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Post waterflood CO{sub 2} miscible flood in light oil fluvial - dominated deltaic reservoirs. Fourth quarterly progress report, July 1, 1995--September 30, 1995

Description: Production from the Marg Area 1 at Port Neches is averaging 222 BOPD for this quarter. The production drop is due in part to mechanical problems and to poor sweep efficiency caused by water blockage that prevented the CO{sub 2} from contacting new residual oil deeper in the reservoir. Alternating water and gas injection assisted to some extent in maintaining oil production and improved the reservoir yield by reducing the gas production. A workover was performed on well Kuhn No. 38 to correct failed gravel pack setting. Production from the well was restored to 60 BOPD. Plugging of the injection wells continue to be a problem, reducing the injection rate in critical areas of the reservoir, near well Kuhn No. 15R. Texaco drilled the well Polk B No. 39 to The Marg Area 3 reservoir to gain structural position based on the 3D seismic, and found the sand present as anticipated. However, the sand did not have any hydrocarbon accumulation. For this reason, Texaco will abandon testing the idea of utilizing CO{sub 2} to accelerate the primary production rate and reduce water production and primary production cycle time, in the reservoir.
Date: November 10, 1995
Partner: UNT Libraries Government Documents Department

Productivity and injectivity of horizontal wells. Quarterly report, January 1, 1996--March 31, 1996

Description: A reservoir simulator solves the flow equations numerically on grids defining a reservoir region. However, when a well is located in a grid-block, the block pressure is not equal to the well pressure. In order to join the well to the grid blocks in which the well is located, it is usual to use a single phase model to obtain the appropriate Well Index. The Well Index is based on the concept of an effective well radius at which the pressure of the block applies. This approach requires the flow in the area around the well to be radial. Peaceman has proposed more general expressions for the effective radius, but all based on 2D flow. As reservoirs are generally thin, a horizontal well cannot be far from the top or bottom boundary. In the case of multilateral wells, the situation is even worse, since the flow is perturbed not only by the boundaries but also by the other wells. Moreover, horizontal wells can be efficient in low permeability reservoirs, where the steady-state (or pseudo-steady-state) regime does not establish rapidly. This means that a single constant value for the well index cannot be used for all times. The objective of this study is then to evaluate well indices for different configurations of horizontal wells. The well index will be computed for a homogeneous anisotropic single-phase flow and will then be reintroduced in the simulator for the full three-phase study. The well index relates the pressure in the block to the pressure in the well for a given flow rate. If these two pressures are known, the well index can be deduced easily. The block pressure can be evaluated by a simulator. The well pressure for a three-dimensional single-phase flow is not known analytically in general, but can be computed by the ...
Date: May 1, 1996
Creator: Aziz, K.
Partner: UNT Libraries Government Documents Department

Development of cost-effective surfactant flooding technology. Quarterly report, July 1995--September 1995

Description: The objective of this research is to develop cost-effective surfactant flooding technology by using surfactant simulation studies to evaluate and optimize alternative design strategies taking into account reservoir characteristics, process chemistry, and process design options such as horizontal wells. Task 1 is the development of an improved numerical method for our simulator that will enable us to solve a wider class of these difficult simulation problems accurately and affordably. Task 2 is the application of this simulator to the optimization of surfactant flooding to reduce its risk and cost.
Date: December 31, 1995
Creator: Pope, G.A. & Sepehrnoori, K.
Partner: UNT Libraries Government Documents Department

Reservoir technology research at the INEL

Description: Reservoir engineering research at INEL was aimed at developing a better understanding of The Geysers and developing better tools with which to study flow in fractured geothermal reservoirs in general. Two specific topics were studies in the last year: matrix fracture interactions and decline curve analysis. A third project, revisiting the behavior of the `high-temperature reservoir` (HTR), was started near the end of 1995. These projects are being conducted in collaboration with other researchers and/or private industry. For example, our HTR studies are motivated in part because of new isotopic analyses conducted elsewhere (Walters et al., in preparation). The ultimate goal of these projects is to improve predictive capabilities and reservoir management practices and to extend the commercial life of The Geysers. In addition to conducting engineering research for the Reservoir Technology Program, INEL also continued to assist the Geothermal Technology Organization (GTO) with the development and execution of cooperative research projects. In support of the overall mission of the Reservoir Technology program, INEL also entered into a broad program of subcontracts with industrial groups and universities. These programs support the Reservoir Technology mission by providing support for research topics considered particularly important by the geothermal industry. The GTO projects are summarized below.
Date: May 1, 1996
Creator: Renner, J. L.; Shook, G. M. & Faulder, D. D.
Partner: UNT Libraries Government Documents Department

