| Title | Geothermal Potential in the Basins of Northeastern Nevada |
|---|---|
| Authors | Gwynn, Mark; Allis, Rick; Sprinkel, Doug; Blackett, Robert; Hardwick, Christian |
| Year | 2014 |
| Conference | Geothermal Resources Council Transactions |
| Keywords | Heat flow; thermal conductivity; bottom-hole temperatures; stratigraphic reservoir; porosity; permeability; Marys River Basin; Toano Draw; Pine Valley |
| Abstract | Previous geothermal exploration, including many relatively shallow thermal gradient wells, has shown that NE Nevada is a region with high heat flow and geothermal potential. This study reassesses over 150 publicly available bottom-hole temperatures (BHTs) and drill stem tests (DSTs) from past oil exploration to evaluate the thermal regime at 2?4 km depth. The region consists of numerous basins containing low-thermal-conductivity sediments and volcanics overlying Paleozoic bedrock consisting primarily of carbonates and lesser amounts of siliciclastics. Several Paleozoic formations are known to have high permeability and may be potential reservoirs. The depth of most basins ranges from about 2 km up to about 4 km, and due to the insulating properties of the basin-fill, the highest temperatures and best geothermal prospects may lie beneath the basins. Results show the heat flow ranges from about 75 mW/m2 in the Ruby and Goshute Valleys in the southeast part of the study area, to more than 90 mW/m2 in Marys River Basin and Huntington Valley. In the highest heat-flow basins, the temperatures are in the range of 160°C to more than 180°C at 3?4 km depth, and appear to be close to the economic temperature-depth target for stratigraphic geothermal reservoirs of 150?200°C at 2?4 km depth identified in other work. The quality of the downhole temperature data is not sufficient to determine whether the temperature scatter within basins is due to the effects of deep groundwater circulation, or is simply excessive, uncorrected cooling due to the effects of drilling immediately before the BHT and DST measurements were made. |