Estimate of Geothermal Energy Resource in Major U.S. Sedimentary Basins
Recently, there has been renewed interest in recovering the geothermal energy stored in sedimentary basins for electricity production. Because most sedimentary basins have been explored for oil and gas, well logs, temperatures at depth, and reservoir properties are known. This reduces exploration risk and allows development of geologic exploration models for each basin as well as a relative assessment of geologic risk elements for each play. This study estimates the magnitude of recoverable geothermal energy from fifteen major known US sedimentary basins and ranks these basins relative to their potential. The total available thermal resource for each basin was estimated using the volumetric heat-in-place method originally proposed by Muffler(1) (USGS), and a recovery factor was used to estimate the size of the recoverable thermal resource.
Total sedimentary thickness maps, stratigraphic columns, cross sections, and temperature gradient Information was gathered for each basin from published articles, USGS reports, and state geological survey reports. When published data was insufficient, thermal gradients and reservoir properties were derived from oil and gas well logs obtained on oil and gas commission websites. Basin stratigraphy, structural history, and groundwater circulation patterns were studied in order to develop a model that estimates resource size, temperature distribution and a probable recovery factor. The resource estimate will be used to develop an alternative sedimentary basin supply curve.
(1) Muffler, L.P.J., and Cataldi, R., 1978, Methods for regional assessment of geothermal resources: Geothermics, v. 7, p. 53-89.
AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California