Influence of pore pressure and production-induced changes in pore pressure on in situ stress

Description: Knowledge of in situ stress and how stress changes with reservoir depletion and pore pressure drawdown is important in a multi-disciplinary approach to reservoir characterization, reservoir management, and improved oil recovery projects. This report summarizes a compilation of in situ stress data from six fields showing the effects of pore pressure and production-induced changes in pore pressure on the minimum horizontal stress. The in situ stress data and corresponding pore pressure data were obtained from field records of the operating companies and published reports. Horizontal stress was determined from closure pressure data of hydraulic fractures and leak-off tests. The stress measurements clearly demonstrate that the total minimum-horizontal stress is dependent on pore pressure. A decrease in pore pressure either by geologic processes or production of a reservoir will result in a decrease in the total minimum-horizontal stress. The magnitude of changes in stress state with net changes in pore pressure is dependent on local field conditions and cannot be accurately predicted by the uniaxial strain model that is commonly used by the petroleum industry.
Date: February 1, 1996
Creator: Teufel, L.W.
Partner: UNT Libraries Government Documents Department

High performance computing for domestic petroleum reservoir simulation

Description: This is the final report of a two-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory. High-performance computing offers the prospect of greatly increasing the resolution at which petroleum reservoirs can be represented in simulation models. The increases in resolution can be achieved through large increases in computational speed and memory, if machine architecture and numerical methods for solution of the multiphase flow equations can be used to advantage. Perhaps more importantly, the increased speed and size of today`s computers make it possible to add physical processes to simulation codes that heretofore were too expensive in terms of computer time and memory to be practical. These factors combine to allow the development of new, more accurate methods for optimizing petroleum reservoir production.
Date: June 1, 1996
Creator: Zyvoloski, G.; Auer, L. & Dendy, J.
Partner: UNT Libraries Government Documents Department

Field verification of CO{sub 2} Foam. Final report

Description: The East Vacuum Grayburg/San Andres Unit (EVGSAU), operated by Phillips Petroleum Company, was the site selected for a comprehensive evaluation of the use of foam for improving the effectiveness of a CO{sub 2} flood. This project, entitled {open_quotes}Field Verification of CO{sub 2-}Foam,{close_quotes} was jointly funded by the EVGSAU working interest owners, the U.S. Department of Energy (DOE), and the State of New Mexico. The DOE provided $2 million or approximately 34% of the total project costs, the EVGSAU provided $2.46 million, the State of New Mexico contributed approximately $1.2 million, and about $103,000 of other industrial funds were used. The Petroleum Recovery Research Center (PRRC), a division of the New Mexico Institute of Mining and Technology, provided laboratory and research support for the project. A joint project advisory team composed of technical representatives from several major oil companies provided input, review, and guidance for the project. The project, which began in 1989, had a scheduled duration of four years, but the DOE granted a no-cost extension to the end of March 1995 for the purpose of continued project evaluation. A field test of the CO{sub 2}-foam has been successfully conducted, and preliminary results are promising. Response in the foam injection well has been as anticipated, and an offset producing well experienced a positive oil response as a result of the foam test. Based on the favorable results observed in the foam injection test, a second foam test was conducted. The monitoring program included analysis of injectivity data, pressure falloff tests, observation well logs, interwell tracer response, production logs, history of production rates, and changes in gas-oil ratio. This report presents an overview of the project and provides results of the laboratory work, simulation studies, and field tests.
Date: February 1, 1996
Creator: Martin, F.D.; Heller, J.P. & Weiss, W.W.
Partner: UNT Libraries Government Documents Department

The bridge permeameter; An alternative method for single-phase, steady-state permeability measurements

