Analysis of Fracture Propagation Under Thermal Stress in Geothermal Reservoirs

Abstract

Thermal stimulation has been considered as a means of enhancing reservoir permeability. The plausibility and the conditions for success of such approach are investigated using d numerical modeling and analysis. Influence of cooling on fractures and their propagation has been considered for two example problems: sudden cooling of surface of infinite half-space and injection/extraction process in wellbore and fractures. Interaction of multiple secondary thermal fractures and their trajectory is also considered. Results indicate that length of the secondary cracks is mainly determined by the temperature distribution in the geothermal reservoir and under suitable conditions of in-situ stress regime and cooling, thermal stimulation can lead to significant fracture propagation.