Preliminary definition of the geothermal resources potential of West Virginia

Most of West Virginia is underlain by Paleozoic sedimentary rocks. Crystalline rocks are limited to two areas: a small area in the Harpers Ferry region and some basic intrusives and extrusives in Pendleton County. In the Valley and Ridge province the rocks are folded and faulted. The deformation appears to be confined to the sediments overlying the crystalline basement. The Appalachian Basin is characterized by moderately dipping sediments which may reach ticknesses of 7600 meters (25,000 feet) in eastern West Virginia. The 38th parallel fracture zone may extend through West Virginia and serve to localize geothermal resources. Heat flow in West Virginia appears to be rather uniform and in the range of 1.12 to 1.26 heat flow units. Bottomhole temperatures from oil and gas tests show no abnormally hot spots. Warm springs are limited to the eastern portion of West Virginia in the folded Appalachians and appear to be located on the flanks of anticlines at topographic lows. Geothermometry suggests subsurface temperatures in the 45 to 65{sup 0}C (113 to 149{sup 0}F) range. The Appalachian Basin provides a thick sequence of rocks with normal geothermal gradient (18.2{sup 0}C/kilometer, 1{sup 0}F/100 feet). High temperatures are expected at great depths, but production rates are likely to be low. Several oil and gas tests in West Virginia have encountered pressures about twice the normal pressure expected at the depth. However, the overpressured zones appear to be of small extent