Description: Laboratory measurements of single-phase, steady-state permeability of porous rock are important for a number of different applications. The oil and gas industry uses permeability data as a key indicator of the producability of a hydrocarbon reservoir; effective containment of large volumes of oil in underground salt caverns is directly dependent upon the permeability of the adjacent cavern walls; and safe, long term underground isolation of radioactive and hazardous waste is contingent upon the flow and transport characteristics of the surrounding geologic formations. An alternative method for measuring single-phase, steady-state permeability of porous rock is presented. The use of troublesome and expensive mass flow meters is eliminated and replaced with a bridge configuration of flow resistors. Permeability values can be determined directly from differential pressures across the bridge network, resulting in potentially significant cost savings and simplification for conducting these types of measurements. Results from the bridge permeameter are compared with results obtained using conventional methods.
Date: March 1, 1994
Creator: Graf, D.C. & Warpinski, N.R.
Partner: UNT Libraries Government Documents Department

Seismic data acquisition through tubing

Description: We have collected good quality crosswell seismic data through production tubing in active oil fields at realistic interwell distances (300 ft). The data were collected at the Aera Cymric field (1998) and at a Chevron site (1997); both located in the Central Valley of California. The Aera data were used to produce travel-time tomographic images of the interwell region. Both sites have similar geology, namely siliceous shale (diatomite) with moderate to highly attenuating reservoir rocks. In addition we confirmed modeling predictions that typical tubing attenuation losses are on the order of 12 dB. We expect that the use of stronger sources and tube wave suppression will allow for crosswell imaging at realistic distances even for low Q or high noise situations. We are searching for an industrial partner now for a data collection in the gas wells of the San Juan Basin or South Texas.
Date: July 1, 1999
Creator: Buettner, H M & Jervis, M
Partner: UNT Libraries Government Documents Department

Characterization of Mixed Wettability at Different Scales and its Impact on Oil Recovery Efficiency

Description: The objectives of this project was to: (1) quantify the pore scale mechanisms that determine the wettability state of a reservoir, (2) study the effect of crude oil, brine and mineral compositions in the establishment of mixed wet states, (3) clarify the effect of mixed - wettability on oil displacement efficiency in waterfloods, (4) develop a new tracer technique to measure wettability, fluid distributions, residual saturation's and relative permeabilities, and (5) develop methods for properly incorporating wettability in up-scaling from pore to core to reservoir scales.
Date: January 28, 2002
Creator: Sharma, Mukul M. & Hirasaki, George J.
Partner: UNT Libraries Government Documents Department

A Physically Based Approach for Modeling Multiphase Fracture-Matrix Interaction in Fractured Porous Media

Description: Modeling fracture-matrix interaction within a complex multiple phase flow system is a key issue for fractured reservoir simulation. Commonly used mathematical models for dealing with such interactions employ a dual- or multiple-continuum concept, in which fractures and matrix are represented as overlapping, different, but interconnected continua, described by parallel sets of conservation equations. The conventional single-point upstream weighting scheme, in which the fracture relative permeability is used to represent the counterpart at the fracture-matrix interface, is the most common scheme by which to estimate flow mobility for fracture-matrix flow terms. However, such a scheme has a serious flaw, which may lead to unphysical solutions or significant numerical errors. To overcome the limitation of the conventional upstream weighting scheme, this paper presents a physically based modeling approach for estimating physically correct relative permeability in calculating multiphase flow between fractures and the matrix, using continuity of capillary pressure at the fracture-matrix interface. The proposed approach has been implemented into two multiphase reservoir simulators and verified using analytical solutions and laboratory experimental data. The new method is demonstrated to be accurate, numerically efficient, and easy to implement in dual- or multiple-continuum models.
Date: March 16, 2004
Creator: Wu, Y.; Pan, L. & Pruess, K.
Partner: UNT Libraries Government Documents Department

Model for Residual Saturations and Capillary Imbibition and Drainage Pressures

Description: A pore saturation model expresses the capillary pressure as a function of a characteristic pore pressure and the wetting phase saturation. Singularity analyses of the total energies of the wetting and nonwetting phases give the residual saturations for the two phases. The total energy consists of a potential term and a work term associated with the effective pressure gradient for each phase. The derived residual wetting saturation is 0.236, and the derived residual nonwetting saturation is 0.884. The model includes separate pressures for imbibition and drainage to account for capillary hysteresis. In the model, the pressure gradient for the wetting phase defines the imbibition pressure, and the nonwetting phase pressure gradient defines the drainage pressure. At the residual nonwetting saturation, the two pressures differ by the characteristic pore pressure. The two pressures coincide at a critical minimum saturation of 0.301. The model also includes an entry head to account for the minimum force required for drainage to begin. The model utilizes a single fitting parameter, a characteristic pore pressure, which can be related to a characteristic pore diameter.
Date: April 1, 2004
Creator: LAURINAT, JAMESE
Partner: UNT Libraries Government Documents Department

