HR: 1630h
AN: V54C-03    [Abstracts]
TI: 3D Finite Element Analysis of Stress, Second Order Fractures and Fluid-Flow Pathways for the Coso Geothermal Field
AU: * Eckert, A
EM: andreas.eckert@gpi-uni-karlsruhe.de
AF: Geophysical Institute, University of Karlsruhe, Hertzstrasse 16, Karlsruhe, 76187, Germany
AU: Connolly, P
EM: Peter.Connolly@chevron.com
AF: Chevron, Rock Mechanics Team, 1500 Louisiana Street, Houston, TX 77002-7308, United States
AB: 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 3D finite element analysis to simulate the 3D state of stress of the tectonic setting of the Coso Range within the ECSZ. The modeling is based on a multi-scale approach of the ECSZ and the Coso Range releasing bend setting. The modeling results are calibrated against stress magnitudes and orienations and the received 3D state of stress is used for subsequent anaylsis. The tectonically induced differential stresses are used to infer second order fracture likelihood and orientation. The mean stress ditribution is used to derive possible fluid flow vectors. The results show that the Coso Range and adjacent areas are regions of increased likelihood of second order fracture generation and that 2nd order fracures coincide with clusters of regional seismicity. 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.
DE: 8111 Continental tectonics: strike-slip and transform
DE: 8122 Dynamics: gravity and tectonics
DE: 8164 Stresses: crust and lithosphere
DE: 8168 Stresses: general
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting