538 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Geologic Models"  
Results: 1 - 24 next

Increasing Waterflood Reserves in the Wilmington Oil Field Through Improved Reservoir Characterization and Reservoir Management

Description: The objectives of this quarterly report are to summarize the work conducted under each task during the reporting period January - March 1998 and to report all technical data and findings as specified in the "Federal Assistance Reporting Checklist". The main objective of this project is the transfer of technologies, methodologies, and findings developed and applied in this project to other operators of Slope and Basin Clastic Reservoirs. This project will study methods to identify sands with high remaining oil saturation and to recomplete existing wells using advanced completion technology. The identification of the sands with high remaining oil saturation will be accomplished by developing a deterministic three dimensional (3-D) geologic model and by using a state of the art reservoir management computer software. The wells identified by the geologic and reservoir engineering work as having the best potential will be logged with cased-hole logging tools. The application of the logging tools will be optimized in the lab by developing a rock-log model. This rock-log model will allow us to translate measurements through casing into effective porosity and hydrocarbon saturation. The wells that are shown to have the best oil production potential will be recompleted. The recompletions will be optimized by evaluating short radius lateral recompletions as well as other recompletion techniques such as the sand consolidation through steam injection.
Date: April 22, 1998
Creator: Phillips, Chris; Moos, Dan; Clarke, Don; Nguyen, John; Tagbor, Kwasi; Koerner, Roy et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Advanced Chemistry Basins Model

Description: The advanced Chemistry Basin Model project has been operative for 48 months. During this period, about half the project tasks are on projected schedule. On average the project is somewhat behind schedule (90%). Unanticipated issues are causing model integration to take longer then scheduled, delaying final debugging and manual development. It is anticipated that a short extension will be required to fulfill all contract obligations.
Date: May 1, 2004
Creator: Goddard, William, III; Cathles, Lawrence, III; Blanco, Mario; Manhardt, Paul; Meulbroek, Peter & Tang, Yongchun
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Mapping of Reservoir Properties and Facies Through Integration of Static and Dynamic Data

Description: The goal of this project was to develop computationally efficient automatic history matching techniques for generating geologically plausible reservoir models which honor both static and dynamic data. Solution of this problem is necessary for the quantification of uncertainty in future reservoir performance predictions and for the optimization of reservoir management.
Date: March 5, 2002
Creator: Oliver, Dean S.; Reynolds, Albert C.; Zhang, Fengjun; Li, Ruijian; Abacioglu, Yafes & Dong, Yannong
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Mapping of Reservoir Properties and Facies Through Integration of Static and Dynamic Data

Description: The goal of this project was to develop computationally efficient automatic history matching techniques for generating geologically plausible reservoir models which honor both static and dynamic data. Solution of this problem was necessary for the quantification of uncertainty in future reservoir performance predictions and for the optimization of reservoir management.
Date: March 10, 2003
Creator: Reynolds, Albert C.; Oliver, Dean S.; Zhang, Fengjun; Dong, Yannong; Skjervheim, Jan Arild & Liu, Ning
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Characterization of Turbiditic Oil Reservoirs Based on Geophysical Models of Their Formation

Description: A hierarchy of models and results are presented for the simulation of the dynamics and deposition of concentrated turbidity currents. The turbidity flows are assumed to be two-dimensional due to a constant flux release of dense suspensions spreading over a nonerodible flat surface. The three models presented are the Suspension Balance Model (SBM), the Simplified Suspension Balance Model (SSBM) and the Vertically Averaged Simplified Suspension Balance Model (VASSBM). The SBM is computationally intensive. However, simulations of the SBM indicate that the only a subset of the terms in the equations for the SBM are significant. The VASSBM is significantly faster computationally, and it is shown here to be an accurate approximation of the SBM model. For all the models, the two parameters that determine the dynamics and deposition of a concentrated turbidity current due to a constant flux release are the inlet volume fraction and the buoyancy number, a ratio of the buoyancy forces to viscous forces acting on the current. A parameter study is conducted for a volume fraction ranging from 10 to 40% and buoyancy numbers ranging from 0.01 to 0.2, typical of many real concentrated turbidity flows. It is found that the length or extent of deposit is mostly determined by inlet volume fraction and is relatively insensitive to the buoyancy number. The converse, though, is found for the thickness of the deposit.
Date: April 1, 2004
Creator: Bonnecaze, Roger T. & Lakshminarasimhan, Srivatsan
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

