Simulation of geothermal reservoirs including changes in porosity and permeability due to silica-water reactions

Conference · Sun Jan 01 04:00:00 EST 1978

OSTI ID:892551

Li, Todd M.C.; Mercer, J W; Faust, C R; Greenfield, R J

Changes in porosity and permeability due to water-rock reactions may affect a geothermal reservoir in two important ways. One is the possibility of clogging of the pore space in the vicinity of a reinjection well. The second concerns the long term evolution of a geothermal system, for example, the development of a self-sealing cap rock. Two major types of reactions that may affect the porosity and permeability in the reservoir are dissolution-precipitation reactions and alteration reactions. Silica precipitation is the major self-sealing process in hot-water geothermal reservoirs. The purpose of this work is to develop a mathematical model which can simulate the changes in porosity and permeability resulting from water-rock reactions in a geothermal reservoir. The model being developed describes the flow of hot water in an axially symmetric porous medium. The model is a vertical cross-section in r-z coordinates. For simplicity, only a single dissolved chemical species is being modeled. The fluid is single-phase water and only dissolution and precipitation of quartz are considered.

• Research Organization: US Geological Survey, Reston, VA
• Sponsoring Organization: USDOE
• OSTI ID: 892551
• Report Number(s): SGP-TR-30; CONF-781222-40
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
15 GEOTHERMAL ENERGY
CAP ROCK
DISSOLUTION
GEOTHERMAL SYSTEMS
Geothermal Legacy
HOT WATER
MATHEMATICAL MODELS
PERMEABILITY
POROSITY
PRECIPITATION
QUARTZ
REINJECTION
RESERVOIR ENGINEERING
SILICA
SIMULATION
WATER