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Stimulation and reservoir engineering of geothermal resources. First annual report, June 1, 1977-March 31, 1978

Description: The large geothermal reservoir model has been used to investigate the specific energy extraction capabilities of various production methods and to determine the rate of heat loss from various rock formations. A parallel laboratory and field study in radon analysis is described. In order to quantify the emission rates of radon from reservoir rocks, an experimental apparatus is under construction to provide exact information on the temperature, pressure, and rock property dependence of the radon production. Laboratory cores were used in bench-scale experiments to determine steam/water relative permeability curves for permeable formation; to investigate the property of vapor pressure lowering of water confined in porous media at low saturations; and to determine the effects of high confining pressures and temperatures on the absolute permeability of porous rocks. The well test analysis and educatonal programs are reported. (MHR)
Date: April 1, 1978
Creator: Kruger, P. & Ramey, H.J. Jr.
Partner: UNT Libraries Government Documents Department

Stimulation and reservoir engineering of geothermal resources. Second annual report, July 1, 1978-September 30, 1979

Description: Individual projects are grouped under four main areas of study: energy extraction, bench-scale flow experiments, radon tracer techniques, and well test analysis. The energy extraction experiments concern the efficiency with which the in-place heat and fluids can be produced in the most economical manner. The bench-scale flow experiments cover the results of three models used to examine the properties of flow through porous media at elevated temperature and pressures. Random tracer techniques describe accelerated efforts to field test several geothermal reservoirs by both transient and transect test procedures. The well test analysis section describes several new developments: analysis of earth-tide effects, pressure transient analysis of multilayered systems, interference testing with storage and skin effects, determination of steam-water relative permeability from wellhead data, well test analysis for wells produced at constant pressure, the parallelepiped model, slug test DST analysis, and pressure transient behavior in naturally fractured reservoirs. (MHR)
Date: September 1, 1979
Creator: Kruger, P. & Ramey, H.J. Jr.
Partner: UNT Libraries Government Documents Department

A New Derivative Type-Curve for Pressure Buildup Analysis with Boundary Effects

Description: This study investigates pressure buildup behavior of wells with wellbore storage and skin in bounded circular reservoirs, when inner and outer boundary effects interact to fully or partially dominate the well pressure response. Using dimensionless pressure derivative as the dependent variable, we show that early time response is governed by C{sub D}e{sup 2S} and late time response by r{sub eD}{sup 2}/C{sub D}. Equations are provided to estimate the limits of the intermediate time period, which corresponds to infinite acting radial flow and a semi-log straight line on a pressure-time graph. We present a new buildup derivative type curve, incorporating inner boundary (early-time) and outer boundary (late-time) effects. Applications of this type curve in buildup test design and interpretation are discussed. 2 figs., 8 refs.
Date: January 20, 1987
Creator: Mishra, S. & Ramey, H.J. Jr.
Partner: UNT Libraries Government Documents Department

Effects of confining pressure, pore pressure and temperature on absolute permeability. SUPRI TR-27

Description: This study investigates absolute permeability of consolidated sandstone and unconsolidated sand cores to distilled water as a function of the confining pressure on the core, the pore pressure of the flowing fluid and the temperature of the system. Since permeability measurements are usually made in the laboratory under conditions very different from those in the reservoir, it is important to know the effect of various parameters on the measured value of permeability. All studies on the effect of confining pressure on absolute permeability have found that when the confining pressure is increased, the permeability is reduced. The studies on the effect of temperature have shown much less consistency. This work contradicts the past Stanford studies by finding no effect of temperature on the absolute permeability of unconsolidated sand or sandstones to distilled water. The probable causes of the past errors are discussed. It has been found that inaccurate measurement of temperature at ambient conditions and non-equilibrium of temperature in the core can lead to a fictitious permeability reduction with temperature increase. The results of this study on the effect of confining pressure and pore pressure support the theory that as confining pressure is increased or pore pressure decreased, the permeability is reduced. The effects of confining pressure and pore pressure changes on absolute permeability are given explicitly so that measurements made under one set of confining pressure/pore pressure conditions in the laboratory can be extrapolated to conditions more representative of the reservoir.
Date: October 1, 1981
Creator: Gobran, B.D.; Ramey, H.J. Jr. & Brigham, W.E.
Partner: UNT Libraries Government Documents Department

