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• 1. [Image] Geothermal Heating System for the Children's Museum of Utah

  	The results of a study to determine the engineering and economic feasibility of using the Wasatch Hot Spring resource for space heating of the Children's Library building are presented. The Wasatch Hot ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Heating System for the Children's Museum of Utah Author: Karlsson, T. Year: 1984 The results of a study to determine the engineering and economic feasibility of using the Wasatch Hot Spring resource for space heating of the Children's Library building are presented. The Wasatch Hot Spring with a reported flow of about 63 gpm (240 l/min) at an average temperature of 104/sup 0/F is not capable of furnishing the needed heat for the Children's Museum building. The underground paths along which the thermal waters flow to their outlets at the Warm Springs Fault are not presently known. It is possible if the thermal water ascends from the deep layers of the earth along the Warm Springs Fault that increased geothermal flow at a higher temperature can be produced by drilling into the fault. Assuming that sufficient geothermal fluid quantity is produced by drilling in the area, an analysis is made of a geothermal heating system for the building based on different fluid temperatures. It is assumed that the present and planned heating systems be left intact with the gas fired boilers taking over during cold periods when the geothermal system fails to provide sufficient heat. Economic analysis shows that the geothermal system is very attractive, even for the lowest geothermal fluid temperature considered (110/sup 0/F) Title: Geothermal Heating System for the Children's Museum of Utah Author: Karlsson, T. Year: 1984 The results of a study to determine the engineering and economic feasibility of using the Wasatch Hot Spring resource for space heating of the Children's Library building are presented. The Wasatch Hot Spring with a reported flow of about 63 gpm (240 l/min) at an average temperature of 104/sup 0/F is not capable of furnishing the needed heat for the Children's Museum building. The underground paths along which the thermal waters flow to their outlets at the Warm Springs Fault are not presently known. It is possible if the thermal water ascends from the deep layers of the earth along the Warm Springs Fault that increased geothermal flow at a higher temperature can be produced by drilling into the fault. Assuming that sufficient geothermal fluid quantity is produced by drilling in the area, an analysis is made of a geothermal heating system for the building based on different fluid temperatures. It is assumed that the present and planned heating systems be left intact with the gas fired boilers taking over during cold periods when the geothermal system fails to provide sufficient heat. Economic analysis shows that the geothermal system is very attractive, even for the lowest geothermal fluid temperature considered (110/sup 0/F) 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 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

• 3. [Image] Geothermal Investigations in Idaho. Part 8. Heat Flow Study of the Snake River Plain Region, Idaho

  	The Snake River Plain of Idaho has recent lava flows and a large number of thermal springs and wells. A heat flow study was initiated which, together with available geological and geophysical information, ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Investigations in Idaho. Part 8. Heat Flow Study of the Snake River Plain Region, Idaho Author: Brott, C.A. Year: 1976 The Snake River Plain of Idaho has recent lava flows and a large number of thermal springs and wells. A heat flow study was initiated which, together with available geological and geophysical information, allows a better definition of the geothermal resource and evaluation of the geothermal potential. Local geothermal anomalies were not the objects of this study and have not been studied in detail. The quality of the heat flow values obtained varies as interpretation was necessary to determine geothermal gradients for many of the holes which had disturbances. A major problem in determining the heat flow values is the lack of knowledge of the in situ porosity of the rocks. The heat flow values obtained for the Eastern Snake River Plain are from shallow wells (< 200 m), hence the heat flow there is low (< 0.5 HFU) because of the water movement in the Snake Plain aquifer. The anomalous regional heat flow pattern around the Snake River Plain, together with other geophysical and geological data, suggest the presence of a major crustal heat source. With the exception of the area of the Snake Plain aquifer, high geothermal gradients were found in all areas of southern Idaho (40 to 100/sup 0/C/km). Temperatures hot enough for space heating can be found most anywhere in the Plain at relatively shallow depths (1 to 2 km). Temperatures hot enough for electrical power generation (200/sup 0/C) can be found beneath southern Idaho almost anywhere at depths of 3 to 4 kilometers. The Plain is fault bounded and hot water circulating along the fault zones from depths can be a very important geothermal resource at shallow depths. The margins of the Plain have the highest heat flow values, are the most faulted, and have possibly the highest geothermal resource potential Title: Geothermal Investigations in Idaho. Part 8. Heat Flow Study of the Snake River Plain Region, Idaho Author: Brott, C.A. Year: 1976 The Snake River Plain of Idaho has recent lava flows and a large number of thermal springs and wells. A heat flow study was initiated which, together with available geological and geophysical information, allows a better definition of the geothermal resource and evaluation of the geothermal potential. Local geothermal anomalies were not the objects of this study and have not been studied in detail. The quality of the heat flow values obtained varies as interpretation was necessary to determine geothermal gradients for many of the holes which had disturbances. A major problem in determining the heat flow values is the lack of knowledge of the in situ porosity of the rocks. The heat flow values obtained for the Eastern Snake River Plain are from shallow wells (< 200 m), hence the heat flow there is low (< 0.5 HFU) because of the water movement in the Snake Plain aquifer. The anomalous regional heat flow pattern around the Snake River Plain, together with other geophysical and geological data, suggest the presence of a major crustal heat source. With the exception of the area of the Snake Plain aquifer, high geothermal gradients were found in all areas of southern Idaho (40 to 100/sup 0/C/km). Temperatures hot enough for space heating can be found most anywhere in the Plain at relatively shallow depths (1 to 2 km). Temperatures hot enough for electrical power generation (200/sup 0/C) can be found beneath southern Idaho almost anywhere at depths of 3 to 4 kilometers. The Plain is fault bounded and hot water circulating along the fault zones from depths can be a very important geothermal resource at shallow depths. The margins of the Plain have the highest heat flow values, are the most faulted, and have possibly the highest geothermal resource potential Close