SMALL-VOLUME BASALTIC VOLCANOES: ERUPTIVE PRODUCTS AND PROCESSES, AND POST-ERUPTIVE GEOMORPHIC EVOLUTION IN CRATER FLAT (PLEISTOCENE), SOUTHERN NEVADA

Description: Five Pleistocene basaltic volcanoes in Crater Flat (southern Nevada) demonstrate the complexity of eruption processes associated with small-volume basalts and the effects of initial emplacement characteristics on post-eruptive geomorphic evolution of the volcanic surfaces. The volcanoes record eruptive processes in their pyroclastic facies ranging from ''classical'' Strombolian mechanisms to, potentially, violent Strombolian mechanisms. Cone growth was accompanied, and sometimes disrupted, by effusion of lavas from the bases of cones. Pyroclastic cones were built upon a gently southward-sloping surface and were prone to failure of their down-slope (southern) flanks. Early lavas flowed primarily southward and, at Red and Black Cone volcanoes, carried abundant rafts of cone material on the tops of the flows. These resulting early lava fields eventually built platforms such that later flows erupted from the eastern (at Red Cone) and northern (at Black Cone) bases of the cones. Three major surface features--scoria cones, lava fields with abundant rafts of pyroclastic material, and lava fields with little or no pyroclastic material--experienced different post-eruptive surficial processes. Contrary to previous interpretations, we argue that the Pleistocene Crater Flat volcanoes are monogenetic, each having formed in a single eruptive episode lasting months to a few years, and with all eruptive products having emanated from the area of the volcanoes main cones rather than from scattered vents. Geochemical variations within the volcanoes must be interpreted within a monogenetic framework, which implies preservation of magma source heterogeneities through ascent and eruption of the magmas.
Date: April 4, 2006
Creator: Valentine, G. A.; Perry, F. V.; Krier, D.; Keating, G. N.; Kelley, R. E. & Cogbill, A. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Deliverable 2.4.4 -- Evaluation and single-well models for the demonstration wells, Class 1

Description: Two single-well models were developed for Michelle Ute and Malnar Pike wells. The perforated intervals span thousands of feet in both the wells. Geological properties were calculated for all the perforated beds. The information was used to develop models for these two wells. These were comprehensive models since they took into account all the perforated beds.
Date: July 12, 2000
Creator: Deo, Milind & D., Morgan Craig
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Analytic solutions for seismic travel time and ray path geometry through simple velocity models.

Description: The geometry of ray paths through realistic Earth models can be extremely complex due to the vertical and lateral heterogeneity of the velocity distribution within the models. Calculation of high fidelity ray paths and travel times through these models generally involves sophisticated algorithms that require significant assumptions and approximations. To test such algorithms it is desirable to have available analytic solutions for the geometry and travel time of rays through simpler velocity distributions against which the more complex algorithms can be compared. Also, in situations where computational performance requirements prohibit implementation of full 3D algorithms, it may be necessary to accept the accuracy limitations of analytic solutions in order to compute solutions that satisfy those requirements. Analytic solutions are described for the geometry and travel time of infinite frequency rays through radially symmetric 1D Earth models characterized by an inner sphere where the velocity distribution is given by the function V (r) = A-Br{sup 2}, optionally surrounded by some number of spherical shells of constant velocity. The mathematical basis of the calculations is described, sample calculations are presented, and results are compared to the Taup Toolkit of Crotwell et al. (1999). These solutions are useful for evaluating the fidelity of sophisticated 3D travel time calculators and in situations where performance requirements preclude the use of more computationally intensive calculators. It should be noted that most of the solutions presented are only quasi-analytic. Exact, closed form equations are derived but computation of solutions to specific problems generally require application of numerical integration or root finding techniques, which, while approximations, can be calculated to very high accuracy. Tolerances are set in the numerical algorithms such that computed travel time accuracies are better than 1 microsecond.
Date: December 1, 2007
Creator: Ballard, Sanford
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

