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U.S. Department of Energy
Office of Scientific and Technical Information

Geohydrological environmental effects of geothermal power production - phase IIb. Final report, 1 June 1975-30 November 1977

Technical Report ·
OSTI ID:5696560

The goal of this program was to develop, validate, and apply modeling techniques for predicting the behavior of a geothermal reservoir system during fluid production and injection. Individual computer models were developed for the multi-dimensional, multi-phase, time-dependent transport of fluid mass and heat in a heterogeneous reservoir and for the associated rock response. A procedure was developed to couple the rock response to the interactive fluid flow processes as well as an equation of state for flashing saline solutions. The effects of salt precipitation caused by information flashing were evaluated. The reservoir simulator was also applied to a crosssectional model of the Wairakei geothermal system to successfully reproduce the fluid production history over the interval 1953-1967; the ground surface subsidence history of the field was examined in terms of the calculated two-phase flow and the local geology. The temperature inversion often observed in geothermal fields was modeled in terms of hot fluid channeled upward through a vertical fault penetrating a horizontal aquifer. The set of governing equations was analyzed to determine the conditions under which the pressure work and/or viscous dissipation terms need to be retained in the energy balance relation. A preproduction model of a section of the Salton Sea geothermal system in the California Imperial Valley was synthesized from available data and the reservoir simulator. Predictions for the performance of the field to alternate production/injection scenarios were calculated. Coupled reservoir/subsidence calculations were performed for a synthetic reservoir system.

Research Organization:
Systems, Science and Software, La Jolla, CA (USA)
OSTI ID:
5696560
Report Number(s):
PB-294136
Country of Publication:
United States
Language:
English