• 4. [Image] Transient well testing in two-phase geothermal reservoirs

  	A study of well test analysis techniques in two-phase geothermal reservoirs has been conducted using a three-dimensional, two-phase, wellbore and reservoir simulation model. Well tests from Cerro Prieto ...
  	Citation × Citation Citation Abstract Copy Title: Transient well testing in two-phase geothermal reservoirs Author: Aydelotte, S.R. Year: 1980 A study of well test analysis techniques in two-phase geothermal reservoirs has been conducted using a three-dimensional, two-phase, wellbore and reservoir simulation model. Well tests from Cerro Prieto and the Hawaiian Geothermal project have been history matched. Using these well tests as a base, the influence of reservoir permeability, porosity, thickness, and heat capacity, along with flow rate and fracturing were studied. Single and two-phase transient well test equations were used to analyze these tests with poor results due to rapidly changing fluid properties and inability to calculate the flowing steam saturation in the reservoir. The injection of cold water into the reservoir does give good data from which formation properties can be calculated. Title: Transient well testing in two-phase geothermal reservoirs Author: Aydelotte, S.R. Year: 1980 A study of well test analysis techniques in two-phase geothermal reservoirs has been conducted using a three-dimensional, two-phase, wellbore and reservoir simulation model. Well tests from Cerro Prieto and the Hawaiian Geothermal project have been history matched. Using these well tests as a base, the influence of reservoir permeability, porosity, thickness, and heat capacity, along with flow rate and fracturing were studied. Single and two-phase transient well test equations were used to analyze these tests with poor results due to rapidly changing fluid properties and inability to calculate the flowing steam saturation in the reservoir. The injection of cold water into the reservoir does give good data from which formation properties can be calculated. Close

• 5. [Image] Geothermal Modeling of the Raft River Geothermal Field

  	The results to date of chemical modeling of the Raft River KGRA are presented. Earlier work indicated a northwest-southeast anomaly in the contours. Modeling techniques applied to more complete data allowed ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Modeling of the Raft River Geothermal Field Author: Overton, H.L. Year: 1979 The results to date of chemical modeling of the Raft River KGRA are presented. Earlier work indicated a northwest-southeast anomaly in the contours. Modeling techniques applied to more complete data allowed further definition of the anomaly. Models described in this report show the source of various minerals in the geothermal water. There appears to be a regional heat source that gives rise to uniform conductive heat flow in the region, but convective flow is concentrated near the upwelling in the Crook well vicinity. Recommendations are made concerning field expansion and additional work needed to refine the overall reservoir model; EGG-2004 Title: Geothermal Modeling of the Raft River Geothermal Field Author: Overton, H.L. Year: 1979 The results to date of chemical modeling of the Raft River KGRA are presented. Earlier work indicated a northwest-southeast anomaly in the contours. Modeling techniques applied to more complete data allowed further definition of the anomaly. Models described in this report show the source of various minerals in the geothermal water. There appears to be a regional heat source that gives rise to uniform conductive heat flow in the region, but convective flow is concentrated near the upwelling in the Crook well vicinity. Recommendations are made concerning field expansion and additional work needed to refine the overall reservoir model; EGG-2004 Close

• 6. [Image] Geothermal investigations at selected thermal systems of the northern Wasatch Front Weber and Box Elder Counties, Utah. Report of investigation No. 141

  	Numerous thermal springs are present along the Wasatch Front from Utah valley on the south to the state line on the north. These systems are just west of the Wasatch Mountains at the eastern edge of the ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal investigations at selected thermal systems of the northern Wasatch Front Weber and Box Elder Counties, Utah. Report of investigation No. 141 Author: Murphy, P. Year: 1979 Numerous thermal springs are present along the Wasatch Front from Utah valley on the south to the state line on the north. These systems are just west of the Wasatch Mountains at the eastern edge of the Basin and Range physiographic province and within the active seismic zone referred to as the Intermountain Seismic Belt. This Report of Investigation is a summary of UGMS investigations at four northern Wasatch Front geothermal systems: Utah, Crystal (Madsen), and Udy hot springs; and the Little Mountain - south system. All of these resources are deep circulation systems and the water is heated by the normal heat flow of the Basin and Range Province. Heat from volcanic sources is not believed to contribute to the warming of any northern Wasatch Front springs. Data collected under the DOE/DGE state coupled program are presented for use by individuals interested in these systems; DOE/ET/28393-18 Title: Geothermal investigations at selected thermal systems of the northern Wasatch Front Weber and Box Elder Counties, Utah. Report of investigation No. 141 Author: Murphy, P. Year: 1979 Numerous thermal springs are present along the Wasatch Front from Utah valley on the south to the state line on the north. These systems are just west of the Wasatch Mountains at the eastern edge of the Basin and Range physiographic province and within the active seismic zone referred to as the Intermountain Seismic Belt. This Report of Investigation is a summary of UGMS investigations at four northern Wasatch Front geothermal systems: Utah, Crystal (Madsen), and Udy hot springs; and the Little Mountain - south system. All of these resources are deep circulation systems and the water is heated by the normal heat flow of the Basin and Range Province. Heat from volcanic sources is not believed to contribute to the warming of any northern Wasatch Front springs. Data collected under the DOE/DGE state coupled program are presented for use by individuals interested in these systems; DOE/ET/28393-18 Close

