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• 11. [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

• 12. [Image] Assessment of low- to moderate-temperature geothermal resources of Nevada. Final report, April 1978-June 1979

  	The ultimate goal of the project was to produce a geothermal resource map of Nevada that provided detailed information on low- to moderate-temperature geothermal systems, and that also evaluated their ...
  	Citation × Citation Citation Abstract Copy Title: Assessment of low- to moderate-temperature geothermal resources of Nevada. Final report, April 1978-June 1979 Author: Trexler, D.T Year: 1979 The ultimate goal of the project was to produce a geothermal resource map of Nevada that provided detailed information on low- to moderate-temperature geothermal systems, and that also evaluated their potential for direct non-electric utilization. The investigation consisted of these six tasks: edit and verify existing USGS GEOTHERM file for springs and wells in Nevada; supplement GEOTHERM file with NBMG data; digitize the location of springs and wells on 1:250,000 scale maps of Nevada; update water chemistry by sampling areas devoid of data; field check springs and wells designated as hot or warm; and prepare a 1:500,000 scale map of Nevada that evaluates geothermal resource areas of potential for direct use. This report described the completed tasks, delineates problems encountered, and presents additional miscellaneous information that augments the investigation. The information shown on the accompanying map can be divided into two categories: spot data and regional assessment (or potential evaluation). Specific geochemical information, such as temperature, pH, and chemical species, is represented by approximately 300 circle and diamond-shaped symbols. Thirty-seven larger regions were evaluated for their potential for direct-use on the basis of a numerical technique, which is fully described in this report. An additional 15 sites were designated as areas that may provide a basis for investigations, but that lack sufficient data for a detailed potential evaluation at this time. ; NVO-01556-1 Title: Assessment of low- to moderate-temperature geothermal resources of Nevada. Final report, April 1978-June 1979 Author: Trexler, D.T Year: 1979 The ultimate goal of the project was to produce a geothermal resource map of Nevada that provided detailed information on low- to moderate-temperature geothermal systems, and that also evaluated their potential for direct non-electric utilization. The investigation consisted of these six tasks: edit and verify existing USGS GEOTHERM file for springs and wells in Nevada; supplement GEOTHERM file with NBMG data; digitize the location of springs and wells on 1:250,000 scale maps of Nevada; update water chemistry by sampling areas devoid of data; field check springs and wells designated as hot or warm; and prepare a 1:500,000 scale map of Nevada that evaluates geothermal resource areas of potential for direct use. This report described the completed tasks, delineates problems encountered, and presents additional miscellaneous information that augments the investigation. The information shown on the accompanying map can be divided into two categories: spot data and regional assessment (or potential evaluation). Specific geochemical information, such as temperature, pH, and chemical species, is represented by approximately 300 circle and diamond-shaped symbols. Thirty-seven larger regions were evaluated for their potential for direct-use on the basis of a numerical technique, which is fully described in this report. An additional 15 sites were designated as areas that may provide a basis for investigations, but that lack sufficient data for a detailed potential evaluation at this time. ; NVO-01556-1 Close

• 13. [Image] Report of the Geophysical Measurements in Geothermal Wells Workshop, Airport Marina Hotel, Albuquerque, New Mexico, September 17--19, 1975

