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• 1. [Image] Interactive Fracture Design Model

  	A computer program is described that can be used to design a fracture stimulation treatment for a geothermal reservoir. The program uses state-of-the-art methods to calculate the temperature of the fracture ...
  	Citation × Citation Citation Abstract Copy Title: Interactive Fracture Design Model Author: Petroleum Training and Technical Services Year: 1980 A computer program is described that can be used to design a fracture stimulation treatment for a geothermal reservoir. The program uses state-of-the-art methods to calculate the temperature of the fracture fluid as a function of time and distance in the fracture. This information is used to determine the temperature dependent properties of the fracture fluid. These fluid properties are utilized to calculate the fracture geometry as a function of time. The fracture geometry and temperature distribution of the fracture fluid are coupled so the subroutines that calculate these distributions have been made interactive Title: Interactive Fracture Design Model Author: Petroleum Training and Technical Services Year: 1980 A computer program is described that can be used to design a fracture stimulation treatment for a geothermal reservoir. The program uses state-of-the-art methods to calculate the temperature of the fracture fluid as a function of time and distance in the fracture. This information is used to determine the temperature dependent properties of the fracture fluid. These fluid properties are utilized to calculate the fracture geometry as a function of time. The fracture geometry and temperature distribution of the fracture fluid are coupled so the subroutines that calculate these distributions have been made interactive Close

• 2. [Image] Geological and Geophysical Analysis of Coso Geothermal Exploration Hole No. 1 (CGEH-1), Coso Hot Springs KGRA, California

  	The Coso Geothermal Exploration Hole number one (CGEH-1) was drilled in the Coso Hot Springs KGRA, California from September 2 to December 2, 1977. Chip samples were collected at ten foot intervals and ...
  	Citation × Citation Citation Abstract Copy Title: Geological and Geophysical Analysis of Coso Geothermal Exploration Hole No. 1 (CGEH-1), Coso Hot Springs KGRA, California Author: Galbraith, R.M. Year: 1978 The Coso Geothermal Exploration Hole number one (CGEH-1) was drilled in the Coso Hot Springs KGRA, California from September 2 to December 2, 1977. Chip samples were collected at ten foot intervals and extensive geophysical logging surveys were conducted to document the geologic character of the geothermal system as penetrated by CGEH-1. The major rock units encountered include a mafic metamorphic sequence and a leucogranite which intruded the metamorphic rocks. Only weak hydrothermal alteration was noted in these rocks. Drillhole surveys and drilling rate data indicate that the geothermal system is structurally controlled and that the drillhole itself was strongly influenced by structural zones. Water chemistry indicates that this geothermal resource is a hot-water rather than a vapor-dominated system. Several geophysical logs were employed to characterize the drillhole geology. The natural gamma and neutron porosity logs indicate gross rock type and the acoustic logs indicate fractured rock and potentially permeable zones. A series of temperature logs run as a function of time during and after the completion of Drilling were most Useful in delineating the zones of maximum heat flux. Convective heat flow and temperatures greater than 350/sup 0/F appear to occur only along an open fracture system encountered between depths of 1850 and 2775 feet. Temperature logs indicate a negative thermal gradient below 3000 feet Title: Geological and Geophysical Analysis of Coso Geothermal Exploration Hole No. 1 (CGEH-1), Coso Hot Springs KGRA, California Author: Galbraith, R.M. Year: 1978 The Coso Geothermal Exploration Hole number one (CGEH-1) was drilled in the Coso Hot Springs KGRA, California from September 2 to December 2, 1977. Chip samples were collected at ten foot intervals and extensive geophysical logging surveys were conducted to document the geologic character of the geothermal system as penetrated by CGEH-1. The major rock units encountered include a mafic metamorphic sequence and a leucogranite which intruded the metamorphic rocks. Only weak hydrothermal alteration was noted in these rocks. Drillhole surveys and drilling rate data indicate that the geothermal system is structurally controlled and that the drillhole itself was strongly influenced by structural zones. Water chemistry indicates that this geothermal resource is a hot-water rather than a vapor-dominated system. Several geophysical logs were employed to characterize the drillhole geology. The natural gamma and neutron porosity logs indicate gross rock type and the acoustic logs indicate fractured rock and potentially permeable zones. A series of temperature logs run as a function of time during and after the completion of Drilling were most Useful in delineating the zones of maximum heat flux. Convective heat flow and temperatures greater than 350/sup 0/F appear to occur only along an open fracture system encountered between depths of 1850 and 2775 feet. Temperature logs indicate a negative thermal gradient below 3000 feet Close

• 3. [Image] Potential of Low-Temperature Geothermal Resources in Northern California. Report No. TR13

