Lario, C.J. Dabrio, C. Zazo, J.L. Goy, F. Borja, A. Cabero, T. Bardají, P.G. Silva, 2010, Comment on “Formation of chenier plain of the Doñana marshland (SW Spain): Observations and geomorphic model” by A. Rodríguez-Ramírez and C.M. Yáñez-Camacho [Marine Geology 254 (2008) 187–196], Marine Geology, this Issue] and other

J. Rodríguez-Vidal; A. M. M. Soares; F. Ruiz; L. M. Cáceres

2010-01-01

235

Structural Geology  

NSDL National Science Digital Library

Created by the University of Nebraska-Lincoln, this site describes the basics of structural geology with text and images. The page includes the discussion of stress, strain, strike and dip, faults, folds, mountain building, erosion, economic geology, and environmental geology. This is a nice introduction to the basic topics in geology. Images from the field help to enhance the topics on the site. Instructors can use this resource to help create or simply enhance their curriculum.

2009-05-21

236

Geological Time  

NSDL National Science Digital Library

"Why do engineers need to know about geologic time?" That question is answered in this resource from the University of Saskatchewan's Department of Civil and Geological Engineering. Provided here is a discussion of the concepts of geological time; relative dating methods, such as correlation; and absolute dating methods, such as radiometric methods. Diagrams and charts are included to demonstrate these complex concepts.

2008-04-17

237

Oahu Geology Field Exercises  

NSDL National Science Digital Library

Three field guides are available to sites of geologic interest on Oahu. One is a visit to a landslide occurring in a neighborhood; another focuses on developing observational skills and determining the sequence of geologic events evident in a stratigraphic section; a third examines features associated with formation of a volcanic tuff ring. The worksheets are designed for teachers to implement as-is or modify for their classes.

238

Advances in Planetary Geology  

NASA Technical Reports Server (NTRS)

The surface of Mars displays a broad range of channel and valley features. There is as great a range in morphology as in scale. Some of the features of Martian geography are examined. Geomorphic mapping, crater counts on selected surfaces, and a detailed study of drainage basins are used to trace the geologic evolution of the Margaritifer Sinus Quandrangle. The layered deposits in the Valles Marineris are described in detail and the geologic processes that could have led to their formation are analyzed.

Grant, John A., III; Nedell, Susan S.

1987-01-01

239

National Geologic Map Database  

NSDL National Science Digital Library

The National Geologic Map Database (NGMDB) is an Internet-based system for query and retrieval of earth-science map information, created as a collaborative effort between the USGS and the Association of American State Geologists. Its functions include providing a catalog of available map information; a data repository; and a source for general information on the nature and intended uses of the various types of earth-science information. The map catalog is a comprehensive, searchable catalog of all geoscience maps of the United States, in paper or digital format. It includes maps published in geological survey formal series and open-file series, maps in books, theses and dissertations, maps published by park associations, scientific societies, and other agencies, as well as publications that do not contain a map but instead provide a geological description of an area (for example, a state park). The geologic-names lexicon (GEOLEX) is a search tool for lithologic and geochronologic unit names. It now contains roughly 90% of the geologic names found in the most recent listing of USGS-approved geologic names. Current mapping activities at 1:24,000- and 1:100,000-scale are listed in the Geologic Mapping in Progress Database. Information on how to find topographic maps and list of geology-related links is also available.

1997-01-01

240

CO{sub 2} Sequestration Capacity and Associated Aspects of the Most Promising Geologic Formations in the Rocky Mountain Region: Local-Scale Analyses  

SciTech Connect

The purpose of this report is to provide a summary of individual local-­?scale CCS site characterization studies conducted in Colorado, New Mexico and Utah. These site-­? specific characterization analyses were performed as part of the “Characterization of Most Promising Sequestration Formations in the Rocky Mountain Region” (RMCCS) project. The primary objective of these local-­?scale analyses is to provide a basis for regional-­?scale characterization efforts within each state. Specifically, limits on time and funding will typically inhibit CCS projects from conducting high-­? resolution characterization of a state-­?sized region, but smaller (< 10,000 km{sup 2}) site analyses are usually possible, and such can provide insight regarding limiting factors for the regional-­?scale geology. For the RMCCS project, the outcomes of these local-­?scale studies provide a starting point for future local-­?scale site characterization efforts in the Rocky Mountain region.

Laes, Denise; Eisinger, Chris; Morgan, Craig; Rauzi, Steve; Scholle, Dana; Scott, Phyllis; Lee, Si-Yong; Zaluski, Wade; Esser, Richard; Matthews, Vince; McPherson, Brian

2013-07-30

241

Physical Characteristics, Geologic Setting, and Possible Formation Processes of Spring Deposits on Mars Based on Terrestrial Analogs  

Microsoft Academic Search

Spring deposits are predicted as a result of former aquifers on Mars. This study examines the large-scale morphology and their physical processes of formation, growth, and evolution in terms that relate to the search for former aqueous environments on Mars.

L. S. Crumpler

2003-01-01

242

Geologic structure generated by large-impact basin formation observed at the South Pole-Aitken basin on the Moon  

NASA Astrophysics Data System (ADS)

South Pole-Aitken (SPA) basin is the largest clearly recognized basin on the lunar surface. Determining the composition and structure of the SPA basin interior provides critical constraints on the deep crustal and/or mantle composition of the Moon and improves our understanding of large-basin-forming impact processes. Here we present a new mineralogical map of the SPA basin interior, based on high-spatial-resolution reflectance spectra using the SELENE (Kaguya) multiband imager, which is combined with topographic data in order to interpret the geologic context. The derived mineralogical map suggests extensive distribution of ejected low-Ca pyroxene-dominant mantle material with the presence of purest anorthosite crustal materials surrounding a possible melt pool of 0.26 to 0.33 of the basin diameter near the basin center, which is significantly smaller than that suggested by the crater-scaling law. The absence of clear evidence of lower crustal material is consistent with recent impact simulation results.

Ohtake, Makiko; Uemoto, Kisara; Yokota, Yasuhiro; Morota, Tomokatsu; Yamamoto, Satoru; Nakamura, Ryosuke; Haruyama, Junichi; Iwata, Takahiro; Matsunaga, Tsuneo; Ishihara, Yoshiaki

2014-04-01

243

Coupling geothermal energy capture with carbon dioxide sequestration in permeable, porous geologic formations II: Numerical modeling and preliminary results  

NASA Astrophysics Data System (ADS)

Carbon dioxide (CO2) sequestration in deep saline aquifers and exhausted oil fields has been widely considered as a means for reducing CO2 emissions to the atmosphere as a counter-measure to global warming. However, rather than treating CO2 as a waste fluid in need of permanent disposal, it could additionally be used as a working fluid in geothermal energy capture as its thermodynamic properties suggest it transfers heat more efficiently than water. Therefore, utilizing CO2 may permit more widespread implementation of geothermal power systems. Here, we present numerical modeling results of coupled CO2 injection into a brine and heat transfer in geothermal reservoirs under conditions relevant for both CO2 sequestration and geothermal electricity generation. In particular, we examine subsurface flow and heating of the sequestered CO2, cooling of the geothermal reservoir, and changes in pore-fluid pressures under a variety of generalized CO2 injection and production scenarios and reservoir characteristics. While additional research is required, modeling results at present suggest that geologic reservoirs with CO2 as the heat mining fluid would be viable geothermal energy sources for electric power production for decades, potentially even in regions with relatively low geothermal temperatures and heat flow rates.

Randolph, J. B.; Saar, M. O.

2009-12-01

244

The geological significance of the boundary between the Fort Sill and Signal Mountain Formations in the lower Arbuckle Group (Cambrian)  

SciTech Connect

During the upper Cambrian, a transgression inundated the Southern Oklahoma aulacogen enveloping a landscape that consisted of hills of Cambrian-aged rhyolite up to 350 m in height. Initial deposits on this topography--the Reagan Formation--consist of siliciclastics that were deposited as alluvium and succeeding tidally-influenced marine sandstones and shales. The siliciclastics grains are made up of local rhyolite, quartz and authigenic glauconite. The overlying Honeycreek Formation is defined by the addition of carbonated detritus in the form of tidally-influenced pelmatozoan grainstones. The passage from the Honeycreek to the overlying Fort Sill Formation of the Arbuckle Group is marked by the incoming of beds of lime mudstone and the gradual disappearance of grainstones and siliciclastics. The contact between the Fort Sill and the overlying thinly-bedded dark grey bioclastic limestones of the Signal Mountain Formation is one of the most distinctive horizons in the Arbuckle Group. The contact evidently marks a substantial change in depositional environment. In detail the contact is sharp and shows evidence of minor erosion, although no karsting has been detected. The authors suggest that the contact surface records a regression, perhaps associated with dolomitization and followed by some erosion. A regression is also indicated by the local occurrence of a laminated tidal flat unit with traces of evaporites that outcrops in the far west of the Slick Hills immediately below the formation contact. They suggest that the Signal Mountains as a transgressive unit, incorporating siliciclastics transported into the area during the regression. It has been suggested that the unconformity reflects localized tectonism associated with the evolution of the Southern Oklahoma aulacogen. On the other hand the surface may correlate with a craton--wide Sauxian' hiatus.

Hosey, R.; Donovan, R.N. (Texas Christian Univ., Ft Worth, TX (United States). Geology Dept.)

1993-02-01

245

Isotope modeling of nitric acid formation in the atmosphere: Testing the importance of NO oxidation, heterogeneous reactions, and nighttime chemistry  

NASA Astrophysics Data System (ADS)

Atmospheric nitrate (NO3-atm = HNO3 and particulate nitrate) is the primary sink of NOx and its isotopic composition can yield important information about oxidation pathways. In particular oxygen isotope anomalies, the 17O excess (?17O values), have potential to determine the relative importance of NOx oxidation pathways (OH, NO3 or N2O5). We have developed a new isotope tracer model to test whether ?17O is a viable tracer for heterogeneous N2O5 hydrolysis and or NO3 radical reactions. The model uses the Regional Atmospheric Chemical Mechanism (RACM) and the isotope mass balance transfer mechanism we previously suggested. RACM was modified to account for heterogeneous uptake using three different parameterization schemes. We then conducted a sensitivity analysis that varied trace gas concentrations (NOx, VOC’s, biogenic organics), aerosol properties (mass, composition), and meteorology (RH, temperature, solar flux) and monitored the ?17O values in NO3-atm product. The model predicts that under most conditions, NO3-atm ?17O values are between 19 and 34‰ in agreement with observations. The model predicts that the D17O value in NO3-atm should have temperature dependence, as well as a seasonal effect. There was a small, but significant difference in predicted ?17O values based on which N2O5 hydrolysis scheme was used suggesting that ?17O analysis of NO3-atm may be a way of validating which scheme is most accurately reflecting the actual chemistry of the atmosphere. The model output results suggest that the oxidation pathway of NO3 to NO2, either by ozone or by peroxy radicals, has a pronounced impact on the resulting ?17O values and can lead to ?17O values lower than those observed in the existing data sets (8-18‰). There is a strong correlation between NO oxidation pathway and ?17O value in NO3-atm. The accuracy of the predictions of ?17O values made by the model can be tested by selecting unique environments and collecting NO3-atm then analyzing it for its ?17O composition. Such a data set may be helpful in understanding the role of nighttime and heterogeneous reactions in converting NOx into NO3-atm.

Michalski, G.; Xu, F.

2009-12-01

246

Exploration geology and depositional modeling of a continental tight sand reservoir, Abo Formation, Chaves County, New Mexico  

Microsoft Academic Search

The Wolfcampian-Leonardian age Abo Formation has been the major objective of exploration efforts in southeastern New Mexico since 1980. Producing sandstones are characterized by very low in-situ permeabilities (0.006 to 0.01 md) and porosities (determined from CNL density logs) ranging from 5 to 12%. Petrographic analysis of the producing zones yields only traces of visible porosity (approx. = 1%), indicating

Alberto A. Gutierrez

1983-01-01

247

The geological significance of the boundary between the Fort Sill and Signal Mountain Formations in the lower Arbuckle Group (Cambrian)  

Microsoft Academic Search

During the upper Cambrian, a transgression inundated the Southern Oklahoma aulacogen enveloping a landscape that consisted of hills of Cambrian-aged rhyolite up to 350 m in height. Initial deposits on this topography--the Reagan Formation--consist of siliciclastics that were deposited as alluvium and succeeding tidally-influenced marine sandstones and shales. The siliciclastics grains are made up of local rhyolite, quartz and authigenic

R. Hosey; R. N. Donovan

1993-01-01

248

A new hominin from the Basal Member of the Hadar Formation, Dikika, Ethiopia, and its geological context  

Microsoft Academic Search

In this paper we report for the first time hominin remains from the Basal Member of the Hadar Formation at Dikika, in the Awash Valley of Ethiopia, dating to greater than 3.4Ma. The new fossil, DIK-2-1, is a fragment of a left mandible and associated dentition. The mandible is attributed to Australopithecus afarensis. However, the new fossil exhibits some metric

Zeresenay Alemseged; Jonathan G. Wynn; William H. Kimbel; Denné Reed; Denis Geraads; René Bobe

2005-01-01

249

Geological, mineralogical and geochemical aspects of Archean Banded Iron-Formation-hosted gold deposits: Some examples from Southern Africa  

Microsoft Academic Search

This paper reports on different styles of gold mineralization observed in Archean gold deposits hosted by Algoma-type Banded\\u000a Iron-Formations (BIF) in southern Africa. Genetic aspects of various occurrences are discussed in the context of mineralogical\\u000a as well as geochemical data of BIFs from the greenstone terranes of the Zimbabwe and Kaapvaal cratons. The study revealed\\u000a that, in spite of their

T. Oberthür; R. Saager; H. P. Tomschi

1990-01-01

250

The geology, carbonaceous materials, and origin of the epigenetic uranium deposits in the Tertiary Sespe Formation in Ventura County, California  

Microsoft Academic Search

Uranium deposits have been known in western Ventura County, California, since about 1959. These epigenetic uranium deposits are found in and are probably derived from the Tertiary Sespe Formation, which is of continental origin. The sandstone-filled paleochannels served as ground-water conduits that carried uranium-bearing solutions to the depositional site. The uranium mineralization took place when the humate was deposited (perhaps

K. A. Dickinson; J. S. Leventhal

1988-01-01

251

Geological setting and paleomagnetism of the Eocene red beds of Laguna Brava Formation (Quebrada Santo Domingo, northwestern Argentina)  

NASA Astrophysics Data System (ADS)

The red bed succession cropping out in the Quebrada Santo Domingo in northwestern Argentina had been for long considered as Upper Triassic-Lower Jurassic in age based on weak radiometric and paleontological evidence. Preliminary paleomagnetic data confirmed the age and opened questions about the nature of fossil footprints with avian features discovered in the section. Recently the stratigraphic scheme was reviewed with the identification of previously unrecognized discontinuities, and a radiometric dating obtained in a tuff, indicated an Eocene age for the Laguna Brava Formation and the fossil bird footprints, much younger than the previously assigned. We present a detailed paleomagnetic study interpreted within a regional tectonic and stratigraphic framework, looking for an explanation for the misinterpretation of the preliminary paleomagnetic data. The characteristic remanent magnetizations pass a tilt test and a reversal test. The main magnetic carrier is interpreted to be low Ti titanomagnetites and to a lesser extent hematite. The characteristic remanent magnetization would be essentially detrital. The obtained paleomagnetic pole (PP) for the Laguna Brava Formation has the following geographic coordinates and statistical parameters: N = 29, Lon. = 184.5° E, Lat. = 75.0° S, A95 = 5.6° and K = 23.7. When this PP is compared with another one with similar age obtained in an undeformed area, a declination anomaly is recognized. This anomaly can be interpreted as Laguna Brava Formation belonging to a structural block that rotated about 16° clockwise along a vertical axis after about 34 Ma. This block rotation is consistent with the regional tectonic framework, and would have caused the fortuitous coincidence of the PP with Early Jurassic poles. According to the interpreted magnetostratigraphic correlation, the Laguna Brava Formation would have been deposited during the Late Eocene with a mean sedimentation rate of about 1.4 cm per thousand years, probably in relation to the onset of the Andean deformation.

Vizán, H.; Geuna, S.; Melchor, R.; Bellosi, E. S.; Lagorio, S. L.; Vásquez, C.; Japas, M. S.; Ré, G.; Do Campo, M.

2013-01-01

252

Petroleum systems and geologic assessment of undiscovered oil and gas, Cotton Valley group and Travis Peak-Hosston formations, East Texas basin and Louisiana-Mississippi salt basins provinces of the northern Gulf Coast region. Chapters 1-7.  

USGS Publications Warehouse

The purpose of the U.S. Geological Survey's (USGS) National Oil and Gas Assessment is to develop geologically based hypotheses regarding the potential for additions to oil and gas reserves in priority areas of the United States. The USGS recently completed an assessment of undiscovered oil and gas potential of the Cotton Valley Group and Travis Peak and Hosston Formations in the East Texas Basin and Louisiana-Mississippi Salt Basins Provinces in the Gulf Coast Region (USGS Provinces 5048 and 5049). The Cotton Valley Group and Travis Peak and Hosston Formations are important because of their potential for natural gas resources. This assessment is based on geologic principles and uses the total petroleum system concept. The geologic elements of a total petroleum system include hydrocarbon source rocks (source rock maturation, hydrocarbon generation and migration), reservoir rocks (sequence stratigraphy and petrophysical properties), and hydrocarbon traps (trap formation and timing). The USGS used this geologic framework to define one total petroleum system and eight assessment units. Seven assessment units were quantitatively assessed for undiscovered oil and gas resources.

Geological Survey (U.S.)

