Geothermal Resources in the Williston Basin: North Dakota

Abstract

Temperatures in four geothermal aquifers in the Williston Basin are in the range for low and moderate temperature geothermal resources within an area of about 128,000 km2 in North Dakota. The accessible resource base is 13,500 x 10/18 J., represent a greater quantities 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 is 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 (3.0 W/m/K), and Paleozoic dolomites (4.0 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.