History Matching in Parallel Computational Environments

Description: In the probabilistic approach for history matching, the information from the dynamic data is merged with the prior geologic information in order to generate permeability models consistent with the observed dynamic data as well as the prior geology. The relationship between dynamic response data and reservoir attributes may vary in different regions of the reservoir due to spatial variations in reservoir attributes, fluid properties, well configuration, flow constrains on wells etc. This implies probabilistic approach should then update different regions of the reservoir in different ways. This necessitates delineation of multiple reservoir domains in order to increase the accuracy of the approach. The research focuses on a probabilistic approach to integrate dynamic data that ensures consistency between reservoir models developed from one stage to the next. The algorithm relies on efficient parameterization of the dynamic data integration problem and permits rapid assessment of the updated reservoir model at each stage. The report also outlines various domain decomposition schemes from the perspective of increasing the accuracy of probabilistic approach of history matching. Research progress in three important areas of the project are discussed: {lg_bullet}Validation and testing the probabilistic approach to incorporating production data in reservoir models. {lg_bullet}Development of a robust scheme for identifying reservoir regions that will result in a more robust parameterization of the history matching process. {lg_bullet}Testing commercial simulators for parallel capability and development of a parallel algorithm for history matching.
Date: August 31, 2004
Creator: Bryant, Steven; Srinivasan, Sanjay; Barrera, Alvaro & Yadav, Sharad
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Mechanistically-Based Field-Scale Models of Uranium Biogeochemistry from Upscaling Pore-Scale Experiments and Models

Description: Effective environmental management of DOE sites requires reliable prediction of reactive transport phenomena. A central issue in prediction of subsurface reactive transport is the impact of multiscale physical, chemical, and biological heterogeneity. Heterogeneity manifests itself through incomplete mixing of reactants at scales below those at which concentrations are explicitly defined (i.e., the numerical grid scale). This results in a mismatch between simulated reaction processes (formulated in terms of average concentrations) and actual processes (controlled by local concentrations). At the field scale, this results in apparent scale-dependence of model parameters and inability to utilize laboratory parameters in field models. Accordingly, most field modeling efforts are restricted to empirical estimation of model parameters by fitting to field observations, which renders extrapolation of model predictions beyond fitted conditions unreliable. The objective of this project is to develop a theoretical and computational framework for (1) connecting models of coupled reactive transport from pore-scale processes to field-scale bioremediation through a hierarchy of models that maintain crucial information from the smaller scales at the larger scales; and (2) quantifying the uncertainty that is introduced by both the upscaling process and uncertainty in physical parameters. One of the challenges of addressing scale-dependent effects of coupled processes in heterogeneous porous media is the problem-specificity of solutions. Much effort has been aimed at developing generalized scaling laws or theories, but these require restrictive assumptions that render them ineffective in many real problems. We propose instead an approach that applies physical and numerical experiments at small scales (specifically the pore scale) to a selected model system in order to identify the scaling approach appropriate to that type of problem. Although the results of such studies will generally not be applicable to other broad classes of problems, we believe that this approach (if applied over time to many types of problems) …
Date: April 19, 2007
Creator: Scheibe, Tim; Tartakovsky, Alexandre; Wood, Brian & Seymour, Joe
Item Type: Refine your search to only Poster
Partner: UNT Libraries Government Documents Department

