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• 1. [Image] Geothermal Injection Treatment: Process Chemistry, Field Experiences, And Design Options

  	The successful development of geothermal reservoirs to generate electric power will require the injection disposal of approximately 700,000 gal/h (2.0 x 106 l/h) of heat-depleted brine for every 50,000 ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Injection Treatment: Process Chemistry, Field Experiences, And Design Options Author: Kindle, C. H. Year: 1984 The successful development of geothermal reservoirs to generate electric power will require the injection disposal of approximately 700,000 gal/h (2.0 x 106 l/h) of heat-depleted brine for every 50,000 kW of generating capacity. To maintain injectability, the spent brine must be compatible with the receiving formation. The factors that influence this brine/formation compatibility and tests to quantify them are discussed in this report Title: Geothermal Injection Treatment: Process Chemistry, Field Experiences, And Design Options Author: Kindle, C. H. Year: 1984 The successful development of geothermal reservoirs to generate electric power will require the injection disposal of approximately 700,000 gal/h (2.0 x 106 l/h) of heat-depleted brine for every 50,000 kW of generating capacity. To maintain injectability, the spent brine must be compatible with the receiving formation. The factors that influence this brine/formation compatibility and tests to quantify them are discussed in this report Close

• 2. [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

• 3. [Image] Drilling fluid/formation interaction at simulated in situ geothermal conditions. Final report

  	Interaction of drilling fluids with a geothermal reservoir formation can result in significant permeability impairment and therefore reduced well productivity. This interaction is studied under simulated ...
  	Citation × Citation Citation Abstract Copy Title: Drilling fluid/formation interaction at simulated in situ geothermal conditions. Final report Author: Enniss, D.O Year: 1980 Interaction of drilling fluids with a geothermal reservoir formation can result in significant permeability impairment and therefore reduced well productivity. This interaction is studied under simulated in situ geothermal conditions of overburden stress, pore fluid pressure, temperature, and pore fluid chemistry. Permeability impairment of an East Mesa KGRA reservoir material is evaluated as a function of stagnation time, drilling fluid, and temperature. Results indicate that all of these parameters contribute significantly to the magnitude and the reversibility of the impairment. Title: Drilling fluid/formation interaction at simulated in situ geothermal conditions. Final report Author: Enniss, D.O Year: 1980 Interaction of drilling fluids with a geothermal reservoir formation can result in significant permeability impairment and therefore reduced well productivity. This interaction is studied under simulated in situ geothermal conditions of overburden stress, pore fluid pressure, temperature, and pore fluid chemistry. Permeability impairment of an East Mesa KGRA reservoir material is evaluated as a function of stagnation time, drilling fluid, and temperature. Results indicate that all of these parameters contribute significantly to the magnitude and the reversibility of the impairment. Close

• 4. [Image] Control of Hydrogen Sulfide Emission from Geothermal Power Plants, Annual Status Report, June 1, 1975 - May 31, 1976