2006-01-01

253

CO2 injection modeling in large scale heterogeneous aquifers  

NASA Astrophysics Data System (ADS)

Numerical modeling of CO2 injection in heterogeneous media remains a challenging issue with actual computing facilities when considering large size models. In addition, the lack of data available for modeling calibration induces a large degree of uncertainties on the reservoir heterogeneity estimates. We propose here the study of three scenarios using different geological context. The first case is based on the Tenth SPE Comparative Solution Project Model 2. This fine-scale geological model contains 1.1 million cells with a top part representative of a prograding near shore environment while the lower part is fluvial. Simulated CO2 injection has been conducted considering the possibility of water re-injection to maintain the overpressure below the fracture pressure. The second case is based on the French Paris Basin geological context. The area covers a 100 km by 100 km domain (South East of Paris) in which data from about 70 wells and seismic grid have been used to build a 3D grid containing the Dogger carbonate formation as well as the lower part of the Oxfordian clay formation (the caprock) and the upper part of the Aalenian (below the Dogger). Major faults of the geological system have also been incorporated in the structural scheme. Petrophysical properties have been generated using stochastic approach. Porosity variability is simulated for each facies and correlated to permeability. Injection point has been selected in order to avoid fault reactivation. The last case is a representative of the Trias geological formation in France. The 3D regular Cartesian grid contains facies variability built using process based method to represent fluvial deposit architecture. The high geothermal gradient identified in this geological formation allows for the consideration of geothermal production. In this context, we performed CO2 injection simulation to evaluate the mass flow and heat extraction rates from enhanced geothermal injection-production systems using CO2 as heat transmission fluid. Two numerical codes have been used to perform the simulation and handling the high computing demand: (i) TOUGH2-MP, a parallel version of the TOUGH2 code; and (ii) COORES, a black oil reservoir simulator developed at IFPEN. From this study, the limitations of flow simulator to provide pertinent evaluation of overpressure, and plume migration with regard to the considered scale and the role of reservoir heterogeneities on the CO2 storage performance and security is discussed and analyzed.

Audigane, P. D.; Michel, A.; Trenty, L.; Yamamoto, H.; Gabalda, S.; Anciaux Sedrakian, A.; Chiaberge, C.

2011-12-01

254

Re-Evaluation of Plate Tectonic Models for Formation of the Amerasian Basin of the Arctic Ocean: Geologic Constraints from the Russian Arctic  

NASA Astrophysics Data System (ADS)

The most widely accepted plate tectonic model for the formation of the Amerasian Basin of the Arctic involves rifting and counter-clockwise rotation of the Arctic Alaska-Chukotka microplate (AACM) away from the Canadian Arctic margin to its present position. Accordingly, the Lomonosov Ridge (between the Eurasian and Amerasian Basins) represents a transform margin. The Alpha-Mendeleev Ridge (between the Makarov and Canada Basins) is thought to represent a post-rift structure, perhaps a hot-spot track (e.g. Lawver et al., 2002). Although this model satisfies many stratigraphic and geophysical constraints for the Alaskan and Canadian part of the reconstruction, it presents a growing set of problems with respect to geologic relations, sedimentary sources and timing of events in the Russian Arctic. A revised paleogeographic reconstruction of the Arctic places the Chukotka part of the Arctic Alaska plate closer to Russia but seeks to maintain a rotational opening for the Canada Basin. This paleogeographic reconstruction revives the hypothesis that the Makarov Basin formed by rifting orthogonal to the Lomonosov Ridge, and also suggests that the Mendeleev Ridge is a remnant of the rifted continental margin. This is supported by the morphology of normal faulted tilted block structures visible in updated bathymetric data, by recent reflection seismic profiles collected in the region (Coakley, 2006), and by new Russian refraction velocity data, coupled with the dredging and piston coring of sedimentary rocks from the Mendeleev ridge (Lebedeva-Ivanova et al., 2006). Our reconstruction also suggests that there may be a large component of strike-slip motion along the South Anyui suture (bounding the AACM to the south) which may have operated as a transform fault during opening of the Makarov Basin. Geologic relations suggest that if the Makarov Basin formed by rifting orthogonal to the Russian continental margin, its formation must have taken place after the cessation of collision-related shortening in the early Cretaceous (about 135 Ma), perhaps during a widespread episode of plutonism accompanied by NW-SE to E- W extension (from about 120 to 110 Ma), and was clearly over by the time the Okhotsk- Chukotka volcanic belt began to develop. Formation of the Makarov Basin and Amerasian Basin may have been localized by hot spot magmatism but was likely ultimately driven by Pacific-ward trench retreat in the Cretaceous.

Miller, E. L.; Toro, J.

2006-12-01

255

GeoTemp™ 1.0: A MATLAB-based program for the processing, interpretation and modelling of geological formation temperature measurements  

NASA Astrophysics Data System (ADS)

The evaluation of potential and resources during geothermal exploration requires accurate and consistent temperature characterization and modelling of the sub-surface. Existing interpretation and modelling approaches of 1D temperature measurements are mainly focusing on vertical heat conduction with only few approaches that deals with advective heat transport. Thermal regimes are strongly correlated to rock and fluid properties. Currently, no consensus exists for the identification of the thermal regime and the analysis of such dataset. We developed a new framework allowing the identification of thermal regimes by rock formations, the analysis and modelling of wireline logging and discrete temperature measurements by taking into account the geological, geophysical and petrophysics data. This framework has been implemented in the GeoTemp software package that allows the complete thermal characterization and modelling at the formation scale and that provides a set of standard tools for the processing wireline and discrete temperature data. GeoTempTM operates via a user friendly graphical interface written in Matlab that allows semi-automatic calculation, display and export of the results. Output results can be exported as Microsoft Excel spreadsheets or vector graphics of publication quality. GeoTemp™ is illustrated here with an example geothermal application from Western Australia and can be used for academic, teaching and professional purposes.

Ricard, Ludovic P.; Chanu, Jean-Baptiste

2013-08-01

256

Geological setting of oil shales in the Permian phosphoria formation and some of the geochemistry of these rocks  

USGS Publications Warehouse

Recent studies of the Meade Peak and the Retort Phosphatic Shale Members of the Phosphoria Formation have investigated the organic carbon content and some aspects of hydrocarbon generation from these rocks. Phosphorite has been mined from the Retort and Meade Peak members in southeastern Idaho, northern Utah, western Wyoming and southwestern Montana. Organic carbon-rich mudstone beds associated with the phosphorite in these two members also were natural sources of petroleum. These mudstone beds were differentially buried throughout the region so that heating of these rocks has been different from place to place. Most of the Phosphoria source beds have been deeply buried and naturally heated to catagenetically form hydrocarbons. Deepest burial was in eastern Idaho and throughout most of the northeastern Great Basin where high ambient temperatures have driven the catagenesis to its limit and beyond to degrade or to destroy the hydrocarbons. In southwest Montana, however, burial in some areas has been less than 2 km, ambient temperatures remained low and the kerogen has not produced hydrocarbons (2). In these areas in Montana, the kerogen in the carbonaceous mudstone has retained the potential for hydrocarbon generation and the carbon-rich Retort Member is an oil shale from which hydrocarbons can be synthetically extracted. The Phosphoria Formation was deposited in a foreland basin between the Cordilleran geosyncline and the North American craton. This foreland basin, which coincides with the area of deposition of the two organic carbon-rich mudstone members of the Phosphoria, has been named the Sublett basin (Maughan, 1979). The basin has a northwest-southeast trending axis and seems to have been deepest in central Idaho where deep-water sedimentary rocks equivalent to the Phosphoria Formation are exceptionally thick. The depth of the basin was increasingly shallower away from central Idaho toward the Milk River uplift - a land area in Montana, the ancestral Rocky Mountains. The basin is composed of land areas in Colorado, the Humboldt highland in northeastern Nevada and intervening carbonate shelves in Utah and Wyoming. The phosphorites and the carbonaceous mudstones were deposited on the foreslope between the carbonate and littoral sand deposits on the shelf and the dominantly cherty mudstone sediments in the axial part of the basin. Paleomagnetic evidence indicates that in the Permian the region would have been within the northern hemispheric trade wind belt; and wind-direction studies determined from studies of sand dunes, indicate that the prevailing winds from the Milk River uplift would have blown offshore across the Phosphoria sea. Offshore winds would have carried surface water away from the shore and generated upwelling in the sea in eastern Idaho and adjacent areas in Montana, Wyoming and Utah. Prior to deposition of the Phosphoria, the region was the site of extensive deposition of shallow-water carbonate sediments. Equivalent rocks in the northern part of the basin are dominantly sandstone derived from the adjacent Milk River uplift and similar sandstone strata in the southeastern sector were derived from the ancestral Rocky Mountains uplift. Tectonic subsidence of the Sublett basin in part of the region seems to have provided a sea-floor profile favorable for upwelling circulation and the shift in deposition from regional carbonates and local sandstone into a more complex depositional pattern that included the accumulation of the mudstone-chert-phosphorite facies that comprises the Phosphoria Formation. High biological productivity and the accumulation of sapropel on the sea floor is associated with contemporary coastal upwelling (1) and similar environmental and depositional conditions are attributed to the rich accumulations of organic matter in the Phosphoria Formation. Sapropelic mudstone and phosphorite composing the Meade Peak Member are approximately 60 m thick near the center of the Sublett basin. The Meade

Maughan, E. K.

1983-01-01

257

Certain aspects of the formation and identification of nanosized oxide components in heterogeneous catalysts prepared by different methods  

NASA Astrophysics Data System (ADS)

The results of studies into the relationship 'methods and synthesis conditions of a catalyst?catalyst structure?catalytic properties' in highly efficient crystallo-graphically amorphous copper- and iron-containing heterogeneous systems obtained by different chemical methods are generalized. Polymorphism of active phases and catalytic properties of nanostructured copper-containing zinc, zirconium, manganese and cerium oxides are discussed. Unusual transformations of nanosized Pt- and Pd-containing components on the ?-Al2O3 surface in nanostructured catalysts of ethanol steam reforming into synthesis gas and reductive dehydration of ethanol to alkanes are considered. The results of comparative studies on the crystallographically amorphous mixed iron oxide catalysts synthesized by either the alkoxy method or the deposition on various supports obtained by the Mössbauer and XAFS spectroscopy and magnetic susceptibility measurements are presented. These materials are shown to be efficient catalysts of important processes such as liquid-phase oxidation of hydrocarbons, synthesis of alkenes and alkylaromatic hydrocarbons from CO and H2, hydrogenative transformation of brown coal organic mass to hydrocarbons.

Ellert, Ol'ga G.; Tsodikov, Mark V.; Novotortsev, Vladimir M.

2010-10-01

258

Impacts experiments onto heterogeneous targets simulating impact breccia: Implications for impact strength of asteroids and formation of the asteroid families  

NASA Astrophysics Data System (ADS)

A series of impact experiments onto solid decimeter-sized cylinders made of porous gypsum admixed with approximately 1 cm-sized pebbles have been performed. The target densities and their heterogeneous structures could be representative of those of the asteroids Ida, Eros and many others, because asteroid sub-surface could be the consolidated boulders made by self-compaction and/or by impact compaction. Impact velocities in the experiments ranged from 2.0 km/s to 6.7 km/s (collision velocity in the asteroid main belt is approximately 5 km/s). It was found that the slope of the cumulative number distribution of post-impact fragments strongly depends on the specific energy of the impact. The presence of pebbles strongly influences the impact strength of the target as well as the size distribution of the post-impact fragments. Results of the experiments presented here are aimed at identifying the analogy between the laboratory results and the damage of small asteroids or their catastrophic disruption after impacts.

Leliwa-Kopystynski, J.; Arakawa, M.

2014-06-01

259

Separation and capture of CO2 from large stationary sources and sequestration in geological formations--coalbeds and deep saline aquifers.  

PubMed

The topic of global warming as a result of increased atmospheric CO2 concentration is arguably the most important environmental issue that the world faces today. It is a global problem that will need to be solved on a global level. The link between anthropogenic emissions of CO2 with increased atmospheric CO2 levels and, in turn, with increased global temperatures has been well established and accepted by the world. International organizations such as the United Nations Framework Convention on Climate Change (UNFCCC) and the Intergovernmental Panel on Climate Change (IPCC) have been formed to address this issue. Three options are being explored to stabilize atmospheric levels of greenhouse gases (GHGs) and global temperatures without severely and negatively impacting standard of living: (1) increasing energy efficiency, (2) switching to less carbon-intensive sources of energy, and (3) carbon sequestration. To be successful, all three options must be used in concert. The third option is the subject of this review. Specifically, this review will cover the capture and geologic sequestration of CO2 generated from large point sources, namely fossil-fuel-fired power gasification plants. Sequestration of CO2 in geological formations is necessary to meet the President's Global Climate Change Initiative target of an 18% reduction in GHG intensity by 2012. Further, the best strategy to stabilize the atmospheric concentration of CO2 results from a multifaceted approach where sequestration of CO2 into geological formations is combined with increased efficiency in electric power generation and utilization, increased conservation, increased use of lower carbon-intensity fuels, and increased use of nuclear energy and renewables. This review covers the separation and capture of CO2 from both flue gas and fuel gas using wet scrubbing technologies, dry regenerable sorbents, membranes, cryogenics, pressure and temperature swing adsorption, and other advanced concepts. Existing commercial CO2 capture facilities at electric power-generating stations based on the use of monoethanolamine are described, as is the Rectisol process used by Dakota Gasification to separate and capture CO2 from a coal gasifier. Two technologies for storage of the captured CO2 are reviewed--sequestration in deep unmineable coalbeds with concomitant recovery of CH4 and sequestration in deep saline aquifers. Key issues for both of these techniques include estimating the potential storage capacity, the storage integrity, and the physical and chemical processes that are initiated by injecting CO2 underground. Recent studies using computer modeling as well as laboratory and field experimentation are presented here. In addition, several projects have been initiated in which CO2 is injected into a deep coal seam or saline aquifer. The current status of several such projects is discussed. Included is a commercial-scale project in which a million tons of CO2 are injected annually into an aquifer under the North Sea in Norway. The review makes the case that this can all be accomplished safely with off-the-shelf technologies. However, substantial research and development must be performed to reduce the cost, decrease the risks, and increase the safety of sequestration technologies. This review also includes discussion of possible problems related to deep injection of CO2. There are safety concerns that need to be addressed because of the possibilities of leakage to the surface and induced seismic activity. These issues are presented along with a case study of a similar incident in the past. It is clear that monitoring and verification of storage will be a crucial part of all geological sequestration practices so that such problems may be avoided. Available techniques include direct measurement of CO2 and CH4 surface soil fluxes, the use of chemical tracers, and underground 4-D seismic monitoring. Ten new hypotheses were formulated to describe what happens when CO2 is pumped into a coal seam. These hypotheses provide significant insight into the fundamental chemical, physical, a

White, Curt M; Strazisar, Brian R; Granite, Evan J; Hoffman, James S; Pennline, Henry W

2003-06-01

260

The geology of the terrestrial planets  

NASA Technical Reports Server (NTRS)

The geologic history of the terrestrial planets is outlined in light of recent exploration and the revolution in geologic thinking. Among the topics considered are planet formation; planetary craters, basins, and general surface characteristics; tectonics; planetary atmospheres; and volcanism.

Carr, M. H. (editor); Saunders, R. S.; Strom, R. G.; Wilhelms, D. E.

1984-01-01

261

North Cascades Geology: Geologic Time  

NSDL National Science Digital Library

This article describes the period of geologic time spanned by the rocks of the North Cascades area of Washington. Users can access a simplified geologic time scale that provides links to geologic events in the North Cascades region. These include the deposition of various terranes, periods of intrusion and metamorphism, the beginning of the Cascade volcanic arc, and periods of major glaciation. Links to related materials are also provided.

262

Kinetic Monte Carlo simulation of surface heterogeneity in graphite anodes for lithium-ion batteries: Passive layer formation  

Microsoft Academic Search

The properties and chemical composition of the solid-electrolyte-interface (SEI) layer have been a subject of intense research due to their importance in the safety, capacity fade, and cycle life of Li-ion secondary batteries. Kinetic Monte Carlo (KMC) simulation is applied to explore the formation of the passive SEI layer in the tangential direction of the lithium- ion intercalation in a

Ravi N. Methekar; Paul W. C. Northrop; Kejia Chen; Richard D. Braatz; Venkat R. Subramanian

2011-01-01

263

Yosemite Geology  

NSDL National Science Digital Library

The National Park Service maintains the Yosemite National Park Web site and the corresponding Geology page. This Web site gives an overview of the geologic history of the site, tells how the Sierra Nevada range formed, explains the basics of granitic rock, shows how glaciers carved out the canyons, and much more.[JAB

264

Engineering Geology  

ERIC Educational Resources Information Center

Engineering geology remains a potpourri of applied classical geology, and 1977 witnessed an upswing in demand for these services. Traditional foundation-related work was slight, but construction related to national needs increased briskly. Major cities turned to concerns of transit waste-water treatment and solid-waste disposal. (Author/MA)

Hatheway, Allen W.

1978-01-01

265

Geologic Time.  

ERIC Educational Resources Information Center

One of a series of general interest publications on science topics, the booklet provides those interested in geologic time with an introduction to the subject. Separate sections discuss the relative time scale, major divisions in geologic time, index fossils used as guides for telling the age of rocks, the atomic scale, and the age of the earth.…

Newman, William L.

266

Physical geology  

SciTech Connect

The book integrates current thinking on processes (plate techtonics, chemical cycles, changes throughout geologic time). It is an introduction to investigations into the way the earth works, how mountains are formed, how the atmosphere, hydrosphere, crust and mantle interact with each other. Treatments on climate, paleoclimatology and landscape evolution are included, as is a discussion on how human activity affects geological interactions.

Skinner, B.; Porter, S.