  	Economically feasible uses for geothermal heat at temperatures too low for conventional electrical power generation at present are delineated. Several geothermal resource areas in northern California that ...
  	Citation × Citation Citation Abstract Copy Title: Potential of Low-Temperature Geothermal Resources in Northern California. Report No. TR13 Author: Hannah, J.L. Year: 1975 Economically feasible uses for geothermal heat at temperatures too low for conventional electrical power generation at present are delineated. Several geothermal resource areas in northern California that have development potential are described, and applications of the heat found in each area are suggested. Plates are included of the following field study areas: the east side of the Sierra-Cascade Range north of Bishop, and the northern Coast Range from San Francisco Bay to Clear Lake. The counties included in the study area are Mo doc, Lassen, Sierra, Plumas, Placer, Alpine, Mono, Mendocino, Lake, and Sonoma. (LBS) Title: Potential of Low-Temperature Geothermal Resources in Northern California. Report No. TR13 Author: Hannah, J.L. Year: 1975 Economically feasible uses for geothermal heat at temperatures too low for conventional electrical power generation at present are delineated. Several geothermal resource areas in northern California that have development potential are described, and applications of the heat found in each area are suggested. Plates are included of the following field study areas: the east side of the Sierra-Cascade Range north of Bishop, and the northern Coast Range from San Francisco Bay to Clear Lake. The counties included in the study area are Mo doc, Lassen, Sierra, Plumas, Placer, Alpine, Mono, Mendocino, Lake, and Sonoma. (LBS) Close

• 4. [Image] Geothermal Energy Resource Assessment

  	This report covers the objectives and the status of a long-range program to develop techniques for assessing the resource potential of liquid-dominated geothermal systems. Field studies underway in northern ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Energy Resource Assessment Author: Wollenberg, H.A. Year: 1975 This report covers the objectives and the status of a long-range program to develop techniques for assessing the resource potential of liquid-dominated geothermal systems. Field studies underway in northern Nevada comprise a systematic integrated program of geologic, geophysical, and geochemical measurements, necessary to specify a drilling program encompassing heat flow holes, deep calibration holes, and ultimately, deep test wells. The status of Nevada field activities is described. The areas under study are in a region characterized by high heat flow where temperatures at depth in some geothermal systems exceed 180 C. Areas presently being examined include Beowawe Hot Springs in Whirlwind Valley. Buffalo Valley Hot Springs, Leach Hot Springs in Grass Valley, and Kyle Hot Springs in Buena Vista Valley. Geologic studies encompass detailed examinations of structure and lithology to establish the geologic framework of the areas. The geothermal occurrences are characterized by zones of intense fault intersection, which furnish permeable channelways for the introduction of meteoric water into regions of high temperature at depth Title: Geothermal Energy Resource Assessment Author: Wollenberg, H.A. Year: 1975 This report covers the objectives and the status of a long-range program to develop techniques for assessing the resource potential of liquid-dominated geothermal systems. Field studies underway in northern Nevada comprise a systematic integrated program of geologic, geophysical, and geochemical measurements, necessary to specify a drilling program encompassing heat flow holes, deep calibration holes, and ultimately, deep test wells. The status of Nevada field activities is described. The areas under study are in a region characterized by high heat flow where temperatures at depth in some geothermal systems exceed 180 C. Areas presently being examined include Beowawe Hot Springs in Whirlwind Valley. Buffalo Valley Hot Springs, Leach Hot Springs in Grass Valley, and Kyle Hot Springs in Buena Vista Valley. Geologic studies encompass detailed examinations of structure and lithology to establish the geologic framework of the areas. The geothermal occurrences are characterized by zones of intense fault intersection, which furnish permeable channelways for the introduction of meteoric water into regions of high temperature at depth Close

• 5. [Image] Electricity from Hot Dry Rock Geothermal Energy: Technical and Economic Issues

  	Extraction of energy from hot dry rock would make available a nearly unlimited energy source. Some of the technical problems and possible economic tradeoffs involved in a power generating system are examined ...
  	Citation × Citation Citation Abstract Copy Title: Electricity from Hot Dry Rock Geothermal Energy: Technical and Economic Issues Author: Tester, J.W. Year: 1979 Extraction of energy from hot dry rock would make available a nearly unlimited energy source. Some of the technical problems and possible economic tradeoffs involved in a power generating system are examined and possible solutions proposed. An intertemporal optimization computer model of electricity production from a hot dry rock geothermal source has been constructed. The effects of reservoir degradation, variable fluid flow rate, and drilling operations are examined to determine optimal strategies for reservoir management and necessary conditions for economic feasibility Title: Electricity from Hot Dry Rock Geothermal Energy: Technical and Economic Issues Author: Tester, J.W. Year: 1979 Extraction of energy from hot dry rock would make available a nearly unlimited energy source. Some of the technical problems and possible economic tradeoffs involved in a power generating system are examined and possible solutions proposed. An intertemporal optimization computer model of electricity production from a hot dry rock geothermal source has been constructed. The effects of reservoir degradation, variable fluid flow rate, and drilling operations are examined to determine optimal strategies for reservoir management and necessary conditions for economic feasibility Close

• 6. [Image] Research on the Physical Properties of Geothermal Reservoir Rocks. Progress Report 2, September 1, 1976--January 10, 1977