  	This report presents results of a Workshop on Geophysical Measurements in Geothermal Wells, hosted in Albuquerque, September 17-19, by Sandia Laboratories and jointly sponsored by the United States Geological ...
  	Citation × Citation Citation Abstract Copy Title: Report of the Geophysical Measurements in Geothermal Wells Workshop, Airport Marina Hotel, Albuquerque, New Mexico, September 17--19, 1975 Author: Baker, L.E. Year: 1975 This report presents results of a Workshop on Geophysical Measurements in Geothermal Wells, hosted in Albuquerque, September 17-19, by Sandia Laboratories and jointly sponsored by the United States Geological Survey and the Energy Research and Development Administration. During the workshop, tutorial papers dealing with the geothermal resource, geothermal logging, and high temperature technology were followed by working panel sessions. Three panels deliberated, respectively, well and reservoir parameters, log interpretation, and high temperature technology. In a final session, the reports of the panels were heard and discussed by the full workshop. A summary of the workshop conclusions and recommendations, as well as the complete panel statements, are presented. (auth) Title: Report of the Geophysical Measurements in Geothermal Wells Workshop, Airport Marina Hotel, Albuquerque, New Mexico, September 17--19, 1975 Author: Baker, L.E. Year: 1975 This report presents results of a Workshop on Geophysical Measurements in Geothermal Wells, hosted in Albuquerque, September 17-19, by Sandia Laboratories and jointly sponsored by the United States Geological Survey and the Energy Research and Development Administration. During the workshop, tutorial papers dealing with the geothermal resource, geothermal logging, and high temperature technology were followed by working panel sessions. Three panels deliberated, respectively, well and reservoir parameters, log interpretation, and high temperature technology. In a final session, the reports of the panels were heard and discussed by the full workshop. A summary of the workshop conclusions and recommendations, as well as the complete panel statements, are presented. (auth) Close

• 14. [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 acoustics 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 acoustics 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

• 15. [Image] Evaluation and Design of Downhole Heat Exchangers for Direct Application; Annual Report, May 1, 1976 - July 1, 1977

  	Progress in an experimental and analytical research program to evaluate and improve the design of downhole heat exchangers (DHEs) for direct applications of geothermal energy is reported. Significant progress ...
  	Citation × Citation Citation Abstract Copy Title: Evaluation and Design of Downhole Heat Exchangers for Direct Application; Annual Report, May 1, 1976 - July 1, 1977 Author: Culver, G.G. Year: 1977 Progress in an experimental and analytical research program to evaluate and improve the design of downhole heat exchangers (DHEs) for direct applications of geothermal energy is reported. Significant progress has been achieved in characterizing flows in wells and without perforated casings and DHEs installed, determination of energy extraction rates for conventional DHEs in both cased and uncased wells, and utilization of information obtained to develop and substantiate models of heat transfer within the well. Flow characterization was obtained by experimentally measuring temperature and velocity profiles. In uncased wells, there was a relatively large vertical temperature gradient (approximately 0.5{sup 0}C/m) and insignificant measured vertical flow, while for the same wells when cased the temperature gradient was essentially zero (approximately 0.03{sup 0}C/m) and a large vertically upward flow was measured (9 to 14 cm/s as measured with a hot-film anemometer). These show that a significant connection cell is established after installation of the casing. The energy extraction rates for a conventional DHE both before and after casing of a 60 m deep well was experimentally measured. In the uncased well up to 300 kW was obtained while the cased well produced over 500 kW. Analytical heat transfer models were developed for the cased well both with and without DHEs. For the cased well without a DHE, the model predicts flow rates that agree with the measured value within about 30 percent. Further, the energy extraction rates predicted by the models agree even better with the measured values. These models allow the energy extraction rates of design parameter variations to be evaluated. At this stage, only trends can be shown but with additional substantiation they should produce optimum energy extraction designs Title: Evaluation and Design of Downhole Heat Exchangers for Direct Application; Annual Report, May 1, 1976 - July 1, 1977 Author: Culver, G.G. Year: 1977 Progress in an experimental and analytical research program to evaluate and improve the design of downhole heat exchangers (DHEs) for direct applications of geothermal energy is reported. Significant progress has been achieved in characterizing flows in wells and without perforated casings and DHEs installed, determination of energy extraction rates for conventional DHEs in both cased and uncased wells, and utilization of information obtained to develop and substantiate models of heat transfer within the well. Flow characterization was obtained by experimentally measuring temperature and velocity profiles. In uncased wells, there was a relatively large vertical temperature gradient (approximately 0.5{sup 0}C/m) and insignificant measured vertical flow, while for the same wells when cased the temperature gradient was essentially zero (approximately 0.03{sup 0}C/m) and a large vertically upward flow was measured (9 to 14 cm/s as measured with a hot-film anemometer). These show that a significant connection cell is established after installation of the casing. The energy extraction rates for a conventional DHE both before and after casing of a 60 m deep well was experimentally measured. In the uncased well up to 300 kW was obtained while the cased well produced over 500 kW. Analytical heat transfer models were developed for the cased well both with and without DHEs. For the cased well without a DHE, the model predicts flow rates that agree with the measured value within about 30 percent. Further, the energy extraction rates predicted by the models agree even better with the measured values. These models allow the energy extraction rates of design parameter variations to be evaluated. At this stage, only trends can be shown but with additional substantiation they should produce optimum energy extraction designs Close