1987-01-01

267

Heterogeneous formation of nitryl chloride and its role as a nocturnal NOx reservoir species during CalNex-LA 2010  

NASA Astrophysics Data System (ADS)

nocturnal conversion of dinitrogen pentoxide (N2O5) to nitryl chloride (ClNO2) on chloride-containing aerosol can be a regionally important NOx (= NO + NO2) recycling and halogen activation pathway that affects oxidant photochemistry the following day. Here we present a comprehensive measurement data set acquired at Pasadena, California, during the CalNex-LA campaign 2010 that included measurements of odd nitrogen and its major components (NOy = NOx + NO3 + 2N2O5 + ClNO2 + HNO3 + HONO + peroxyacyl, alkyl, and aerosol nitrates) and aerosol size distribution and composition. Nitryl chloride was present during every night of the study (median mixing ratio at sunrise 800 pptv) and was usually a more significant nocturnal NOx and odd oxygen (Ox = O3 + NO2 + 3N2O5 + ClNO2) reservoir species than N2O5 (whose concentrations were calculated from its equilibrium with NO2 and NO3). At sunrise, ClNO2 accounted for 21% of NOz (=NOy - NOx), 4% of NOy, and 2.5% of Ox, respectively (median values). Kinetic parameters for the N2O5 to ClNO2 conversion were estimated by relating ClNO2 concentrations to their time-integrated heterogeneous production from N2O5 and were highly variable between nights. Production of ClNO2 required conversion of N2O5 on submicron aerosol with average yield (?) and N2O5 reactive uptake probability (?) of ?? = 0.008 (maximum 0.04), scaled with submicron aerosol chloride content, and was suppressed by aerosol organic matter and liquid water content. Not all of the observed variability of ClNO2 production efficiency could be rationalized using current literature parameterizations.

Mielke, L. H.; Stutz, J.; Tsai, C.; Hurlock, S. C.; Roberts, J. M.; Veres, P. R.; Froyd, K. D.; Hayes, P. L.; Cubison, M. J.; Jimenez, J. L.; Washenfelder, R. A.; Young, C. J.; Gilman, J. B.; Gouw, J. A.; Flynn, J. H.; Grossberg, N.; Lefer, B. L.; Liu, J.; Weber, R. J.; Osthoff, H. D.

2013-09-01

268

Geology Fieldnotes: Timpanogos National Monument, Utah  

NSDL National Science Digital Library

Timpanogos Cave National Monument, in the Wasatch Mountains, features spectacularly decorated caverns, each of which has unique colors and formations. Features of the site include park geology information, maps, photographs of cave formations, related links, and visitor information. The park geology section discusses the caves' geologic history, structural geology, and details the discovery of the Hansen and Middle Caves (by Martin, George, and Wayne Hansen) and the Timpanogos Cave (by Veral Manwill).

269

Sudbury project (University of Muenster-Ontario Geological Survey): Origin of the polymict, allochthonous breccias of the Onaping Formation  

NASA Technical Reports Server (NTRS)

The Sudbury structure has been interpreted as a deeply eroded remnant of a peak-ring basin. The polymict, allochthonous breccias of the Onaping Formation (OF) occur in the central part of the Sudbury structure, which is surrounded by the 1.85-Ga-old 'Sudbury Igneous Complex' (SIC). From bottom to top the OF can be divided into Basal, Gray, Green, and lower and upper Black members. The breccias were mapped in detail in the east range of the structure. The SIC and the lower part of the OF (Basal Member) are interpreted as the impact melt system. The overlying Gray Member is a breccia unit with a clastic matrix and has a sharp contact to the Basal Member. The Green Member is considered as a continuous uniform breccia layer on top of the Gray Member and comprises the former 'chlorite shard horizon'. The uppermost unit of the OF (Black Member) can be subdivided into a lower and an upper Black Member unit. The lower part (100-150 m thick) still shows petrographic features of suevitic breccias, small fragments of basement rocks, melt particles, chloritized particles, and breccia fragments in a dark, clastic matrix.

Avermann, M. E.

1992-01-01

270

The relationship of dynamical heterogeneity to the Adam-Gibbs and random first-order transition theories of glass formation  

PubMed Central

We carefully examine common measures of dynamical heterogeneity for a model polymer melt and test how these scales compare with those hypothesized by the Adam and Gibbs (AG) and random first-order transition (RFOT) theories of relaxation in glass-forming liquids. To this end, we first analyze clusters of highly mobile particles, the string-like collective motion of these mobile particles, and clusters of relative low mobility. We show that the time scale of the high-mobility clusters and strings is associated with a diffusive time scale, while the low-mobility particles' time scale relates to a structural relaxation time. The difference of the characteristic times for the high- and low-mobility particles naturally explains the well-known decoupling of diffusion and structural relaxation time scales. Despite the inherent difference of dynamics between high- and low-mobility particles, we find a high degree of similarity in the geometrical structure of these particle clusters. In particular, we show that the fractal dimensions of these clusters are consistent with those of swollen branched polymers or branched polymers with screened excluded-volume interactions, corresponding to lattice animals and percolation clusters, respectively. In contrast, the fractal dimension of the strings crosses over from that of self-avoiding walks for small strings, to simple random walks for longer, more strongly interacting, strings, corresponding to flexible polymers with screened excluded-volume interactions. We examine the appropriateness of identifying the size scales of either mobile particle clusters or strings with the size of cooperatively rearranging regions (CRR) in the AG and RFOT theories. We find that the string size appears to be the most consistent measure of CRR for both the AG and RFOT models. Identifying strings or clusters with the “mosaic” length of the RFOT model relaxes the conventional assumption that the “entropic droplets” are compact. We also confirm the validity of the entropy formulation of the AG theory, constraining the exponent values of the RFOT theory. This constraint, together with the analysis of size scales, enables us to estimate the characteristic exponents of RFOT.

Starr, Francis W.; Douglas, Jack F.; Sastry, Srikanth

2013-01-01

271

The relationship of dynamical heterogeneity to the Adam-Gibbs and random first-order transition theories of glass formation.  

PubMed

We carefully examine common measures of dynamical heterogeneity for a model polymer melt and test how these scales compare with those hypothesized by the Adam and Gibbs (AG) and random first-order transition (RFOT) theories of relaxation in glass-forming liquids. To this end, we first analyze clusters of highly mobile particles, the string-like collective motion of these mobile particles, and clusters of relative low mobility. We show that the time scale of the high-mobility clusters and strings is associated with a diffusive time scale, while the low-mobility particles' time scale relates to a structural relaxation time. The difference of the characteristic times for the high- and low-mobility particles naturally explains the well-known decoupling of diffusion and structural relaxation time scales. Despite the inherent difference of dynamics between high- and low-mobility particles, we find a high degree of similarity in the geometrical structure of these particle clusters. In particular, we show that the fractal dimensions of these clusters are consistent with those of swollen branched polymers or branched polymers with screened excluded-volume interactions, corresponding to lattice animals and percolation clusters, respectively. In contrast, the fractal dimension of the strings crosses over from that of self-avoiding walks for small strings, to simple random walks for longer, more strongly interacting, strings, corresponding to flexible polymers with screened excluded-volume interactions. We examine the appropriateness of identifying the size scales of either mobile particle clusters or strings with the size of cooperatively rearranging regions (CRR) in the AG and RFOT theories. We find that the string size appears to be the most consistent measure of CRR for both the AG and RFOT models. Identifying strings or clusters with the "mosaic" length of the RFOT model relaxes the conventional assumption that the "entropic droplets" are compact. We also confirm the validity of the entropy formulation of the AG theory, constraining the exponent values of the RFOT theory. This constraint, together with the analysis of size scales, enables us to estimate the characteristic exponents of RFOT. PMID:23556792

Starr, Francis W; Douglas, Jack F; Sastry, Srikanth

2013-03-28

272

Briefing on geological sequestration  

EPA Science Inventory

Geological sequestration (GS) is generally recognized as the injection and long-term (e.g., hundreds to thousands of years) trapping of gaseous, liquid or supercritical carbon dioxide (CO2) in subsurface media ? primarily saline formations, depleted or nearly depleted oil and gas...

273

Geologic History  

NSDL National Science Digital Library

This unit introduces younger students to the concept of relative versus absolute time and how geologists determine the age of geologic events and features. Topics include the laws that determine relative age (superposition, cross-cutting relationships, included fragments, and others), and how to re-construct the geologic history of an area using these relationships. There is also information on geologic correlation and the use of index fossils to determine relative age. The section on absolute time discusses some ways of measurement (tree rings, radioactive dating) and introduces the concepts of natural selection and mass extinctions. A vocabulary and downloadable, printable student worksheets are provided.

Medina, Philip

2010-09-03

274

Geologic Time  

NSDL National Science Digital Library

The Earth is very old -- 4.5 billion years or more -- according to recent estimates. This vast span of time, called geologic time by earth scientists, is difficult to comprehend in the familiar time units of months and years, or even centuries. How then do scientists reckon geologic time, and why do they believe the Earth is so old? A great part of the secret of the Earth's age is locked up in its rocks, and our centuries-old search for the key led to the beginning and nourished the growth of geologic science.

Newman, William L.

1997-01-01

275

Architecture, internal heterogeneity, and resulting drainage efficiency of Upper Oligocene Frio Formation inner-shelf sandstone reservoirs in West Fulton Beach Field, Aransas County, Texas  

SciTech Connect

The architecture, internal heterogeneity, and production history of selected reservoirs in West Fulton Beach field, Copano Bay, Aransas County, Texas, were examined as part of a project to identify additional oil and gas reserves on Texas state lands. Upper Oligocene Frio Formation reservoirs in this field have yielded more than 146 bcf of gas and 8 MMbbl of oil. A high-resolution genetic stratigraphic analysis of inner-shelf sandstone reservoirs used well log and petrophysical data to locate uncontacted or incompletely drained reservoir compartments. Shelf sandstone reservoirs are composed of thin (2-6 ft) sandstones that are laterally isolated but commonly vertically stacked and amalgamated into units as much as 16 ft thick. Individual sandstones constitute separate reservoir compartments that are vertically isolated if surrounded by inner-shelf shales or are in partial communication if vertically stacked, separated by a low-permeability bioturbated sandstone or siltstone layer of varying thickness. Heterogeneity within individual sandstone units is low. Deposition of inner-shelf sandstones varies - from proximal settings, below fair-weather wave base but above storm wave base, where the sandstones are thicker, more commonly amalgamated, and form well-interconnected compartments - to distal settings below storm wave base, where they are thinner and more commonly isolated. Production histories indicate that completions in proximal settings can drain more than 600 ac in a gas reservoir, whereas those in distal settings drain less than 200 ac. High-resolution stratigraphic analysis of inner-shelf sand-stone reservoirs at West Fulton Beach field has identified 11 bcf of additional reserves in untapped and incompletely drained reservoir compartments. The 63 other major fields of the downdip Frio barrier-bar/strandplain play of the central Texas Gulf Coast may contain as much as 500 bcf of additional gas that could be identified through similar efforts.

Knox, P.R. [Univ. of Texas, Austin, TX (United States)

1994-09-01

276

[Spatiotemporal heterogeneity and its formation causes of soil physical properties in karst peak-cluster depression area of northwest Guangxi, China].  

PubMed

Soil samples were collected from the grassland, shrub land, secondary forest, and original forest on the hill slope in a typical karst peak-cluster depression area of northwest Guanxi, with the spatiotemporal heterogeneity of soil physical properties investigated by classical statistics, and the formation causes of the heterogeneity analyzed by redundancy analysis (RDA). In 0-15 cm soil layer, the clay (< 0.002 mm) and silt (0.002-0.05 mm) contents of shrub land and original forest had significant differences with those of grassland and secondary forest, respectively, but the clay, silt, and sand (0.05-2.0 mm) contents had no significant differences between grassland and secondary forest. No significant difference was observed in the soil sand content among the four land types, but the soil bulk density of grassland was significantly different from that of other three land types. The soil clay content of grassland increased with increasing elevation, while that of the other three land types was the highest on medium slope, and had no significant differences for the same land types among different slope locations. The soil clay content in different layers of 0-30 cm had a greater variation extent in original forest (14.55%) than in grassland (7.12%), shrub land (11.24%), and secondary forest (13.77%), and the soil particle size composition was greatly affected by the disturbance of human activities. Soil organic carbon (SOC) and vegetation type were the dominant factors affecting the soil physical properties, and the bare rock ratio had greater effects on soil sand content. PMID:21265145

Liu, Shu-juan; Zhang, Wei; Wang, Ke-lin; Chen, Hong-song; Wei, Guo-fu

2010-09-01

277

Geologic Timeline  

NSDL National Science Digital Library

Dive into the depths of time with this Geologic Timeline. The farther you scroll down, the farther back in time you'll travel. Also, the longer a period is on this page, the longer it lasted in history!

2000-01-01

278

Numerical modeling of formation damage by two-phase particulate transport processes during CO 2 injection in deep heterogeneous porous media  

NASA Astrophysics Data System (ADS)

Prediction of CO 2 injection performance in deep subsurface porous media relies on the ability of the well to maintain high flow rates of carbon dioxide during several decades typically without fracturing the host formation or damaging the well. Dynamics of solid particulate suspensions in permeable media are recognized as one major factor leading to injection well plugging in sandstones. The invading supercritical liquid-like fluid can contain exogenous fine suspensions or endogenous particles generated in situ by physical and chemical interactions or hydrodynamic release mechanisms. Suspended solids can plug the pores possibly leading to formation damage and permeability reduction in the vicinity of the injector. In this study we developed a finite volume simulator to predict the injectivity decline near CO 2 injection wells and also for production wells in the context of enhanced oil recovery. The numerical model solves a system of two coupled sets of finite volume equations corresponding to the pressure-saturation two-phase flow, and a second subsystem of solute and particle convection-diffusion equations. Particle transport equations are subject to mechanistic rate laws of colloidal, hydrodynamic release from pore surfaces, blocking in pore bodies and pore throats, and interphase particle transfer. The model was validated against available laboratory experiments at the core scale. Example results reveal that lower CO 2 residual saturation and formation porosity enhance CO 2-wet particle mobility and clogging around sinks and production wells. We conclude from more realistic simulations with heterogeneous permeability spanning several orders of magnitude that the control mode of mobilization, capture of particles, and permeability reduction processes strongly depends on the type of permeability distribution and connectivity between injection and production wells.

Sbai, M. A.; Azaroual, M.

2011-01-01

279

A primer in lunar geology  

NASA Technical Reports Server (NTRS)

Primary topics in lunar geology range from the evolution of the solar system to lunar photointerpretation, impact crater formation, and sampling to analyses on various Apollo lunar landing site geomorphologies.

Greeley, R. (editor); Schultz, P. H. (editor)

1974-01-01

280

faults role in geological processes. Repeated changing of activity mode and magnitude from basin formation to mountain belt staking: the case of the Sicilian Chain (Central Mediterranean)  

NASA Astrophysics Data System (ADS)

Faults reactivation (positive, oblique or negative inversions) often drives mountain building processes, from basin formation to accretionary wedge emplacement and its syn- and post-orogenic modifications. Several analytical studies on faults reactivation highlighted the importance of pre-existing fault orientation in the stress field, even though reactivation processes have only recently been considered as an important control in fault propagation. A better understanding of reactivation is essential to establish whether a fault is extinct or not, to better evaluate possible episodic fault activity and to determine the effects of reactivation on fault-growth behaviour and scaling relationships. Inherited normal faults pattern deriving from basin formation (i.e.: passive margin evolution), involved later in orogenic processes, may represents a constraint feature that controls the chain architecture and so the emplacement pattern and kinematic partition. In fact, these faults form zones of mechanical weakness that influence the architecture, kinematic pattern and distribution of crustal-scale deformation in both continental and oceanic regions. As long as a pre-existing fault remains mechanically weaker than its surroundings, strain is preferentially concentrated in the fault zone. This occurs, irrespective of whether the deformation is continuous or interrupted by periods of little activity, because pre-existing faults are surfaces along which the cohesive strength and the friction coefficient are lower than those of unfractured rock volumes. Otherwise, new-timed of thrust geometries firstly activated in convergent settings may act as a preferential strain partitioning zones during intra-collisional kinematic evolution processes driving the chain building, for example related to the mechanical status of the chain-foredeep-foreland system (i.e.: wedge subcritical, critical or supercritical stages). Multistep faults activities may be recognised through mesostructural analysis of master and minor faults populations recorded within the basin successions that experienced afterwards positive inversion to form thrust sheets in collisional-dominated settings. In Sicily (Central Mediterranean) a lot of pre-, syn- and post-orogenic brittle structures have been analysed. These faults have often recorded overprinted kinematic indicators, suggesting repeated interplay between extensional/oblique/compressional stress fields during geologic time. A comparison of structural and syn-deformational stratigraphic features allow us to recognise the palaeotectonic history of the Sicilian Chain and to hypothesise its kinematic evolution, from basin formation to the chain building and -earlier- chain modification of this segment of the Maghrebides African Margin. These faults experienced repeated changing of activity mode (positive and negative reactivations), magnitude and surface geometries, determining obstacles or preferential ways for strain partitioning, with regards to their size and orientation, during the syn- and post-orogenic processes.

