Stress and Fluid-Flow Interaction for the Coso Geothermal Field Derived from 3D Numerical Models

Abstract

The efficiency of geothermal energy production at the Coso Geothermal Field in eastern California is reliant on the knowledge of fluid flow directions associated with fracture networks. We use finite element analysis to establish the 3D state of stress within the tectonic setting of the Coso Range. The mean and differential stress distributions are used to infer fluid flow vectors and second order fracture likelihood and orientation. The results show that the Coso Range and adjacent areas are regions of increased likelihood of second order fracture generation. The mean stress distribution indicates that the geothermal field occurs in a favorable location for fluid through-flow locally derived from the north and west, but more regionally from the Sierra Nevada, and that fluid storage may occur at the southern end of the Coso Wash Fault. Predicted second order structures either support or constrain fluid flow. This indicates the importance of fracture networks for fluid migration in tectonically active regions such as the Coso Range.