Beneficial effects of groundwater entry into liquid-dominated geothermal systems

Conference · Sun Apr 01 00:00:00 EST 1990

OSTI ID:6981593

Lippmann, M J ^[1]; Truesdell, A H ^[2]

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1. Lawrence Berkeley Lab., CA (USA)
2. Geological Survey, Menlo Park, CA (USA)

In all active liquid-dominated geothermal systems there is continuous circulation of mass and transfer of heat, otherwise they would slowly cool and fade away. In the natural state these systems are in dynamic equilibrium with the surrounding colder groundwater aquifers. The ascending geothermal fluids cool conductively, boil, or mix with groundwaters, and ultimately may discharge at the surface as fumaroles or hot springs. With the start of fluid production and the lowering of reservoir pressure, the natural equilibrium is disrupted and cooler groundwater tends to enter the reservoir. Improperly constructed or damaged wells, and wells located near the margins of the geothermal system, exhibit temperature reductions (and possibly scaling from mixing of chemically distinct fluids) as the cooler-water moves into the reservoir. These negative effects, especially in peripheral wells are, however, compensated by the maintenance of reservoir pressure and a reduction in reservoir boiling that might result in mineral precipitation in the formation pores and fractures. The positive effect of cold groundwater entry on the behavior of liquid-dominated system is illustrated by using simple reservoir models. The simulation results show that even though groundwater influx into the reservoir causes cooling of fluids produced from wells located near the cold-water recharge area, it also reduces pressure drawdown and boiling in the exploited zone, and sweeps the heat stored in the reservoir rocks toward production wells, thus increasing the productive life of the wells and field. 9 refs.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• Sponsoring Organization: DOE/CE
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6981593
• Report Number(s): LBL-28971; CONF-900823-11; ON: DE90015726
• Resource Relation: Conference: Annual meeting of the Geothermal Resources Council and international symposium on geothermal energy, Kailua Kona, HI (USA), 20-24 Aug 1990
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
GEOTHERMAL FIELDS
WATER INFLUX
COMPUTERIZED SIMULATION
CIRCULATING SYSTEMS
GEOTHERMAL GRADIENTS
GROUND WATER
HEAT TRANSFER
M CODES
NUMERICAL ANALYSIS
RESERVOIR FLUIDS
RESERVOIR PRESSURE
COMPUTER CODES
ENERGY TRANSFER
FLUIDS
HYDROGEN COMPOUNDS
MATHEMATICS
OXYGEN COMPOUNDS
SIMULATION
TEMPERATURE GRADIENTS
WATER
Geothermal Legacy
150200* - Geology & Hydrology of Geothermal Systems