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Experimental study of two-phase flow in rough fractures

Description: Two-phase (air-water) flow experiments were conducted in horizontal artificial fractures. The fractures were between glass plates (1 x 0.5 m) artificially roughened by gluing a layer of glass beads of Imm diameter. Three rough fractures were studied: one with the two surfaces in contact, and two without contact. Videotape observations revealed flow structures similar to those observed in two-phase flow in pipes, with structures depending upon the gas and liquid flow rates. The data of flow rate… more
Date: January 1, 1992
Creator: Fourar, M.; Bories, S. & Lenormand, R.
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Partner: UNT Libraries Government Documents Department
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Interference test analysis at the Takigami geothermal field, JP

Description: A long term interference test was conducted under conditions of multiwell variable flow rate at Takigami for about ten months in 1987. The test data have been analyzed with an on-line analysis method on the basis of the linesource solution. This method employs Kalman filtering to process the data and then provides the best estimates of reservoir transmissivity and storativity when a new pressure data at an observation well becomes available. The pressure changes measured at seven observation we… more
Date: January 28, 1993
Creator: Itol, Ryuichi; Fukuda, Michihiro; Jinno, Kenji & Gotoh, Hiroki
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Partner: UNT Libraries Government Documents Department
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Interpretation of Borehole Tides and Other Elastomechanical Oscillatory Phenomena in Geothermal Systems

Description: Ultralow to low-frequency oscillatory phenomena of elastomechanical nature have been observed in a number of geothermal areas. These include pressure and water level oscillations in the tidal frequency range 10{sup -6} to 10{sup -4} Hz (White, 1968), flow oscillations at around 10{sup -3} Hz (Bodvarsson and Bjornsson, 1976) and ground noise in the range 10{sup -1} to 10 Hz (Douze and Sorrel, 1972). The presence of such oscillations conveys certain information on the underlying geothermal system… more
Date: December 14, 1977
Creator: Bodvarsson, Gunnar
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Partner: UNT Libraries Government Documents Department
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Interpretation of interference effects in three production wells in the Kawerau geothermal field, New Zealand

Description: Downhole temperature and pressure, mass flow, and enthalpy measurements on three production wells at Kawerau geothermal field are interpretted to illustrate interference effects between these wells. Feed zone locations within the wells, together with geology and chemistry are discussed. Downhole measurements are made in one well while production flow changes are made on another well to monitor pressure transient effects. The interference effects have implications for planning future production … more
Date: January 24, 1996
Creator: Stevens, Lynell & Koorey, Kevin J.
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Partner: UNT Libraries Government Documents Department
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Interpretation of pre- and post-fracturing well tests in a geothermal reservoir

Description: Pre- and post-fracturing well tests in TG-2 well drilled next to the Matsukawa field are interpreted for evaluating effects of a massive hydraulic fracturing treatment. The interpreted data include multiple-step rate tests, a two-step rate test, and falloff tests. Pressure behaviors of massive hydraulic fracturing are matched by a simulator of dynamic fracture option. Fracture parting pressures can be evaluated from the multiple-step rate test data. The multiple-step rates during the massive hy… more
Date: January 26, 1995
Creator: Arihara, Norio; Fukagawa, Hiroshi; Hyodo, Masami & Abbaszadeh, Maghsood
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Partner: UNT Libraries Government Documents Department
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Interpretation of the return profile of a tracer test in the Thelamork geothermal field, Iceland

Description: As a part of a full scale production test, a long term tracer test was performed in the Thelamork low temperature geothermal system, in N-Iceland. The tracer test was aimed at recovering the transport properties of fractures connecting the injection and production wells. Hence, the estimated parameters might be used in determining the performance of the system under various injection schemes. A qualitative evaluation the tracer return profile showed the presence of strong recirculation effects.… more
Date: January 24, 1996
Creator: Kocabas, I.; Axelsson, G. & Bjornsson, G.
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Partner: UNT Libraries Government Documents Department
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An inverse problem solution to the flow of tracers in naturally fractured reservoirs

Description: This paper presents a solution for the inverse problem to the flow of tracers in naturally fractured reservoirs. The models considered include linear flow in vertical fractures, radial flow in horizontal fractures, and cubic block matrix-fracture geometry. The Rosenbrock method for nonlinear regression used in this study, allowed the estimation of up to six parameters for the cubic block matrix fracture geometry. The nonlinear regression for the three cases was carefully tested against syntetic… more
Date: January 20, 1994
Creator: S., Jetzabeth Ramirez; V., Fernando Samaniego; Rodriguez, Fernando & R., Jesus Rivera
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Partner: UNT Libraries Government Documents Department
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An investigation of radial tracer flow in naturally fractured reservoirs