• 7. [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

• 8. [Image] Site-Specific Analysis of Hybrid Geothermal / Fossil Power Plants Volume One: Roosevelt Hot Springs KGRA

  	The economics of a particular hybrid plant must be evaluated with respect to a specific site. This volume focuses on the Roosevelt Hot Springs KGRA. The temperature, pressure, and flow rate data given ...
  	Citation × Citation Citation Abstract Copy Title: Site-Specific Analysis of Hybrid Geothermal / Fossil Power Plants Volume One: Roosevelt Hot Springs KGRA Author: Burbank City Public Service Dept., CA (USA) Year: 1977 The economics of a particular hybrid plant must be evaluated with respect to a specific site. This volume focuses on the Roosevelt Hot Springs KGRA. The temperature, pressure, and flow rate data given suggests the site deserves serious consideration for a hybrid plant. Key siting considerations which must be addressed before an economic judgment can be attempted are presented as follows: the availability, quality, and cost of coal; the availability of water; and the availability of transmission. Seismological and climate factors are presented Title: Site-Specific Analysis of Hybrid Geothermal / Fossil Power Plants Volume One: Roosevelt Hot Springs KGRA Author: Burbank City Public Service Dept., CA (USA) Year: 1977 The economics of a particular hybrid plant must be evaluated with respect to a specific site. This volume focuses on the Roosevelt Hot Springs KGRA. The temperature, pressure, and flow rate data given suggests the site deserves serious consideration for a hybrid plant. Key siting considerations which must be addressed before an economic judgment can be attempted are presented as follows: the availability, quality, and cost of coal; the availability of water; and the availability of transmission. Seismological and climate factors are presented Close

• 9. [Image] Assessment of geothermal resources of Caliente, Nevada

  	An assessment of the geothermal resources of Caliente, Nevada was made to provide information on resource characteristics and to site 2 (two) 500 ft (152 m) test wells to confirm the resource. The strategy ...
  	Citation × Citation Citation Abstract Copy Title: Assessment of geothermal resources of Caliente, Nevada Author: Trexler, D.T. Year: 1980 An assessment of the geothermal resources of Caliente, Nevada was made to provide information on resource characteristics and to site 2 (two) 500 ft (152 m) test wells to confirm the resource. The strategy used in the resource assessment employed a logical sequence of work elements that included 1) baseline data collection, 2) field investigations, 3) laboratory analyses and 4) data interpretation and synthesis. Airphoto interpretation indicated that a series of normal faults produced a stepped arrangement in the canyon walls on the west side of Meadow Valley Wash north of downtown Caiente. This area coincides with the area of known geothermal occurrences. Temperature measurements in existing wells indicate a rapid cooling of the geothermal waters as they mix with cold groundwater flows in Meadow Valley Wash. Soil mercury analyses range from 15 ppB to as high as 120 ppB. Trends in soil mercury content may indicate the presence of buried faults. Temperature measured in 2-meter deep auger holes indicated temperatures as high as 40/sup 0/C in an area north of the Lincoln County Medical Facility. Interpretation of chemical analyses, both major and minor, of waters collected from wells and streams in the area failed to conclusively show any mechanisms for the mixing of thermal and nonthermal waters. The selection of sites for the 2 (two) 500 ft (152 m) reservoir confirmation wells was made using the results of temperature surveys, geologic structure and historic observations; DOE/NV/10039-1 Title: Assessment of geothermal resources of Caliente, Nevada Author: Trexler, D.T. Year: 1980 An assessment of the geothermal resources of Caliente, Nevada was made to provide information on resource characteristics and to site 2 (two) 500 ft (152 m) test wells to confirm the resource. The strategy used in the resource assessment employed a logical sequence of work elements that included 1) baseline data collection, 2) field investigations, 3) laboratory analyses and 4) data interpretation and synthesis. Airphoto interpretation indicated that a series of normal faults produced a stepped arrangement in the canyon walls on the west side of Meadow Valley Wash north of downtown Caiente. This area coincides with the area of known geothermal occurrences. Temperature measurements in existing wells indicate a rapid cooling of the geothermal waters as they mix with cold groundwater flows in Meadow Valley Wash. Soil mercury analyses range from 15 ppB to as high as 120 ppB. Trends in soil mercury content may indicate the presence of buried faults. Temperature measured in 2-meter deep auger holes indicated temperatures as high as 40/sup 0/C in an area north of the Lincoln County Medical Facility. Interpretation of chemical analyses, both major and minor, of waters collected from wells and streams in the area failed to conclusively show any mechanisms for the mixing of thermal and nonthermal waters. The selection of sites for the 2 (two) 500 ft (152 m) reservoir confirmation wells was made using the results of temperature surveys, geologic structure and historic observations; DOE/NV/10039-1 Close

• 10. [Image] Geothermal direct heat project, Marlin, Texas: Environmental assessment

