Reservoir simulation studies: Wairakei Geothermal Field, New Zealand. Final report

Technical Report · Tue Jan 01 00:00:00 EST 1980

DOI:https://doi.org/10.2172/6779927· OSTI ID:6779927

Pritchett, J W; Rice, L F; Garg, S K

Numerical reservoir simulation techniques were used to perform a history-match of the Wairakei geothermal system in New Zealand. First, a one-dimensional (vertical) model was chosen; realistic stratigraphy was incorporated and the known production history was imposed. The effects of surface and deep recharge were included. Good matches were obtained, both for the reservoir pressure decline history and changes in average discharge enthalpy with time. Next, multidimensional effects were incorporated by treating with a two-dimensional vertical section. Again, good history matches were obtained, although computed late-time discharge enthalpies were slightly high. It is believed that this disparity arises from inherently three-dimensional effects. Predictive calculations using the two-dimensional model suggest that continued future production will cause little additional reservoir pressure drop, but that thermal degradation will occur. Finally, ground subsidence data at Wairakei was examined. It was concluded that traditional elastic pore-collapse models based on classical soil-mechanics concepts are inadequate to explain the observed surface deformation. It is speculated that the measured subsidence may be due to structural effects such as aseismic slippage of a buried reservoir boundary fault.

• Research Organization: Systems, Science and Software, La Jolla, CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6779927
• Report Number(s): LBL-11497; GREMP-11; SSS-R-80-4313
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
WAIRAKEI GEOTHERMAL FIELD
COMPUTERIZED SIMULATION
MATHEMATICAL MODELS
RESERVOIR ENGINEERING
GEOLOGIC STRUCTURES
GROUND SUBSIDENCE
ONE-DIMENSIONAL CALCULATIONS
PRESSURE GRADIENTS
RECHARGE
TEMPERATURE DISTRIBUTION
TWO-DIMENSIONAL CALCULATIONS
ENGINEERING
GEOTHERMAL FIELDS
SIMULATION
Geothermal Legacy
150904* - Geothermal Engineering- Geothermal Reservoir & Well Performance