Multidisciplinary Imaging of Rock Properties in Carbonate Reservoirs for Flow-Unit Targeting

Description: Excellent progress continues to be made on most objectives and goals. Primary focus during the past 6 months has been (1) simulation of reservoir performance using the reservoir model constructed for the Phase 1 study area, (2) extension of core and log characterization activities to the Phase 2 study area, (3) development of an initial velocity-based inversion model from the 3-D seismic volume for porosity characterization, (4) continuation of quality-control analysis of wireline logs. Preliminary results of the study were presented at a technology-transfer workshop in May 2003 in Midland/Odessa Texas.
Date: July 1, 2003
Creator: Ruppel, Stephen C.
Partner: UNT Libraries Government Documents Department

Application of artifical intelligence to reservoir characterization: An interdisciplinary approach. Annual report, October 1993--October 1994

Description: This basis of this research is to apply novel techniques from Artificial Intelligence and Expert Systems in capturing, integrating and articulating key knowledge from geology, geostatistics, and petroleum engineering to develop accurate descriptions of petroleum reservoirs. The ultimate goal is to design and implement a single powerful expert system for use by small producers and independents to efficiently exploit reservoirs.
Date: July 1, 1995
Creator: Kelkar, B.G.; Gamble, R.F.; Kerr, D.R.; Thompson, L.G. & Shenoi, S.
Partner: UNT Libraries Government Documents Department

An object-oriented cluster search algorithm

Description: In this work we describe two object-oriented cluster search algorithms, which can be applied to a network of an arbitrary structure. First algorithm calculates all connected clusters, whereas the second one finds a path with the minimal number of connections. We estimate the complexity of the algorithm and infer that the number of operations has linear growth with respect to the size of the network.
Date: January 24, 2003
Creator: Silin, Dmitry & Patzek, Tad
Partner: UNT Libraries Government Documents Department

Multidisciplinary Imaging of Rock Properties in Carbonate Reservoirs for Flow-Unit Targeting

Description: During the period major accomplishments were in (1) characterization of facies and cyclicity in subsurface cores and in outcrop, (2) construction of a preliminary stratigraphic framework, (3) definition of rock fabrics, and (4) correlation of 3-D seismic data.
Date: October 8, 2002
Creator: Ruppel, Stephen C.
Partner: UNT Libraries Government Documents Department

FUNDAMENTALS OF RESERVOIR SURFACE ENERGY AS RELATED TO SURFACE PROPERTIES, WETTABILITY, CAPILLARY ACTION, AND OIL RECOVERY FROM FRACTURED RESERVOIRS BY SPONTANEOUS IMBIBITION

Description: The objective of this project is to increase oil recovery from fractured reservoirs through improved fundamental understanding of the process of spontaneous imbibition by which oil is displaced from the rock matrix into the fractures. Spontaneous imbibition is fundamentally dependent on the reservoir surface free energy but this has never been investigated for rocks. In this project, the surface free energy of rocks will be determined by using liquids that can be solidified within the rock pore space at selected saturations. Thin sections of the rock then provide a two-dimensional view of the rock minerals and the occupant phases. Saturations and oil/rock, water/rock, and oil/water surface areas will be determined by advanced petrographic analysis and the surface free energy which drives spontaneous imbibition will be determined as a function of increase in wetting phase saturation. The inherent loss in surface free energy resulting from capillary instabilities at the microscopic (pore level) scale will be distinguished from the decrease in surface free energy that drives spontaneous imbibition. A mathematical network/numerical model will be developed and tested against experimental results of recovery versus time over broad variation of key factors such as rock properties, fluid phase viscosities, sample size, shape and boundary conditions. Two fundamentally important, but not previously considered, parameters of spontaneous imbibition, the capillary pressure acting to oppose production of oil at the outflow face and the pressure in the nonwetting phase at the no-flow boundary versus time, will also be measured and modeled. Simulation and network models will also be tested against special case solutions provided by analytic models. In the second stage of the project, application of the fundamental concepts developed in the first stage of the project will be demonstrated. The fundamental ideas, measurements, and analytic/numerical modeling will be applied to mixed-wet rocks. Imbibition measurements will include ...
Date: April 1, 2005
Creator: Morrow, Norman R.; Fischer, Herbert; Li, Yu; Mason, Geoffrey; Ruth, Douglas; Seth, Siddhartha et al.
Partner: UNT Libraries Government Documents Department