  	The Federal action addressed is retrofitting a heating and hot water system in a hospital at Marlin, Texas, with a geothermal preheat system. The project will be located within the existing hospital boiler ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal direct heat project, Marlin, Texas: Environmental assessment Year: 1979 The Federal action addressed is retrofitting a heating and hot water system in a hospital at Marlin, Texas, with a geothermal preheat system. The project will be located within the existing hospital boiler room. One supply well will be drilled in an existing adjacent parking lot. Fluid disposal from operation will depend on fluid properties and may be by surface disposal to existing street drains, by surface disposal to a new drainage system, or by injection into a new injection well, depending on total dissolved solids (TDS) content. Environmental impacts of construction are expected to be small because of the existing structures and paved areas. Construction run-off and geothermal flow-test fluid will pass through a small pond in the city park, lowering its water quality, at least temporarily. Construction noise is not expected to be out of character with existing noises around the hospital. Project operation is not expected to produce significant impacts because of the decision point to determine fluid composition prior to designating a disposal method. Injection would be into a saline aquifer, and surface discharge would not appreciably lower water quality in the Brazos River; DOE/EA-0067 Title: Geothermal direct heat project, Marlin, Texas: Environmental assessment Year: 1979 The Federal action addressed is retrofitting a heating and hot water system in a hospital at Marlin, Texas, with a geothermal preheat system. The project will be located within the existing hospital boiler room. One supply well will be drilled in an existing adjacent parking lot. Fluid disposal from operation will depend on fluid properties and may be by surface disposal to existing street drains, by surface disposal to a new drainage system, or by injection into a new injection well, depending on total dissolved solids (TDS) content. Environmental impacts of construction are expected to be small because of the existing structures and paved areas. Construction run-off and geothermal flow-test fluid will pass through a small pond in the city park, lowering its water quality, at least temporarily. Construction noise is not expected to be out of character with existing noises around the hospital. Project operation is not expected to produce significant impacts because of the decision point to determine fluid composition prior to designating a disposal method. Injection would be into a saline aquifer, and surface discharge would not appreciably lower water quality in the Brazos River; DOE/EA-0067 Close

• 11. [Image] Hot Dry Rock Energy Extraction Field Test: 75 Days of Operation of a Prototype Reservoir at Fenton Hill, Segment 2 of Phase I

  	Results from the first extensive field test of a man-made hot dry rock (HDR) geothermal reservoir in low permeability crystalline rock are presented. A reservoir with a small heat transfer area was utilized ...
  	Citation × Citation Citation Abstract Copy Title: Hot Dry Rock Energy Extraction Field Test: 75 Days of Operation of a Prototype Reservoir at Fenton Hill, Segment 2 of Phase I Author: Tester, J.W. (ed.) Year: 1979 Results from the first extensive field test of a man-made hot dry rock (HDR) geothermal reservoir in low permeability crystalline rock are presented. A reservoir with a small heat transfer area was utilized to study the characteristics of a prototype HDR system over a shortened lifetime. The resulting accelerated thermal drawdown was modeled to yield an effective area of 8000 m/sup 2/. In addition to the thermal effects, this test provided an opportunity to examine equipment operation, water permeation into the formation, geochemical interaction between the circulating fluid and the rock and flow characteristics including impedance and residence time distributions. Continuous monitoring for induced seismic effects showed that no activity to a Richter threshold of -1.0 was detected during the 75-day experiment Title: Hot Dry Rock Energy Extraction Field Test: 75 Days of Operation of a Prototype Reservoir at Fenton Hill, Segment 2 of Phase I Author: Tester, J.W. (ed.) Year: 1979 Results from the first extensive field test of a man-made hot dry rock (HDR) geothermal reservoir in low permeability crystalline rock are presented. A reservoir with a small heat transfer area was utilized to study the characteristics of a prototype HDR system over a shortened lifetime. The resulting accelerated thermal drawdown was modeled to yield an effective area of 8000 m/sup 2/. In addition to the thermal effects, this test provided an opportunity to examine equipment operation, water permeation into the formation, geochemical interaction between the circulating fluid and the rock and flow characteristics including impedance and residence time distributions. Continuous monitoring for induced seismic effects showed that no activity to a Richter threshold of -1.0 was detected during the 75-day experiment Close

• 12. [Image] Petrology of the Quaternary Volcanics of the Roosevelt KGRA, and Adjoining Area, Utah. Final Report, Volume 1

  	The Roosevelt KGRA (Known Geothermal Resource Area) located near Milford, Utah, is associated with a suite of quaternary silicic volcanics distributed for 15 km along the crest and western flank of the ...
  	Citation × Citation Citation Abstract Copy Title: Petrology of the Quaternary Volcanics of the Roosevelt KGRA, and Adjoining Area, Utah. Final Report, Volume 1 Author: Nash, W.P. Year: 1976 The Roosevelt KGRA (Known Geothermal Resource Area) located near Milford, Utah, is associated with a suite of quaternary silicic volcanics distributed for 15 km along the crest and western flank of the Mineral Mountains, a large tertiary granite batholith. The volcanics are high-silica rhyolites and occur as domes, flows and tuffs. Initial eruptions resulted in two flows of low viscosity, phenocryst-poor rhyolite. Later activity consisted of pyroclastic eruptions and the emplacement of at least 9 viscous domes. In addition to abundant glass the rhyolites contain alkali feldspar, plagioclase, biotite, iron-titanium oxides and small amounts of hornblende, allanite, apatite, zircon, sphene and topaz. Magmatic temperatures were about 700C and water fugacities ranged from 350 to 3450 bars. Based on water fugacity calculations it is concluded that there may have been one or more shallow magma chambers in the Mineral Range at depths of about 1.6 km. Title: Petrology of the Quaternary Volcanics of the Roosevelt KGRA, and Adjoining Area, Utah. Final Report, Volume 1 Author: Nash, W.P. Year: 1976 The Roosevelt KGRA (Known Geothermal Resource Area) located near Milford, Utah, is associated with a suite of quaternary silicic volcanics distributed for 15 km along the crest and western flank of the Mineral Mountains, a large tertiary granite batholith. The volcanics are high-silica rhyolites and occur as domes, flows and tuffs. Initial eruptions resulted in two flows of low viscosity, phenocryst-poor rhyolite. Later activity consisted of pyroclastic eruptions and the emplacement of at least 9 viscous domes. In addition to abundant glass the rhyolites contain alkali feldspar, plagioclase, biotite, iron-titanium oxides and small amounts of hornblende, allanite, apatite, zircon, sphene and topaz. Magmatic temperatures were about 700C and water fugacities ranged from 350 to 3450 bars. Based on water fugacity calculations it is concluded that there may have been one or more shallow magma chambers in the Mineral Range at depths of about 1.6 km. Close

