Solution chemistry and scaling in hot dry rock geothermal systems

Conference · Sat Jan 01 04:00:00 EST 1977

OSTI ID:7255725

Tester, J W; Holley, Jr, C E; Blatz, L A

Field and laboratory experiments have focused on measuring the kinetics and equilibria associated with the transport of minerals from granite to circulating aqueous solutions. Presently two wellbores drilled to a depth of approximately 10,000 ft in the Valles Caldera region of the New Mexico Jemez mountains permit closed-loop circulation of fluid through a hydraulically fractured granite geothermal reservoir containing rock at 200/sup 0/C. Field measurements have dealth primarily with the buildup of dissolved and suspended material in water as it is circulated through the fractured region. Chemical treatment methods, involving the selective dissolution of quartz (SiO/sub 2/), a major component of granite, with sodium carbonate solutions have been employed to increase the in situ permeability of the rock matrix. Laboratory measurements have concentrated on identifying the effects of temperature, pH and chemical additives on the solubility of granite samples taken from the two test wellbores. Promising results from these solubility experiments are tested in a laboratory-scale circulating system to examine kinetic parameters influencing rock dissolution and reprecipitation (scaling) under conditions that simulate the in situ reservoir and heat exchange environments.

• Research Organization: Los Alamos Scientific Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 7255725
• Report Number(s): LA-UR-77-611; CONF-770310-2
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150904 -- Geothermal Engineering-- Geothermal Reservoir & Well Performance
152003* -- Geothermal Data & Theory-- Rock-Water-Gas Interactions
ADDITIVES
ALKALI METAL COMPOUNDS
AQUEOUS SOLUTIONS
BIOTITE
CARBON COMPOUNDS
CARBONATES
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMICAL REACTION KINETICS
COMMINUTION
DISPERSIONS
DISSOLUTION
EQUILIBRIUM
FLUID INJECTION
FLUIDS
FRACTURING
GEOTHERMAL FLUIDS
GEOTHERMAL SYSTEMS
GRANITES
Geothermal Legacy
HOT-DRY-ROCK SYSTEMS
HYDRAULIC FRACTURING
IGNEOUS ROCKS
JEMEZ MOUNTAINS
KINETICS
MASS TRANSFER
MICA
MINERALS
MIXTURES
MOUNTAINS
NEW MEXICO
NORTH AMERICA
OXIDES
OXYGEN COMPOUNDS
PERMEABILITY
PH VALUE
PRECIPITATION
QUARTZ
REACTION KINETICS
RESERVOIR ROCK
ROCK-FLUID INTERACTIONS
ROCKS
SCALING
SEPARATION PROCESSES
SILICON COMPOUNDS
SILICON OXIDES
SODIUM CARBONATES
SODIUM COMPOUNDS
SOLUBILITY
SOLUTIONS
SOUTHWEST REGION
USA
WELL STIMULATION