• 16. [Image] Equipment Development Report: Borehole-Fluid Sampling Tool

  	The design and development of a tool for collecting fluid samples from hot, deep geothermal boreholes are discussed. This tool has performed satisfactorily in the field at downhole temperatures of 200/sup ...
  	Citation × Citation Citation Abstract Copy Title: Equipment Development Report: Borehole-Fluid Sampling Tool Author: Archuleta, J.R. Year: 1978 The design and development of a tool for collecting fluid samples from hot, deep geothermal boreholes are discussed. This tool has performed satisfactorily in the field at downhole temperatures of 200/sup 0/C and pressures of 34.5 MPa (5000 psi). Assembly and operating instructions are included Title: Equipment Development Report: Borehole-Fluid Sampling Tool Author: Archuleta, J.R. Year: 1978 The design and development of a tool for collecting fluid samples from hot, deep geothermal boreholes are discussed. This tool has performed satisfactorily in the field at downhole temperatures of 200/sup 0/C and pressures of 34.5 MPa (5000 psi). Assembly and operating instructions are included Close

• 17. [Image] Hot Dry Rock Geothermal Energy Development Project: Cablehead Assembly, Equipment Development Report

  	The development, design, and service history of a multiconductor cablehead capable of operation at 275/sup 0/C and 103 MPa (15,000 psi) are discussed. This high-temperature cablehead has been in service ...
  	Citation × Citation Citation Abstract Copy Title: Hot Dry Rock Geothermal Energy Development Project: Cablehead Assembly, Equipment Development Report Author: Archuleta, J.R. Year: 1978 The development, design, and service history of a multiconductor cablehead capable of operation at 275/sup 0/C and 103 MPa (15,000 psi) are discussed. This high-temperature cablehead has been in service for about 18 months; conclusions drawn from this test period are summarized Title: Hot Dry Rock Geothermal Energy Development Project: Cablehead Assembly, Equipment Development Report Author: Archuleta, J.R. Year: 1978 The development, design, and service history of a multiconductor cablehead capable of operation at 275/sup 0/C and 103 MPa (15,000 psi) are discussed. This high-temperature cablehead has been in service for about 18 months; conclusions drawn from this test period are summarized Close

• 18. [Image] Field drilling tests on improved geothermal unsealed roller-cone bits: Final report