Description: This study presents a general solution for the radial flow of tracers in naturally fractured reservoirs. Continuous and finite step injection of chemical and radioactive tracers are considered. The reservoir is treated as being composed of two regions: a mobile region where longitudinal dispersion and convection take place and a stagnant region where only diffusion and adsorption are allowed. Radioactive decay is considered in both regions. The model of this study is thoroughly compared to thos… more
Date: January 1, 1991
Creator: Jetzabeth, Ramirez-Sabag; Fernando, Samaniego V.; Jesus, Rivera R. & Rodriguez, Fernando
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Partner: UNT Libraries Government Documents Department
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Japanese Primary Energy Supply and Geophysical Well Logging

Description: Japan is scarce in domestic natural resources. In fact, the degree of dependence on imports of basic raw materials is quite high. This paper describes primary energy supply as a background to the status of geothermal energy developments, and geophysical well logging in geothermal wells. 3 refs., 5 tabs., 5 figs.
Date: December 14, 1977
Creator: Hirakawa, Seiichi
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Partner: UNT Libraries Government Documents Department
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Kamchatka geothermal resources development: Problems and perspectives

Description: There are four long-term exploited geothermal fields in Kamchatka: one steam-water field Pauzhetka (south of Kamchatka peninsula) and three hot water fields: Paratunka (near by town of Petropavlovsk-Kamchatsky) and Esso and Anavgay (center of peninsula). Pauzhetka and Paratunka fields are exploited during almost 28 years. Esso and Anavgay fields are exploited during 25 years. In Pauzhetka 11 MWe geothermal power plant work and on the other fields thermal energy of hot water is directly used. Ka… more
Date: January 24, 1966
Creator: Pashkevich, Roman I.
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Partner: UNT Libraries Government Documents Department
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Laboratory measurement of sorption in porous media

Description: A new apparatus for measuring steam adsorption-desorption isothermally on rock samples has been installed and initial runs made for rock samples from geothermal reservoirs. The amounts adsorbed measured in these experiments are the same order of magnitude as previous experiments.
Date: January 1, 1992
Creator: Harr, M. S.; Pettit, P. & Ramey, J. J., Jr.
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Partner: UNT Libraries Government Documents Department
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Laboratory measurements on reservoir rocks from The Geysers geothermal field

Description: A suite of laboratory measurements have been conducted on Geysers metagraywacke and metashale recovered from a drilled depth of 2599 to 2602 meters in NEGU-17. The tests have been designed to constrain the mechanical and water-storage properties of the matrix material. Various measurements have been made at a variety of pressures and at varying degrees of saturation. Both compressional and shear velocities exhibit relatively little change with effective confining pressure. In all of the samples… more
Date: January 26, 1995
Creator: Boitnott, G.N.
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Partner: UNT Libraries Government Documents Department
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Laboratory studies of injection into horizonal fractures

Description: Most geothermal reservoirs are extensively fractured and injected fluids usually enter the reservoir formation at distinct feed points. As the cold water passes through the hot rock, it is heated, and may be recovered at production wells for power production. The influence of fractures is two-fold. Firstly, preferential pathways exist along major faults and the general motion of fluids away from injection wells is controlled by the effective permeability structure. Secondly, since fractures can… more
Date: January 24, 1996
Creator: Fitzgerald, Shaun D.; Pruess, Karsten & van Rappard, Diederik M.
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Partner: UNT Libraries Government Documents Department
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Liquid-phase dispersion during injection into vapor-dominated reservoirs

Description: The behavior of water injection plumes in vapor-dominated reservoirs is examined. Stressing the similarity to water infiltration in heterogeneous soils, we suggest that everpresent heterogeneities in individual fractures and fracture networks will cause a lateral broadening of descending injection plumes. The process of lateral spreading of liquid phase is viewed in analogy to transverse dispersion in miscible displacement. To account for the postulated “phase dispersion” the conventional two-p… more
Date: January 20, 1994
Creator: Pruess, Karsten
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Partner: UNT Libraries Government Documents Department
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Locating an Active Fault Zone in Coso Geothermal Field by Analyzing Seismic Guided Waves From Microearthquake Data

Description: Active fault systems usually provide high-permeability channels for hydrothermal outflow in geothermal fields. Locating such fault systems is of a vital importance to plan geothermal production and injection drilling, since an active fault zone often acts as a fracture-extensive low-velocity wave guide to seismic waves. We have located an active fault zone in the Coso geothermal field, California, by identifying and analyzing a fault-zone trapped Rayleigh-type guided wave from microearthquake d… more
Date: January 26, 1995
Creator: Lou, M.; Malin, P. E. & Rial, J. A.
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Partner: UNT Libraries Government Documents Department
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Proceedings of the Workshop on Geothermal Reservoir Engineering: 1977

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… more
Date: December 15, 1977
Creator: Ramey, H. J., Jr. & Kruger, P. (eds.)
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Partner: UNT Libraries Government Documents Department
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Results from a discrete fracture network model of a Hot Dry Rock system