Geothermal reservoir engineering, second workshop summaries, December 1-3, 1976

Description: Workshop proceedings included the following: (1) During the Overview Session some papers, among others, discussed 'Geothermal Reservoir Engineering Research' and 'Geothermal Reservoir Engineering in Industry'; (2) Session I, Reservoir Physics, included papers on 'Steam Zone Temperature Gradients at the Geysers' and 'Water Influx in a Steam Producing Well'; (3) Session II, Well Testing, included papers on 'Borehole Geophysics in Geothermal Wells--Problems and Progress' and 'Herber-Pressure Interference Study'; (4) Session III, Field Development, included papers on 'A Reservoir Engineering Study of the East Mesa KGRA' and 'Determining the Optimal Rate of Geothermal Energy Extraction'; (5) Session IV, Well Stimulation, included papers on 'Fluid Flow Through a Large Vertical Crack in the Earth's Crust' and 'Explosive Stimulation of Geothermal Wells'; and (6) Session V, Modeling, included papers on 'Steam Transport in Porous Media' and 'Large-Scale Geothermal Field Parameters and Convection Theory.'
Date: December 1, 1976
Creator: Kruger, P. & Ramey, H.J. Jr.
Partner: UNT Libraries Government Documents Department

Geothermal Reservoir Engineering Research

Description: This report first describes reservoir engineering within the broad field of petroleum engineering. The report next describes the general pattern of reservoir engineering in terms of performance observations, hypothesis construction and testing, and reservoir development planning, and emphasizes the importance of searching for the hypothesis about the nature of the reservoir system derived from all known facts instead of a model that includes only selected fact. The history since 1900 of gas, oil, and geothermal reservoir engineering research is briefly described.
Date: December 1, 1976
Creator: Ramey, H.J. Jr. & Miller, Frank G.
Partner: UNT Libraries Government Documents Department

DECLINE CURVE ANALYSIS FOR INFINITE DOUBLE-POROSITY SYSTEMS WITHOUT WELLBORE SKIN

Description: This paper presents a transient pressure analysis method for analyzing the rate decline of a constant pressure well producing in an infinite double-porosity reservoir, without wellbore skin. This analysis method may be used to interpret well test rate data, and to compute the rate behavior of an infinitely acting reservoir that is being produced at constant pressure. The development of the pseudo steady state log-log type curve Is presented along with a hypothetical example of its use. This type curve allows the estimation of the two controlling parameters in double-porosity systems: {lambda} and {omega}. The first parameter, {lambda}, describes the interporosity flow, and the second parameter, {omega} describes the relative fracture storativity. This paper considers the estimation of these two parameters. The estimations of permeabilities and storativities have been described in the past, hence, are not considered. In a double-porosity system, with pseudo steady state interporosity flow, the initial infinite acting rate decline, representing only the fracture system, is followed by a constant rate flow period. The length of this constant rate flow period is controlled by the parameter {omega}. The beginning of this period is controlled by the interporosity flow parameter, {lambda}. Following this constant rate period, the rate resumes an infinite homogeneous decline, representing the total system, fractures and matrix. The parameters {lambda} and {omega} may be estimated from a log-log match of rate data to the type curve. A comparison between rate responses of two transient flowing matrices and the pseudo steady state matrix Is presented. Transient interporosity flow allows the matrix to increase the well flowrate in the early and transition portions of the flow. The final decline, representing the total system, is identical to the decline with a pseudo steady state matrix.
Date: January 22, 1985
Creator: Sageev, A.; Da Prat, G. & Ramey, H. J., Jr.
Partner: UNT Libraries Government Documents Department

Multiphase, Multicomponent Compressibility in Geothermal Reservoir Engineering

Description: Coefficients of compressibilities below the bubble point were computer with a thermodynamic model for single and multicomponent systems. Results showed coefficients of compressibility below the bubble point larger than the gas coefficient of compressibility at the same conditions. Two-phase compressibilities computed in the conventional way are underestimated and may lead to errors in reserve estimation and well test analysis. 10 refs., 9 figs.
Date: January 20, 1987
Creator: Macias-Chapa, L. & Ramey, H. J., Jr.
Partner: UNT Libraries Government Documents Department