History Matching in Parallel Computational Environments

Description: A novel methodology for delineating multiple reservoir domains for the purpose of history matching in a distributed computing environment has been proposed. A fully probabilistic approach to perturb permeability within the delineated zones is implemented. The combination of robust schemes for identifying reservoir zones and distributed computing significantly increase the accuracy and efficiency of the probabilistic approach. The information pertaining to the permeability variations in the reservoir that is contained in dynamic data is calibrated in terms of a deformation parameter rD. This information is merged with the prior geologic information in order to generate permeability models consistent with the observed dynamic data as well as the prior geology. The relationship between dynamic response data and reservoir attributes may vary in different regions of the reservoir due to spatial variations in reservoir attributes, well configuration, flow constrains etc. The probabilistic approach then has to account for multiple r{sub D} values in different regions of the reservoir. In order to delineate reservoir domains that can be characterized with different r{sub D} parameters, principal component analysis (PCA) of the Hessian matrix has been done. The Hessian matrix summarizes the sensitivity of the objective function at a given step of the history matching to model parameters. It also measures the interaction of the parameters in affecting the objective function. The basic premise of PC analysis is to isolate the most sensitive and least correlated regions. The eigenvectors obtained during the PCA are suitably scaled and appropriate grid block volume cut-offs are defined such that the resultant domains are neither too large (which increases interactions between domains) nor too small (implying ineffective history matching). The delineation of domains requires calculation of Hessian, which could be computationally costly and as well as restricts the current approach to some specific simulators. Therefore a robust technique to …
Date: August 31, 2006
Creator: Bryant, Steven; Srinivasan, Sanjay; Barrera, Alvaro; Kim, Yonghwee & Yadav, Sharad
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Economic Recovery of Oil Trapped at Fan Margins Using High Angle Wells Multiple Hydraulic Fractures

Description: This project attempts to demonstrate the effectiveness of exploiting thin-layered, low-energy deposits at the distal margin of a prograding turbidite complex through the use of hydraulically fractured horizontal or high-angle wells. The combination of a horizontal or high-angle well and hydraulic fracturing will allow greater pay exposure than can be achieved with conventional vertical wells while maintaining vertical communication between thin interbedded layers and the wellbore. A high-angle well will be drilled in the fan-margin portion of a slope-basin clastic reservoir and will be completed with multiple hydraulic-fracture treatments. Geologic modeling, reservoir characterization, and fine-grid reservoir simulation will be used to select the well location and orientation. Design parameters for the hydraulic-fracture treatments will be determined, in part, by fracturing an existing test well. Fracture azimuth will be predicted by passive seismic monitoring of a fracture-stimulation treatment in the test well using logging tools in an offset well.
Date: October 30, 1997
Creator: Laue, Mike L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Geological and petrophysical characterization of the Ferron Sandstone for 3-D simulation of a fluvial-deltaic reservoir. Quarterly report, July 1--September 30, 1997

Description: The objective of this project is to develop a comprehensive, interdisciplinary, and quantitative characterization of a fluvial-deltaic reservoir which will allow realistic inter-well and reservoir-scale modeling to be constructed for improved oil-field development in similar reservoirs world-wide. The geological and petrophysical properties of the Cretaceous Ferron Sandstone in east-central Utah will be quantitatively determined. Both new and existing data will be integrated into a three-dimensional representation of spatial variations in porosity, storativity, and tensorial rock permeability at a scale appropriate for inter-well to regional-scale reservoir simulation. Results could improve reservoir management through proper infill and extension drilling strategies, reduction of economic risks, increased recovery from existing oil fields, and more reliable reserve calculations. Two activities continued this quarter as part of the geological and petrophysical characterization of the fluvial-deltaic Ferron Sandstone: (1) evaluation of the Ivie Creek and Willow Springs Wash case-study areas and (2) technology transfer.
Date: November 1, 1997
Creator: Allison, M. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Feasibility of Optimizing and Reserves from a Mature and Geological Complex Multiple Turbidite Offshore California Reservoir Through the Drilling and Completion of a Trilateral Horizontal Well.