Description: The work described represents a move towards better representations of the natural fracture system. The discrete fracture network model used during the study was the NAPSAC code (Grindrod et al, 1992). The goals of the work were to investigate the application of discrete fracture network models to Hot Dry Rock systems, increase the understanding of the basic thermal extraction process and more specifically the understanding of the Rosemanowes Phase 2B system. The aim in applying the work to the… more
Date: January 28, 1993
Creator: Lanyon, G.W.; Batchelor, A.S. & Ledingham, P.
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Partner: UNT Libraries Government Documents Department
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Seventeenth workshop on geothermal reservoir engineering: Proceedings

Description: PREFACE The Seventeenth Workshop on Geothermal Reservoir Engineering was held at Stanford University on January 29-31, 1992. There were one hundred sixteen registered participants which equaled the attendance last year. Participants were from seven foreign countries: Italy, Japan, United Kingdom, France, Belgium, Mexico and New Zealand. Performance of many geothermal fields outside the United States was described in the papers. The Workshop Banquet Speaker was Dr. Raffaele Cataldi. Dr. Cataldi … more
Date: January 31, 1992
Creator: Ramey, Henry J., Jr.; Kruger, Paul; Miller, Frank G.; Horne, Roland N.; Brigham, William E. & Cook, Jean W.
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Partner: UNT Libraries Government Documents Department
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Significance of Crack Opening Monitoring for Determining the Growth Behavior of Hydrofractures

Description: A method for determining the size of a crack induced by hydraulic fracturing is presented. The procedure is based on the measurement of the crack opening displacement and the fracture mechanics approach. The proposed method has been tested by conducting laboratory small-scale hydraulic fracturing tests on a granite. It is shown from the preliminary tests that the method provides a reasonable prediction of experimentally observed crack sizes.
Date: January 28, 1993
Creator: Hashida, Toshiyuki; Sato, Kazushi & Takahashi, Hideaki
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Partner: UNT Libraries Government Documents Department
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Simple numerical simulation for liquid dominated geothermal reservoir

Description: A numerical model for geothermal reservoir has been developed. The model used is based on an idealized, two-dimensional case, where the porous medium is isotropic, nonhomogeneous, filled with saturated liquid. The fluids are assumed to have constant and temperature dependent viscosity. A Boussinesq approximation and Darcy’s law are used. The model will utilize a simple hypothetical geothermal system, i.e. graben within horsts structure, with three layers of different permeabilities. Vorticity p… more
Date: January 24, 1996
Creator: Wintolo, Djoko; Sutrisno; Sudjatmiko & Sudarman, S.
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Partner: UNT Libraries Government Documents Department
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Simulating a challenging water dominated geothermal system: The Cerro Prieto field, Baja California, Mexico

Description: A three dimensional, multiphase, numerical simulation model of the Cerro Prieto field was developed and used to verify that the present installed capacity (620 MW) can be sustained for 30 years and to evaluate the impact of an 80 MW addition to the installed capacity in the NE-E of the field on the present production areas. Cerro Prieto is the largest known water-dominated geothermal reservoir in the world, with more than 175 wells drilled to date and 17 years of production history. Wells here … more
Date: January 1, 1991
Creator: Antunez, E.U.; Menzies, A.J. & Sanyal, S.K.
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Partner: UNT Libraries Government Documents Department
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Simulating the effects of adsorption and capillary forces in geothermal reservoirs

Description: Until recently, geothermal reservoir simulators use flat interface thermodynamics to determine the thermodynamic state of the reservoir. Development of new simulators and the modification of existing ones has now incorporated the physics of curved interface thermodynamics. These simulators account for the effects of sorption and capillary forces. The simulators GSS and TETRAD were used to simulate the performance of a hypothetical vapordominated geothermal reservoir. GSS is a simulator specific… more
Date: January 24, 1996
Creator: Sta. Maria, Roman B. & Pingol, Alponso S.
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Partner: UNT Libraries Government Documents Department
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Simulating wellflow of high-nonocondensable-gas geofluids using laboratory measurements on secondary fluids

Description: An experimental simulation of an actual steam-water geothermal well based on field data obtained in New Zealand is carried out in a two-phase flow facility using dichlorotetrafluoroethane, known commercially as refrigerant 114. The simulation of steam-water flow is accomplished by a similarity theory which is achieved by using appropriate dimensionless numbers; namely, the Mach, Froude, and Reynolds numbers at the flashing front. The theory is used to scale the flow properties from that of wate… more
Date: January 1, 1991
Creator: Laoulache, R.N. & Dipippo, R.
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Partner: UNT Libraries Government Documents Department
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Simulation of Saturated-Unsaturated Deformable Porous Media

Description: A multiphase consolidation theory is presented which considers a three-dimensional deformation field coupled with a three-dimensional hydrologic flow field. The governing system of equations describes the components of displacement, the fluid pressures and the saturations. The system of equations governing saturated-unsaturated consolidation is obtained as a subset of the above equations. A mixed stress-displacement formulation of the governing equations is introduced, and it facilitates handli… more
Date: December 14, 1977
Creator: Safai, Nader M. & Pinder, George F.
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Partner: UNT Libraries Government Documents Department
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