• 13. [Image] DHE (Downhole Heat Exchangers)

  	The use of downhole heat exchangers (DHE) for residential or commercial space and domestic water heating and other applications has several desirable features. Systems are nearly or completely passive ...
  	Citation × Citation Citation Abstract Copy Title: DHE (Downhole Heat Exchangers) Author: Culver, G. Year: 1990 The use of downhole heat exchangers (DHE) for residential or commercial space and domestic water heating and other applications has several desirable features. Systems are nearly or completely passive -- that is, no or very little geothermal water or steam is produced from the well either reducing or completely eliminating surface environmental concerns and the need for disposal systems or injection wells. Initial cost of pumps and installation are eliminated or reduced along with pumping power costs and maintenance costs associated with pumping often corrosive geothermal fluids. Many residential and small commercial systems do not require circulating pumps because the density difference in the incoming and outgoing sides of the loop are sufficient to overcome circulating friction losses in the entire system. The major disadvantage of DHEs is their dependence on natural heat flow. In areas where geological conditions provide high permeability and a natural hydraulic gradient, DHEs can provide a substantial quantity of heat. A single 500-ft (152 m) well in Klamath Falls, Oregon, supplies over one megawatt thermal and output is apparently limited by the surface area of pipe that can be installed in the well bore. In contrast, DHEs used in conjunction with heat pumps may supply less than 8 KW from a well of similar depth. Here output is limited by conductive heat flow with perhaps a small contribution from convection near the well bore. The highest capacity DHE reported to date, in Turkey, supplies 6 MW thermal from an 820-ft (250 m) well. There were two main goals for this project. The first was to gather, disseminate and exchange internationally information on DHEs. The second was to perform experiments that would provide insight into well bore/aquifer interaction and thereby provide more information on which to base DHE designs. 27 refs., 31 figs., 3 tabs. Title: DHE (Downhole Heat Exchangers) Author: Culver, G. Year: 1990 The use of downhole heat exchangers (DHE) for residential or commercial space and domestic water heating and other applications has several desirable features. Systems are nearly or completely passive -- that is, no or very little geothermal water or steam is produced from the well either reducing or completely eliminating surface environmental concerns and the need for disposal systems or injection wells. Initial cost of pumps and installation are eliminated or reduced along with pumping power costs and maintenance costs associated with pumping often corrosive geothermal fluids. Many residential and small commercial systems do not require circulating pumps because the density difference in the incoming and outgoing sides of the loop are sufficient to overcome circulating friction losses in the entire system. The major disadvantage of DHEs is their dependence on natural heat flow. In areas where geological conditions provide high permeability and a natural hydraulic gradient, DHEs can provide a substantial quantity of heat. A single 500-ft (152 m) well in Klamath Falls, Oregon, supplies over one megawatt thermal and output is apparently limited by the surface area of pipe that can be installed in the well bore. In contrast, DHEs used in conjunction with heat pumps may supply less than 8 KW from a well of similar depth. Here output is limited by conductive heat flow with perhaps a small contribution from convection near the well bore. The highest capacity DHE reported to date, in Turkey, supplies 6 MW thermal from an 820-ft (250 m) well. There were two main goals for this project. The first was to gather, disseminate and exchange internationally information on DHEs. The second was to perform experiments that would provide insight into well bore/aquifer interaction and thereby provide more information on which to base DHE designs. 27 refs., 31 figs., 3 tabs. Close

• 14. [Image] Atlantic coastal plain geothermal test holes, New Jersey: Hole completion reports

  	A description of the Atlantic Coastal Plains Geothermal Drilling Program and data for the following Geothermal test holes drilled in New Jersey are summarized: Site No. 40, Fort Monmouth; Site No. 41, ...
  	Citation × Citation Citation Abstract Copy Title: Atlantic coastal plain geothermal test holes, New Jersey: Hole completion reports Author: Cobb, L.B. Year: 1979 A description of the Atlantic Coastal Plains Geothermal Drilling Program and data for the following Geothermal test holes drilled in New Jersey are summarized: Site No. 40, Fort Monmouth; Site No. 41, Sea Girt; Site No. 39-A, Forked River; Site No. 38, Atlantic City; and Site No. 36, Cape May; NVO-1558-1 Title: Atlantic coastal plain geothermal test holes, New Jersey: Hole completion reports Author: Cobb, L.B. Year: 1979 A description of the Atlantic Coastal Plains Geothermal Drilling Program and data for the following Geothermal test holes drilled in New Jersey are summarized: Site No. 40, Fort Monmouth; Site No. 41, Sea Girt; Site No. 39-A, Forked River; Site No. 38, Atlantic City; and Site No. 36, Cape May; NVO-1558-1 Close