Description: The main objective of this project is to devise an effective redevelopment strategy to combat producibility problems related to the Repetto turbidite sequences of the Carpinteria Field. The lack of adequate reservoir characterization, high-water cut production, and scaling problems have in the past contributed to the field`s low productivity. To improve productivity and enhance recoverable reserves, the following specific goals are proposed: (1) Develop an integrated database of all existing data from work done by the former ownership group. (2) Expand reservoir drainage and reduce sand problems through horizontal well drilling and completion. (3) Operate and validate reservoirs` conceptual model by incorporating new data from the proposed trilateral well. (4) Transfer methodologies employed in geologic modeling and drilling multilateral wells to other operators with similar reservoirs. Since the last progress report (January - March, 1997) additional work has been completed in the area of well log interpretation and geological modeling. During this period an extensive effort was made to refine our 3-D geological model both in the area of a refined attribute model and an enhanced structural model. Also, efforts to refine our drilling plans for budget period 11 were completed during this reporting period.
Date: August 25, 1997
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

IMPROVED OIL RECOVERY FROM UPPER JURASSIC SMACKOVER CARBONATES THROUGH THE APPLICATION OF ADVANCED TECHNOLOGIES AT WOMACK HILL OIL FIELD, CHOCTAW AND CLARKE COUNTIES, ALABAMA, EASTERN GULF COASTAL PLAIN

Description: The principal research effort for Year 1 of the project is drilling an infill well in the Womack Hill Field, Choctaw and Clarke Counties, Alabama. The objectives of the project are to drill and core an infill well in Womack Hill Field; to utilize samples from the core to evaluate further the feasibility of implementing an immobilized enzyme technology project in the field; and to use the new information resulting from the drilling of the well to revise and modify the 3-D geologic model, to further modify the injection strategy for the existing pressure maintenance program, and to assess whether a second infill well should be drilled using lateral/multilateral well completions.
Date: December 13, 2004
Creator: Mancini, Ernest A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Collaborative Research: Analysis and Interpretation of Multi-Scale Phenomena in Crustal Deformation Processes Using Numerical Simulations of Complex Nonlinear Earth Systems

Description: In both our past work and the work in progress we focused on understanding the physics and statistical patterns in earthquake faults and fault systems. Our approach had three key aspects. The first was to look for patterns of seismic activity in earthquake fault systems. The second was to understand the physics of a sequence of models for faults and fault systems that are increasingly more realistic. The third key element was to connect the two previous approaches by investigating specific properties found in models to see if they are indeed properties of real faults. A specific example of how this approach works can be seen in the following: In the papers discussed below, we demonstrated that the cellular automation (CA) versions of the slider block models with long range stress transfer are ergodic and could be described by a Boltzmann-Gibbs distribution in the meanfield limit. The ergodicity follows from the fact that the long range stress transfer makes the model meanfield. The meanfield nature of the CA models, generated by long range stress transfer, also allows a description of the CA models by a Langevin equation. The Langevin equation indicates that evolution of seismicity in the model over relatively short times is linear in time. This appears to be consistent with the success of a forecasting algorithm we have developed that is based on a linear evolution of seismicity patterns. This algorithm has had considerable success in that the regions of the Southern California fault system which have been predicted to have a higher probability of an event greater than magnitude 5 have consistently been the sites where such events occur. These two results have led to the question as to whether the Southern California fault system is ergodic and can be described by a Langevin equation like the …
Date: December 31, 2004
Creator: Rundle, John B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Improved Miscible Nitrogen Flood Performance Utilizing Advanced Reservoir Characterization and Horizontal Laterals in a Class I Reservoir - East Binger (Marchand) Unit Quarterly Report

