IN SITU STRESS, FRACTURE AND FLUID FLOW ANALYSIS— EAST FLANK OF THE COSO GEOTHERMAL FIELD

Abstract

High rock temperatures, a high degree of fracturing, high tectonic stresses, and low permeability are the combination of qualities that define an ideal candidate—Enhanced Geothermal System (EGS) reservoir. The Coso Geothermal Field is an area where fluid temperatures exceeding 300°C have been measured at depths less than 10,000 feet and the reservoir is both highly fractured and tectonically stressed. Some of the wells within this portion of the reservoir are relatively impermeable, particularly on the margins of the field. Geoscientists from the Coso Operating Company, EGI-Utah, and GeoMechanics International Inc. are using well datasets from the east flank of the Coso Geothermal Field to develop an understanding of the relationships between natural fracture distribution, fluid flow, and the ambient tectonic stresses that exist within the resource. Technical results from the first year of analysis are presented.