• 15. [Image] Potential Growth of Electric Power Production from Imperial Valley Geothermal Resources

  	The growth of geothermal electric power operations in Imperial Valley, California is projected over the next 40 years. With commercial power forecast to become available in the 1980's, the scenario considers ...
  	Citation × Citation Citation Abstract Copy Title: Potential Growth of Electric Power Production from Imperial Valley Geothermal Resources Author: Ermak, D.L. Year: 1977 The growth of geothermal electric power operations in Imperial Valley, California is projected over the next 40 years. With commercial power forecast to become available in the 1980's, the scenario considers three subsequent growth rates: 40, 100, and 250 MW per year. These growth rates, along with estimates of the total resource size, result in a maximum level of electric power production ranging from 1000 to 8000 MW to be attained in the 2010 to 2020 time period. Power plant siting constraints are developed and used to make siting patterns for the 400- through 8000-MW level of power production. Two geothermal technologies are included in the scenario: flashed steam systems that produce cooling water from the geothermal steam condensate and emit noncondensable gases to the atmosphere; and high pressure, confined flow systems that inject the geothermal fluid back into the ground. An analysis of the scenario is made with regard to well drilling and power plant construction rates, land use, cooling water requirements, and hydrogen sulfide emissions Title: Potential Growth of Electric Power Production from Imperial Valley Geothermal Resources Author: Ermak, D.L. Year: 1977 The growth of geothermal electric power operations in Imperial Valley, California is projected over the next 40 years. With commercial power forecast to become available in the 1980's, the scenario considers three subsequent growth rates: 40, 100, and 250 MW per year. These growth rates, along with estimates of the total resource size, result in a maximum level of electric power production ranging from 1000 to 8000 MW to be attained in the 2010 to 2020 time period. Power plant siting constraints are developed and used to make siting patterns for the 400- through 8000-MW level of power production. Two geothermal technologies are included in the scenario: flashed steam systems that produce cooling water from the geothermal steam condensate and emit noncondensable gases to the atmosphere; and high pressure, confined flow systems that inject the geothermal fluid back into the ground. An analysis of the scenario is made with regard to well drilling and power plant construction rates, land use, cooling water requirements, and hydrogen sulfide emissions Close

• 16. [Image] Hot-Dry-Rock Geothermal-Energy Development Program. Annual Report, Fiscal Year 1981

  	During fiscal year 1981, activities of the Hot Dry Rock Geothermal Energy Development Program were concentrated in four principal areas: (1) data collection to permit improved estimates of the hot dry ...
  	Citation × Citation Citation Abstract Copy Title: Hot-Dry-Rock Geothermal-Energy Development Program. Annual Report, Fiscal Year 1981 Author: Smith, M.C. (comp.) Year: 1981 During fiscal year 1981, activities of the Hot Dry Rock Geothermal Energy Development Program were concentrated in four principal areas: (1) data collection to permit improved estimates of the hot dry rock geothermal energy resource base of various regions of the United States and of the United States as a whole, combined with detailed investigations of several areas that appear particularly promising either for further energy extraction experiments or for future commercial development; (2) successful completion of a 9-month, continuous, closed-loop, recirculating flow test in the enlarged Phase I System at Fenton Hill, New Mexico - a pressurized-water heat-extraction loop developed in low-permeability granitic rock by hydraulic fracturing; (3) successful completion at a depth of 4084 m (13,933 ft) of well EE-3, the production well of a larger, deeper, and hotter, Phase II System at Fenton Hill. Well EE-3 was directionally drilled with control of both azimuth and inclination. Its inclined section is about 380 m (1250 ft) vertically above the injection well, EE-2, which was completed in FY80; and (4) supporting activities included new developments in downhole instrumentation and equipment, geochemical and geophysical studies, rock-mechanics and fluid-mechanics investigations, computer analyses and modeling, and overall system design. Under an International Energy Agency agreement, the New Energy Development Organization, representing the Government of Japan has joined Kernforschungsanlage-Juelich GmbH, representing the Federal Republic of Germany, and the US Department of Energy as an active participant in the Fenton Hill Hot Dry Rock Project Title: Hot-Dry-Rock Geothermal-Energy Development Program. Annual Report, Fiscal Year 1981 Author: Smith, M.C. (comp.) Year: 1981 During fiscal year 1981, activities of the Hot Dry Rock Geothermal Energy Development Program were concentrated in four principal areas: (1) data collection to permit improved estimates of the hot dry rock geothermal energy resource base of various regions of the United States and of the United States as a whole, combined with detailed investigations of several areas that appear particularly promising either for further energy extraction experiments or for future commercial development; (2) successful completion of a 9-month, continuous, closed-loop, recirculating flow test in the enlarged Phase I System at Fenton Hill, New Mexico - a pressurized-water heat-extraction loop developed in low-permeability granitic rock by hydraulic fracturing; (3) successful completion at a depth of 4084 m (13,933 ft) of well EE-3, the production well of a larger, deeper, and hotter, Phase II System at Fenton Hill. Well EE-3 was directionally drilled with control of both azimuth and inclination. Its inclined section is about 380 m (1250 ft) vertically above the injection well, EE-2, which was completed in FY80; and (4) supporting activities included new developments in downhole instrumentation and equipment, geochemical and geophysical studies, rock-mechanics and fluid-mechanics investigations, computer analyses and modeling, and overall system design. Under an International Energy Agency agreement, the New Energy Development Organization, representing the Government of Japan has joined Kernforschungsanlage-Juelich GmbH, representing the Federal Republic of Germany, and the US Department of Energy as an active participant in the Fenton Hill Hot Dry Rock Project Close