Nigro, Fabrizio; Renda, Pietro; Favara, Rocco

2010-05-01

281

Diffusive leakage of carbon, variable migration rates of solutes, multiple reaction fronts: what happens when CO2 is injected into geologic formations  

NASA Astrophysics Data System (ADS)

A complex set processes occur when CO2-charged water resulting from CO2 injection into a geologic formation interacts with the resident formation water and sediment. First, the sequestration efficiency depends on the rate of CO2 injection and sediment texture (porosity and permeability). Second, acid and bicarbonates resulting from the hydration of CO2 interact with the resident water to create multiple solute migration fronts, and also simultaneously induce complex interactions with the resident minerals. All of these features, and accurate mass-balancing, can be achieved using a new water-rock interaction and reactive-transport simulator Sym.CS. Water-rock interaction and reactive transport modeling is an important tool for deciphering chemical and physical reactions occurring in sediments and rocks that are not accessible for monitoring. Traditional models solve a large set of conservation of mass equations written for aqueous solute species. Typically, reactions are solved separately from mass-transfer equations through loosely coupled sequentially iterated numerical algorithms. Resulting simulators therefore fall short of achieving the full extent of the theoretical accuracy and the nonlinearly of the reactive-transport and water-rock interaction phenomena. A new method is presented that uses conservation equations written for chemical elements, and tight coupling between mass-transfer and reactions. Derivation of the elemental conservation equation from the theoretically correct solute conservation equation involves one parametric conversion. The tight coupling between mass-transfer and reactions entails using explicitly discretized form of mass-transfer terms of the conservation equation when solving for the reactions. This explicitly coupled iteration method allows accurate solution of the conservation equations to be achieved. More importantly, this method allows (1) accurate bookkeeping of mass as effluents are injected and reactions progress among various phases, and (2) capturing the flow-reaction feedback that determines the efficiency of injection practice and reservoir capacity usage. The third component of the model is a composite media petrophysical model that allows the monitoring of changing reservoir characteristics as chemical and textural compositions evolve. The simulator Sym.CS, which includes all of above processes, is used to model interaction between CO2-charged water with formation water in sandstone reservoirs. Results demonstrate the utility of the model that preserves the nonlinearity of mass-transfer and reaction processes. Accurate mass-balance is also achieved and demonstrated. The results also show the importance of diffusive properties of highly reactive solutes, as they form one or more reaction fronts ahead of sweep fronts, as well as significant quantity of carbon to leak out of the reservoir.

Park, A. J.

2009-12-01

282

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

SciTech Connect

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.

Mancini, E.A.

1990-01-01

283

Leakage and Seepage from Geologic Carbon Sequestration Sites.  

National Technical Information Service (NTIS)

Geologic carbon sequestration involves the injection of large quantities of carbon dioxide (CO2) into geological formations such as depleted oil and gas reservoirs and brine formations. Pressure and buoyancy forces provide a driving force for stored CO2 t...

C. M. Oldenburg A. J. A. Unger R. P. Hepple P. D. Jordan

2002-01-01

284

Structural Geology  

NASA Astrophysics Data System (ADS)

Structural geology and continental tectonics were ushered in to the modern quantitative age of geosciences with the arrival of the global plate tectonics paradigm (circa 1968), derived using new data from the oceans' depths, and John Ramsay's 1967 seminal work, Folding and Fracturing of Rocks. Fossen is to be applauded for crafting a unique, high-caliber, and accessible undergraduate textbook on structural geology that faithfully reflects this advance and the subsequent evolution of the discipline. This well-written text draws on Fossen's wealth of professional experience, including his broad and diverse academic research and experience in the petroleum industry. This book is beautifully illustrated, with excellent original color diagrams and with impressive color field photographs that are all keyed to locations and placed into geologic context.

Weber, John; Frankel, Kurt L.

2011-05-01

285

Teaching Geology  

NSDL National Science Digital Library

This rather remarkable website contains a great collection of resources for web-based instruction and demonstrations of geology concepts. The collection includes, under Classroom demonstration, the very useful SeisMac 3.0, which is an application for Mac OS X that turns a laptop computer into a " low-resolution strong-motion accelerometer," or a basic seismograph. It works by accessing the computer's Sudden Motion Sensor in order to display real-time, three axis accelerations graphs. Visitors can use the application to watch the seismic waves go up and down just by tapping their feet on the floor nearby. Other resources include Virtual Earth (an "interactive minicourse on thermal convection") and a link to Geology in the news, which collates important news stories with a geological theme.

286

Monitoring of Water and Thermic Transfers in the Vadose Zone of a Geological Carbonate Formation : Example of and Underground Quarry, Gironde, France  

NASA Astrophysics Data System (ADS)

The aim of this study is the monitoring of water and thermic transfers in vadose zone of a geological carbonate formation during three hydrological cycles (August 2001- November 2004). The application of the Time Domain Reflectometry (TDR) and Self-Potential (SP) methods to determine the water content of porous rock has been widely investigated. More than 285 studied point measurements of rock water content observed during three hydrological cycles and distributed among an abandoned underground quarry in Gironde, France, show a permanently undersaturated limestone (between 35 and 50 percents). We also investigated the unsaturated zone in a borehole between 0 and 20 m depth until the water table. 14 TDR and SP electrodes investigate the vadose zone. For the understanding of the streaming potential and electric behaviour from the SP method of a vadose zone we performed an experimental device which allows us to quantify the measurements of electrokinetic coupling coefficient at various saturation conditions. The results show that the vadose zone is characterized by three different sub-zones which are different water dynamics. The shallow zone down to a depth of seven meters corresponds to a zone with a significant variation of water saturation related to evapotranspiration dynamic water. The second zone (so-called transition zone) between seven to sixteen meters displays a high stability. The third zone (zone of capillary fringe) between sixteen to twenty meter shows a high and constant water saturation. Experimental results show three periods of maximum water content corresponding to three occurring effective precipitations. The dephasing and the amplitude attenuation of the hydraulic and thermic waves with the depth can be modelled and explained by the physical properties of the porous medium in an unsaturated zone such as the diffusivity, the water relative permeability, the capillarity pressure versus water saturation and the effective porosity.

Cerepi, A.; Loisy, C.; Burlot, R.; Mao, L.

2007-12-01

287

Radon-222 as a Tracer of Water-Air Dynamics in the Unsaturated Zone of Geological Carbonate Formation: Example of an Underground Quarry (Oligocene Aquitain Limestone, France)  

NASA Astrophysics Data System (ADS)

Complex process in the unsaturated zone affect the transfers of fluids. Within the context of an integrated study on the process of the meteoric diagenesis in a carbonate formation, we try to determine the time transit of fluids. The aim of this study is to see whether radon 222 is a good natural tracer of fluids vertical diffusivity. Radon is an inert radioactive gas. It has three isotopes 222Rn, 220Rn, 219Rn. 222Rn comes from the decay of 238U. The 222Rn half-life (3.82 days) allows it to be transported far from its origin (Fleischer et al., 1981). Temporal variations of radon activity in soil gas depend on several factors such as meteorological variables (temperature, rainfall, atmospheric pressure, etc) and geological variables (concentration of radium in the soil, porosity, grain size, tectonic activity, etc.) (Abbad et al., 1993). The radon was measured on an experimental site : soil (0.40 meter thick) is lying on the Oligocene limestone (15 meters thick). This limestone was exploited in underground quarry with several levels (7 meters and 10 meters deep). Radon product comes from soil clays and limons for the major part and quaternary loess trapped in the limestone karstic framework for an other part. In the unsaturated zone, radon moves vertically in the gaseous phase under piston effect of the liquid phase. It moves as well dissolve in the liquid phase. The underground quarry atmosphere of the two levels shows variations of radon concentration in the time. The results show correlation between the maxima of effective precipitations and the maxima ones of radon concentration in the underground quarry atmosphere with a seven months dephasing. Dephasing between the maxima of effective precipitations and the maxima of moisture in the porous rock is only five months. This correlation leads to a diffusion model of radon in the unsaturated zone.

Loisy, C.; Franceschi, M.; Cerepi, A.

2006-12-01

288

Geologic Explorations  

NSDL National Science Digital Library

One of the latest offerings from the North Carolina State University's Web site Science Junction (last mentioned in the November 25, 1998 Scout Report) is the Geologic Explorations page. By clicking on the respective coordinates of each location, users can explore twelve areas in the western United States with 360-degree panoramic QuickTime movies and digital photography. Set up as a type of lesson for students, the main page suggests paying close attention to the unique geologic features and gives a few questions to answer about each area. The site is very easy to use and provides some breathtaking vistas of some of the most beautiful areas of the US.

Bodzin, Alec M.

2001-01-01

289

Geology Programs and Disciplinary Accreditation  

NSDL National Science Digital Library

This report raises the question of whether accreditation may be coming to the geology discipline, and attempts to quantify the positions on accreditation of academic department heads/chairs. The study makes a distinction between institutional and specialized (or disciplinary) accreditation and explores attitudes toward both types. Results of the analysis are presented with a discussion of two methods of data interpretation, a multivariate analysis technique and the Chi square test for heterogeneity or independence. The report concludes that there is currently insufficient support for establishing disciplinary accreditation in geology.

Corbett, Robert; Corbett, Erica

2001-03-01

290

Digital solar system geology  

NASA Technical Reports Server (NTRS)

All available synoptic maps of the solid-surface bodies of the Solar System were digitized for presentation in the planned Atlas of the Solar System by Greeley and Batson. Since the last report (Batson et al., 1990), preliminary Uranian satellite maps were replaced with improved versions, Galilean satellite geology was simplified and digitized, structure was added to many maps, and the maps were converted to a standard format, with corresponding standing colors for the mapped units. Following these changes, the maps were re-reviewed by their authors and are now undergoing final editing before preparation for publication. In some cases (for Mercury, Venus, and Mars), more detailed maps were digitized and then simplified for the Atlas. Other detailed maps are planned to be digitized in the coming year for the Moon and the Galilean satellites. For most of the remaining bodies such as the Uranian satellites, the current digitized versions contain virtually all the detail that can be mapped given the available data; those versions will be unchanged for the Atlas. These digital geologic maps are archived at the digital scale of 1/16 degree/ pixel, in sinusoidal format. The availability of geology of the Solar System in a digital database will facilitate comparisons and integration with other data: digitized lunar geologic maps have already been used in a comparison with Galileo SSI observations of the Moon.

Batson, R. M.; Kozak, R. C.; Isbell, Nancy K.

1991-01-01

291

Geology Fieldnotes: Oregon Caves National Monument  

NSDL National Science Digital Library

Oregon Caves National Monument is an active marble cave created by natural forces over hundreds of thousands of years in one of the world's most diverse geologic realms. Features of the site include park geology information, maps, photographs, related links, and visitor information. The park geology section discusses the cave's development and geologic history, its formations, and its development as a National Monument. The maps section includes an area map of the National Monument.

292

Novel nitro-PAH formation from heterogeneous reactions of PAHs with NO2, NO3/N2O5, and OH radicals: prediction, laboratory studies, and mutagenicity.  

PubMed

The heterogeneous reactions of benzo[a]pyrene-d12 (BaP-d12), benzo[k]fluoranthene-d12 (BkF-d12), benzo[ghi]perylene-d12 (BghiP-d12), dibenzo[a,i]pyrene-d14 (DaiP-d14), and dibenzo[a,l]pyrene (DalP) with NO2, NO3/N2O5, and OH radicals were investigated at room temperature and atmospheric pressure in an indoor Teflon chamber and novel mono-NO2-DaiP and mono-NO2-DalP products were identified. Quartz fiber filters (QFF) were used as a reaction surface and the filter extracts were analyzed by GC/MS for nitrated-PAHs (NPAHs) and tested in the Salmonella mutagenicity assay, using Salmonella typhimurium strain TA98 (with and without metabolic activation). In parallel to the laboratory experiments, a theoretical study was conducted to rationalize the formation of NPAH isomers based on the thermodynamic stability of OH-PAH intermediates, formed from OH-radical-initiated reactions. NO2 and NO3/N2O5 were effective oxidizing agents in transforming PAHs to NPAHs, with BaP-d12 being the most readily nitrated. Reaction of BaP-d12, BkF-d12, and BghiP-d12 with NO2 and NO3/N2O5 resulted in the formation of more than one mononitro isomer product, while the reaction of DaiP-d14 and DalP resulted in the formation of only one mononitro isomer product. The direct-acting mutagenicity increased the most after NO3/N2O5 exposure, particularly for BkF-d12 in which di-NO2-BkF-d10 isomers were measured. The deuterium isotope effect study suggested that substitution of deuterium for hydrogen lowered both the direct and indirect acting mutagenicity of NPAHs and may result in an underestimation of the mutagencity of the novel NPAHs identified in this study. PMID:24350894

Jariyasopit, Narumol; McIntosh, Melissa; Zimmermann, Kathryn; Arey, Janet; Atkinson, Roger; Cheong, Paul Ha-Yeon; Carter, Rich G; Yu, Tian-Wei; Dashwood, Roderick H; Massey Simonich, Staci L

2014-01-01

293

Geologic and Hydrologic Controls Critical to Coalbed Methane Producibility and Resource Assessment: Williams Fork Formation, Piceance Basin, Northwest Colorado. Topical Report, December 1, 1993-November 30, 1995.  

National Technical Information Service (NTIS)

The objectives of this report are: To further evaluate the interplay of geologic and hydrologic controls on coalbed methane production and resource assessment; to refine and validate our basin-scale coalbed methane producibility model; and to analyze the ...

A. R. Scott C. M. Tremain H. S. Nance M. J. Mavor R. Tyler R. G. McMurry W. R. Kaiser

1996-01-01

294

Geology Fieldnotes  

NSDL National Science Digital Library

This National Park Service (NPS) site delivers a brief description of the geology of the Black Hills National Park. Links to park maps, a photo album, books, videos, CDs, and a searchable data base of research needs that have been identified by the National Park Service are included. General information about the park's education and interpretive programs are also abailable.

National Park Services (NPS)

295

Antarctica Geology  

NSDL National Science Digital Library

This site contains information about the continent of Antarctica. There is a classroom practice and instructional module. The students will be able to describe the general geology of the land under the Antarctic ice and to explain from where the rocks may have come.

296

Geologic Time.  

ERIC Educational Resources Information Center

Discusses the historical development of the concept of geologic time. Develops the topic by using the major discoveries of geologists, beginning with Steno and following through to the discovery and use of radiometric dating. An extensive reference list is provided. (JM)

Albritton, Claude C., Jr.

1984-01-01

297

Impacts of Anthropogenic Emissions in the Southeastern U.S. on Heterogeneous Chemistry of Isoprene-Derived Epoxides Leading to Secondary Organic Aerosol Formation (Invited)  

NASA Astrophysics Data System (ADS)

Isoprene is a major source of secondary organic aerosol (SOA); however, the exact manner in which it forms SOA remains unclear. Improving our fundamental understanding of isoprene-derived SOA is key to improving existing air quality models, especially in the southeastern U.S. where models currently underestimate observations. By combining organic synthesis, computational calculations, mass spectrometry, smog chamber studies, and field measurements, we show that reactive epoxides, which include methacrylic acid epoxide (MAE) and isomeric isoprene epoxydiols (IEPOX), produced from the photochemical oxidation of isoprene are key to SOA formation. Furthermore, anthropogenic pollutants (NOx and SO2) enhance isoprene-derived epoxides as an SOA source. In the laboratory, we find that the reactive uptake of synthetic IEPOX and MAE standards onto acidified sulfate aerosol yields known isoprene-derived SOA tracers (2-methlytetrols, 2-methylglyceric acid, C5-alkene triols, 3-methyltetrahydrofuran-3,4-diols, dimers and organosulfates) that we measure in fine aerosol collected from multiple sites across the southeastern U.S. using gas chromatography/mass spectrometry (GC/MS) and liquid chromatography coupled to diode array detection and electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (LC/DAD-ESI-QTOFMS). Notably, IEPOX- and MAE-derived SOA tracers account for ~19% of the organic aerosol mass in Yorkville, GA. Moreover, real-time continuous chemical measurements of fine aerosol made using an Aerodyne Aerosol Chemical Speciation Monitor (ACSM) during summer 2011 and summer 2013 in Atlanta, GA, and Look Rock, TN, respectively, resolved an IEPOX-oxygenated organic aerosol (IEPOX-OOA) factor when applying positive matrix factorization (PMF) to the organic mass spectral time series. In Atlanta, this factor is found to account for ~33% of the fine OA mass and is correlated with IEPOX-derived SOA tracers (r2 = 0.6), sulfate (r2 = 0.5), and to some extent with aerosol acidity (measured as nmol H+ m-3, r2 = 0.3). Altogether, the Community Multiscale Air Quality model is updated to predict isoprene aerosol from IEPOX and MAE. The new aqueous aerosol pathways allow for explicit predictions of IEPOX- and MAE-derived SOA tracers that are more consistent with observations than estimates based on semivolatile partitioning, supporting the role of acid-catalyzed heterogeneous reactions leading to SOA formation.

Surratt, J. D.; Pye, H.; Lin, Y.; Budisulistiorini, S.; Zhang, H.; Marth, W.; Cui, T.; Arashiro, M.; Chu, K.; Zhang, Z.; Sexton, K.; Piletic, I.; Xie, Y.; Capps, S. L.; Luecken, D.; Hutzell, W. T.; Jaoui, M.; Canagaratna, M. R.; Croteau, D.; Jayne, J. T.; Worsnop, D. R.; Offenberg, J.; Kleindienst, T. E.; Lewandowski, M.; Edney, E.; Pinder, R. W.; Bartolotti, L.; Gold, A.

2013-12-01

298

SEISMIC DETERMINATION OF RESERVOIR HETEROGENEITY: APPLICATION TO THE CHARACTERIZATION OF HEAVY OIL RESERVOIRS  

SciTech Connect

The objective of the project was to examine how seismic and geologic data can be used to improve characterization of small-scale heterogeneity and their parameterization in reservoir models. The study focused on West Coalinga Field in California. The project initially attempted to build reservoir models based on different geologic and geophysical data independently using different tools, then to compare the results, and ultimately to integrate them all. We learned, however, that this strategy was impractical. The different data and tools need to be integrated from the beginning because they are all interrelated. This report describes a new approach to geostatistical modeling and presents an integration of geology and geophysics to explain the formation of the complex Coalinga reservoir.

Matthias G. Imhof; James W. Castle

2005-02-01

299

Geology Fulbrights  

NASA Astrophysics Data System (ADS)

Fulbright grants in geology for 1988-89 remain open. Specific opportunities are available in Egypt, German Democratic Republic, Hungary, Iceland, Iraq, Kuwait, Morocco, Mozambique, Oman, Poland, Sudan, Syria, Tanzania, Turkey, U.S.S.R., West Bank, Yemen, and Zimbabwe. Other countries are also open to applications in any discipline, and geology is among their preferred fields.The grants are available until awarded and are open only to U.S. citizens. In Central and South America and French-speaking Africa, knowledge of host-country language is required. For more information, contact the Council for International Exchange of Scholars (CIES), 11 Dupont Circle N.W., Suite 300, Washington, DC 20036; tel. 202-939-5401.

