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Geology and thermal regime, geothermal test USA No. 11-36, Grass Valley, Nevada

Description: This report summarizes the results of drilling of an 8,565 foot geothermal test near Leach Hot Springs, Pershing County, Nevada, by Sunoco Energy Development Company. USA No.11-36 is located 500 feet south and 500 feet east of the northwest corner of Section 36, T. 32 N., R. 38 E (Mount Diablo Meridian), elevation 4,573 feet. It was drilled between May 15 and July 2, 1980. USA No.11-36 was deemed unsuccessful, having encountered no temperature higher than 270 F and no significant permeability, and was plugged and abandoned without testing prior to releasing the rig.
Date: August 1, 1980
Creator: Wilde, Walter R. & Koenig, James B.
Partner: UNT Libraries Government Documents Department

Tracer Recovery and Mixing from Two Geothermal Injection-Backflow Studies

Description: Injection-backflow tracer testing on a single well is not a commonly used procedure for geothermal reservoir evaluation, and, consequently, there is little published information on the character or interpretation of tracer recovery curves. Two field experiments were conducted to develop chemical tracer procedures for use with injection-backflow testing, one on the fracture-permeability Raft River reservoir and the other on the matrix-permeability East Mesa reservoir. Results from tests conducted with incremental increases in the injection volume at both East Mesa and Raft River suggests that, for both reservoirs, permeability remained uniform with increasing distance from the well bore. Increased mixing during quiescent periods, between injection and backflow, at Raft River suggest an area near the well bore that has a hydrologic character different from the far well bore environment. Increased flow rates for East Mesa testing resulted in a general decrease in mixing. Comparison of recovery curves from the Raft River reservoir with those from the East Mesa reservoir suggests that mixing is greatest, and therefore permeability is greatest, in the fractured reservoir. These test results indicate that injection-backflow testing with tracers can be used successfully to characterize flow in the near-well bore environment.
Date: December 15, 1983
Creator: Capuano, R.M.; Adams, M.C. & Wright, P.M.
Partner: UNT Libraries Government Documents Department

Session: Hot Dry Rock

Description: This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of four presentations: ''Hot Dry Rock - Summary'' by George P. Tennyson, Jr.; ''HDR Opportunities and Challenges Beyond the Long Term Flow Test'' by David V. Duchane; ''Start-Up Operations at the Fenton Hill HDR Pilot Plant'' by Raymond F. Ponden; and ''Update on the Long-Term Flow Testing Program'' by Donald W. Brown.
Date: January 1, 1992
Creator: Tennyson, George P., Jr.; Duchane, David V.; Ponden, Raymond F. & Brown, Donald W.
Partner: UNT Libraries Government Documents Department

Ninth workshop on geothermal reservoir engineering: Proceedings

Description: The attendance at the Workshop was similar to last year's with 123 registered participants of which 22 represented 8 foreign countries. A record number of technical papers (about 60) were submitted for presentation at the Workshop. The Program Committee, therefore, decided to have several parallel sessions to accommodate most of the papers. This format proved unpopular and will not be repeated. Many of the participants felt that the Workshop lost some of its unique qualities by having parallel sessions. The Workshop has always been held near the middle of December during examination week at Stanford. This timing was reviewed in an open discussion at the Workshop. The Program Committee subsequently decided to move the Workshop to January. The Tenth Workshop will be held on January 22-24, 1985. The theme of the Workshop this year was ''field developments worldwide''. The Program Committee addressed this theme by encouraging participants to submit field development papers, and by inviting several international authorities to give presentations at the Workshop. Field developments in at least twelve countries were reported: China, El Salvador, France, Greece, Iceland, Italy, Japan, Kenya, Mexico, New Zealand, the Philippines, and the United States. There were 58 technical presentations at the Workshop, of which 4 were not made available for publication. Several authors submitted papers not presented at the Workshop. However, these are included in the 60 papers of these Proceedings. The introductory address was given by Ron Toms of the U.S. Department of Energy, and the banquet speaker was A1 Cooper of Chevron Resources Company. An important contribution was made to the Workshop by the chairmen of the technical sessions. Other than Stanford Geothermal Program faculty members, they included: Don White (Field Developments), Bill D'Olier (Hydrothermal Systems), Herman Dykstra (Well Testing), Karsten Pruess (Well Testing), John Counsil (Reservoir Chemistry), Malcolm Mossman (Reservoir ...
Date: December 15, 1983
Creator: Ramey, H. J., Jr.; Kruger, P.; Miller, F.G.; Horne, R.N.; Brigham, W.E. & Gudmundsson, J.S. (Stanford Geothermal Program)
Partner: UNT Libraries Government Documents Department

