Fracture Permeability and its Relationship to In-Situ Stress in the Dixie Valley, Nevada, Geothermal Reservoir

Authors

Colleen A. Barton, Stanford University
Stephen Hickman, US. Geological Survey, Menlo Park
Roger H. Morin, Denver Federal CenterFollow
Mark D. Zoback, Stanford UniversityFollow
Thomas Finkbeiner, Stanford UniversityFollow
John Sass, U.S. Geological Survey, Flagstaff
Dick Benoit, Oxbow Geothermal Corp., RenoFollow

Date of this Version

1997

Comments

Published in PROCEEDINGS. Twenty-Second Workshop on Geothermal Reservoir Engineering Stanford University, Stanford. California, January 27-29, 1997 SGP-TR- 155

Abstract

An extensive suite of spinner flowmeter, high-resolution temperature and borehole televiewer logs were acquired in a 2.7-km-deep well drilled into a fault-hosted geothermal reservoir at Dixie Valley, Nevada. Localized perturbations to wellbore temperature and flow were used to identify hydraulically conductive fractures. Comparison of these data with fracture orientations from the borehole televiewer logs indicates that hydraulically conductive fractures in crystalline rocks within and adjacent to the producing fault zone have an orientation distinct from the overall fracture population. In conjunction with in-situ stress measurements from this well, Coulomb analysis indicates that these permeable fractures are critically stressed, potentially active normal faults in the current west-northwest extensional stress regime at Dixie Valley.