Testing Reservoir Simulation Models for the Broadlands Geothermal Field Using Precision Gravity Data
- Key words
- Reservoir Engineering; Exploration; New Zealand; Broadlands; Numerical Modeling; Numerical Simulators; Gravity; Saturation; Ohaaki
- Location
- Broadlands, New Zealand; Taupo Volcanic Zone
- Conference
- Geothermal Resources Council Transactions
- Year
- 1990
- Session
- Reservoir modeling; Computer modeling; Geophysical surveys;
- Language
- English
Abstract
A powerful and independent method of testing 3D numerical reservoir simulation models using repeat, precise gravity measurements is demonstrated. The models predict changes in vapor saturation with time, and hence changes in density, and therefore changes in gravity. By comparing the measured gravity difference with those calculated for the models, the validity of the models can be tested. Three 3D simulation models of the Broadlands Geothermal Field have been tested. The tests indicate that, for the drawdown period (1967-1971), changes in vapor saturation within the Ohaaki area were over estimated, and their lateral extent was under estimated. The upper part of the production zone may be shallower, thinner, have greater porosity, and extend further than considered in the models.
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