  	In the art of interpretation of geophysical well surveys, empirical correlations between pairs of physical properties of rocks are used. These correlations permit measurements made of one physical property ...
  	Citation × Citation Citation Abstract Copy Title: Research on the Physical Properties of Geothermal Reservoir Rocks. Progress Report 2, September 1, 1976--January 10, 1977 Author: Keller, G.V. Year: 1977 In the art of interpretation of geophysical well surveys, empirical correlations between pairs of physical properties of rocks are used. These correlations permit measurements made of one physical property in a well bore to be interpreted in terms of another physical property which is of more significance in evaluating the reservoir behavior of a rock. Often, these correlations are developed through a series of laboratory measurements because the properties which are needed in evaluating a reservoir cannot be measured directly with the rock in place. In the evaluation of oil and gas reservoirs, interpretations based on such an approach have reached a high degree of development Title: Research on the Physical Properties of Geothermal Reservoir Rocks. Progress Report 2, September 1, 1976--January 10, 1977 Author: Keller, G.V. Year: 1977 In the art of interpretation of geophysical well surveys, empirical correlations between pairs of physical properties of rocks are used. These correlations permit measurements made of one physical property in a well bore to be interpreted in terms of another physical property which is of more significance in evaluating the reservoir behavior of a rock. Often, these correlations are developed through a series of laboratory measurements because the properties which are needed in evaluating a reservoir cannot be measured directly with the rock in place. In the evaluation of oil and gas reservoirs, interpretations based on such an approach have reached a high degree of development Close

• 7. [Image] Planning, Drilling, Logging, and Testing of Energy Extraction Hole EE-1, Phases I and II

  	Energy Extraction Hole No. 1 (EE-1) is the second deep hole drilled into the Precambrian-age granitic rocks of the Jemez Mountains of north-central New Mexico. EE-1 was drilled to intersect a hydraulic ...
  	Citation × Citation Citation Abstract Copy Title: Planning, Drilling, Logging, and Testing of Energy Extraction Hole EE-1, Phases I and II Author: Pettitt, R.A. Year: 1977 Energy Extraction Hole No. 1 (EE-1) is the second deep hole drilled into the Precambrian-age granitic rocks of the Jemez Mountains of north-central New Mexico. EE-1 was drilled to intersect a hydraulic fracture extending outward from near the bottom of previously drilled hole GT-2, thus completing the underground circulation loop required for the hot dry rock geothermal energy extraction experiment. Directional drilling techniques were used to intersect the fracture zone. In addition, high-temperature instrumentation and equipment development, hydraulic fracturing experiments, pressure-flow testing of the fracture systems, and fracture mapping and borehole-ranging technique activities were conducted. The drilling, logging, and testing operations in EE-1 are described Title: Planning, Drilling, Logging, and Testing of Energy Extraction Hole EE-1, Phases I and II Author: Pettitt, R.A. Year: 1977 Energy Extraction Hole No. 1 (EE-1) is the second deep hole drilled into the Precambrian-age granitic rocks of the Jemez Mountains of north-central New Mexico. EE-1 was drilled to intersect a hydraulic fracture extending outward from near the bottom of previously drilled hole GT-2, thus completing the underground circulation loop required for the hot dry rock geothermal energy extraction experiment. Directional drilling techniques were used to intersect the fracture zone. In addition, high-temperature instrumentation and equipment development, hydraulic fracturing experiments, pressure-flow testing of the fracture systems, and fracture mapping and borehole-ranging technique activities were conducted. The drilling, logging, and testing operations in EE-1 are described Close

• 8. [Image] Research on the Physical Properties of Geothermal Reservoir Rock. Quarterly Report.

  	Laboratory measurements of thermal conductivity and capillary pressure have been undertaken for samples of Cenozoic Volcanic rocks collected from the Columbia Plateau Volcanic basin. These measurements ...
  	Citation × Citation Citation Abstract Copy Title: Research on the Physical Properties of Geothermal Reservoir Rock. Quarterly Report. Author: Skokan, C.K. Year: 1978 Laboratory measurements of thermal conductivity and capillary pressure have been undertaken for samples of Cenozoic Volcanic rocks collected from the Columbia Plateau Volcanic basin. These measurements were performed at atmospheric pressure and room temperature. Various methods of measuring thermal conductivity were investigated and finally a flash method was chosen. The equipment was constructed and tested. The results were favorable. Numerous capillary pressure curves were obtained by use of the mercury injection technique. These curves indicate pore structure: pore size, pore distribution, pore volume, and pore geometry. Measurements of this type help to explain variations in rock properties such as seismic velocities and resistivities Title: Research on the Physical Properties of Geothermal Reservoir Rock. Quarterly Report. Author: Skokan, C.K. Year: 1978 Laboratory measurements of thermal conductivity and capillary pressure have been undertaken for samples of Cenozoic Volcanic rocks collected from the Columbia Plateau Volcanic basin. These measurements were performed at atmospheric pressure and room temperature. Various methods of measuring thermal conductivity were investigated and finally a flash method was chosen. The equipment was constructed and tested. The results were favorable. Numerous capillary pressure curves were obtained by use of the mercury injection technique. These curves indicate pore structure: pore size, pore distribution, pore volume, and pore geometry. Measurements of this type help to explain variations in rock properties such as seismic velocities and resistivities Close