  	The development and field testing of a 222 mm (8-3/4 inch) unsealed, insert type, medium hard formation, high-temperature bit are described. Increased performance was gained by substituting improved materials ...
  	Citation × Citation Citation Abstract Copy Title: Field drilling tests on improved geothermal unsealed roller-cone bits: Final report Author: Hendrickson, R.R. Year: 1980 The development and field testing of a 222 mm (8-3/4 inch) unsealed, insert type, medium hard formation, high-temperature bit are described. Increased performance was gained by substituting improved materials in critical bit components. These materials were selected on bases of their high temperature properties, machinability and heat treatment response. Program objectives required that both machining and heat treating could be accomplished with existing rock bit production equipment. Six of the experimental bits were subjected to air drilling at 240/sup 0/C (460/sup 0/F) in Franciscan graywacke at the Geysers (California). Performances compared directly to conventional bits indicate that in-gage drilling time was increased by 70%. All bits at the Geysers are subjected to reaming out-of-gage hole prior to drilling. Under these conditions the experimental bits showed a 30% increase in usable hole drilled, compared with the conventional bits. The materials selected improved roller wear by 200%, friction per wear by 150%, and lug wear by 150%. These tests indicate a potential well cost savings of 4 to 8%. Savings of 12% are considered possible with drilling procedures optimized for the experimental bits; SAND-80-7079 Title: Field drilling tests on improved geothermal unsealed roller-cone bits: Final report Author: Hendrickson, R.R. Year: 1980 The development and field testing of a 222 mm (8-3/4 inch) unsealed, insert type, medium hard formation, high-temperature bit are described. Increased performance was gained by substituting improved materials in critical bit components. These materials were selected on bases of their high temperature properties, machinability and heat treatment response. Program objectives required that both machining and heat treating could be accomplished with existing rock bit production equipment. Six of the experimental bits were subjected to air drilling at 240/sup 0/C (460/sup 0/F) in Franciscan graywacke at the Geysers (California). Performances compared directly to conventional bits indicate that in-gage drilling time was increased by 70%. All bits at the Geysers are subjected to reaming out-of-gage hole prior to drilling. Under these conditions the experimental bits showed a 30% increase in usable hole drilled, compared with the conventional bits. The materials selected improved roller wear by 200%, friction per wear by 150%, and lug wear by 150%. These tests indicate a potential well cost savings of 4 to 8%. Savings of 12% are considered possible with drilling procedures optimized for the experimental bits; SAND-80-7079 Close

• 19. [Image] Geology of the Colado Geothermal Area, Pershing County, Nevada

  	The Colado geothermal area in south-central Pershing County, Nevada is defined by hot water wells in alluvium just west of the West Humboldt Range. Geothermal gradient holes have encountered temperatures ...
  	Citation × Citation Citation Abstract Copy Title: Geology of the Colado Geothermal Area, Pershing County, Nevada Author: Sibbett, B.S. Year: 1980 The Colado geothermal area in south-central Pershing County, Nevada is defined by hot water wells in alluvium just west of the West Humboldt Range. Geothermal gradient holes have encountered temperatures up to 113.5/sup 0/C at a depth of 76 m (250 ft) with a gradient reversal in the alluvium below this depth. The West Humboldt Range consists mainly of Triassic to Jurassic slaty shale to quartzite of the Auld Lang Syne Group. Carbonate rocks of the Jurassic Lovelock Formation have been thrust over pelitic rocks on the south end of the area. Erosional remnants of Tertiary tuffs and sediments overlay the metasediments in the West Humboldt Range. The principal structures are high-angle faults striking north-northwest, northeast and north-south. The horst-to-graben transition along the range front consists of several step faults trending irregularly north. The structural pattern in the west edge of the range probably continues to the west under the Quaterary alluvium where the source of the hot water is located. Thermal waters probably rise along a major fault intersection in the Mesozoic rocks then spread out in an aquifer in the alluvium. Several thrust faults are exposed south of Coal Canyon, and a structural break in the Mesozoic rock exists under the canyon. Several low-angle faults are present north of Coal Canyon but their effect, if any, on the geothermal occurrence is not known; DOE/ID/12079-8; ESL-38 Title: Geology of the Colado Geothermal Area, Pershing County, Nevada Author: Sibbett, B.S. Year: 1980 The Colado geothermal area in south-central Pershing County, Nevada is defined by hot water wells in alluvium just west of the West Humboldt Range. Geothermal gradient holes have encountered temperatures up to 113.5/sup 0/C at a depth of 76 m (250 ft) with a gradient reversal in the alluvium below this depth. The West Humboldt Range consists mainly of Triassic to Jurassic slaty shale to quartzite of the Auld Lang Syne Group. Carbonate rocks of the Jurassic Lovelock Formation have been thrust over pelitic rocks on the south end of the area. Erosional remnants of Tertiary tuffs and sediments overlay the metasediments in the West Humboldt Range. The principal structures are high-angle faults striking north-northwest, northeast and north-south. The horst-to-graben transition along the range front consists of several step faults trending irregularly north. The structural pattern in the west edge of the range probably continues to the west under the Quaterary alluvium where the source of the hot water is located. Thermal waters probably rise along a major fault intersection in the Mesozoic rocks then spread out in an aquifer in the alluvium. Several thrust faults are exposed south of Coal Canyon, and a structural break in the Mesozoic rock exists under the canyon. Several low-angle faults are present north of Coal Canyon but their effect, if any, on the geothermal occurrence is not known; DOE/ID/12079-8; ESL-38 Close

