Geothermal resource assessment for North Dakota. Final Report

Temperatures in four geothermal aquifers, inyan Kara (Cretaceous), Mission Canyon (Mississippian), Duperow (Devonian), and Red River (Ordovician) are in the range for low and moderate temperature geothermal resources within an area of about 130,000 km{sup 2} in North Dakota. The accessible resource base is 13,500 x 10{sup 18} J., which, assuming a recovery factor of 0.001, may represent a greater quantity of recoverable energy than is present in the basin in the form of petroleum. A synthesis of heat flow, thermal conductivity, and stratigraphic data was found to be significantly more accurate in determining formation temperatures than the use of linear temperature gradients derived from bottom hole temperature data. The thermal structure of the Williston Basin is determined by the thermal conductivities of four principal lithologies: Tertiary silts and sands (1.6 W/m/K), Mesozoic shales (1.2 W/m/K), Paleozoic limestones (3.2 W/m/K), and Paleozoic dolomites (3.5 W/m/K). The stratigraphic placement of these lithologies leads to a complex, multi-component geothermal gradient which precludes use of any single component gradient for accurate determination of subsurface temperatures