Session 20: Injection Overview

Description: The test program was initiated at the Raft River Geothermal Field in southern Idaho in September 1982. A series of eight short-term injection and backflow tests, followed by a long-term injection test, were conducted on one well in the field. Tracers were added during injection and monitored during backflow as well. The principal objective was to determine if tracers could be effectively used as a means to assess reservoir characteristics in a one-well test. The test program resulted in a unique data set which shows promise as a means to improve understanding of the reservoir characteristics. In December 1982, an RFP was issued to obtain an industrial partner to obtain follow-on data on the injection/backflow technique in a second field, and to study any alternate advanced concepts for injection testing which the industrial community might recommend. The East Mesa Geothermal Field was selected for the second test series. Two wells were utilized for testing, and a series of ten tests were conducted in July and August 1983, aimed principally at further evaluation of the injection/backflow technique.
Date: December 1, 1983
Creator: Prestwich, Susan
Partner: UNT Libraries Government Documents Department

Low-to-moderate temperature hydrothermal reservoir engineering program plan

Description: The objective of this program is to assure that appropriate methods of reservoir testing and analysis are available to facilitate the development and utilization of low-to-moderate temperature (< 150 C) hydrothermal resources by private industry. A major impediment to the commercialization of low-to-moderate temperature hydrothermal resources is the lack of confidence that the reservoir is adequately large and that it will satisfactorily produce during the life of the project. These resources cannot generally be developed for economic electrical generation; most will be developed for small-scale, direct heat applications. To increase reservoir confidence, there is a need for low cost methods for the prediction of long-term reservoir performance. The high permeabilities, lower pressures and low heat content of these resources make much of the technology developed for high temperature reservoirs inappropriate or unnecessarily expensive when applied to single phase systems. Frequently, modified groundwater analysis techniques are more applicable. This program develops cost-effective reservoir testing and analysis methods that can be readily applied to low-to-moderate temperature reservoirs. The program will aid and accelerate the development of the known low-to-moderate temperature hydrothermal resources in the US. Development of energy associated with these resources (72% of the total identified) has the potential to offset 6 x 10{sup 13} barrels of oil (USGS Circular 790).
Date: July 1, 1982
Partner: UNT Libraries Government Documents Department

Fracture Detection and Mapping

Description: Because the costs of drilling, completing, and testing a well can be extremely high, it is important to develop better tools and methods for locating high permeability zones prior to drilling, and to develop better tools and methods for identifying and characterizing major fracture zones during the drilling and well testing stages. At the recommendation of the LBL Industry Review Panel on Geothermal Reservoir Technology, we organized and convened a one-day workshop this past July to discuss various aspects of DOE's current and planned activities in fracture detection, to review the geothermal industry's near-term and long-term research needs, to determine the priority of those needs, to disseminate to industry the status of research in progress, and to discuss the possibility of future joint research between industry and DOE. In this paper we present a brief overview of the workshop from the perspective of those who participated in it and provided us with written comments to a questionnaire that was distributed.
Date: January 21, 1986
Creator: Goldstein, Norman E. & Iovenitti, Joseph L.
Partner: UNT Libraries Government Documents Department

Well Test Analysis and Improved Models for Geopressured-Geothermal Systems

Description: In accordance with the S-CUBED Subcontract Work Statement, S-CUBED has concentrated on the synthesis, correlation and analysis of all pertinent data from the Department of Energy (DOE) geopressured-geothermal research wells undergoing testing during the contract period. This work has included the development of reservoir simulation models for the geopressured-geothermal resource in hydrological connection with each well. Existing S-CUBED simulation techniques have been applied to develop, update and improve the models for the reservoirs tested. During the contract period, data have been available from the Gladys McCall, Pleasant Bayou and Hulin test wells. S-CUBED has also contributed to the design of the well tests and participated in DOE's planning and review meetings in support of the geopressured-geothermal program. Detailed technical Topical Reports have been prepared and issued as appropriate during the contract period as referenced in the following summary of the work performed during the final year of the S-CUBED Subcontract to UTA.
Date: December 1, 1990
Creator: Riney, T.D.
Partner: UNT Libraries Government Documents Department