The Effect of Temperature on the Absolute Permeability to Distilled Water of Unconsolidated Sand Cores

Description: The work presented herein is a study of the effect of temperature on the absolute permeability to distilled water of unconsolidated sandstones at one confining pressure. The absolute permeability to distilled water of Ottawa silica sand was not dependent on the temperature level.
Date: December 16, 1980
Creator: Sageev, A.; Gobran, B.D.; Brigham, W.E. & Ramey, H.J. Jr.
Partner: UNT Libraries Government Documents Department

Steam distillation effect and oil quality change during steam injection

Description: Steam distillation is an important mechanism which reduces residual oil saturation during steam injection. It may be the main recovery mechanism in steamflooding of light oil reservoirs. As light components are distilled the residual (initial) oil, the residuum becomes heavier. Mixing the distilled components with the initial oil results in a lighter produced oil. A general method has been developed to compute steam distillation yield and to quantify oil quality changes during steam injection. The quantitative results are specific because the California crude data bank was used. But general principles were followed and calculations were based on information extracted from the DOE crude oil assay data bank. It was found that steam distillation data from the literature can be correlated with the steam distillation yield obtained from the DOE crude oil assays. The common basis for comparison was the equivalent normal boiling point. Blending of distilled components with the initial oil results in API gravity changes similar to those observed in several laboratory and field operations.
Date: January 1, 1992
Creator: Lim, K.T.; Ramey, H.J. Jr. & Brigham, W.E.
Partner: UNT Libraries Government Documents Department

SUPRI Heavy Oil Research Program, SUPRI TR 85

Description: This report concerns progress made during the 1990--1991 fiscal year. Information is given an the following projects: (1) A Study of End Effects in Displacement Experiments; (2) Kinetics of In-Situ Combustion; (3) In-Situ Combustion with Metallic Additives; (4) Steam-Foam Studies in the Presence of Residual Oil; (5) Characterization of Surfactants in the Presence of Oil for Steam-Foam Applications; (6) CT Imaging of Steam and Steam Foam Laboratory Experiments; (7) Microvisualization of Foam Flow in Porous Media; (8) Transient Foam Flow in Porous Media with Cat Scanner; (9) Study of Matrix/Fracture Transfer During Steam Injections; (10) Transient Behavior of Gravity Drainage Wells; (11) Multivariate Optimization of Production Systems; (12) Ultrasonic Flowmeter. (VC)
Date: May 1, 1992
Creator: Brigham, W.E.; Ramey, H.J. Jr. & Castanier, L.M.
Partner: UNT Libraries Government Documents Department

SUPRI heavy oil research program

Description: The 14th Annual Report of the SUPRI Heavy Oil Research Program includes discussion of the following topics: (1) A Study of End Effects in Displacement Experiments; (2) Cat Scan Status Report; (3) Modifying In-situ Combustion with Metallic Additives; (4) Kinetics of Combustion; (5) Study of Residual Oil Saturation for Steam Injection and Fuel Concentration for In-Situ Combustion; (6) Analysis of Transient Foam Flow in 1-D Porous Media with Computed Tomography; (7) Steam-Foam Studies in the Presence of Residual Oil; (8) Microvisualization of Foam Flow in a Porous Medium; (9) Three- Dimensional Laboratory Steam Injection Model; (10) Saturation Evaluation Following Water Flooding; (11) Numerical Simulation of Well-to-Well Tracer Flow Test with Nonunity Mobility Ratio.
Date: December 1, 1991
Creator: Aziz, K.; Ramey, H.J. Jr. & Castanier, L.M.
Partner: UNT Libraries Government Documents Department

Research on oil recovery mechanisms in heavy oil reservoirs

Description: The goal of the Stanford University Petroleum Research Institute is to conduct research directed toward increasing the recovery of heavy oils. Presently, SUPRI is working in five main directions: Assess the influence of different reservoir conditions (temperature and pressure) on the absolute and relative permeability to oil and water and on capillary pressure; evaluate the effect of different reservoir parameters on the in-situ combustion process. This project includes the study of the kinetics of the reactions; investigate the mechanisms of the process using commercially available surfactants for reduction of gravity override and channeling of steam; investigate and improve techniques of formation evaluation such as tracer tests and pressure transient tests; and provide technical support for design and monitoring of DOE sponsored or industry initiated field projects.
Date: January 1, 1991
Creator: Brigham, W.E.; Aziz, K. & Ramey, H.J. Jr.
Partner: UNT Libraries Government Documents Department