• 17. [Image] Geothermal Reservoir Categorization and Stimulation Study

  	Analyses of the fraction of geothermal wells that are dry (dry-hole fraction) indicate that geothermal reservoirs can be fitted into four basic categories: (i) Quaternary to late Tertiary sediments (almost ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Reservoir Categorization and Stimulation Study Author: Overton, H.L. Year: 1977 Analyses of the fraction of geothermal wells that are dry (dry-hole fraction) indicate that geothermal reservoirs can be fitted into four basic categories: (i) Quaternary to late Tertiary sediments (almost no dry holes); (ii) Quaternary to late Tertiary extrusives (approximately 20 percent dry holes); (iii) Mesozoic or older metamorphic rocks (approximately 25-30 percent dry holes); and (iv) Precambrian or younger rocks (data limited to Roosevelt Springs where 33 percent of the wells were dry). Failure of geothermal wells to flow economically is due mainly to low-permeability formations in unfractured regions. Generally the permeability correlates inversely with the temperature-age product and directly with the original rock porosity and pore size. However, this correlation fails whenever high-stress fields provide vertical fracturing or faulting, and it is the high-stress/low-permeability category that is most amenable to artificial stimulation by hydraulic fracturing, propellant fracturing, or chemical explosive fracturing. Category (i) geothermal fields (e.g., Cerro Prieto, Mexico; Niland, CA; East Mesa, CA) are not recommended for artificial stimulation because these younger sediments almost always produce warm or hot water. Most geothermal fields fit into category (ii) (e.g., Wairakei, New Zealand; Matsukawa, Japan; Ahuachapan, El Salvador) and in the case of Mt. Home, ID, and Chandler, AZ, possess some potential for stimulation. The Geysers is a category (iii) field, and its highly stressed brittle rocks should make this site amenable to stimulation by explosive fracturing techniques. Roosevelt Springs, UT, Well 9-1 is in category (iv) and is a flow failure. It represents a prime candidate for stimulation by hydraulic fracturing because it has a measured temperature of 227/sup 0/C, is cased and available for experimentation, and is within 900 m of an excellent geothermal producing well Title: Geothermal Reservoir Categorization and Stimulation Study Author: Overton, H.L. Year: 1977 Analyses of the fraction of geothermal wells that are dry (dry-hole fraction) indicate that geothermal reservoirs can be fitted into four basic categories: (i) Quaternary to late Tertiary sediments (almost no dry holes); (ii) Quaternary to late Tertiary extrusives (approximately 20 percent dry holes); (iii) Mesozoic or older metamorphic rocks (approximately 25-30 percent dry holes); and (iv) Precambrian or younger rocks (data limited to Roosevelt Springs where 33 percent of the wells were dry). Failure of geothermal wells to flow economically is due mainly to low-permeability formations in unfractured regions. Generally the permeability correlates inversely with the temperature-age product and directly with the original rock porosity and pore size. However, this correlation fails whenever high-stress fields provide vertical fracturing or faulting, and it is the high-stress/low-permeability category that is most amenable to artificial stimulation by hydraulic fracturing, propellant fracturing, or chemical explosive fracturing. Category (i) geothermal fields (e.g., Cerro Prieto, Mexico; Niland, CA; East Mesa, CA) are not recommended for artificial stimulation because these younger sediments almost always produce warm or hot water. Most geothermal fields fit into category (ii) (e.g., Wairakei, New Zealand; Matsukawa, Japan; Ahuachapan, El Salvador) and in the case of Mt. Home, ID, and Chandler, AZ, possess some potential for stimulation. The Geysers is a category (iii) field, and its highly stressed brittle rocks should make this site amenable to stimulation by explosive fracturing techniques. Roosevelt Springs, UT, Well 9-1 is in category (iv) and is a flow failure. It represents a prime candidate for stimulation by hydraulic fracturing because it has a measured temperature of 227/sup 0/C, is cased and available for experimentation, and is within 900 m of an excellent geothermal producing well Close

• 18. [Image] The Definition of Engineering Development and Research Problems Relating to the Use of Geothermal Fluids for Electric Power Generation and Nonelectric Heating

  	The use of geothermal fluids for electric power generation and nonelectric purposes causes problems not normally encountered when pure water is used for similar purposes. These problems must be identified ...
  	Citation × Citation Citation Abstract Copy Title: The Definition of Engineering Development and Research Problems Relating to the Use of Geothermal Fluids for Electric Power Generation and Nonelectric Heating Author: Apps, J.A. Year: 1977 The use of geothermal fluids for electric power generation and nonelectric purposes causes problems not normally encountered when pure water is used for similar purposes. These problems must be identified and means developed to overcome them before geothermal energy resources can become an important source of electric power or thermal energy in the United States. Research and development projects aimed at solving problems arising from the use of geothermal fluids from known sources in the United States are listed. Problem areas covered are: impact on engineering design caused by chemical, thermodynamic, and transport properties of geothermal fluids; scaling and sludge formation; gases, volatile brine constituents, condensate chemistry; environmental problems. The research projects identified are general in nature and are not site specific. (JGB) Title: The Definition of Engineering Development and Research Problems Relating to the Use of Geothermal Fluids for Electric Power Generation and Nonelectric Heating Author: Apps, J.A. Year: 1977 The use of geothermal fluids for electric power generation and nonelectric purposes causes problems not normally encountered when pure water is used for similar purposes. These problems must be identified and means developed to overcome them before geothermal energy resources can become an important source of electric power or thermal energy in the United States. Research and development projects aimed at solving problems arising from the use of geothermal fluids from known sources in the United States are listed. Problem areas covered are: impact on engineering design caused by chemical, thermodynamic, and transport properties of geothermal fluids; scaling and sludge formation; gases, volatile brine constituents, condensate chemistry; environmental problems. The research projects identified are general in nature and are not site specific. (JGB) Close