300

Physical Geology  

NSDL National Science Digital Library

This Tulane University course covers the nature of the Earth, the development of its surficial features, and the results of the interaction of chemical, physical, and biological factors on the planet. Lecture notes are about energy and minerals; igneous, metamorphic and sedimentary rocks; weathering and soils; geologic time; mass wasting; streams; groundwater; wind action and deserts; oceans; deformation of rock; earthquakes and the interior of the Earth; global tectonics; planetary changes; and glaciers.

Nelson, Stephen

301

Green River Formation Water Flood Demonstration Project, Uinta Basin, Utah. Quarterly technical progress report, October 1, 1994December 31, 1994  

Microsoft Academic Search

The project is designed to increase recoverable petroleum reserves in the United States. In 1987, Lomax Exploration Company started a water flood in the Monument Butte unit, targeting the Green River Formation. This was a low-energy, geologically heterogeneous reservoir producing a waxy crude oil. Primary production yielded about 5% of the OOIP. The water flood was very successful, and it

J. D. Lomax; D. L. Nielson; M. D. Deo

1994-01-01

302

Geological processes and evolution  

USGS Publications Warehouse

Geological mapping and establishment of stratigraphic relationships provides an overview of geological processes operating on Mars and how they have varied in time and space. Impact craters and basins shaped the crust in earliest history and as their importance declined, evidence of extensive regional volcanism emerged during the Late Noachian. Regional volcanism characterized the Early Hesperian and subsequent to that time, volcanism was largely centered at Tharsis and Elysium, continuing until the recent geological past. The Tharsis region appears to have been largely constructed by the Late Noachian, and represents a series of tectonic and volcanic centers. Globally distributed structural features representing contraction characterize the middle Hesperian. Water-related processes involve the formation of valley networks in the Late Noachian and into the Hesperian, an ice sheet at the south pole in the middle Hesperian, and outflow channels and possible standing bodies of water in the northern lowlands in the Late Hesperian and into the Amazonian. A significant part of the present water budget occurs in the present geologically young polar layered terrains. In order to establish more firmly rates of processes, we stress the need to improve the calibration of the absolute timescale, which today is based on crater count systems with substantial uncertainties, along with a sampling of rocks of unknown provenance. Sample return from carefully chosen stratigraphic units could calibrate the existing timescale and vastly improve our knowledge of Martian evolution.

Head, J. W.; Greeley, R.; Golombek, M. P.; Hartmann, W. K.; Hauber, E.; Jaumann, R.; Masson, P.; Neukum, G.; Nyquist, L. E.; Carr, M. H.

2001-01-01

303

Geologic Time  

NSDL National Science Digital Library

This Classroom Connectors lesson plan discusses the characteristics of geologic time, including the law of superposition, fossil preservation, casts and molds, and various events through the history of the Earth. The site provides goals, objectives, an outline, time required, materials, activities, and closure ideas for the lesson. The Classroom Connectors address content with an activity approach while incorporating themes necessary to raise the activity to a higher cognition level. The major motivation is to employ instructional strategies that bring the students physically and mentally into touch with the science they are studying.

304

Elements of petroleum geology  

SciTech Connect

This work surveys the modern science of petroleum geology. Its aim is twofold: to describe generation, migration, and entrapment of oil and gas, and to outline the various procedures used in their location, evaluation, and production. Selley begins the book with an account of the physical and chemical properties of petroleum, followed by a review of the methods of petroleum exploration and production, including drilling, geophysical exploration techniques, wireline logging, and subsurface geological mapping. Selley next describes the temperatures and pressures of the subsurface environment and the composition and hydrodynamics of connate fluids. He goes on to examine the generation and migration of petroleum, reservoir rocks, and trapping mechanisms, the habitat of petroleum in sedimentary basins, and the composition and formation of tar sands and oil shales. Selley ends the book with a brief review of prospect risk analysis, reserve estimation, and other economic topics.

Selley, R.C.

1985-01-01

305

Si-rich layer formation on olivine surfaces during reaction with water and supercritical carbon dioxide under conditions relevant for geologic carbon storage  

NASA Astrophysics Data System (ADS)

The reaction of Mg-silicate minerals (i.e. olivine) with carbon dioxide (CO2) is a promising method for secure, long-term, geologic carbon storage. Several technical challenges must be overcome before implementing mineral carbonation technology on a large scale, one of which is slow reaction kinetics. This study probes surface reaction limitations of olivine carbonation, specifically the formation of a passivating, Si-rich layer on olivine surfaces upon exposure to water and CO2 under sequestration conditions (elevated temperature and pressure). A series of batch reactions were performed at 60°C and 100 bar CO2 pressure in Dickson-style rocker bombs, varying the length of reaction and the amount of mixing (rocking). The initial aqueous phase was spiked with 29Si. Fluid samples were taken periodically and analyzed for cation content, alkalinity, and dissolved inorganic carbon. At the end of each experiment, the solid products were analyzed with a Sensitive High Resolution Ion Microprobe Reverse Geometry (SHRIMP-RG) in order to measure the amount of 29Si incorporated into the Si-rich layer on reacted olivine grains. We also cut cross sections of reacted grains from each experiment using a Focused Ion Beam (FIB) which were thinned to <100nm and imaged using Transmission Electron Microscopy (TEM). SHRIMP-RG results show incorporation of 29Si on olivine grain surfaces reacted for 19 days with no mixing, and TEM images of olivine grains from the same experiment show an amorphous, Si-rich layer that is 30nm thick. Similarly, SHRIMP-RG results for olivine grains reacted for 19 days with mixing indicate 29SiO2 precipitation and TEM images reveal a Si-rich layer 60nm thick. In both experiments, EDS (energy dispersive spectroscopy) data show a step change in composition from the bulk rock to the surface layer in addition to the sharp crystalline/amorphous interface visible in the TEM images. Olivine from the unmixed experiment also has a slow decrease in Mg relative to Si before the step change, suggesting that, at least in this experiment, a Si-rich layer precipitated on top of a Mg-depleted layer that formed via a leaching process. SHRIMP-RG data also imply the presence of a precipitated Si-rich layer on top of a leached Si-rich layer, as the 29Si penetration depth is only 25-65% of the total Si-rich layer thickness. The combination of SHRIMP-RG and FIB/TEM analysis leads us to hypothesize that a Si-rich layer forms quickly on olivine surfaces due to preferential Mg removal from the surface (the traditional 'leached' layer), and as the reaction proceeds, amorphous silica reaches saturation in the fluid and precipitates on surfaces inside the reactor (including olivine grains).

Johnson, N. C.; Jackson, A.; Maher, K.; Bird, D. K.; Brown, G. E.

2013-12-01

306

Design and Implementation of Heterogeneous Wireless Gateway  

Microsoft Academic Search

This study proposed a software-based heterogeneous wireless gateway (HWG) to achieve the integration of multiple heterogeneous wireless networks. In an HWG, received packet is temporarily saved with buffer. And then a packet format conversion mechanism is adopted to enable packet under different wireless network protocols be converted to appropriate formats. Therefore, when the transmission demand occurs, the source nodes and

Hung-Chi Chu; Shih-Lung Chang; Ying-Hsiang Liao; Yan-Ting Pan

2009-01-01

307

GEOLOGY OF THE PALEOCENE SEPULTURA FORMATION, MESA DE LA SEPULTURA, BAJA CALIFORNIA GEOLOGIA DE LA FORMACION SEPULTURA DEL PALEOCENO, EN MESA DE LA SEPULTURA, BAJA CALIFORNIA  

Microsoft Academic Search

At its Mesa de La Sepultura type area, the upper-lower to upper Paleocene Sepultura Formation lies with apparent disconformity on the lower Maastrichtian, marine upper slope and shelf deposits of the Rosario Formation. In places the uppermost Rosario Formation is marked by a kaolinite-rich paleosol. The Sepultura Formation is a deepening-upward sequence divided into a lower glauconitic-clastic member and an

Patrick L. Abbott; Andrew D. Hanson; Celeste N. Thomson; Deirdre L. Logue; Kristine D. Bradshaw; Woody Joe Pollard; Thomas E. Seeliger

308

Pre-test geological and geochemical evaluation of the Caprock, St. Peter Sandstone and formation fluids, Yakley Field, Pike County, Illinois  

SciTech Connect

The goal of these studies is to ensure long-term stable containment of air in the underground reservoirs used in conjunction with compressed air energy storage (CAES) plants. The specific objective is to develop stability criteria and engineering guidelines for designing CAES reservoirs in each of the three major reservoir types, including aquifers, salt cavities, and mined hard rock caverns. This document characterizes the geologic nature of porous media constituents native to the aquifer field test site near Pittsfield, Illinois. The geologic samples were subjected to geochemical evaluations to determine anticipated responses to cyclic air injection, heating and moisture - conditions typical of an operating CAES reservoir. This report documents the procedures used and results obtained from these analyses.

Not Available

1983-03-01

309

Upper Cenozoic Geologic Map, Yellowstone Plateau Volcanic Field  

NSDL National Science Digital Library

This geologic map shows Tertiary and Quaternary rock formations, volcanic and surficial deposits, faults, contacts, and other geologic features in Yellowstone National Park. The map is freely downloadable as a PDF file.

Robert, Christiansen; Survey, U. S.

310

Heterogenized transition metal halides in the preparation of highly dispersed metal and metal complex catalysts. vi. the formation of the active surface of cupric chloride heterogenized on silica gel and its catalytic activity in the oxidation of cumene  

SciTech Connect

X-ray photoelectron and ESR spectroscopy was used to study the distribution and state of the active component on the support surface after the heterogenization of cupric chloride on lithium-modified silica gel. The chemisorption of CuC1/sub 2/ is mainly insular in nature. The catalytic activity of the catalysts obtained was studied in the liquid-phase oxidation of cumene to give cumyl hydroperoxide. The nature of the dependence of the specific catalytic activity on the surface concentration of the supported halide may be explained assuming insular nature for the chemisorption of CuC1/sub 2/. A comparison was carried out for the catalytic activity, selectivity and stability of the catalyst obtained with its impregnation analog and a number of significant advantages of the former were found relative to all these parameters.

Yuffa, A.Y.; Kucherov, A.V.; Matsenko, G.P.; Shelpakova, N.A.; Slinkin, A.A.; Vorontsova, N.V.

1986-08-01

311

Tumor heterogeneity in neoplasms of breast, colon, and skin  

Microsoft Academic Search

BACKGROUND: Different cell subpopulations in a single tumor may show diverse capacities for growth, differentiation, metastasis formation, and sensitivity to treatments. Thus, heterogeneity is an important feature of tumors. However, due to limitations in experimental and analytical techniques, tumor heterogeneity has rarely been studied in detail. PRESENTATION OF THE HYPOTHESIS: Different tumor types have different heterogeneity patterns, thus heterogeneity could

Jian Li; Kai Wang; Thomas Dyrsø Jensen; Shengting Li; Lars Bolund; Carsten Wiuf

2010-01-01

312

Illinois State Geological Survey  

NSDL National Science Digital Library

The Illinois State Geological Survey (ISGS) homepage provides information on geologic mapping, earthquakes, fossils, groundwater, wetlands, glacial geology, bedrock geology, and Lake Michigan geology. Educational materials include field trip guides, short publications on Illinois geology for students and teachers, online tours, single-page maps, and a geologic column. Other materials include databases and collections of GIS data, well records, drill cores, and mining information; a bibliography of Illinois geology; online maps and data; and information on water and land use, resource development, and geologic hazards.

313

SWENT. 3D Transport Simulation Geologic Medium  

Microsoft Academic Search

SWENT (Simulator for Water, Energy, and Nuclide Transport) simulates the transient transport of fluid, heat, an inert component, and any number of radionuclides through a heterogeneous geologic medium either in three dimensional or radial geometries. The first three transport processes are coupled by the fluid properties of density and viscosity. The velocity field is derived from the solution of the

Golis

1988-01-01

314

Geology Fieldnotes: Capitol Reef National Park, Utah  

NSDL National Science Digital Library

This Capitol Reef National Park site contains park geology information, park maps, photographs, visitor information, and a teacher feature (resources for teaching geology with National Park examples). Geologic data includes descriptions of the Waterpocket Fold, a monocline formed in the Laramide Orogeny and made of sedimentary rock. Also covered is erosion, and details about the Cathedral Valley outcrop of gypsum. This formation is Permian to Cretaceous in age (270-80 million years old).

315

Geology of California  

SciTech Connect

This book reviews some of the basic principles of geology and includes a chapter on the Klamath Mountains. Chapters cover the geologic history of California and the geologic features of the various deserts, mountain ranges, plateaus, basins, and valleys of the state, including offshore geology and the San Andreas fault. The authors discuss exotic and suspect terranes, and current theories concerning California geology.

Norris, R.M.; Webb, R.W.

1990-01-01

316

Method of analysis at the U.S. Geological Survey California Water Science Center, Sacramento Laboratory - determination of haloacetic acid formation potential, method validation, and quality-control practices  

USGS Publications Warehouse

An analytical method for the determination of haloacetic acid formation potential of water samples has been developed by the U.S. Geological Survey California Water Science Center Sacramento Laboratory. The haloacetic acid formation potential is measured by dosing water samples with chlorine under specified conditions of pH, temperature, incubation time, darkness, and residual-free chlorine. The haloacetic acids formed are bromochloroacetic acid, bromodichloroacetic acid, dibromochloroacetic acid, dibromoacetic acid, dichloroacetic acid, monobromoacetic acid, monochloroacetic acid, tribromoacetic acid, and trichloroacetic acid. They are extracted, methylated, and then analyzed using a gas chromatograph equipped with an electron capture detector. Method validation experiments were performed to determine the method accuracy, precision, and detection limit for each of the compounds. Method detection limits for these nine haloacetic acids ranged from 0.11 to 0.45 microgram per liter. Quality-control practices include the use of blanks, quality-control samples, calibration verification standards, surrogate recovery, internal standard, matrix spikes, and duplicates.

Zazzi, Barbara C.; Crepeau, Kathryn L.; Fram, Miranda S.; Bergamaschi, Brian A.

2005-01-01

317

Separation and Capture of CO2 from Large Stationary Sources and Sequestration in Geological Formations: A Summary of the 2003 Critical Review  

SciTech Connect

Increasing amounts of carbon dioxide (CO2) in the atmosphere, and the resulting global warming effect, is a major air quality concern. CO2 is the most abundant greenhouse gas emitted by fossil-fuel combustion for power generation, transportation, and heating. Reducing worldwide emissions of CO2 will require many mitigation measures, including reductions in energy consumption, more efficient use of available energy, renewable energy sources, and carbon sequestration. The feasibility of capturing CO2 from large point sources and subsequent geological sequestration is the subject of this year’s Critical Review.

White, C.M.; Strazisar, B.R.; Granite, E.J.; Hoffman, J.S.; Pennline, H.W.

2003-06-01

318

Briefing on geological sequestration (Tulsa)  

EPA Science Inventory

Geological sequestration (GS) is generally recognized as the injection and long-term (e.g., hundreds to thousands of years) trapping of gaseous, liquid or supercritical carbon dioxide (CO2) in subsurface media ? primarily saline formations, depleted or nearly depleted oil and gas...

319

Geologic Technician New Curriculum  

ERIC Educational Resources Information Center

Describes a developing two-year geologic technician program at Bakersfield College in which a student may major in five areas - geologic drafting, land and legal, geologic assistant, engineering or paleontology. (RR)

Karp, Stanley E.

1970-01-01

320

Geological Time Scale  

NSDL National Science Digital Library

This document describes how geologic time is approached in discussions of geologic topics. The uses of relative time and absolute time are compared, and a geologic time scale is provided to represent both concepts. References are provided.

321

Fe(HSO 4) 3 as an inexpensive, eco-friendly, heterogeneous and reusable catalyst for acetal\\/ketal formation and their facile regeneration  

Microsoft Academic Search

Fe(HSO4)3 has been used as an efficient and recyclable catalyst for acetalization and ketalization of carbonyl compounds with neopentyl glycol. The advantage of this method is the use of a novel catalyst system which is inexpensive, heterogeneous and stable with an easy procedure and short reaction times. The catalyst can be recovered and reused without significant loss of activity. In

Hossein Eshghi; Mohammad Rahimizadeh; Sattar Saberi

2008-01-01

322

The conchostracan subgenus Orthestheria (Migransia) from the Tacuarembó Formation (Late Jurassic–?Early Cretaceous, Uruguay) with notes on its geological age  

Microsoft Academic Search

Conchostracans from the Tacuarembó Formation s.s. of Uruguay are reassigned to the subgenus Orthestheria (Migransia) Chen and Shen. They show more similarities to genera of Late Jurassic age in the Congo Basin and China than to those of Early Cretaceous age. On the basis of the character of the conchostracans, we suggest that the Tacuarembó Formation is unlikely to be

Shen Yanbin; Oscar F Gallego; Sergio Mart??nez

2004-01-01

323

Biochemical evolution III: Polymerization on organophilic silica-rich surfaces, crystal-chemical modeling, formation of first cells, and geological clues  

PubMed Central

Catalysis at organophilic silica-rich surfaces of zeolites and feldspars might generate replicating biopolymers from simple chemicals supplied by meteorites, volcanic gases, and other geological sources. Crystal–chemical modeling yielded packings for amino acids neatly encapsulated in 10-ring channels of the molecular sieve silicalite-ZSM-5-(mutinaite). Calculation of binding and activation energies for catalytic assembly into polymers is progressing for a chemical composition with one catalytic Al–OH site per 25 neutral Si tetrahedral sites. Internal channel intersections and external terminations provide special stereochemical features suitable for complex organic species. Polymer migration along nano/micrometer channels of ancient weathered feldspars, plus exploitation of phosphorus and various transition metals in entrapped apatite and other microminerals, might have generated complexes of replicating catalytic biomolecules, leading to primitive cellular organisms. The first cell wall might have been an internal mineral surface, from which the cell developed a protective biological cap emerging into a nutrient-rich “soup.” Ultimately, the biological cap might have expanded into a complete cell wall, allowing mobility and colonization of energy-rich challenging environments. Electron microscopy of honeycomb channels inside weathered feldspars of the Shap granite (northwest England) has revealed modern bacteria, perhaps indicative of Archean ones. All known early rocks were metamorphosed too highly during geologic time to permit simple survival of large-pore zeolites, honeycombed feldspar, and encapsulated species. Possible microscopic clues to the proposed mineral adsorbents/catalysts are discussed for planning of systematic study of black cherts from weakly metamorphosed Archaean sediments.

