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• 1. [Image] An Experimental Investigation of the Permeability of Kayenta and St. Peter Sandstones to Hypersaline Brine in the Temperature Interval 70 to 90 C at 10. 3-MPa Confining Pressure

  	Permeabilities of 10.2 cm in length, 2.5 cm in diameter Kayenta (porosity, 20.7, +- 1.66%) and St. Peter (porosity, 13.6, +- 0.13%) sandstones to Magmamax No. 1 brine containing suspended solids were determined ...
  	Citation × Citation Citation Abstract Copy Title: An Experimental Investigation of the Permeability of Kayenta and St. Peter Sandstones to Hypersaline Brine in the Temperature Interval 70 to 90 C at 10. 3-MPa Confining Pressure Author: Piwinskii, A.J. Year: 1977 Permeabilities of 10.2 cm in length, 2.5 cm in diameter Kayenta (porosity, 20.7, +- 1.66%) and St. Peter (porosity, 13.6, +- 0.13%) sandstones to Magmamax No. 1 brine containing suspended solids were determined from 70 to 90/sup 0/C at 10.3-MPa confining pressure. Measurements were performed without filters, with one 10-..mu..m filter, and with two 10-..mu..m filters inserted upstream of the core sample. In all cases, there was a dramatic decrease in permeability within the first hour of flow or few hundred pore volumes of flow through the core. Experiments conducted without filters or with one filter yield permeabilities that represent both the rock and the 2- to 3-mm amorphous silica-iron layer on the top face of the core. The experimental results show that if the Salton Sea Geothermal Field (SSGF) were composed of porous, sedimentary formations similar to Kayenta sandstone, long-term injection of unmodified Magmamax brine would not be feasible. In the case of acidified brine, most of the permeability decline may result from the mobilization of calcite Title: An Experimental Investigation of the Permeability of Kayenta and St. Peter Sandstones to Hypersaline Brine in the Temperature Interval 70 to 90 C at 10. 3-MPa Confining Pressure Author: Piwinskii, A.J. Year: 1977 Permeabilities of 10.2 cm in length, 2.5 cm in diameter Kayenta (porosity, 20.7, +- 1.66%) and St. Peter (porosity, 13.6, +- 0.13%) sandstones to Magmamax No. 1 brine containing suspended solids were determined from 70 to 90/sup 0/C at 10.3-MPa confining pressure. Measurements were performed without filters, with one 10-..mu..m filter, and with two 10-..mu..m filters inserted upstream of the core sample. In all cases, there was a dramatic decrease in permeability within the first hour of flow or few hundred pore volumes of flow through the core. Experiments conducted without filters or with one filter yield permeabilities that represent both the rock and the 2- to 3-mm amorphous silica-iron layer on the top face of the core. The experimental results show that if the Salton Sea Geothermal Field (SSGF) were composed of porous, sedimentary formations similar to Kayenta sandstone, long-term injection of unmodified Magmamax brine would not be feasible. In the case of acidified brine, most of the permeability decline may result from the mobilization of calcite Close

• 2. [Image] Stratigraphy and Alteration, 15 Shallow Thermal Gradient Holes, Roosevelt Hot Springs KGRA and Vicinity, Millard and Beaver Counties, Utah