Description: Progress on the East Binger Unit (EBU) project has slowed as difficulties have been encountered with obtaining satisfactory production from well EBU 37G-3H, the new horizontal well. Remedial operations have been conducted and stimulation operations were about to get under way at the end of the reporting period. International Reservoir Technologies, Inc. has made additional progress on the pilot area simulation model, reaching a point with the history match that we are awaiting more definitive production data from the horizontal well. Planning future development of the EBU hinges on evaluating the results of well EBU 37G-3H. Performance of this well must be understood in order to evaluate development scenarios involving horizontal wells and compare them with development scenarios involving vertical wells.
Date: October 26, 2001
Creator: Sinner, Joe
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Discrete Feature Approach for Heterogeneous Reservoir Production Enhancement

Description: The report presents summaries of technology development for discrete feature modeling in support of the improved oil recovery (IOR) for heterogeneous reservoirs. In addition, the report describes the demonstration of these technologies at project study sites.
Date: July 26, 2002
Creator: Dershowitz, William S.; Curran, Brendan; Einstein, Herbert; LaPointe, Paul; Shuttle, Dawn & Klise, Kate
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

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

Description: 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. Throughout the project, however, we learned that this strategy was impractical because the different data and model are complementary instead of competitive. For the complex Coalinga field, we found that a thorough understanding of the reservoir evolution through geologic times provides the necessary framework which ultimately allows integration of the different data and techniques.
Date: February 1, 2005
Creator: Imhof, Matthias G. & Castle, James W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Use of Numerical Groundwater Modeling to Evaluate Uncertainty in Conceptual Models of Recharge and Hydrostratigraphy

Description: Numerical groundwater models are based on conceptualizations of hydrogeologic systems that are by necessity developed from limited information and therefore are simplifications of real conditions. Each aspect (e.g. recharge, hydrostratigraphy, boundary conditions) of the groundwater model is often based on a single conceptual model that is considered to be the best representation given the available data. However, the very nature of their construction means that each conceptual model is inherently uncertain and the available information may be insufficient to refute plausible alternatives, thereby raising the possibility that the flow model is underestimating overall uncertainty. In this study we use the Death Valley Regional Flow System model developed by the U.S. Geological Survey as a framework to predict regional groundwater flow southward into Yucca Flat on the Nevada Test Site. An important aspect of our work is to evaluate the uncertainty associated with multiple conceptual models of groundwater recharge and subsurface hydrostratigraphy and quantify the impacts of this uncertainty on model predictions. In our study, conceptual model uncertainty arises from two sources: (1) alternative interpretations of the hydrostratigraphy in the northern portion of Yucca Flat where, owing to sparse data, the hydrogeologic system can be conceptualized in different ways, and (2) uncertainty in groundwater recharge in the region as evidenced by the existence of several independent approaches for estimating this aspect of the hydrologic system. The composite prediction of groundwater flow is derived from the regional model that formally incorporates the uncertainty in these alternative input models using the maximum likelihood Bayesian model averaging method. An assessment of the joint predictive uncertainty of the input conceptual models is also produced. During this process, predictions of the alternative models are weighted by model probability, which is the degree of belief that a model is more plausible given available prior information (expert opinion) …
Date: January 19, 2007
Creator: Pohlmann, Karl; Ye, Ming; Pohll, Greg & Chapman, Jenny
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department

Telluric and D.C. Resistivity Techniques Applied to the Geophysical Investigation of Basin and Range Geothermal Systems, Part II: A Numberical Model Study of the Dipole-Dipole and Schlumberger Resistivity Methods

Description: This paper is a two-dimensional numerical model study and comparison of the polar dipole-dipole and Schlumberger resistivity arrays. A catalog of dipole-dipole and Schlumberger apparent resistivity pseudo-sections is presented. It is concluded that: for the Schlumberger array, data can be accurately interpreted only if the resistivity structure is horizontally layered, and conductive bodies having a depth of burial greater than their width are not observed; for the dipole-dipole array, complex anomaly patterns unrelated in appearance to the causative structure result from simple models, hence, a familiarity with model results is essential to interpretation of these data.
Date: June 1, 1977
Creator: Beyer, J.H.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
Back to Top of Screen