Two-dimensional simulation of heat and fluid flow in geothermal systems.

This study is concerned with the development and the applications of an efficient two-dimensional (x-y), finite difference type computer geothermal reservoir simulator (CGS). The simulator (CGS) can be used for simulating either one-phase (compressed-water or superheated-steam) or two-phase (water-stream), homogeneous or heterogeneous, isotropic or anisotropic geothermal reservoir systems with sinks and sources included. The simulator model is made up of two coupled nonlinear partial differential equations describing the horizontal transport of fluid and heat in a geothermal reservoir. Pressure and enthalpy are the two unknown dependent variables to be solved. The solution technique is based on the approach of sequential numerical method in petroleum reservoir simulation. SIP (strongly implicit procedure) is used as the matrix solution method for solving the system of equations obtained in the finite difference formulation of the simulator equations. Two examples of the applications of CGS to both hypothetical and realistic geothermal reservoirs are included