Numerical simulation of the Sumikawa geothermal field in the natural state

Description: This paper presents some results from a numerical simulation study of the natural state of the liquid-dominated high-temperature Sumikawa geothermal prospect (Pritchett et. al., 1989). Sumikawa is located in the Hachimantai volcanic zone of the Sengan thermal area in northern Honshu, Japan. Exploratory studies have been in progress at Sumikawa since 1981 by Mitsubishi Materials Corporation (MMC) and Mitsubishi Gas Chemical Corporation (MGC); this comprehensive program incorporates a variety of geochemical and geophysical surveys and an extensive preliminary drilling investigation (now exceeding sixteen wells). The drilling program has revealed a complex geological structure and has made possible a very thorough pressure-transient testing program involving both single-well and long-term interference tests. These exploratory studies have been carried out jointly by MMC and NEDO (the New Energy and Industrial Technology Development Organization, an agency of the Japanese government).
Date: January 1, 1991
Creator: Pritchett, J. W.; Garg, S. K.; Ariki, K. & Kawano, Y.
Partner: UNT Libraries Government Documents Department

The Bulalo geothermal reservoir Makiling-Banahao area, Philippines

Description: The Bulalo field, located within the Makiling-Banahao geothermal prospect, is being explored and developed by Philippine Geothermal Incorporated (PGI), a branch of the Union Oil Company of California. During the past four years, twenty-eight wells have been drilled and completed in the Bulalo heat anomaly. These wells have defined a large geothermal reservoir characterized by a high-temperature effluent which can be spontaneously produced to generate commercial power. An extensive flow testing program has resulted in the production of over thirteen billion pounds of reservoir effluent. After flashing the steam to atmospheric conditions, nearly seven billion pounds of produced reservoir fluid have been reinjected into the Bulalo reservoir. In spite of the large quantity of reservoir effluent that has been produced and reinjected, insufficient testing has been conducted to determine the total commercial power generating capacity of this large liquid-dominated reservoir. The preliminary estimate of generating capacity has led to the current installation of 220 MW. Field development for the installation of four 55 MW units is in progress. The initial 55 MW unit is scheduled for operation in July, 1979, with Unit 2 to operate in the four quarter of 1979. Continued drilling and production testing up to the initiation of commercial operation will afford periodic reserve updating and confirmation for additional power generating units. After commercial power generation commences, data will be available to establish a more reliable estimate of the Bulalo field potential.
Date: January 1, 1978
Creator: Messer, Philip H. & de las Alas, Val
Partner: UNT Libraries Government Documents Department

Mechanism of reservoir testing

Description: In evaluating geothermal resources we are primarily interested in data on the distribution of temperature and fluid conductivity within the reservoir, the total volume of the productive formations, recharge characteristics and chemical quality of the thermal fluids. While geophysical exploration by surface methods may furnish some data on the temperature field and give indications as to the reservoir volume, they furnish practically no information on the fluid conductivity and production characteristics. Such information will generally have to be obtained by tests performed within the reservoir, primarily by production tests on sufficiently deep wells. Reservoir testing is therefore one of the most important tasks in a general exploration program. In principal, reservoir testing has much in common with conventional geophysical exploration. Although the physical fields applied are to some extent different, they face the same type of selection between controlled and natural drives, forward and inverse problem setting, etc. The basic philosophy (Bodvarsson, 1966) is quite similar. In the present paper, they discuss some fundamentals of the theory of reservoir testing where the fluid conductivity field is the primary target. The emphasis is on local and global aspects of the forward approach to the case of liquid saturated (dominated) Darcy type formations. Both controlled and natural driving pressure or strain fields are to be considered and particular emphasis is placed on the situation resulting from the effects of a free liquid surface at the top of the reservoir.
Date: January 1, 1987
Creator: Bodvarsson, Gunnar
Partner: UNT Libraries Government Documents Department

Numerical modeling of the initial state and matching of well test data from the Zunil geothermal field, Guatemala

Description: A significant amount of geoscientific and reservoir engineering data have been collected from the Zunil geothermal field since 1973. The data have been used to define a conceptual model for the field which has formed the basis for the construction of a three dimensional numerical simulation model. The numerical model has successfully matched both the initial state of the reservoir, as indicated by subsurface temperature and pressure distributions within the presently drilled area, and available well test data. The well test data include short and long term discharge tests and a comprehensive pressure interference test. Calibration of the model will continue during 1991 when the results from drilling and testing of three additional deep wells are available. The model will then be used to study various long term production scenarios for the proposed 15 MW power development.
Date: January 1, 1991
Creator: Menzies, A.J.; Granados, E.E.; Sanyal, .K.; Merida-I., L. & Caicedo-A, A.
Partner: UNT Libraries Government Documents Department

