Preliminary Analysis of Stress in the Newberry EGS Well NWG 55-29
- Key words
- Geothermal; EGS; image log; fracture; stress; borehole breakout; Newberry
- Location
- Newberry Volcano, Oregon
- Conference
- Geothermal Resources Council Transactions
- Year
- 2011
- Session
- HDR/EGS; Well logging; Fractures; Reservoir modeling; Hydros
- Language
- English
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.
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