Smith, Joseph V.; Arnold, Frederick P.; Parsons, Ian; Lee, Martin R.

1999-01-01

324

Geologic Mapping on Mars  

NSDL National Science Digital Library

This lab is part of a Lunar and Planetary Geology course offered to both geology and non-geology majors, and it involves basic geological mapping of an area within the Tyrrhena Patera region on Mars. Students are encouraged to work in groups to prepare a geological map from a photomosaic map and to interpret the geologic stratigraphy from a geological map of the greater area. This activity reinforces mapping skills as well as group work skills, and aims to teach students more about Martian stratigraphy and geology through a hands-on activity.

De Villiers, Germari

325

Geological structure of central East Antarctica from geophysical data  

NASA Astrophysics Data System (ADS)

Examination of the subglacial topography of central East Antarctica reveals the block structure of the Earth’s crust in this region. The intracontinental blocks of the subglacial Vostok Highlands (400 masl), Komsomol’sky Mountains (700 masl), Schmidt Basin (150 masl), and Aurora Basin (-300 masl) are distinguished. The geological nature of the Komsomol’sky Subglacial Mountains (KSM) and the Schmidt Subglacial Basin (SSB) is interpreted from gravity measurements and regional aerogeophysical routes. The basin of Vostok Subglacial Lake (VSL) is located in the conjugation zone of these blocks. The KSM are considered to be a block of the Proterozoic mobile belt disturbed by a system of normal and reverse faults. The SSB is a rigid cratonic block partly overlapped by platform cover. The localization of the VSL Graben in the zone of conjugation of heterogeneous blocks testifies to its formation in a deep fault zone characterized by intense normal and reverse dislocations.

Leonov, V. O.; Popov, S. V.

2009-07-01

326

The Necessity of Geologic Disposal  

SciTech Connect

Nuclear wastes are the radioactive byproducts of nuclear power generation, nuclear weapons production, and other uses of nuclear material. Experts from around the world agree that deep geologic disposal of nuclear waste in a mined repository is the most environmentally sound means of removing these potential sources of radiation from interaction with the biosphere. Of the 360 millirem of background radiation received annually by the average American, from both natural and man-made sources, less than 1 millirem results from the nuclear fuel cycle. Spent nuclear fuel and high-level radioactive waste, destined for geologic disposal, are located at 126 sites in 39 states. The proposed repository site at Yucca Mountain, Nevada, is far more isolated from the general population than any sites where these radioactive materials are presently located. Only solid forms of high-level wastes will be transported for disposal in a geologic repository. For more than 50 years, nuclear materials have been safely transported in North America, Europe, and Asia, without a single significant radiation release. Since the 1950s, select panels from the National Academy of Sciences-National Research Council and interagency advisory groups, and international experts selected by the OECD/Nuclear Energy Agency, have examined the environmental, ethical, and intergenerational aspects of nuclear waste disposal, plus alternatives to geologic disposal. All have concluded that deep geologic disposal in a mined repository is clearly the preferred option. The concept of deep geologic disposal is based on the analogy to ore deposits, which are formed deep within the Earth's crust, commonly remain isolated from the biosphere for millions to billions of years, and are, generally, extremely difficult to detect. Before selecting the unsaturated tuffs at Yucca Mountain, DOE evaluated salt formations, basalts, and both crystalline and sedimentary rocks. Other nations generating nuclear power also plan to use deep geologic disposal, and are evaluating sites in granites, argillaceous rocks, and salt formations.

R. Linden

2004-07-01

327

Conversion of geologic quadrangle maps to geologic coverages  

USGS Publications Warehouse

Three hundred sixty-eight geologic map$ of 7-1/2 minute quadrangles in Tennessee were coverted to geographic information system (GIS) coverages. The procedure used was documented and a list was made of the quadrangles included in the coverages. Maps were converted to GIS coverages by making film copies of scribecoats of the maps. The film copies were scanned, vectorized, and written into a generate format. Coverage polygons were tagged with symbels to identify geologic units, and coverage lines were tagged with line types to designate stratigraphic contacts.

Connell, Joseph F.; Barron, William R.; Mitchell, Reavis L.

1994-01-01

328

Method of Analysis by the U.S. Geological Survey California District Sacramento Laboratory?Determination of Trihalomethane Formation Potential, Method Validation, and Quality-Control Practices  

USGS Publications Warehouse

An analytical method for the determination of the trihalomethane formation potential of water samples has been developed. The trihalomethane formation potential is measured by dosing samples with chlorine under specified conditions of pH, temperature, incubation time, darkness, and residual-free chlorine, and then analyzing the resulting trihalomethanes by purge and trap/gas chromatography equipped with an electron capture detector. Detailed explanations of the method and quality-control practices are provided. Method validation experiments showed that the trihalomethane formation potential varies as a function of time between sample collection and analysis, residual-free chlorine concentration, method of sample dilution, and the concentration of bromide in the sample.

Crepeau, Kathryn L.; Fram, Miranda S.; Bush, Noel

2004-01-01

329

Geology and Radiometry of West Macedonia (Greece).  

National Technical Information Service (NTIS)

Car borne scintillometry survey in W. Macedonia (Greece) showed that the granitic rocks of the area, the zone centered on the Tertiary volcanic rocks of Almopia zone and a large part of adjacent sediments constitute the most promising geological formation...

D. G. Minatidis

1984-01-01

330

Digital Geology of Idaho  

NSDL National Science Digital Library

This online course systematically divides Idaho geology into 15 individual teaching modules which correspond with a two-credit, 15-week classroom course. Each module covers a specific area or type of geology in the state of Idaho. Topics include geology of basement rocks, rocks and geology of the Belt Supergroup, tectonic regimes, and geologic history. There are also modules on rocks and geology of the Idaho Batholith, volcanic history and deposits of the Snake River Plain and Columbia Plateau, and Pleistocene glaciation and floods from Lakes Missoula and Bonneville. Each of the modules provides geologic maps from a recently developed Geologic Map of Idaho, produced by the Idaho Geological Survey, and most also feature fly-throughs in which geologic information is draped over topography to provide visualizations of the geology along Idaho rivers.

331

Colorado Geological Survey  

NSDL National Science Digital Library

The Colorado Geological Survey (CGS) is an agency of state government within the Department of Natural Resources whose mission is to help reduce the impact of geologic hazards on the citizens of Colorado, to promote the responsible economic development of mineral and mineral fuel resources, to provide geologic insight into water resources, and to provide geologic advice and information to a variety of constituencies. This site contains extensive information about Colorado geology such as maps, a geologic time scale for the state, program information, and state field trip information. This site hosts the Avalanche Information Center which contains avalanche forecasting and education center details. Publications report on geologic hazards, land use, environmental geology, mineral resources, oil, gas, coal, geologic mapping and earthquake information for the state. There are online editions of RockTalk, which is a quarterly newsletter published by the Colorado Geological Survey dealing with all aspects of geology throughout the state of Colorado. Links are provided for more resources.

332

Regional Diagenesis of Sandstones in the Upper Jurassic Morrison Formation, San Juan Basin, New Mexico and Colorado: Geologic, Chemical, and Kinetic Constraints.  

National Technical Information Service (NTIS)

The Upper Jurassic Morrison Formation is the major uranium- and vanadium-bearing unit on the Colorado Plateau and, as such, has been the focus of numerous sedimentologic, petrologic, and geochemical studies. As a result, most research has concentrated on ...

P. L. Hansley

1990-01-01

333

Stratigraphic Dip Analysis – A Novel Application for Detailed Geological Modeling of Point Bars, and Predicting Bitumen Grade, McMurray Formation, Muskeg River Mine, Northeast Alberta  

Microsoft Academic Search

At the Muskeg River Mine, bitumen is hosted in the clastic sediments of the lower Cretaceous McMurray Formation. Within the\\u000a mine area, the McMurray Formation is divided informally into mappable units representing fluvial, continental floodplain,\\u000a open estuarine, estuarine channel complex (ECC), and marine environments. Fluvial, open estuarine, and ECC deposits host more\\u000a than 90% of the mineable bitumen reserves. Bitumen

Milovan Fustic

2007-01-01

334

Preliminary Safety Analysis of the Gorleben Site: Thermo-mechanical Analysis of the Integrity of the Geological Barrier in the Gorleben Salt Formation - 13307  

SciTech Connect

Exploration work at the Gorleben salt dome has been carried out since 1977 to investigate the site regarding its suitability as a final repository for high-level radioactive wastes. In the framework of the 'Preliminary Safety Analysis of the Gorleben Site' a comprehensive assessment is being performed with focus on long-term safety. Because the integrity of the geological barrier is crucial for protection from damage caused by ionising radiation during the post-operational phase, 2D and 3D thermo-mechanical calculations for a reference section through the salt dome were carried out, all looking at two different waste emplacement concepts: emplacement in drifts and in boreholes. The calculated stresses are the basis for evaluating the barrier integrity on the basis of the dilatancy criterion and the fluid pressure criterion. (authors)

Eickemeier, R.; Heusermann, S.; Nipp, H.K. [Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, D-30655 Hannover (Germany)] [Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, D-30655 Hannover (Germany); Knauth, M.; Minkley, W.; Popp, T. [Institute for Geomechanics (IfG), Friederikenstrasse 60, D-04279 Leipzig (Germany)] [Institute for Geomechanics (IfG), Friederikenstrasse 60, D-04279 Leipzig (Germany)

2013-07-01

335

Subsurface geology and porosity distribution, Madison Limestone and underlying formations, Powder River basin, northeastern Wyoming and southeastern Montana and adjacent areas  

USGS Publications Warehouse

To evaluate the Madison Limestone and associated rocks as potential sources for water supplies in the Powder River Basin and adjacent areas, an understanding of the geologic framework of these units, their lithologic facies patterns, the distribution of porosity zones, and the relation between porosity development and stratigraphic facies is necessary. Regionally the Madison is mainly a fossiliferous limestone. However, in broad areas of the eastern Rocky Mountains and western Great Plains, dolomite is a dominant constituent and in places the Madison is almost entirely dolomite. Within these areas maximum porosity development is found and it seems to be related to the coarser crystalline dolomite facies. The porosity development is associated with tabular and fairly continuous crystalline dolomite beds separated by non-porous limestones. The maximum porosity development in the Bighorn Dolomite, as in the Madison, is directly associated with the occurrence of a more coarsely crystalline sucrosic dolomite facies. Well data indicate, however, that where the Bighorn is present in the deeper parts of the Powder River Basin, it may be dominated by a finer crystalline dolomite facies of low porosity. The 'Winnipeg Sandstone' is a clean, generally well-sorted, medium-grained sandstone. It shows good porosity development in parts of the northern Powder River Basin and northwestern South Dakota. Because the sandstone is silica-cemented and quartzitic in areas of deep burial, good porosity is expected only where it is no deeper than a few thousand feet. The Flathead Sandstone is a predominantly quartzose, slightly feldspathic sandstone, commonly cemented with iron oxide. Like the 'Winnipeg Sandstone,' it too is silica-cemented and quartzitic in many places so that its porosity is poor in areas of deep burial. Illustrations in this report show the thickness, percent dolomite, and porosity-feet for the Bighorn Dolomite and the Madison Limestone and its subdivisions. The porosity-feet for the 'Winnipeg' and Flathead Sandstones and four regional geologic sections are also shown.

Peterson, James A.

1978-01-01

336

The National Park Service: Park Geology  

NSDL National Science Digital Library

A National Park Service (NPS) site primarily composed of three main sections corresponding to the following program areas within the Geologic Resources Division (GRD): Disturbed Lands Restoration and Abandoned Mineral Lands (AML), Mineral Management Programs, and Geology and Soils Programs. Of these, the first two consist principally of textual resources pertaining to Park System procedures, policies, and regulations - as well as reports on example restoration projects with a focus on stream corridor restoration, bioengineering, riparian management, and revegetation. Perhaps of most interest to educators will be the third main program area, the Geology and Soils Programs section. Here are included textual resources pertaining to NPS-GRD programs on cave and karst formations, coastal and shoreline geology, paleontology, soils (e.g., soil biology and soil surveying), geological indicators (geoindicators), and stratigraphy. Lastly, a searchable photographic collection and geologic glossary are available.

337

Testing the Injectivity of CO2 in a Sub-surface Heterogeneous Reservoir  

NASA Astrophysics Data System (ADS)

This case study on subsurface reservoir characterization, considers the effect of geological heterogeneities on the storage capacity and injectivity of the Johansen Formation, which is a deep, saline aquifer underlying the Troll Gas Field off the Norwegian coast. The Johansen Formation has been interpreted as a sandy, prograding unit, deposited in a shallow marine environment during Early Jurassic time, and is overlain by a shaly unit; the Amundsen Formation. It appears as a wedge shaped sandstone body, up to 140m thick, with an areal extent in the order of 10 000 km2. The Johansen Formation is currently being considered for large scale CO2 storage from two gas power plants situated on the west coast of Norway, both of which will operate with full scale CO2 handling, as proposed by Norwegian authorities. The storage capacity needed is in the order of 3 Mt CO2/year. With access to a new 3D seismic survey (Gassnova, 2010), and based on existing well log data from 25 penetrating wells, we have studied large scale geometries and intra-formational features, and built a geo-conceptual model of the Johansen Formation. The reservoir is heterogeneous, with distinct permeability zonation within clinothems separated by less permeable layers. In order to obtain better understanding of crucial reservoir parameters and supplement limited data, comparison of data from easily accessible analogue rock units is useful. For this purpose the unit should be well exposed and thoroughly documented, such as the Panther Tongue Member (Star Point Formation, Mesa Verde Group) in Book Cliffs, from which we have collected some comparable permeability estimates for the model. On a micro scale, mineralogy, grain size/shape and pore geometry constitue major controls on reservoir porosity and permeability. Direct geological information is at this point in time limited to a few meters of core, from which detailed mineralogical information has been derived (optical microscopy, SEM, XRD), and some additional data from side wall cores and cuttings. From this we evaluate facies dependence related to observed diagenetic features and compositional variations due to burial depth (2-4km), mainly considering chlorite coatings (preserving porosity) and cementation (calcite and quartz). Using Schlumberger soft-wares; Petrel (reservoir) and Eclipse (fluid flow), we are testing injection scenarios (one point, several points, bleeding wells) in several intra-formational geological settings. These results will be evaluated relative to the distribution of facies and heterogeneities in the reservoir, considering multiphase flow given the local pressure regime.

Sundal, A.; Nystuen, J.; Dypvik, H.; Aagaard, P.

2011-12-01

338

Maryland Geological Survey  

NSDL National Science Digital Library

The Maryland Geological Survey (MGS) homepage contains information from MGS programs on hydrogeology, hydrology, coastal and estuarine geology, environmental geology and mineral resources; an online guide to Maryland geology; and information on oyster habitat restoration projects. There are also maps, data, information on MGS publications, MGS news, and online educational resources.

339

Analysis of 3d complex structure and heterogeneity effects on formation and propagation of regional phases in Eurasia. Final report, 15 August 1992-30 September 1994  

SciTech Connect

This document is the final report for this grant to develop new three-dimensional wave propagation techniques for high frequency waves in heterogeneous media. The report is divided into four sections, each being a published paper sponsored by this grant. In the first section we formulate a one-way wide-angle elastic wave propagation method for arbitrarily heterogeneous media in both the space and wavenumber domains using elastic Rayleigh integrals and local elastic Born scattering theory. In the second section this complex phase screen method is compared with fourth-order finite differences and exact eigenfunction expansion calculations for two-dimensional inhomogeneous media to assess the accuracy of the one-way propagation algorithm. In the third section, an observational study of continental margin structure influence on Lg propagation is presented, using data from the former Soviet stations for nuclear explosions at Novaya Zemlya. We find that bathymetric features can be correlated with energy levels of Lg, suggesting that waveguide structure influences regional phase energy partitioning. This idea is pursued in the fourth section, using Eurasian earthquake and nuclear explosion data along with information about the crustal structure in Eurasia. We develop empirical relations that reduce the scatter in the P/Lg discriminant at low frequency.

Lay, T.; Wu, R.S.

1994-12-13

340

Venus geology  

NASA Astrophysics Data System (ADS)

The Magellan mission to Venus is reviewed. The scientific investigations conducted by 243-day cycles encompass mapping with a constant incidence angle for the radar, observing surface changes from one cycle to the next, and targeting young-looking volcanos. The topography of Venus is defined by the upper boundary of the crust and upwelling from lower domains. Tectonic features such as rift zones, linear mountain belts, ridge belts, and tesserae are described. The zones of tesserae are unique to the planet. Volcanism accounts for about 80 percent of the observed surface, the remainder being volcanic deposits which have been reworked by tectonism or impacts. Magellan data reveal about 900 impact craters with flow-like ejecta resulting from the fall of meteoroids. It is concluded that the age of the Venusian surface varies between 0 and 800 million years. Tectonic and volcanic activities dominate the formation of the Venus topography; such processes as weathering and erosion are relatively unimportant on Venus.