1995 verification flow testing of the HDR reservoir at Fenton Hill, New Mexico

Description: Recent flow testing of the Fenton Hill HDR reservoir has demonstrated that engineered geothermal systems can be shut-in for extended periods of d= with apparently no adverse effects. However, when this particular reservoir at Venton Hill was shut-in for 2 years in a pressurized condition, natural convection within the open-jointed reservoir region appears to have leveled out the preexisting temperature gradient so that the gradient has now approached a condition more typical of liquid-dominated hydrothermal reservoirs which air invariably almost isothermal due to natural convection. As a result of the sudden flow impedance reduction that led to an almost 50% increase in Production flow new the end of the Second Phase of the LTFR in May 1993, we were uncertain as to the state of the reservoir after being shut-in for 2 years. The flow performance observed during the current testing was found to be intermediate between that at-the end of the Second Phase of the LTFT and that following, the subsequent sudden flow increase, implying that whatever caused the sudden reduction in impedance in the first place is probably somehow associated with the cooldown of the reservoir near the injection interval, since temperature recovery at the surfaces of the surrounding open joints is the most obvious phenomenon expected to occur over time within the reservoir.
Date: January 1, 1995
Creator: Brown, D.
Partner: UNT Libraries Government Documents Department


Description: A coordinated program for the development of improved cements specifically designed for geothermal well applications was initiated in April 1976. A successful program will lead to a major advance in the technology required to economically utilize geothermal energy. The goals for the overall program are as follows: (1) Preparation of an integrated research and development plan for the investigation of new well-cementing materials specifically designed for geothermal well applications. (2) To provide the technical basis for the development, testing, and practical demonstration of high-temperature cementing materials for geothermal wells. (3) Rapid transfer and implementation of the technology in the private sector. To date, a preliminary management plan has been prepared and the state of the art of well cementing is being determined by a series of meetings with companies that develop and utilize the technology.
Date: April 1, 1976
Partner: UNT Libraries Government Documents Department

Higher-order differencing for phase-front propagation in geothermal systems

Description: We are testing higher-order differencing total variation diminishing schemes implemented in the reservoir simulator TOUGH2 to reduce numerical dispersion of phase fronts in geothermal flow problems. The schemes are called total variation diminishing because they employ flux limiters to prevent spurious oscillations that sometimes occur with other higher-order differencing schemes near sharp fronts. Thus it appears that total variation diminishing schemes rely on an implicit assumption that the overall variability of advected quantities stays constant or diminishes with time. We use the Leonard total variation diminishing scheme in two special problems designed to test the applicability of the scheme for cases where this implicit assumption is violated. In the first problem, we investigate the isothermal propagation of a phase front in a composite porous medium where phase saturation increases as the front enters the second medium. In the second problem, we investigate the propagation of a phase front where boiling increases the saturation difference across the front as it propagates. In the composite porous medium problem, we find that spurious phase saturations can arise if the weighting scheme is based on relative permeability; for weighting based on phase saturation, no such oscillation arises. In the boiling front propagation problem, the front position is highly sensitive to weighting scheme, and the Leonard total variation diminishing scheme is more accurate than upstream weighting because it decreases numerical dispersion in the thermal energy equation.
Date: January 9, 1998
Creator: Oldenburg, Curtis & Pruess, Karsten
Partner: UNT Libraries Government Documents Department

Hot dry rock geothermal energy for U.S. electric utilities. Draft final report

Description: In order to bring an electric utility component into the study of hot dry rock geothermal energy called for in the Energy Policy Act of 1992 (EPAct), EPRI organized a one-day conference in Philadelphia on January 14,1993. The conference was planned as the first day of a two-day sequence, by coordinating with the U.S. Geological Survey (USGS) and the U.S. Department of Energy (DOE). These two federal agencies were charged under EPAct with the development of a report on the potential for hot dry rock geothermal energy production in the US, especially the eastern US. The USGS was given lead responsibility for a report to be done in association with DOE. The EPRI conference emphasized first the status of technology development and testing in the U.S. and abroad, i.e., in western Europe, Russia and Japan. The conference went on to address the extent of knowledge regarding the resource base in the US, especially in the eastern half of the country, and then to address some practical business aspects of organizing projects or industries that could bring these resources into use, either for thermal applications or for electric power generation.
Date: June 1, 1993
Partner: UNT Libraries Government Documents Department

HGP-A Wellhead Generator Proof-of-Feasibility Project (Well Test) at HGP-A Site Puna, Hawaii. Volume II. Technical Specifications

Description: The purpose of this project is to provide and secure the well test system complete and ready for use. The project comprises the construction of a chemical treatment system (including caustic and hydrogen peroxide handling systems), new condensate piping, wellhead steam piping modifications, ancillary electrical systems and equipment, instrumentation, site improvements and utilities distribution.
Date: March 1, 1979
Partner: UNT Libraries Government Documents Department

