New Geothermal Resource Map of the Northeastern US and Technique for Mapping Temperature at Depth

Abstract

The results of a new EGS geothermal resource assessment of the eastern US, focused on the Northeastern US and based on use of Bottom Hole Temperatures (BHT), are summarized. A total of 5,800 heat flow points are now available for the area as opposed to the 323 used to produce the 2004 Geothermal Map of North America. The challenge is determining heat flow and subsurface temperature in areas where no data or limited conventional heat flow data exist in the previous assessments (most of the eastern 2/3 of the US). The techniques used to allow large scale use of BHT data for heat flow calculations are described. The process for the temperature-at-depth calculation is updated to better accommodate the use of BHT data. The geophysical data are also utilized as an ancillary predictor to the heat flow determination process in areas with limited or no thermal data. This study uses the same process to calculate heat storage when the thermal properties and temperature at depth are known described in the Future of Geothermal Energy report. Heat-in-place values have been updated for the northeastern US. Because of the higher data density the new temperature at depth maps show more localized temperature anomalies then the older maps and are a first step in the identification of site specific geothermal anomalies for further research and development. An important result is the identification and delineation of a significant thermal anomaly in eastern West Virginia.