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• 1. [Image] Potential Uses for a High-Temperature Borehole Gravimeter

  	It is possible to design a canister to cool a borehole gravimeter for use in geothermal and high-temperature (up to 350/sup 0/C) gas wells. Repeat surveys with such a gravimeter could (1) help estimate ...
  	Citation × Citation Citation Abstract Copy Title: Potential Uses for a High-Temperature Borehole Gravimeter Author: Hearst, J.R. Year: 1978 It is possible to design a canister to cool a borehole gravimeter for use in geothermal and high-temperature (up to 350/sup 0/C) gas wells. Repeat surveys with such a gravimeter could (1) help estimate the extent of reservoir plugging in geothermal injection well after one year of operation and (2) detect compaction of a geothermal aquifer if the change in thickness of the aquifer exceeds 1 m. The instrument could be used together with conventional logging tools to evaluate radial dependence of density around a well, or to estimate gas-filled porosity around wells drilled with mud. A high-temperature borehole gravimeter could also be used to evaluate structure and stratigraphy around geothermal and high-temperature gas wells Title: Potential Uses for a High-Temperature Borehole Gravimeter Author: Hearst, J.R. Year: 1978 It is possible to design a canister to cool a borehole gravimeter for use in geothermal and high-temperature (up to 350/sup 0/C) gas wells. Repeat surveys with such a gravimeter could (1) help estimate the extent of reservoir plugging in geothermal injection well after one year of operation and (2) detect compaction of a geothermal aquifer if the change in thickness of the aquifer exceeds 1 m. The instrument could be used together with conventional logging tools to evaluate radial dependence of density around a well, or to estimate gas-filled porosity around wells drilled with mud. A high-temperature borehole gravimeter could also be used to evaluate structure and stratigraphy around geothermal and high-temperature gas wells Close

• 2. [Image] Geothermal Resource Exploration in Boise, Idaho

  	Exploratory drilling in Boise, Idaho, in the vicinity of the Boise Front Fault has confirmed the presence of a 170/sup 0/F (77/sup 0/C) geothermal resource below about 800 ft (244 m) near the Veterans ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Resource Exploration in Boise, Idaho Author: Nelson, L.B. Year: 1980 Exploratory drilling in Boise, Idaho, in the vicinity of the Boise Front Fault has confirmed the presence of a 170/sup 0/F (77/sup 0/C) geothermal resource below about 800 ft (244 m) near the Veterans Hospital of the Military Reserve Park. The Idaho National Engineering Laboratory (INEL), sponsored by the Department of Energy, drilled three exploratory slim holes and two deep exploratory test wells. Study results based on tests of the two exploratory-test wells are reported. Faulting related to the Boise Front Fault defines a major physiographic break in the area that acts as a subsurface conduit through which geothermal water circulates. Hydrologic tests indicate that rocks disturbed by the Boise Front Fault may be as much as ten times more permeable than those removed from the major structural lineament Title: Geothermal Resource Exploration in Boise, Idaho Author: Nelson, L.B. Year: 1980 Exploratory drilling in Boise, Idaho, in the vicinity of the Boise Front Fault has confirmed the presence of a 170/sup 0/F (77/sup 0/C) geothermal resource below about 800 ft (244 m) near the Veterans Hospital of the Military Reserve Park. The Idaho National Engineering Laboratory (INEL), sponsored by the Department of Energy, drilled three exploratory slim holes and two deep exploratory test wells. Study results based on tests of the two exploratory-test wells are reported. Faulting related to the Boise Front Fault defines a major physiographic break in the area that acts as a subsurface conduit through which geothermal water circulates. Hydrologic tests indicate that rocks disturbed by the Boise Front Fault may be as much as ten times more permeable than those removed from the major structural lineament 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] 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