A field example of free surface testing

Description: Theoretical results on free liquid surface dynamics presented by Bodvarsson (1978, this volume), provide the basis for a technique of reservoir probing and testing which can yield results that are supplementary to conventional well testing data. The Laugarnes geothermal area in Iceland which is one of the sources of the Reykjavik District Heating System is a case where both methods are applicable and appear interestingly, to yield quite different results. A brief account of the free surface results is presented.
Date: January 1, 1978
Creator: Bodvarsson, Gunnar & Zais, Elliot
Partner: UNT Libraries Government Documents Department


Description: In bringing you up to date on DOE's geothermal R and D programs, they are going to emphasize first those elements that may be of special interest to a reservoir engineering audience, because the activities in support of an improved understanding of hydrothermal reservoirs deserve attention. Reservoir definition, brine injection, and reservoir stimulation technologies are major elements of the Hydrothermal Research Program, and in total they account for nearly 50% of the fiscal year (FY) 1985 hydrothermal research budget. These elements fall into the essential R and D category; that is, while some basic technologies have been borrowed from the petroleum industry for geothermal service, they are often ill-suited to geothermal requirements, and cannot be used without significant technological innovations. Into this category fall the current reservoir technology, brine injection, and reservoir stimulation projects that are listed in Table 1. The reservoir technology projects include: (1) development of methods for characterizing and mapping reservoir parameters, processes, and spatial dimensions; (2) development of methods to predict and monitor reservoir changes from fluid extraction; (3) evaluation of existing methods and development of new methods for predicting the location and mapping faults and fractures in geothermal reservoirs; and (4) testing of new analysis techniques using field case studies. Brine injection projects include: (1) development of physical and mathematical models to determine the behavior of geothermal reservoirs during injection; (2) tracer testing to determine rapid flow paths between wells; and (3) analysis of pressure responses in the field to injection into one or more wells.
Date: January 22, 1985
Creator: Mock, J.E. & Marshall, J.R.
Partner: UNT Libraries Government Documents Department

Environmental Assessment of the Hawaii Geothermal Project Well Flow Test Program

Description: The Hawaii Geothermal Project, a coordinated research effort of the University of Hawaii, funded by the County and State of Hawaii, and ERDA, was initiated in 1973 in an effort to identify, generate, and use geothermal energy on the Big Island of Hawaii. A number of stages are involved in developing geothermal power resources: exploration, test drilling, production testing, field development, power plant and powerline construction, and full-scale production. Phase I of the Project, which began in the summer of 1973, involved conducting exploratory surveys, developing analytical models for interpretation of geophysical results, conducting studies on energy recovery from hot brine, and examining the legal and economic implications of developing geothermal resources in the state. Phase II of the Project, initiated in the summer of 1975, centers on drilling an exploratory research well on the Island of Hawaii, but also continues operational support for the geophysical, engineering, and socioeconomic activities delineated above. The project to date is between the test drilling and production testing phase. The purpose of this assessment is to describe the activities and potential impacts associated with extensive well flow testing to be completed during Phase II.
Date: November 1, 1976
Partner: UNT Libraries Government Documents Department

Hydrothermally altered and fractured granite as an HDR reservoir in the EPS-1 borehole, Alsace,

Description: As part of the European Hot Dry Rocks Project, a second exploration borehole, EPS-1, has been cored to a depth of 2227 m at Soultz-sous-Forets (France). The target was a granite beginning at 1417 m depth, overlain by post-Paleozoic sedimentary cover. Structural analysis and petrographic examination of the 800-m porphyritic granite core, have shown that this rock has undergone several periods of hydrothermal alteration and fracturing. More than 3000 natural structures were recorded, whose distribution pattern shows clusters where low-density fracture zones (less than 1 per meter) alternate with zones of high fracture density (more than 20 per meter). Vein alteration, ascribed to paleohydrothermal systems, developed within the hydrothermally altered and highly fractured zones, transforming primary biotite and plagioclase into clay minerals. One of these zones at 2.2 km depth produced a hot-water outflow during coring, indicating the existence of a hydrothermal reservoir. Its permeability is provided by the fracture network and by secondary porosity of the granitic matrix resulting from vein alteration. This dual porosity in the HDR granite reservoir must be taken into account in the design of the heat exchanger, both for modeling the water-rock interactions and for hydraulic testing.
Date: January 1, 1992
Creator: Genter, A. & Traineau, H.
Partner: UNT Libraries Government Documents Department