McLaughlin, W. I.

1991-05-01

341

The Geologic Story of Yosemite Valley  

NSDL National Science Digital Library

This website of the United States Geological Survey (USGS) and the National Park Service (NPS) discusses the geology of Yosemite Valley in California, beginning 100 million years ago with the formation of the granite rocks found in this park and continuing with jointing, exfoliation, and erosion through ice and water. Bedrock Geology includes details about the formation, classification, and descriptions of the plutonic bedrock. It also discusses the relationship of landforms to rock composition and structure and their role in shaping the Yosemite valley.

Huber, N.

342

Geologic Maps and Mapping  

NSDL National Science Digital Library

This portal provides access to resources on geologic mapping, and to sources of geologic maps. There is an introduction to geologic mapping, which summarizes its principles and practices, and a history of United States Geological Survey (USGS) mapping activities from 1879 to the present, as well as links to papers on the values and hazards associated with geologic maps and mapping. Online sources of maps include the USGS Geologic Map Database, other federal map products (FEDMAP), state geological survey products (STATEMAP), and university map products (EDMAP).

343

Geological implications and controls on the determination of water saturation in shale gas reservoirs  

NASA Astrophysics Data System (ADS)

A significant challenge to the petrophysical evaluation of shale gas systems can be attributed to the conductivity behaviour of clay minerals and entrained clay bound waters. This is compounded by centimetre to sub-millimetre vertical and lateral heterogeneity in formation composition and structure. Where despite significant variation in formation geological and therefore petrophysical properties, we routinely rely on conventional resistivity methods for the determination of water saturation (Sw), and hence the free gas saturation (Sg) in gas bearing mudstones. The application of resistivity based methods is the subject of continuing debate, and there is often significant uncertainty in both how they are applied and the saturation estimates they produce. This is partly a consequence of the view that "the quantification of the behaviour of shale conductivity....has only limited geological significance" (Rider 1986). As a result, there is a separation between our geological understanding of shale gas systems and the petrophysical rational and methods employed to evaluate them. In response to this uncertainty, many petrophysicists are moving away from the use of more complex 'shaly-sand' based evaluation techniques and returning to traditional Archie methods for answers. The Archie equation requires various parameter inputs such as porosity and saturation exponents (m and n), as well as values for connate fluid resistivity (Rw). Many of these parameters are difficult to determine in shale gas systems, where obtaining a water sample, or carrying out laboratory experiments on recovered core is often technically impractical. Here we assess the geological implications and controls on variations in pseudo Archie parameters across two geological formations, using well data spanning multiple basinal settings for a prominent shale gas play in the northern Gulf of Mexico basin. The results, of numerical analysis and systematic modification of parameter values to minimise the error between core derived Sw (Dean Stark analysis) and computed Sw, links sample structure with composition, highlighting some unanticipated impacts of clay minerals on the effective bulk fluid resistivity (Rwe) and thus formation resistivity (Rt). In addition, it highlights simple corrective empirical adaptations that can significantly reduce the error in Sw estimation for some wells. Observed results hint at the possibility of developing a predictive capability in selecting Archie parameter values based on geological facies association and log composition indicators (i.e. V Clay), establishing a link between formation depositional systems and their petrophysical properties in gas bearing mudstones. Rider, M.H., 1986. The Geological Interpretation of Well Logs, Blackie.

Hartigan, David; Lovell, Mike; Davies, Sarah

2014-05-01

344

Geologic structure and altitude of the top of the Minnelusa Formation, northern Black Hills, South Dakota and Wyoming, and Bear Lodge Mountains, Wyoming  

USGS Publications Warehouse

Beginning in 1981, a 3-yr project was conducted to determine the availability and quality of groundwater in the sedimentary bedrock aquifers in the Black Hills of South Dakota and Wyoming. The project was limited to three bedrock units in order of increasing age: the Cretaceous Inyan kara Group, Permian and Pennsylvanian Minnelusa Formation, and Mississippian Madison (or Pahasapa) Limestone. This map shows the altitude of the top of the Minnelusa Formation in the northern Black Hills, and shows the configuration of the structural features in the northern part of the Black Hills and the eastern part of the Bear Lodge Mountains. In general, the Minnelusa Formation dips away from the Black Hills uplift, either to the northeast and the Williston Basin or, south of the Bear Lodge Mountains, to the southwest and the Powder River basin, which is outside the map area. In the map area, the upper beds of the Minnelusa Formation are an aquifer and the lower beds are a confining or semi-confining unit. The upper part of the Minnelusa Formation has a greater percentage of coarse-grained sandstone beds than the lower part. Furthermore, solution and removal of anhydrite, brecciation, and solution of cement binding the sandstone grains may have increased the permeability of the upper part of the Minnelusa Formation in the Black Hills. Wells completed in the upper part of the Minnelusa have yields that exceed 100 gal/min in some areas and at least one large diameter well is reported to flow 1,000 gal/min in some areas and at least one large diameter well is reported to flow 1,000 gal/min. Flowing wells have been completed in the Minnelusa aquifer in most of the study area in South Dakota and in about the northern one-half of Crook County, Wyoming. (Lantz-PTT)

Peter, Kathy D.; Kyllonen, David P.; Mills, K. R.

1987-01-01

345

The conchostracan subgenus Orthestheria (Migransia) from the Tacuarembó Formation (Late Jurassic-?Early Cretaceous, Uruguay) with notes on its geological age  

NASA Astrophysics Data System (ADS)

Conchostracans from the Tacuarembó Formation s.s. of Uruguay are reassigned to the subgenus Orthestheria (Migransia) Chen and Shen. They show more similarities to genera of Late Jurassic age in the Congo Basin and China than to those of Early Cretaceous age. On the basis of the character of the conchostracans, we suggest that the Tacuarembó Formation is unlikely to be older than Late Jurassic. It is probably Kimmeridgian, but an Early Cretaceous age cannot be excluded. This finding is consistent with isotopic dating of the overlying basalts, as well as the age range of recently described fossil freshwater sharks.

Yanbin, Shen; Gallego, Oscar F.; Martínez, Sergio

346

Early Proterozoic geology of Arizona  

NASA Astrophysics Data System (ADS)

The Early Proterozoic geology of Arizona and adjoining regions was the topic of a workshop convened by Clay M. Conway (U.S. Geological Survey (USGS), Flagstaff, Ariz.), Karl E. Karlstrom (Northern Arizona University (NAU), Flagstaff), and Leon T. Silver (California Institute of Technology (Caltech), Pasadena) in Flagstaff, October 3-5, 1985. The meeting, sponsored by USGS, NAU, Caltech, and the Arizona Geological Survey, was attended by 73 geologists from industry, academia, and governmental agencies. The workshop brought together for the first time workers in a variety of disciplines who have been studying facets of Early Proterozoic crustal evolution in the southwest. From responses during and following the workshop, we judge that the meeting successfully accomplished its objective of furthering communication, cooperation, and collaboration. The meeting encouraged contributions, including progress reports, from all participants and concentrated on specific problems of stratigraphy, structure, petrology, geochemistry, and ore formation, with a view toward understanding overall orogenic evolution and continental accretion.

Conway, Clay M.; Karlstrom, Karl E.

347

Bedrock Geologic Map of Maine  

NSDL National Science Digital Library

In this activity students study a map of bedrock geology which describes the types of rocks that exist in a given area. It shows these rock units as well as their known and inferred contacts. Consideration is also given to folding, faulting, unconformities, and similar rock relationships. These features are often included in bedrock geology maps. Students study the legend and scale and become aware of the other information that is included on the map such as the stratigraphic column, list of formations, and inset map of metamorphic grade. Students then locate their city or town and draw a 40-mile diameter circle around it and identify all the symbols inside the circle and the age of the various rocks. Student question sheets are available at this site. Although this activity was written for a map of Maine, it will work in any state where geological maps are available.

348

Unraveling Geological History: Glaciers and Faults at Discovery Park, Seattle  

NSDL National Science Digital Library

This introductory geology field exercise asks students to make individual observations about parts of an outcrop, then combine their observations in larger teams to interpret the overall geological history of the exposure. Content learning includes stratigraphy, faulting, and local geologic history; process learning includes data gathering and recording, hypothesis formation, and outlining helpful evidence that could be gathered in the future.

Tucker, Trileigh

349

Mineralization and other geologic factors related to the Morrison Formation in particular the northern two-thirds of the Colorado Plateau region; basic data and factor-analysis results  

USGS Publications Warehouse

A vanadium-mercury mineralization factor and five other significant geologic factors were determined by multivariate factor analysis of data for Morrison Formation rock samples from the Colorado Plateau region. The data presented in the report were obtained from an agglomeration of 876 samples which yielded a correlation matrix of 44 variables. The variables consisted of geochemical, petrographic, and geographic location parameters. Mineralization factor scores demonstrate the relative intensity of mineralization in rock samples collected in and around uranium-vanadium ore deposits. The factors affecting composition and texture of the rocks identified from the analysis are: (1) metalliferous mudstones; (2) interstitial carbonate cements; (3) competing sources of different composition; (4) heavy mineral sources; (5) vanadium mineralization; and (6) regional and stratigraphic sampling bias.

Cadigan, Robert Allen

1982-01-01

350

Applications of TOUGH2 to infiltration of liquids in media with strong heterogeneity  

SciTech Connect

Much hydrogeological research during the last decade has focused on the heterogeneity of natural geologic media on different scales. Most of this work has dealt with flow and transport in single-phase, isothermal conditions. The present paper is concerned with multiphase and nonisothermal flows in strongly heterogeneous media. A primary driver of our studies is the hydrogeological system at Yucca Mountain, which is currently being evaluated by the Department of Energy for its suitability as the site of the first geologic repository for civilian high-level nuclear wastes in the US Yucca Mountain is located in the and Southwest, near the Nevada-California border. Going from large scale to small, formation heterogeneities at Yucca Mountain include (i) alternating tilting layers of welded and non-welded tuffs with different matrix permeability and variable degree of fracturing, (ii) major fault systems, (iii) well-connected and permeable fracture networks in low-permeability rocks, and (iv) individual fractures with highly variable apertures.

Pruess, K.; Antunez, E.

1995-02-01

351

Geology of the Fox Hills Formation (Late Cretaceous) in the Williston Basin of North Dakota, with Reference to Uranium Potential. Report of Investigation No. 55.  

National Technical Information Service (NTIS)

The Fox Hills Formation is a marine and brackish sequence of primarily medium and fine clastics within the Late Cretaceous Montana Group. In the Williston basin of North Dakota, four members (in ascending order) are recognized: Trail City, Timber Lake, Ir...

A. M. Cvancara

1976-01-01

352

Radon222 as a Tracer of Water-Air Dynamics in the Unsaturated Zone of Geological Carbonate Formation: Example of an Underground Quarry (Oligocene Aquitain Limestone, France)  

Microsoft Academic Search

Complex process in the unsaturated zone affect the transfers of fluids. Within the context of an integrated study on the process of the meteoric diagenesis in a carbonate formation, we try to determine the time transit of fluids. The aim of this study is to see whether radon 222 is a good natural tracer of fluids vertical diffusivity. Radon is

C. Loisy; M. Franceschi; A. Cerepi

2006-01-01

353

Geologic Characterization and Coalbed Methane Occurrence: Williams Fork Formation, Piceance Basin, Northwest Colorado. Annual Report, December 1, 1993-November 30, 1994.  

National Technical Information Service (NTIS)

The coal-bearing Upper Cretaceous Williams Fork Formation, 1,200 to 2,500 ft thick, is operationally defined on the basis of correlation with the Sand Wash Basin. Net coal thickness is typically 80 to 120 ft and is thickest in a north-south belt west of t...

A. R. Scott H. S. Nance N. Zhou R. Tyler R. G. McMurry W. R. Kaiser

1995-01-01

354

Effects of Physical and Chemical Heterogeneity on non-Fickian Transport  

NASA Astrophysics Data System (ADS)

A key problem in subsurface hydrology centers on modelling the physics of chemical transport in geological media, accounting for heterogeneity of physical properties (e.g., hydraulic conductivity, porosity) and/or of chemical properties (e.g., adsorption, desorption). Natural porous and fractured geological formations contain multi-scale physicochemical heterogeneities, and small-scale variability affects chemical plume migration patterns at much larger scales. The continuous time random walk (CTRW) framework provides an effective means to quantify this transport, allowing for the effects of both physical and chemical heterogeneities over a broad range of temporal and spatial scales. We first examine different types of hydraulic conductivity fields to ascertain the basic structural features that dominate the transport behavior. We contrast two approaches to the analysis, within the framework of the CTRW, to probe how different types of correlation can affect the larger-scale transport behavior. We demonstrate that different kinds of relatively small-scale features do not necessarily lead to distinct large-scale transport patterns. We then consider laboratory experiments involving transport of conservative and sorbing chemicals in porous media with different kinds of physical and chemical heterogeneity. We quantify the resulting non-Fickian transport behaviors using CTRW, demonstrating the effects of multiple scale physical heterogeneities on tailing patterns, and contrasting the parameter values that describe transport of conservative and sorbing species within the same domain. Our analyses further confirm the relevance and applicability of CTRW theory to a wide variety of laboratory- and field-scale observations, and numerical simulations.

Berkowitz, Brian; Scher, Harvey

2010-05-01

355

Superfund GIS - 1:250,000 Geology of Tennessee  

USGS Publications Warehouse

This data set is a digital representation of the printed 1:250,000 geologic maps from the Tennessee Department of Environment and Conservation, Division of Geology. The coverage was designed primarily to provide a more detailed geologic base than the 1:2,500,000 King and Beikman (1974). 1:24,000 scale coverage of the state is available for about 40 percent of the state. Formation names and geologic unit codes used in the coverage are from the Tennessee Division of Geology published maps and may not conform to USGS nomenclature. The Tennessee Division of Geology can be contacted at (615) 532-1500

Greene, D.C.; Wolfe, W.J.

2000-01-01

356

Soil Formation  

NSDL National Science Digital Library

Humans use soil for their daily needs but do not sufficiently take account of its slow formation and fast loss. Discover the amazing geology of soil formation and the basic rock and soil types.Although soil seems the end product from weathering rocks, it is merely a stage in the gigantic cycle of mineral recycling by the movement of tectonic plates.

2008-07-24

357

Geological modeling for methane hydrate reservoir characterization in the eastern Nankai Trough, offshore Japan  

NASA Astrophysics Data System (ADS)

The eastern Nankai trough, which is located offshore of central Japan, is considered as an attractive potential resource field of methane hydrates. Japan Oil, Gas and Metals National Corporation is planning to conduct a production test in early 2013 at the AT1 site in the north slope of Daini-Atsumi Knoll in the eastern Nankai Trough. The depositional environment of methane hydrate-bearing sediments around the production test site is a deep submarine-fan turbidite system, and it is considered that the reservoir properties should show lateral as well as vertical heterogeneity. Since the variations in the reservoir heterogeneity have an impact on the methane hydrate dissociation and gas production performance, precise geological models describing reservoir heterogeneity would be required for the evaluation of reservoir potentials. In preparation for the production test, 3 wells; two monitoring boreholes (AT1-MC and AT1-MT1) and a coring well (AT1-C), were newly acquired in 2012. In addition to a geotechnical hole drilling survey in 2011 (AT1-GT), totally log data from 2 wells and core data from 2 wells were obtained around the production test site. In this study, we conducted well correlations between AT1 and A1 wells drilled in 2003 and then, 3D geological models were updated including AT1 well data in order to refine hydrate reservoir characterization around the production test site. The results of the well correlations show that turbidite sand layers are characterized by good lateral continuity, and give significant information for the distribution morphology of sand-rich channel fills. We also reviewed previously conducted 3D geological models which consist of facies distributions and petrophysical properties distributions constructed from integration of 3D seismic data and a well data (A1 site) adopting a geostatistical approach. In order to test the practical validity of the previously generated models, cross-validation was conducted using AT1 well data. The results show that geological modeling including AT1 well data is important to reduce the uncertainty of the reservoir properties around the production test site. The geological models including AT1 well data were constructed taking into account for the lateral continuity of turbidite formations based on the well correlations. The concepts of these models are considered to be much more effective for describing reservoir continuity and heterogeneity and predicting upcoming production tests.

Tamaki, M.; Komatsu, Y.; Suzuki, K.; Takayama, T.; Fujii, T.

2012-12-01

358

Coal geology of the Paleocene-Eocene Calvert Bluff Formation (Wilcox Group) and the Eocene Manning Formation (Jackson Group) in east-central Texas; field trip guidebook for the Society for Organic Petrology, Twelfth Annual Meeting, The Woodlands, Texas, August 30, 1995  

USGS Publications Warehouse

The Jackson and Wilcox Groups of eastern Texas (fig. 1) are the major lignite producing intervals in the Gulf Region. Within these groups, the major lignite-producing formations are the Paleocene-Eocene Calvert Bluff Formation (Wilcox) and the Eocene Manning Formation (Jackson). According to the Keystone Coal Industry Manual (Maclean Hunter Publishing Company, 1994), the Gulf Coast basin produces about 57 million short tons of lignite annually. The state of Texas ranks number 6 in coal production in the United States. Most of the lignite is used for electric power generation in mine-mouth power plant facilities. In recent years, particular interest has been given to lignite quality and the distribution and concentration of about a dozen trace elements that have been identified as potential hazardous air pollutants (HAPs) by the 1990 Clean Air Act Amendments. As pointed out by Oman and Finkelman (1994), Gulf Coast lignite deposits have elevated concentrations of many of the HAPs elements (Be, Cd, Co, Cr, Hg, Mn, Se, U) on a as-received gm/mmBtu basis when compared to other United States coal deposits used for fuel in thermo-electric power plants. Although regulations have not yet been established for acceptable emissions of the HAPs elements during coal burning, considerable research effort has been given to the characterization of these elements in coal feed stocks. The general purpose of the present field trip and of the accompanying collection of papers is to investigate how various aspects of east Texas lignite geology might collectively influence the quality of the lignite fuel. We hope that this collection of papers will help future researchers understand the complex, multifaceted interrelations of coal geology, petrology, palynology and coal quality, and that this introduction to the geology of the lignite deposits of east Texas might serve as a stimulus for new ideas to be applied to other coal basins in the U.S. and abroad.

edited by Warwick, Peter D.; Crowley, Sharon S.

