NUMERICAL SIMULATION OF RESERVOIR COMPACTION IN LIQUID DOMINATED GEOTHERMAL SYSTEMS

Recently much attention has been focused on the development of geother-mal systems. A large number of geothermal fields are of the hot water type, dominated by circulating liquid that transfers most of the heat and largely controls subsurface pressures. During the exploitation of such systems, a reduction of pressures is inevitable which, in some areas may lead to land subsidence. A numerical model is introduced which simulates the effects of fluid production as well as reinjection on the vertical deformation of water dominated geothermal reservoirs. This program, based on an Integrated Finite Difference technique and Terzaghi's one-dimensional consolidation model, computes the transport of heat and water through porous media, and resulting pore volume changes. Examples are presented to show the effects of reservoir heterogeneities on the compaction of these hot water systems, as well as the effects of different production-injection schemes. The use of isothermal models to simulate the deformation of non-isothermal systems is also investigated