FUNDAMENTALS OF RESERVOIR SURFACE ENERGY AS RELATED TO SURFACE PROPERTIES, WETTABILITY, CAPILLARY ACTION, AND OIL RECOVERY FROM FRACTURED RESERVOIRS BY SPONTANEOUS IMBIBITION

Description: The objective of this project is to increase oil recovery from fractured reservoirs through improved fundamental understanding of the process of spontaneous imbibition by which oil is displaced from the rock matrix into the fractures. Spontaneous imbibition is fundamentally dependent on the reservoir surface free energy but this has never been investigated for rocks. In this project, the surface free energy of rocks will be determined by using liquids that can be solidified within the rock pore space at selected saturations. Thin sections of the rock then provide a two-dimensional view of the rock minerals and the occupant phases. Saturations and oil/rock, water/rock, and oil/water surface areas will be determined by advanced petrographic analysis and the surface free energy which drives spontaneous imbibition will be determined as a function of increase in wetting phase saturation. The inherent loss in surface free energy resulting from capillary instabilities at the microscopic (pore level) scale will be distinguished from the decrease in surface free energy that drives spontaneous imbibition. A mathematical network/numerical model will be developed and tested against experimental results of recovery versus time over broad variation of key factors such as rock properties, fluid phase viscosities, sample size, shape and boundary conditions. Two fundamentally important, but not previously considered, parameters of spontaneous imbibition, the capillary pressure acting to oppose production of oil at the outflow face and the pressure in the nonwetting phase at the no-flow boundary versus time, will also be measured and modeled. Simulation and network models will also be tested against special case solutions provided by analytic models. In the second stage of the project, application of the fundamental concepts developed in the first stage of the project will be demonstrated. The fundamental ideas, measurements, and analytic/numerical modeling will be applied to mixed-wet rocks. Imbibition measurements will include ...
Date: May 1, 2004
Creator: Morrow, Norman R.
Partner: UNT Libraries Government Documents Department

Fundamentals of Reservoir Surface Energy as Related to Surface Properties, Wettability, Capillary Action, and Oil Recovery from Fractured Reservoirs by Spontaneous Imbibition

Description: The objective of this project is to increase oil recovery from fractured reservoirs through improved fundamental understanding of the process of spontaneous imbibition by which oil is displaced from the rock matrix into the fractures. Spontaneous imbibition is fundamentally dependent on the reservoir surface free energy but this has never been investigated for rocks. In this project, the surface free energy of rocks will be determined by using liquids that can be solidified within the rock pore space at selected saturations. Thin sections of the rock then provide a two-dimensional view of the rock minerals and the occupant phases. Saturations and oil/rock, water/rock, and oil/water surface areas will be determined by advanced petrographic analysis and the surface free energy which drives spontaneous imbibition will be determined as a function of increase in wetting phase saturation. The inherent loss in surface free energy resulting from capillary instabilities at the microscopic (pore level) scale will be distinguished from the decrease in surface free energy that drives spontaneous imbibition. A mathematical network/numerical model will be developed and tested against experimental results of recovery versus time over broad variation of key factors such as rock properties, fluid phase viscosities, sample size, shape and boundary conditions. Two fundamentally important, but not previously considered, parameters of spontaneous imbibition, the capillary pressure acting to oppose production of oil at the outflow face and the pressure in the non-wetting phase at the no-flow boundary versus time, will also be measured and modeled. Simulation and network models will also be tested against special case solutions provided by analytic models. In the second stage of the project, application of the fundamental concepts developed in the first stage of the project will be demonstrated. The fundamental ideas, measurements, and analytic/numerical modeling will be applied to mixed-wet rocks. Imbibition measurements will include ...
Date: June 30, 2008
Creator: Morrow, Norman; Fischer, Herbert; Li, Yu; Mason, Geoffrey; Ruth, Douglas; Seth, Siddhartha et al.
Partner: UNT Libraries Government Documents Department

Exploitation and Optimization of Reservoir Performance in Hunton Formation, Oklahoma