Third workshop on geothermal reservoir engineering: Proceedings

Description: The Third Workshop on Geothermal Reservoir Engineering convened at Stanford University on December 14, 1977, with 104 attendees from six nations. In keeping with the recommendations expressed by the participants at the Second Workshop, the format of the Workshop was retained, with three days of technical sessions devoted to reservoir physics, well and reservoir testing, field development, and mathematical modeling of geothermal reservoirs. The program presented 33 technical papers, summaries of which are included in these Proceedings. Although the format of the Workshop has remained constant, it is clear from a perusal of the Table of Contents that considerable advances have occurred in all phases of geothermal reservoir engineering over the past three years. Greater understanding of reservoir physics and mathematical representations of vapor-dominated and liquid-dominated reservoirs are evident; new techniques for their analysis are being developed, and significant field data from a number of newer reservoirs are analyzed. The objectives of these workshops have been to bring together researchers active in the various physical and mathematical disciplines comprising the field of geothermal reservoir engineering, to give the participants a forum for review of progress and exchange of new ideas in this rapidly developing field, and to summarize the effective state of the art of geothermal reservoir engineering in a form readily useful to the many government and private agencies involved in the development of geothermal energy. To these objectives, the Third Workshop and these Proceedings have been successfully directed. Several important events in this field have occurred since the Second Workshop in December 1976. The first among these was the incorporation of the Energy Research and Development Administration (ERDA) into the newly formed Department of Energy (DOE) which continues as the leading Federal agency in geothermal reservoir engineering research. The Third Workshop under the Stanford Geothermal Program was supported ...
Date: December 15, 1977
Creator: Ramey, H.J. Jr. & Kruger, P. (eds.)
Partner: UNT Libraries Government Documents Department

Second workshop geothermal reservoir engineering: Proceedings

Description: The Arab oil embargo of 1973 focused national attention on energy problems. A national focus on development of energy sources alternative to consumption of hydrocarbons led to the initiation of research studies of reservoir engineering of geothermal systems, funded by the National Science Foundation. At that time it appeared that only two significant reservoir engineering studies of geothermal reservoirs had been completed. Many meetings concerning development of geothermal resources were held from 1973 through the date of the first Stanford Geothermal Reservoir Engineering workshop December 15-17, 1975. These meetings were similar in that many reports dealt with the objectives of planned research projects rather than with results. The first reservoir engineering workshop held under the Stanford Geothermal Program was singular in that for the first time most participants were reporting on progress inactive research programs rather than on work planned. This was true for both laboratory experimental studies and for field experiments in producing geothermal systems. The Proceedings of the December 1975 workshop (SGP-TR-12) is a remarkable document in that results of both field operations and laboratory studies were freely presented and exchanged by all participants. With this in mind the second reservoir engineering workshop was planned for December 1976. The objectives were again two-fold. First, the workshop was designed as a forum to bring together researchers active in various physical and mathematical branches of the developing field of geothermal reservoir engineering, to give participants a current and updated view of progress being made in the field. The second purpose was to prepare this Proceedings of Summaries documenting the state of the art as of December 1976. The proceedings will be distributed to all interested members of the geothermal community involved in the development and utilization of the geothermal resources in the world. Many notable occurrences took place between the ...
Date: December 3, 1976
Creator: Kruger, P. & Ramey, H.J. Jr. (eds.)
Partner: UNT Libraries Government Documents Department

Research on oil recovery mechanisms in heavy oil reservoirs

Description: The goal of the Stanford University Petroleum Research Institute is to conduct research directed toward increasing the recovery of heavy oils. Presently, SUPRI is working in five main directions: To assess the influence of different reservoir conditions (temperature and pressure) on the absolute and relative permeability to oil and water and on capillary pressure; To evaluate the effect of different reservoir parameters on the in-situ combustion process. This project includes the study of the kinetics of the reactions; To develop and understand the mechanisms of the process using commercially available surfactants for reduction of gravity override and channeling of steam; To develop and improve techniques of formation evaluation such as tracer tests and pressure transient tests; and To provide technical support for design and monitoring of DOE sponsored or industry initiated field projects.
Date: January 1, 1991
Creator: Brigham, W.E.; Aziz, K. & Ramey, H.J. Jr.
Partner: UNT Libraries Government Documents Department

