RADIAL STEAM FLOW IN 2-PHASE GEOTHERMAL-RESERVOIRS - COMPARISON OF ANALYTICAL AND FINITE-DIFFERENCE SOLUTIONS

A linear closed-form analytical solution for the radial flow of steam toward a producing well in a vapor-dominated geothermal reservoir is compared with a finite difference solution to the nonlinear equations of fluid flow and energy change. Assumptions used in the development of the equations are that (1) the liquid phase, initially uniformly distributed within the reservoir, is immobile, (2) the relative permeability to steam is constant (3) local thermal equilibrium exists within the reservoir, (4) temperature changes are due only to phase change, (5) effects of vapor-pressure lowering are negligible. Results obtained numerically using a finite difference solution to the nonlinear equations of fluid flow and energy agree closely with the analytical approach in spite of the nonlinearities involved.