  	A process for controlling H/sub 2/S emissions at geothermal power plants was evaluated in laboratory scale equipment and by process engineering analysis. The process is based on scrubbing geothermal steam ...
  	Citation × Citation Citation Abstract Copy Title: Control of Hydrogen Sulfide Emission from Geothermal Power Plants, Annual Status Report, June 1, 1975 - May 31, 1976 Author: Harvey, W.W. Year: 1976 A process for controlling H/sub 2/S emissions at geothermal power plants was evaluated in laboratory scale equipment and by process engineering analysis. The process is based on scrubbing geothermal steam with a metal salt solution to selectively remove and precipitate the contained H/sub 2/S. The metal sulfide is roasted or oxygen/acid leached to regenerate the metal salt, and sulfur is rejected from the system as elemental sulfur or as sulfate. Up to 95 percent removal of H/sub 2/S from simulated geothermal steams was obtained in a 2'' diameter scrubbing column packed with 3 feet of 5/8'' Flexirings by use of a recirculating slurry of copper sulfate/copper sulfide. Information is included on the chemistry, thermodynamics, kinetics and process control aspects of the process, scrubber system design, operation, and corrosion, and design proposals and cost estimates for a H/sub 2/S removal system. (LCL) Title: Control of Hydrogen Sulfide Emission from Geothermal Power Plants, Annual Status Report, June 1, 1975 - May 31, 1976 Author: Harvey, W.W. Year: 1976 A process for controlling H/sub 2/S emissions at geothermal power plants was evaluated in laboratory scale equipment and by process engineering analysis. The process is based on scrubbing geothermal steam with a metal salt solution to selectively remove and precipitate the contained H/sub 2/S. The metal sulfide is roasted or oxygen/acid leached to regenerate the metal salt, and sulfur is rejected from the system as elemental sulfur or as sulfate. Up to 95 percent removal of H/sub 2/S from simulated geothermal steams was obtained in a 2'' diameter scrubbing column packed with 3 feet of 5/8'' Flexirings by use of a recirculating slurry of copper sulfate/copper sulfide. Information is included on the chemistry, thermodynamics, kinetics and process control aspects of the process, scrubber system design, operation, and corrosion, and design proposals and cost estimates for a H/sub 2/S removal system. (LCL) Close

• 5. [Image] Geothermal Progress Monitor: Report No. 18, December 1996

  	The near-term challenges of the US geothermal industry and its long-range potential are dominant themes in this issue of the US Department of Energy (DOE) Geothermal Progress Monitor which summarizes calendar-year ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Progress Monitor: Report No. 18, December 1996 Author: Assistant Secretary for Energy and Efficiency and Renewable Energy, Geothermal Division Year: 1996 The near-term challenges of the US geothermal industry and its long-range potential are dominant themes in this issue of the US Department of Energy (DOE) Geothermal Progress Monitor which summarizes calendar-year 1996 events in geothermal development. Competition is seen as an antidote to current problems and a cornerstone of the future. Thus, industry's cost-cutting strategies needed to increase the competitiveness of geothermal energy in world markets are examined. For example, a major challenge facing the US industry today is that the sales contracts of independent producers have reached, or soon will, the critical stage when the prices utilities must pay them drop precipitously, aptly called the cliff. However, Thomas R. Mason, President and CEO of CalEnergy told the DOE 1996 Geothermal Program Review XIV audience that while some of his company's plants have ''gone over the cliff, the world is not coming to an end.'' With the imposition of severe cost-cutting strategies, he said, ''these plants remain profitable... although they have to be run with fewer people and less availability.'' The Technology Development section of the newsletter discusses enhancements to TOUGH2, the general purpose fluid and heat flow simulator and the analysis of drill cores from The Geysers, but the emphasis is on advanced drilling technologies Title: Geothermal Progress Monitor: Report No. 18, December 1996 Author: Assistant Secretary for Energy and Efficiency and Renewable Energy, Geothermal Division Year: 1996 The near-term challenges of the US geothermal industry and its long-range potential are dominant themes in this issue of the US Department of Energy (DOE) Geothermal Progress Monitor which summarizes calendar-year 1996 events in geothermal development. Competition is seen as an antidote to current problems and a cornerstone of the future. Thus, industry's cost-cutting strategies needed to increase the competitiveness of geothermal energy in world markets are examined. For example, a major challenge facing the US industry today is that the sales contracts of independent producers have reached, or soon will, the critical stage when the prices utilities must pay them drop precipitously, aptly called the cliff. However, Thomas R. Mason, President and CEO of CalEnergy told the DOE 1996 Geothermal Program Review XIV audience that while some of his company's plants have ''gone over the cliff, the world is not coming to an end.'' With the imposition of severe cost-cutting strategies, he said, ''these plants remain profitable... although they have to be run with fewer people and less availability.'' The Technology Development section of the newsletter discusses enhancements to TOUGH2, the general purpose fluid and heat flow simulator and the analysis of drill cores from The Geysers, but the emphasis is on advanced drilling technologies Close