Validation of Play Fairway Analysis of the geothermal potential of Camas Prairie, south-central Idaho, by an exploration well

• Published in: Geothermal energy (Heidelberg) Vol. 11; no. 1; pp. 21 - 17
• Main Authors: Lachmar, Thomas E., Neupane, Ghanashyam, Garg, Sabodh K., Dobson, Patrick F., Smith, Connor J., Newell, Dennis L., Shervais, John W., Evans, James P., Mink, Leland L.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 04.08.2023; Springer Nature B.V; Springer Science + Business Media; SpringerOpen
• Subjects: Artesian flow; Basalt; Cold; Cold water; Earth and Environmental Science; Earth Sciences; Fluids; Geochemistry; Geoecology/Natural Processes; Geologic mapping; Geological mapping; Geophysical data; Geophysical logs; Geotechnical Engineering & Applied Earth Sciences; Geothermal exploration; Geothermal power; Geothermal resources; Geothermal springs; Geothermometers; Heat; Helium; Helium isotopes; Hot springs; Hydrothermal solutions; Injection; Injection test; Isotope ratios; Permeability; Renewable and Green Energy; Reservoirs; Sediments; Temperature; Temperature logs; Transmissivity; Volcanic rocks; Water springs; Water temperature; Well water; United States > US; Idaho; Geophysical logs; Geochemistry; Injection test; Geothermometers; Temperature logs
• ISSN: 2195-9706; 2195-9706
• DOI: 10.1186/s40517-023-00264-4

Play Fairway Analysis (PFA) methodology was adapted for geothermal exploration at Camas Prairie, Idaho. Geophysical data, structural and geologic mapping, volcanic rock ages and vent locations, and the distribution of thermal springs and wells all indicated a relatively high geothermal potential along the southern margin of the Prairie. An exploration well (USU Camas-1) was drilled to a depth of 618.3 m to validate the PFA. A permeable zone was encountered at ~ 357.5 m with a maximum measured temperature of ~ 80 °C, which was suppressed following the injection of cold water. A moderate transmissivity of ~ 0.25–1 cm 2 /s estimated from an injection test as well a seasonal artesian flow at ~ 0.7 L/s corroborate the presence of a permeable zone. The existence of a lacustrine clay seal was confirmed near the bottom of the basin-fill sediment occupying the upper 314 m of the well. Geothermometers suggest the USU Camas-1 well water equilibrated at a reservoir temperature of ~ 120 °C. Based on the locations of both thermal and cold wells, geothermal fluids appear to be flowing upward along one or both of two fault systems. The presence of young basalts and elevated helium isotope ratios suggest that the heat source of Camas Prairie is magmatic. However, the faults may be acting as a conduit for geothermal fluids to rise from great depth without a shallow magmatic source being present. Camas Prairie is a promising area for geothermal development, but the relatively low reservoir temperatures indicate this resource may not be suitable for electric generation. Perhaps the best use would be for heating.