A Power Plant Oriented Geothermal Simulation Model

Abstract

To be useful for power plant planning and design, a simulation model must include both a geothermal reservoir and wells, maintaining constant wellhead pressure and varying flow. The well model allow for vertical single- or two-phase flow under steady state, and the reservoir model allows for horizontal axisymmetrical radial single- or two-phase nonisothermal flow under transient conditions. The simulation permits pre- e diction of reservoir evolution on the basis of the first well test results, such as: (1) permeability, porosity, thickness, and (2) static pressure and temperature. The other required input is one of the following versus time: (I) wellhead pressure, (2) power plant output, or (3) wellhead flow. The output consists of the simulated history of pressure, saturation, and temperature fields (the latter both for rocks and fluid). The model has been tested against the actual behavior of a geothermal reservoir.