| Title | Preliminary Analysis of Stress in the Newberry EGS Well NWG 55-29 |
|---|---|
| Authors | Davatzes, Nicholas C.; Hickman, Stephen H. |
| Year | 2011 |
| Conference | Geothermal Resources Council Transactions |
| Keywords | Geothermal; EGS; image log; fracture; stress; borehole breakout; Newberry |
| Abstract | As part of the planning for stimulation of the Newberry Volcano Enhanced Geothermal Systems (EGS) Demonstration project in Oregon, a high-resolution borehole televiewer (BHTV) log was acquired using the ALT ABI85 BHTV tool in the slightly deviated NWG 55-29 well. The image log reveals an extensive network of fractures in a conjugate set striking approximately N-S and dipping 50° that are well oriented for normal slip and are consistent with surface-breaking regional normal faults in the vicinity. Similarly, breakouts indicate a consistent minimum horizontal stress, Shmin, azimuth of 092.3±17.3°. In conjunction with a suite of geophysical logs, a model of the stress magnitudes constrained by the width of breakouts at depth and a model of rock strength independently indicates a predominantly normal faulting stress regime. |