• 20. [Image] Testing Operations Plan: Coso Geothermal Exploratory Hole No. 1 (CGEH-1)

  	Coso Geothermal Exploratory Hole No. 1 (CGEH-1) was drilled to investigate the potential of the Coso Hot Springs Known Geothermal Resource Area (KGRA) in southeastern California. Detailed background information ...
  	Citation × Citation Citation Abstract Copy Title: Testing Operations Plan: Coso Geothermal Exploratory Hole No. 1 (CGEH-1) Author: Nevada Operations Office; Naval Weapons Center, China Lake Year: 1978 Coso Geothermal Exploratory Hole No. 1 (CGEH-1) was drilled to investigate the potential of the Coso Hot Springs Known Geothermal Resource Area (KGRA) in southeastern California. Detailed background information is contained in the drilling plan, ''Coso Geothermal Exploratory Hole No. 1 (CGEH-1),'' NVO-184, dated June 1977. The purpose of this supplement to NVO-184 is to establish a plan of operations for testing the resource after completion of well drilling activities. Major elements of this plan include setting forth the management and organizational concept to be followed, describing the generalized site activities required and the well testing operations, and establishing schedules, environmental considerations, and technical documentation requirements. The objective of this testing is to determine the well productivity and geothermal reservoir parameters. The testing will consist of both static and dynamic measurements. The static measurements will include wellhead pressure monitoring plus downhole temperature and pressure surveys conducted with the well shut in. The dynamic measurements will include downhole and surface pressure, temperature, and flow rate data with the well producing at varying rates. Two types of dynamic tests are contemplated; the first utilizing the James Method and the second utilizing a separator test system, if justified by an evaluation of the resource potential Title: Testing Operations Plan: Coso Geothermal Exploratory Hole No. 1 (CGEH-1) Author: Nevada Operations Office; Naval Weapons Center, China Lake Year: 1978 Coso Geothermal Exploratory Hole No. 1 (CGEH-1) was drilled to investigate the potential of the Coso Hot Springs Known Geothermal Resource Area (KGRA) in southeastern California. Detailed background information is contained in the drilling plan, ''Coso Geothermal Exploratory Hole No. 1 (CGEH-1),'' NVO-184, dated June 1977. The purpose of this supplement to NVO-184 is to establish a plan of operations for testing the resource after completion of well drilling activities. Major elements of this plan include setting forth the management and organizational concept to be followed, describing the generalized site activities required and the well testing operations, and establishing schedules, environmental considerations, and technical documentation requirements. The objective of this testing is to determine the well productivity and geothermal reservoir parameters. The testing will consist of both static and dynamic measurements. The static measurements will include wellhead pressure monitoring plus downhole temperature and pressure surveys conducted with the well shut in. The dynamic measurements will include downhole and surface pressure, temperature, and flow rate data with the well producing at varying rates. Two types of dynamic tests are contemplated; the first utilizing the James Method and the second utilizing a separator test system, if justified by an evaluation of the resource potential Close