  	Fifteen shallow thermal gradient drill holes were recently completed by Geothermal Power Corporation (GPCR) in the vicinity of the Roosevelt Hot Springs KGRA. Five holes penetrated Tertiary granitic rocks ...
  	Citation × Citation Citation Abstract Copy Title: Stratigraphy and Alteration, 15 Shallow Thermal Gradient Holes, Roosevelt Hot Springs KGRA and Vicinity, Millard and Beaver Counties, Utah Author: Hulen, J.B. Year: 1978 Fifteen shallow thermal gradient drill holes were recently completed by Geothermal Power Corporation (GPCR) in the vicinity of the Roosevelt Hot Springs KGRA. Five holes penetrated Tertiary granitic rocks and Precambrian gneiss east of the KGRA. Seven holes completed entirely in alluvium near the southwestern corner of the KGRA encountered a near-surface marker horizon of Pleistocene pumice and perlite. Maximum calculated alluvial sedimentation rates since initial deposition of this pumice and perlite range from 1 foot in 12,500 years to 1 foot in 2,300 years. Three holes east of the Mineral Mountains penetrated late Cenozoic basaltic andesite beneath a thin veneer of alluvium. All 15 GPCR drill holes appear to be peripheral to a central zone of anomalously high thermal gradient and low resisitivity delineated by previous investigations. GPCR-8 and -14, however, are characterized by high heat flow and relatively abundant manganese oxide mineralization, which may reflect a favorable hydrologic system controlling thermal fluid flow at depth. These holes thus seem most encouraging for discovery of a deeper high-temperature geothermal resource Title: Stratigraphy and Alteration, 15 Shallow Thermal Gradient Holes, Roosevelt Hot Springs KGRA and Vicinity, Millard and Beaver Counties, Utah Author: Hulen, J.B. Year: 1978 Fifteen shallow thermal gradient drill holes were recently completed by Geothermal Power Corporation (GPCR) in the vicinity of the Roosevelt Hot Springs KGRA. Five holes penetrated Tertiary granitic rocks and Precambrian gneiss east of the KGRA. Seven holes completed entirely in alluvium near the southwestern corner of the KGRA encountered a near-surface marker horizon of Pleistocene pumice and perlite. Maximum calculated alluvial sedimentation rates since initial deposition of this pumice and perlite range from 1 foot in 12,500 years to 1 foot in 2,300 years. Three holes east of the Mineral Mountains penetrated late Cenozoic basaltic andesite beneath a thin veneer of alluvium. All 15 GPCR drill holes appear to be peripheral to a central zone of anomalously high thermal gradient and low resisitivity delineated by previous investigations. GPCR-8 and -14, however, are characterized by high heat flow and relatively abundant manganese oxide mineralization, which may reflect a favorable hydrologic system controlling thermal fluid flow at depth. These holes thus seem most encouraging for discovery of a deeper high-temperature geothermal resource Close

• 3. [Image] Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States Progress Report, Apr 1, 1977--Jun 30, 1977

  	The objective of this research is to develop and apply targeting procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological, ...
  	Citation × Citation Citation Abstract Copy Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States Progress Report, Apr 1, 1977--Jun 30, 1977 Author: Costain, J.K. Year: 1977 The objective of this research is to develop and apply targeting procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological, geochemical, and geophysical data. Detailed study of the Winnsboro complex, South Carolina, is continuing as part of a broader project to provide insight into the behavior of uranium and thorium in syn- and postmetamorphic granitic plutons Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States Progress Report, Apr 1, 1977--Jun 30, 1977 Author: Costain, J.K. Year: 1977 The objective of this research is to develop and apply targeting procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological, geochemical, and geophysical data. Detailed study of the Winnsboro complex, South Carolina, is continuing as part of a broader project to provide insight into the behavior of uranium and thorium in syn- and postmetamorphic granitic plutons Close

• 4. [Image] Report on Design, Construction and Testing of CO2 Breakout System for Geothermal Brines

  	A skid mounted test facility has been built for determining conditions at which CO2 flashes from geothermal brines. The system has been checked and operated at one geothermal plant. It performed as designed. ...
  	Citation × Citation Citation Abstract Copy Title: Report on Design, Construction and Testing of CO2 Breakout System for Geothermal Brines Author: Robertus, R. J. Year: 1984 A skid mounted test facility has been built for determining conditions at which CO2 flashes from geothermal brines. The system has been checked and operated at one geothermal plant. It performed as designed. The equipment is designed to operate at temperatures and pressures typical of wells near Heber, California. (Nominally IS0°C and 300-500 psig). It has heat exchangers which can cool the brine to less than 70°C. (The cooling water is re-circulated after being cooled by a forced air heat exchanger). Breakout pressures can be determined for any temperature between 70°C and wellhead temperature Title: Report on Design, Construction and Testing of CO2 Breakout System for Geothermal Brines Author: Robertus, R. J. Year: 1984 A skid mounted test facility has been built for determining conditions at which CO2 flashes from geothermal brines. The system has been checked and operated at one geothermal plant. It performed as designed. The equipment is designed to operate at temperatures and pressures typical of wells near Heber, California. (Nominally IS0°C and 300-500 psig). It has heat exchangers which can cool the brine to less than 70°C. (The cooling water is re-circulated after being cooled by a forced air heat exchanger). Breakout pressures can be determined for any temperature between 70°C and wellhead temperature Close

