Thesis (M.S., Geology) -- University of Idaho, December 2014 | Geothermal energy depends on high geothermal gradients, adequate permeability and accessible groundwater supply to support heat exchange with surrounding rock. Some regions may have an adequate heat resource but lack the necessary permeability or deep circulating water. Exploitation of such areas for geothermal energy could occur if permeability can be enhanced enough to provide the necessary heat exchange. This process would produce what is termed an 'enhanced geothermal system' (EGS).
The Snake River Plain in southern Idaho is a high heat flux (110 mW/m^2) region that has been recommended as an EGS target. We consider how the geologic and thermal history of the SRP might influence its EGS potential. We describe core recovered from one of the few deep boreholes located on the SRP. Fracture distribution data are then used to estimate cooling of water temperatures from a production well using a semi-analytical heat transfer model. Results delineate criteria for a hydraulic fracturing plan for augmenting the permeability and connectivity of the reservoir's preexisting fracture network.