Preliminary Analysis of Stress in the Newberry EGS Well NWG 55-29

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 deg 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 deg. 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.