1995-01-01

359

Kentucky Geological Survey  

NSDL National Science Digital Library

The University of Kentucky maintains the Kentucky Geological Survey Web site. Visitors will find a number of educational general information pages on rocks and minerals, fossils, coal, geologic hazards, industrial minerals, maps and GIS, oil and natural gas, and water, as well as the general geology of Kentucky. Each page contains specific information, data, and research summaries from the university. The geology of Kentucky page, for example, shows a map of geologic periods and gives descriptions of the rock strata in the state, a description of its landforms, and a geological photo album of physiographic regions and points of interest.

1997-01-01

360

Glossary of Geologic Terms  

NSDL National Science Digital Library

This page from Iowa State University presents a general glossary of geologic terms. The site would be a good reference for geology coursework. This glossary of geologic terms is based on the glossary in Earth: An Introduction to Geologic Change, by S. Judson and S.M. Richardson (Englewood Cliffs, NJ, Prentice Hall, 1995). Where possible, definitions conform generally, and in some cases specifically, to definitions given in Robert L Bates and Julia A Jackson (editors), Glossary of Geology, 3rd ed., American Geological Institute, Alexandria, Virginia, 1987.

2011-07-18

361

IMPACTS OF ANTHROPOGENIC EMISSIONS IN THE SOUTHEASTERN U.S. ON HETEROGENEOUS CHEMISTRY OF ISOPRENE-DERIVED EPOXIDES LEADING TO SECONDARY ORGANIC AEROSOL FORMATION  

EPA Science Inventory

The proposed activities will yield the formulation of parameterizations that can be incorporated into SOA models that will lead to improvement in the ability to simulate isoprene SOA formation in the southeastern U. S. Specific results include: (1) characterization of reaction...

362

Geology and regional hydrothermal alteration of the crater-fill, Onaping Formation: Association with zinc lead copper mineralization, Sudbury Structure, Canada  

NASA Astrophysics Data System (ADS)

This study of the impact crater-fill sequence (Onaping Formation) in the Sudbury Structure reveals significant features critical to our understanding of modification processes and water-rock interaction in large (˜200 km) impact structures. The crater-fill sequence has a distinct mappable stratigraphy and consists of three informal members, the Garson, Sandcherry and Dowling, that have different vitric morphologies, percentage of matrix and lithic fragments and depositional characteristics. A distinct, coeval set of aphanitic dykes occupy syn-depositional faults and fractures. Similarities of trace, REE and isotopic data of least altered andesitic Onaping Formation melt, felsic norite and quartz diorite of the Sudbury Igneous Complex (SIC) supports the interpretation that they represent an initial melt composition. The Onaping Formation was emplaced early, prior to differentiation and/or emplacement of the SIC in its present position. Stratigraphy, morphology, structural controls and geochemistry of the Onaping Formation constrains the timing and evolution of the Sudbury Structure. A two stage history of crater-fill is recorded. Stage 1 involves, the emplacement of Garson and Sandcherry member units as products of slumping and fallback followed by intrusion of andesitic melt into crater floor-fractures. Stage 2 involves, large-scale, crater wall collapse along superfaults outside of the transient crater followed by melt-water interaction that resulted in "phreatomagmatic" explosive eruptions to produce the Dowling member. The basal intrusion was then injected along pre-existing fractures formed in Stage 1. The crater-fill succession records a major impact-induced, hydrothermal system at 1848.4 +3.8/-1.8 Ma that produced low temperature, (<250°C) carbonate-hosted Zn-Cu-Pb subseafloor replacement-type deposits within the crater-fill. Mineralogical, geochemical and mapping data show a complex hydrothermal history controlled by the structural, magmatic and stratigraphic history of the impact crater. Alteration zones include a regional, upper calcite zone, transition zone, chlorite zone, albite zone and lower silicification zone. Field, textural, stable and radiogenic isotope data for the regional carbonate zone are compatible with magmatic CO2 diluted by Proterozoic seawater. The Sudbury Structure is the largest, well preserved example of a terrestrial impact crater and records a distinct history of crater-fill emplacement and a productive hydrothermal system that is unparalleled in other impact craters on Earth.

Ames, Doreen Elizabeth

363

A simple screening model for selecting CO2 sequestration sites using a semi-analytical model for calculating pressure buildup and phase front movement in thick and heterogeneous geologic settings  

NASA Astrophysics Data System (ADS)

A semi-analytical solution developed by Kumar et al. (2009) has been updated to include multiple rock layers, an expanding constant pressure boundary, and an updated phase front definition. The two phase fronts that are calculated include a dry zone region detailed by Noh et al. (2004) and a two phase region. The semi-analytical model calculates the well pressure needed to inject CO2 at a constant rate at a specified time and the movement of the phase fronts. The updated semi-analytical model can be used for several applications; namely for complex sandstone layering formations, large storage reservoirs, and for quick and easy screening of potential CO2 storage sites. Numerical solutions require significant reservoir characterization effort and simulation time to complete. The updated semi-analytical model can be used with limited reservoir data to estimate well pressure expectations and phase front movements. The algorithm developed by Kumar et al. (2004) can be implemented with transient, steady-state, and pseudo-steady state flow equations. The updated model assumes early-transient flow equations for initialization and steady-state flow equations for later time with a constant pressure boundary. The updated semi-analytical model has been applied to a simplified CO2 storage reservoir and the results have been compared to a comparable TOUGH2 model. The pressure buildup results, defined as the difference between the well pressure and initial reservoir pressure, and two phase front movement and the dry zone front movement show reasonable agreement with some differences.

Sargent, W.; Benson, S.

2012-04-01

364

Potential biofuel additive from renewable sources--Kinetic study of formation of butyl acetate by heterogeneously catalyzed transesterification of ethyl acetate with butanol.  

PubMed

Butyl acetate holds great potential as a sustainable biofuel additive. Heterogeneously catalyzed transesterification of biobutanol and bioethylacetate can produce butyl acetate. This route is eco-friendly and offers several advantages over the commonly used Fischer Esterification. The Amberlite IR 120- and Amberlyst 15-catalyzed transesterification is studied in a batch reactor over a range of catalyst loading (6-12 wt.%), alcohol to ester feed ratio (1:3 to 3:1), and temperature (303.15-333.15K). A butanol mole fraction of 0.2 in the feed is found to be optimum. Amberlite IR 120 promotes faster kinetics under these conditions. The transesterifications studied are slightly exothermic. The moles of solvent sorbed per gram of catalyst decreases (ethanol>butanol>ethyl acetate>butyl acetate) with decrease in solubility parameter. The dual site models, the Langmuir Hinshelwood and Popken models, are the most successful in correlating the kinetics over Amberlite IR 120 and Amberlyst 15, respectively. PMID:21908187

Ali, Sami H; Al-Rashed, Osama; Azeez, Fadhel A; Merchant, Sabiha Q

2011-11-01

365

Inner thermal resonance in thermoelastic geological structures  

NASA Astrophysics Data System (ADS)

When investigating heterogeneous media such as composite materials or geological structures, it is convenient to replace them by macroscopic equivalent media, which simplifies computations a lot. In the paper, we look for the equivalent macroscopic model for describing seismic wave propagation and transient heat transfers in thermoelastic periodic geological structures made of rock or soil. We follow the route described in Auriault (2012), to investigating thermoelastic composite media. We use the method of multi-scale asymptotic expansions. By estimating the dimensionless numbers in the momentum and energy balances, we show that an equivalent macroscopic model exists for describing seismic waves at very low frequencies only. The model then shows a damping which is due to thermal resonance at the heterogeneity scale. At higher frequencies, such an equivalent macroscopic model does not exist. Macroscopic models for describing transient heat transfers do not exist.

Auriault, Jean-Louis

2014-05-01

366

Estimation of the hydraulic parameters of a confined geologic formation from slug test in fully penetrating well using a complete quasi-steady flow model in a forward and in an inverse optimal estimation procedure  

NASA Astrophysics Data System (ADS)

Slug tests offer a fast and inexpensive means of estimating the hydraulic parameters of a geologic formation, and are very well suited for contaminated site assessment because no water is essentially withdrawn. In the great majority of slug tests performed in wells fully penetrating confined geologic formations, and for over-damped conditions, the response data are evaluated with the transient-flow model of Cooper et al. (1967) when the radial hydraulic conductivity Kr and the coefficient of specific storage Ss are to be estimated. That particular analytical solution, however, is computationally involved and awkward to use. Thus, groundwater professionals often use a few pre-prepared type-curves to fit the data by a rough matching procedure, visually or computationally. On the other hand, the method of Hvorslev (1951), which assumes the flow to be quasi-steady, is much simpler but yields only Kr-estimates. Koussis and Akylas (2012) have derived a complete quasi-steady flow model that includes a storage balance inside the aquifer and allows estimating both Kr and Ss, through matching of the well response data to a (dimensionless) type-curve. That model approximates the model of Cooper et al. closely and has the practical advantage that its solution type-curves are generated very simply, even using an electronic spreadsheet. Thus, an optimal fit of data by a type-curve can be readily embedded in an exhaustive search. That forward procedure, however, is semi-automated; it involves repeated computation of the quasi-steady flow solution, until finding an optimal pair of Kr and Ss values, according to some formal criterion of optimality, or visually. In addition, we have developed a fully automated inverse procedure for estimating the optimal hydraulic formation parameters Kr and Ss. We test and compare these two parameter estimation methods for the slug test and discuss their strengths and weaknesses. Cooper, H. H., Jr., J. D. Bredehoeft and I. S. Papadopulos. 1967. Response of a finite-diameter well to an instantaneous charge of water, Water Resour. Res., 3(1): 263-269. Koussis A. D. and E. Akylas (2012) Slug test analysis for confined aquifers in the over-damped case: Quasi-steady flow model, with estimation of the specific storage coefficient, Ground Water, 50(4): 608-613.

Rozos, Evangelos; Akylas, Evangelos; Koussis, Antonis D.

2013-04-01

367

Geologic spatial analysis  

SciTech Connect

This report describes the development of geologic spatial analysis research which focuses on conducting comprehensive three-dimensional analysis of regions using geologic data sets that can be referenced by latitude, longitude, and elevation/depth. (CBS)

Thiessen, R.L.; Eliason, J.R.

1989-01-01

368

GSA Geologic Time Scale  

NSDL National Science Digital Library

This Geological Society of America (GSA) site contains a detailed geologic time scale as an educational resource. It may be downloaded to a larger size, and includes all Eras, Eons, Periods, Epochs and ages as well as magnetic polarity information.

1999-01-01

369

Geophysics & Geology Inspected.  

ERIC Educational Resources Information Center

Summarizes findings of a recently published report of the Canadian Geoscience Council, which includes the following topics regarding college geology: facilities; teaching; undergraduate enrollments; postgraduate enrollments; geologic research; and integration of Canadian geoscience with other countries. (CS)

Neale, E. R. W.

1981-01-01

370

What is Geologic Time?  

NSDL National Science Digital Library

This USGS site employs graphics and text to explain geological time. The different geological eons, eras, epochs and periods are defined and put into perspective. The site also provides links to many terms and concepts for further exploration.

Usgs

371

Massively parallel molecular dynamics simulation of formation of clathrate-hydrate precursors at planar water-methane interfaces: insights into heterogeneous nucleation.  

PubMed

The formation of methane-hydrate precursors at large planar water-methane interfaces has been studied using massively parallel molecular dynamics in systems of varying size from around 10?000 to almost 7 × 10(6) molecules. This process took two distinct steps. First, the concentration of solvated methane clusters increases just inside the aqueous domain via slow diffusion from the methane-water interface, forming "clusters" of solvated methane molecules. Second, the re-ordering process of solvated methane and water molecules takes place in a manner very roughly consistent with the "blob" hypothesis, although with important differences, to form hydrate precursors, necessary for subsequent hydrate nucleation and crystallisation. It was found that larger system sizes serve to promote the formation rate of precursors. PMID:24880318

English, Niall J; Lauricella, Marco; Meloni, Simone

2014-05-28

372

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

USGS Publications Warehouse

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.

Dyman, Thaddeus S.; Schmoker, James W.

2003-01-01

373

A geologic study of the Michigan Basin  

NASA Astrophysics Data System (ADS)

The Michigan Basin contains sediments from Cambrian through Pennsylvanian age. The geologic basin is of greatest depth in Central Michigan with approximately 15,000 ft of strata. To assess efficiently which formations have suitable reservoir characteristics to be included in the Gas Research Institute tight gas sands program, a catalog of the lower-permeability formations and their characteristics was required. The lack of geologic units that were considered to have sufficient extent reservoir characteristics or gas reserves to be of interest as blanket-like gas sands precluded a more detailed inventory and characterization. An overview of all gas productive formations in the Michigan Basin is given.

Peterson, R. E.

1982-05-01

374

Geologic Sequestration Studies with Hawaiian Picrites  

Microsoft Academic Search

Capturing and storing anthropogenic carbon dioxide in deep geologic formations is a potential CO2 mitigation solution being studied to reduce adverse effects of increasing greenhouse gas concentrations on the global climate. Basalt formations, widespread globally, are currently being considered as a long term storage option. Because combustion gas streams often contain impurities, it is also important to consider contaminants (e.g.,

K. T. Johnson; B. P. McGrail; H. T. Schaef

2010-01-01

375

Marine geology: A planet earth perspective  

SciTech Connect

This text provides coverage of the basic geology of the marine development. It starts with the formation of the oceans using plate tectonics, continues with discussions of the mid-ocean ridges, and concludes with coverage of the formation and deformation of the continents.

Anderson, R.N.

1986-01-01

376

South Carolina Geological Survey  

NSDL National Science Digital Library

The South Carolina Geological Survey (SCGS) homepage contains information about state mapping, education and outreach programs, and recent news. For educators, there is the Earth Science education series of publications which includes presentations and page-size graphics on such topics as earthquakes, plate tectonics, geologic time, fossils, and others. Other materials include information on mineral resources, links to organizations in and about South Carolina geology, the South Carolina core repository, the Geologic Map of South Carolina, and others.

377

Iowa Geological Survey Bureau  

NSDL National Science Digital Library

The Iowa Geological Survey Bureau (GSB) homepage contains: general information about the geology of Iowa; the Natural Resources Geographic Information System, which is a collection of databases on geology and water wells; and information about GSB staff, geologic studies, water monitoring programs, and services. There are maps, photographs, general interest articles, technical abstracts, lists of available publications, and an on-line book about the natural resource history of Iowa.

378

North Dakota geology school receives major gift  

NASA Astrophysics Data System (ADS)

Petroleum geology and related areas of study at the University of North Dakota (UND) received a huge financial boost with the announcement on 24 September of $14 million in private and public partnership funding. The university announced the naming of the Harold Hamm School of Geology and Geological Engineering, formerly a department within the College of Engineering and Mines, in recognition of $10 million provided as a gift by oilman Harold Hamm and Continental Resources, Inc. Hamm is the chair and chief executive officer of Continental, the largest leaseholder in the Bakken Play oil formation in North Dakota and Montana, and he is also an energy policy advisor to Republican presidential candidate Mitt Romney. UND also received $4 million from the Oil and Gas Research Program of the North Dakota Industrial Commission to support geology and geological engineering education and research.

Showstack, Randy

2012-10-01

379

3-D seismic delineation and geologic explanation of channelization in the Frio Formation of Javelina/East McCook Field, Hidalgo County, Texas  

SciTech Connect

Sinuous, channel-form features were recognized on seismic amplitude time-slice maps of the shallow Oligocene Frio Formation on several Shell proprietary 3-D seismic surveys in west-central Hidalgo County, Texas. A case study of channel morphologies observed in the Frio Formation within the 50 mi{sup 2} 3-D seismic survey over Javelina/East McCook field was undertaken to better understand the distribution, lithology, origin, and hydrocarbon potential of these features. Ten separate channel-like amplitude features are observed in flattened time slices within a 200 m (approximately 1100 ft) interval on 3-D seismic. The channels have various azimuthal orientations and varying degrees of sinuosity. Several of the features have lengths that span the 3-D survey area (10 mi); apparent channel widths range from 200 to 2000 ft. The channelized seismic events tie to an interval of interbedded mudstones and claystones with siltstones. Two of the channels seen on seismic, and which were penetrated by wells, correlate to siftstone and mudstone intervals that have gross thicknesses of 30 to 60 ft. The lithologies and dimensions of the two channels indicate that they are probably small mudstone/siltstone-filled tributary/distributary channels deposited in a coastal floodplain environment; a comparison of the apparent channel dimensions to the dimensions of small channels/bayous of the modern-day Texas Gulf Coast supports this interpretation. Correlation of wells adjacent to the channels indicates that sandy point-bar facies are not present in association with the channel fill, which discounts the idea that high-quality reservoirs are flanking these particular mud-filled channels.

Gibson, J.L. [Shell Western Exploration and Production, Inc., Houston, TX (United States)

1994-09-01

380

Multiscale Analysis of Landscape Heterogeneity: Scale Variance and Pattern Metrics  

Microsoft Academic Search

A major goal of landscape ecology is to understand the formation, dynamics, and maintenance of spatial heterogeneity. Spatial heterogeneity is the most fundamental characteristic of all landscapes, and scale multiplicity is inherent in spatial heterogeneity. Thus, multiscale analysis is imperative for understanding the structure, function and dynamics of landscapes. Although a number of methods have been used for multiscale analysis

Jianguo Wu; Dennis E. Jelinski; Matt Luck; Paul T. Tueller

2000-01-01