Description: West Carney field--one of the newest fields discovered in Oklahoma--exhibits many unique production characteristics. These characteristics include: (1) decreasing water-oil ratio; (2) decreasing gas-oil ratio followed by an increase; (3) poor prediction capability of the reserves based on the log data; and (4) low geological connectivity but high hydrodynamic connectivity. The purpose of this investigation is to understand the principal mechanisms affecting the production, and propose methods by which we can extend the phenomenon to other fields with similar characteristics. In our experimental investigation section, we continue to describe the use of surfactant to alter the wettability of the rock. By altering the wettability, we may be able to recover additional oil through imbibition and gravity drainage process. In our Engineering and Geological Analysis section, we present a new technique to generate alternate permeability distributions at unsampled wells.
Date: January 1, 2006
Creator: Kelkar, Mohan
Partner: UNT Libraries Government Documents Department

Decline curve derivative analysis for homogeneous and composite reservoirs

Description: In this study, the rate decline and rate decline derivatives of a constant pressure well are presented for infinite, constant pressure outer boundary, and closed outer boundary homogeneous reservoirs. A rate derivative type curve is provided for these cases as well. The effects of the dimensionless reservoir exterior radius are discussed. Rate decline and rate decline derivatives of a constant pressure well in an infinite composite reservoir are also presented. For composite reservoirs, the effects of mobility ratios and discontinuity distance on both rate decline and rate decline derivatives are presented. Type curves for dimensionless wellbore flow rate derivatives for infinite composite reservoirs are provided. A new correlating group for the derivative type curve is provided, and is different than the correlating group for the rate type curve presented in the past. Finally, an analysis method that comprises type curve and derivative type curve matching to determine the dimensionless variables is proposed and demonstrated with a simulated example.
Date: June 1, 1987
Creator: Demski, J.A.
Partner: UNT Libraries Government Documents Department

Effects of stratal architecture and diagenesis on reservoir development in the Grayburg formation: SSouth Cowden field, Ector County, Texas. Annual report, 1 October 1994--30 September 1995

Description: This report presents the results of geological characterization studies in a typical Grayburg reservior in the Permian Basin. The work applies geological models developed in outcrop studies to better constrain the geological reservoir framework and heterogeneity in a typical Grayburg reservoir, The South Cowden Grayburg reservoir. This framework provides a strong basis for defining petrophysical and flow unit properties in the reservior and serves as a prototype model for other Grayburg reservoir characterization studies. The Grayburg Formation in the South Cowden field of eastern Ector County displays an internal stratal architecture that typifies Grayburg shallow-water platform successions throughout the Permian Basin. Study of core and wireline logs in South Cowden field documents three orders of cyclicity in the Grayburg. The entire Grayburg constitutes a single long-duration accommodation cycle that commenced with a major sea-level rise. Two major diagenetic events strongly affect reservoir character in some parts of the field. Recrystallized dolomite is developed along vertical burrows in highly cyclic mud-dominated packstones and wackestones of the HFS 4 Grayburg highstand succussion. Later alteration and removal of anhydrite are focused in structurally low sections along the eastern and southern margins of the field.
Date: February 1, 1996
Creator: Ruppel, S. & Bebout, D.
Partner: UNT Libraries Government Documents Department

Analysis of thermally induced permeability enhancement in geothermal injection wells

Description: Reinjection of spent geothermal brine is a common means of disposing of geothermal effluents and maintaining reservoir pressures. Contrary to the predictions of two-fluid models (two-viscosity) of nonisothermal injection, an increase of injectivity, with continued injection, is often observed. Injectivity enhancement and thermally-affected pressure transients are particularly apparent in short-term injection tests at the Los Azufres Geothermal Field, Mexico. During an injection test, it is not uncommon to observe that after an initial pressure increase, the pressure decreases with time. As this typically occurs far below the pressure at which hydraulic fracturing is expected, some other mechanism for increasing the near-bore permeability must explain the observed behavior. This paper focuses on calculating the magnitude of the nearbore permeability changes observed in several nonisothermal injection tests conducted at the Los Azufres Geothermal Field.
Date: February 1, 1987
Creator: Benson, S.M.; Daggett, J.S.; Iglesias, E.; Arellano, V. & Ortiz-Ramirez, J.
Partner: UNT Libraries Government Documents Department