SUPRI (Stanford University Petroleum Research Institute) heavy oil research program

Description: This report is a summary of the work performed under Department of Energy contract FG19-87BC14126 during the period February 22, 1987 to February 21, 1990. During that period the Stanford University Petroleum Research Institute has published twenty-two technical reports and professional papers. This report presents in general terms the scope of work of SUPRI which is divided in five main projects: reservoir properties, in-situ combustion, improvement of steam injection by additives, well-to-well formation evaluation, and field support services. The results obtained during the period of performance of the contract are then presented in the form of abstracts from the technical reports and papers written during the period of performance.
Date: January 1, 1990
Creator: Brigham, W.E.; Ramey, H.J. Jr.; Aziz, K. & Castanier, L.
Partner: UNT Libraries Government Documents Department

Reservoir and injection technology: Geothermal reservoir engineering research at Stanford: Third annual report for the period October 1, 1986 through September 30, 1987: (Final report)

Description: This paper discusses different aspects of geothermal reservoir engineering. General topics covered are: reinjection technology, reservoir technology, and heat extraction. (LSP)
Date: February 1, 1988
Creator: Ramey, H.J. Jr.; Horne, R.N.; Miller, F.G. & Brigham, W.E.
Partner: UNT Libraries Government Documents Department

Geothermal reservoir engineering research at Stanford University. First annual report, October 1, 1980-September 30, 1981

Description: The work on energy extraction experiments concerns the efficiency with which the in-place heat and fluids can be produced. The work on noncondensable gas reservoir engineering covers both the completed and continuing work in these two interrelated research areas: radon emanation from the rock matrix of geothermal reservoirs, and radon and ammonia variations with time and space over geothermal reservoirs. Cooperative research programs with Italy and Mexico are described. The bench-scale experiments and well test analysis section covers both experimental and theoretical studies. The small core model continues to be used for the study of temperature effects on absolute permeability. The unconsolidated sand study was completed at the beginning of this contract period. The Appendices describe some of the Stanford Geothermal program activities that results in interactions with the geothermal community. These occur in the form of SGP Technical Reports, presentations at technical meetings and publications in the open literature.
Date: September 1, 1981
Creator: Brigham, W.E.; Horne, R.N.; Kruger, P.; Miller, F.G. & Ramey, H.J. Jr.
Partner: UNT Libraries Government Documents Department

Geothermal-reservoir engineering research at Stanford University. Second annual report, October 1, 1981-September 30, 1982

Description: Progress in the following tasks is discussed: heat extraction from hydrothermal reservoirs, noncondensable gas reservoir engineering, well test analysis and bench-scale experiments, DOE-ENEL Cooperative Research, Stanford-IIE Cooperative Research, and workshop and seminars. (MHR)
Date: September 1, 1982
Creator: Ramey, H.J. Jr.; Kruger, P.; Horne, R.N.; Brigham, W.E. & Miller, F.G.
Partner: UNT Libraries Government Documents Department

Reservoir technology - geothermal reservoir engineering research at Stanford. Fifth annual report, October 1, 1984-September 30, 1985

Description: The objective is to carry out research on geothermal reservoir engineering techniques useful to the geothermal industry. A parallel objective is the training of geothermal engineers and scientists. The research is focused toward accelerated development of hydrothermal resources through the evaluation of fluid reserves, and the forecasting of field behavior with time. Injection technology is a research area receiving special attention. The program is divided into reservoir definition research, modeling of heat extraction from fractured reservoirs, application and testing of new and proven reservoir engineering technology, and technology transfer. (ACR)
Date: September 1, 1985
Creator: Ramey, H.J. Jr.; Kruger, P.; Horne, R.N.; Miller, F.G. & Brigham, W.E.
Partner: UNT Libraries Government Documents Department