An industry-DOE cost-shared project is underway to evaluate the technical feasibility of developing an Enhanced Geothermal System (EGS) power generation project in Desert Peak (Nevada) geothermal field. As part of pre-stimulation analysis, a non-commercial well (DP 27-15) in the hydrothermal portion of the field has been image-logged to aid in evaluating lithologies and stress and fracture characterization of potential reservoir units as part of a multidisciplinary study. Borehole images, gamma ray, caliper, and cable tension were recorded by Schlumberger’s Formation Microscanner* tool run in the well and compared with geological features identified by petrologic analysis of well cuttings. The wellbore image log obtained from deeper portions of the well (3057.5-5620 ft; ~932-1712 m) has been analyzed. Features identified from these resistivity-contrast generated images include bedding planes, lithologic contacts, foliations, conductive mineral grains, drilling induced fractures, and natural fractures. This paper describes selected geologic features seen on the image logs that may influence the design and success of stimulation activities in the potential reservoir, as part of a multi-disciplinary approach to understanding EGS systems.

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