• 19. [Image] Delineation of an electrical resistivity anomaly, Malpais area, Beowawe KGRA, Eureka and Lander Counties, Nevada

  	A simple numerical model of previously released bipole-dipole resistivity data shows the margin of the graben to be anomalously conductive below the Malpais. The conductive area has been delineated with ...
  	Citation × Citation Citation Abstract Copy Title: Delineation of an electrical resistivity anomaly, Malpais area, Beowawe KGRA, Eureka and Lander Counties, Nevada Author: Smith, C. Year: 1980 A simple numerical model of previously released bipole-dipole resistivity data shows the margin of the graben to be anomalously conductive below the Malpais. The conductive area has been delineated with data from a dipole-dipole resistivity survey run in April 1980 for this study. Detailed numerical models of these data define a 1250 m wide body with resistivities less than 20 ohm-m that appear to connect The Geysers and the graben boundary. The minimum depth to the conductor is interpreted to be 375 m; its depth extent is undetermined. The electrical data do not resolve whether the anomaly below the Malpais may be the product of a defunct hydrothermal system or the signature of an active system. If thermal gradient data detect an enhanced heat flow anomaly in the same area, the Malpais may be a viable geothermal exploration target within the Beowawe KGRA; DOE/ID/12079-7 Title: Delineation of an electrical resistivity anomaly, Malpais area, Beowawe KGRA, Eureka and Lander Counties, Nevada Author: Smith, C. Year: 1980 A simple numerical model of previously released bipole-dipole resistivity data shows the margin of the graben to be anomalously conductive below the Malpais. The conductive area has been delineated with data from a dipole-dipole resistivity survey run in April 1980 for this study. Detailed numerical models of these data define a 1250 m wide body with resistivities less than 20 ohm-m that appear to connect The Geysers and the graben boundary. The minimum depth to the conductor is interpreted to be 375 m; its depth extent is undetermined. The electrical data do not resolve whether the anomaly below the Malpais may be the product of a defunct hydrothermal system or the signature of an active system. If thermal gradient data detect an enhanced heat flow anomaly in the same area, the Malpais may be a viable geothermal exploration target within the Beowawe KGRA; DOE/ID/12079-7 Close

• 20. [Image] Initial Investigation of Soil Mercury Geochemistry as an Aid to Drill Site Selection in Geothermal Systems

  	A mercury-in-soil survey was conducted at the Roosevelt Hot Springs Known Geothermal Resource Area (KGRA), Utah, to evaluate mercury soil geochemistry as a method of selecting exploration well sites in ...
  	Citation × Citation Citation Abstract Copy Title: Initial Investigation of Soil Mercury Geochemistry as an Aid to Drill Site Selection in Geothermal Systems Author: Capuano, R.M. Year: 1978 A mercury-in-soil survey was conducted at the Roosevelt Hot Springs Known Geothermal Resource Area (KGRA), Utah, to evaluate mercury soil geochemistry as a method of selecting exploration well sites in a hot-water geothermal system. Samples of -80 mesh soil were collected at 30.5 m intervals along traverses crossing known structures, surficial geothermal alteration, and exploration well sites, and were analyzed using a Gold Film Mercury Detector. Strong mercury anomalies occur at locations along known structures in close proximity to subsurface thermal activity; examples include areas over hot spring deposits and near a shallow producing well. In contrast, background mercury concentrations are present in nearby locations with little or no indication of subsurface thermal activity, such as areas around deep marginal producing wells and dry wells, and areas lacking hot spring deposits. These results indicate that mercury geochemical surveys can be useful for identifying and mapping structures controlling fluid flow in geothermal systems and for delineating areas overlying near-surface thermal activity. Soil mercury geochemistry thus provides information which may aid in the cost-effective selection of exploratory well sites Title: Initial Investigation of Soil Mercury Geochemistry as an Aid to Drill Site Selection in Geothermal Systems Author: Capuano, R.M. Year: 1978 A mercury-in-soil survey was conducted at the Roosevelt Hot Springs Known Geothermal Resource Area (KGRA), Utah, to evaluate mercury soil geochemistry as a method of selecting exploration well sites in a hot-water geothermal system. Samples of -80 mesh soil were collected at 30.5 m intervals along traverses crossing known structures, surficial geothermal alteration, and exploration well sites, and were analyzed using a Gold Film Mercury Detector. Strong mercury anomalies occur at locations along known structures in close proximity to subsurface thermal activity; examples include areas over hot spring deposits and near a shallow producing well. In contrast, background mercury concentrations are present in nearby locations with little or no indication of subsurface thermal activity, such as areas around deep marginal producing wells and dry wells, and areas lacking hot spring deposits. These results indicate that mercury geochemical surveys can be useful for identifying and mapping structures controlling fluid flow in geothermal systems and for delineating areas overlying near-surface thermal activity. Soil mercury geochemistry thus provides information which may aid in the cost-effective selection of exploratory well sites Close