Geohydrological environmental effects of geothermal power production: Phase IIA. Final report. [Using reservoir simulators]

Technical Report · Wed Sep 01 00:00:00 EDT 1976

OSTI ID:7311366

Pritchett, J W; Garg, S K; Brownell, Jr, D H; Rice, L F; Rice, M H; Riney, T D; Hendrickson, R R

Results are presented for the second year (Phase IIA) of a three-year research effort to develop and validate computer simulators whereby field information for a specific liquid- or vapor-dominated geothermal system can be used to predict reservoir performance and subsurface environmental effects due to production and reinjection of geothermal fluids. During the first year (Phase I), separate codes were developed for describing the multiphase multidimensional unsteady flow of steam and water in a heterogeneous geologic setting without rock deformation; and for calculating the response of a multidimensional rock matrix to prescribed pore pressure changes without consideration of fluid flow. These codes have now been coupled to produce a fully active geothermal reservoir simulator for simultaneous treatment of fluid flow and ground movement effects. Calculations are presented for a five-spot production/injection pattern which show the numerical techniques employed to be free of grid orientation problems. Reservoir calculations simulating pressure drawdown and buildup well tests are presented. Effects of in-formation flashing and salt precipitation on well deliverability were studied; flashing near the wellbore and above the production horizon were both evaluated. Application of the reservoir simulator to a two-dimensional vertical model of the Wairakei geothermal system has successfully reproduced the total fluid production history over time interval 1953 to 1967. The ground surface subsidence history of the field is examined in terms of the calculated two-phase fluid flow and the local geology. A separate abstract was prepared for the appendix, entitled ''Tests on Cores from the Wairakei Geothermal Project, Wairakei, New Zealand.''

• Research Organization: Systems, Science and Software, La Jolla, CA (USA)
• OSTI ID: 7311366
• Report Number(s): SSS-R-77-2998
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150600 -- Geothermal Energy-- Environmental Aspects
150904* -- Geothermal Engineering-- Geothermal Reservoir & Well Performance
BRINES
COMPUTER CODES
ENGINEERING
ENVIRONMENTAL EFFECTS
EQUATIONS
EQUATIONS OF STATE
EVAPORATION
FINITE DIFFERENCE METHOD
FINITE ELEMENT METHOD
FLASHING
FLUID FLOW
FLUIDS
GEOTHERMAL FIELDS
GEOTHERMAL FLUIDS
GEOTHERMAL SYSTEMS
GEOTHERMAL WELLS
GROUND SUBSIDENCE
HOT-WATER SYSTEMS
HYDROTHERMAL SYSTEMS
ITERATIVE METHODS
MATHEMATICAL MODELS
MULTIPHASE FLOW
NUMERICAL SOLUTION
PERFORMANCE
PHASE TRANSFORMATIONS
PRECIPITATION
PRODUCTIVITY
RESERVOIR ENGINEERING
SALTS
SEPARATION PROCESSES
SIMULATION
TESTING
VAPOR-DOMINATED SYSTEMS
WAIRAKEI GEOTHERMAL FIELD
WELLS