• 5. [Image] Study of Silica Scaling from Geothermal Brines, Final Report, November 15, 1974 - April 30, 1977

  	Condensation of silica from brines supersaturate in silicic acid was studied over a range of pH (4.5 to 6.5), temperature (75 to 105/sup 0/C), salinity, and silicic acid concentration (700 to 1200 ppM ...
  	Citation × Citation Citation Abstract Copy Title: Study of Silica Scaling from Geothermal Brines, Final Report, November 15, 1974 - April 30, 1977 Author: Makrides, A.C. Year: 1978 Condensation of silica from brines supersaturate in silicic acid was studied over a range of pH (4.5 to 6.5), temperature (75 to 105/sup 0/C), salinity, and silicic acid concentration (700 to 1200 ppM as SiO/sub 2/). The experimental technique involved analyses for molybdate-reactive silicic acid as a function of time after a supersaturated solution of Si(OH)/sub 4/ was prepared by mixing aliquots of a stock silicate solution with buffered brine. The isothermal rate of SiO/sub 2/ condensation is a strong function of supersaturation (C/Ce), pH, and salinity. The overall kinetics follow what is expected from the general theory of phase transitions. The kinetic results suggest that growth of nucleated particles is activation controlled, at least initially. The increase of condensation rate with salt content is attributed to a decrease in equilibrium solubility of SiO/sub 2/. In effect, higher salt concentrations increase supersaturation and lead to faster nucleation. Higher nucleation and growth rates are observed at higher pH's. An increase of 1 pH unit increases rates by a factor of about 10. The pH dependence is consistent with the hypothesis that SiO(OH)/sub 3//sup -/ is One of the reacting species. Temperature has little effect on condensation rate at a fixed initial silicic acid concentration. This result suggests that the increase in rate of activated steps brought about by increased temperature is essentially counterbalanced by a decrease in supersaturation (because of higher equilibrium solubility at higher temperatures). The kinetic results yield an activation energy of 17 kcal/mol for addition of silicic acid to a nucleated particle and 45 ergs/cm/sup 2/ for the interfacial energy between precipitated silica and the brine. NaCl, KCl, CaCl/sub 2/ and MgCl/sub 2/ had no specific effect on condensation rate. However, NaF had a large effect on rate; a few ppM (15 to 100) of fluoride ion accelerate condensation substantially Title: Study of Silica Scaling from Geothermal Brines, Final Report, November 15, 1974 - April 30, 1977 Author: Makrides, A.C. Year: 1978 Condensation of silica from brines supersaturate in silicic acid was studied over a range of pH (4.5 to 6.5), temperature (75 to 105/sup 0/C), salinity, and silicic acid concentration (700 to 1200 ppM as SiO/sub 2/). The experimental technique involved analyses for molybdate-reactive silicic acid as a function of time after a supersaturated solution of Si(OH)/sub 4/ was prepared by mixing aliquots of a stock silicate solution with buffered brine. The isothermal rate of SiO/sub 2/ condensation is a strong function of supersaturation (C/Ce), pH, and salinity. The overall kinetics follow what is expected from the general theory of phase transitions. The kinetic results suggest that growth of nucleated particles is activation controlled, at least initially. The increase of condensation rate with salt content is attributed to a decrease in equilibrium solubility of SiO/sub 2/. In effect, higher salt concentrations increase supersaturation and lead to faster nucleation. Higher nucleation and growth rates are observed at higher pH's. An increase of 1 pH unit increases rates by a factor of about 10. The pH dependence is consistent with the hypothesis that SiO(OH)/sub 3//sup -/ is One of the reacting species. Temperature has little effect on condensation rate at a fixed initial silicic acid concentration. This result suggests that the increase in rate of activated steps brought about by increased temperature is essentially counterbalanced by a decrease in supersaturation (because of higher equilibrium solubility at higher temperatures). The kinetic results yield an activation energy of 17 kcal/mol for addition of silicic acid to a nucleated particle and 45 ergs/cm/sup 2/ for the interfacial energy between precipitated silica and the brine. NaCl, KCl, CaCl/sub 2/ and MgCl/sub 2/ had no specific effect on condensation rate. However, NaF had a large effect on rate; a few ppM (15 to 100) of fluoride ion accelerate condensation substantially Close