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• 1. [Image] Geothermal Energy Resource Assessment

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

• 2. [Image] Geologic Interpretation of the Geothermal Potential of the North Bonneville Area

  	Possible geothermal development for the township of North Bonneville, Washington is being investigated because of the proximity of the town to hot springs in a geologic province of good geothermal potential. ...
  	Citation × Citation Citation Abstract Copy Title: Geologic Interpretation of the Geothermal Potential of the North Bonneville Area Author: Nielson, D.L. Year: 1980 Possible geothermal development for the township of North Bonneville, Washington is being investigated because of the proximity of the town to hot springs in a geologic province of good geothermal potential. Surface expression of geothermal resources is provided by conduits through an impermeable reservoir cap and is therefore generally structurally controlled. Near North Bonneville the geologic formations that underlie potential drilling sites are the Eagle Creek formation and the Ohanpecosh Formation. The Lower Miocene Eagle Creek Formation is composed of poorly consolidated volcanic conglomerates, sandstOnes, tuffs, and includes a few minor interbedded lava flows. The Eocene-Oligiocene Ohanapecosh (Weigle) Formation in its nearest exposures to North Bonneville is composed of Volcaniclastics and lava flows. The Ohanapecosh has been altered to zeolites and clays and is therefore Well consolidated and impermeable. The lack of permeability provides the necessary reservoir cap for any geothermal system that may be present at depth. This formation, to the northeast, in the Wind River drainage is greater than 19,000 ft. thick. Circulation of geothermal heated water from this thick sequence of impermeable strata must be associated with penetrating fracture zones Title: Geologic Interpretation of the Geothermal Potential of the North Bonneville Area Author: Nielson, D.L. Year: 1980 Possible geothermal development for the township of North Bonneville, Washington is being investigated because of the proximity of the town to hot springs in a geologic province of good geothermal potential. Surface expression of geothermal resources is provided by conduits through an impermeable reservoir cap and is therefore generally structurally controlled. Near North Bonneville the geologic formations that underlie potential drilling sites are the Eagle Creek formation and the Ohanpecosh Formation. The Lower Miocene Eagle Creek Formation is composed of poorly consolidated volcanic conglomerates, sandstOnes, tuffs, and includes a few minor interbedded lava flows. The Eocene-Oligiocene Ohanapecosh (Weigle) Formation in its nearest exposures to North Bonneville is composed of Volcaniclastics and lava flows. The Ohanapecosh has been altered to zeolites and clays and is therefore Well consolidated and impermeable. The lack of permeability provides the necessary reservoir cap for any geothermal system that may be present at depth. This formation, to the northeast, in the Wind River drainage is greater than 19,000 ft. thick. Circulation of geothermal heated water from this thick sequence of impermeable strata must be associated with penetrating fracture zones Close

• 3. [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

• 4. [Image] Design of a Water Jet Drill for Development of Geothermal Resources. Annual Progress Report, June 1, 1976--May 31, 1977

  	Research was expanded to the drilling of crystalline rock. Advance rates of 40 inches per minute have been achieved at 16,000 psi, 10 gpm flow rate in a 30,000 psi compressive strength rock using the water ...
  	Citation × Citation Citation Abstract Copy Title: Design of a Water Jet Drill for Development of Geothermal Resources. Annual Progress Report, June 1, 1976--May 31, 1977 Author: Rock Mechanics & Explosives Research Center , University of Missouri- Rolla Year: 1977 Research was expanded to the drilling of crystalline rock. Advance rates of 40 inches per minute have been achieved at 16,000 psi, 10 gpm flow rate in a 30,000 psi compressive strength rock using the water alone as the drilling mechanism. The quality of the hole achieved as the jet drilled a variety of rock was found to vary and a hydromechanical drilling bit, combining high pressure water jets with roller cones, has been developed. A field drilling unit has been tested and modified to allow the drilling of holes to 3/sup 1///sub 2/ inch diameter using the hydromechanical drill. Preliminary work on the development of a cavitation test for rock is also included Title: Design of a Water Jet Drill for Development of Geothermal Resources. Annual Progress Report, June 1, 1976--May 31, 1977 Author: Rock Mechanics & Explosives Research Center , University of Missouri- Rolla Year: 1977 Research was expanded to the drilling of crystalline rock. Advance rates of 40 inches per minute have been achieved at 16,000 psi, 10 gpm flow rate in a 30,000 psi compressive strength rock using the water alone as the drilling mechanism. The quality of the hole achieved as the jet drilled a variety of rock was found to vary and a hydromechanical drilling bit, combining high pressure water jets with roller cones, has been developed. A field drilling unit has been tested and modified to allow the drilling of holes to 3/sup 1///sub 2/ inch diameter using the hydromechanical drill. Preliminary work on the development of a cavitation test for rock is also included Close

• 5. [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