Long term behaviour of geothermal reservoirs

Abstract

A number of different aspects of geothermal reservoir behaviour were studied during the week. These ranged from the correct formulation of the thermo-elastic deformation equations for granite, and the possible practical methods of implementing the thermo-elastic effects within the existing large computer codes, to the generation of simple models describing the long term thermal effects.

This report describes the results of simple modelling. The approach was to consider first how the rock cooled as a result of water moving through the network of cracks and then to consider second how this cooling might change the rock stresses and water viscosity, and hence the effective permeability of the cracks, thereby altering the flow pattern from inlet to outlet bore-hole.