Stratabound Geothermal Resources in the Northern Great Plains

Abstract

The identified, accessible, geothermal resource base in northern Great Plains of North Dakota and South Dakota has been doubled by analysis of all aquifers in the Williston and Kennedy basins. This finding suggests that the total stratabound geothermal resource in conduction dominated systems in the United States may be more than twice the current estimates. The geothermal potential of the northern plains is largely determine by litho-stratigraphic control of thermal conductivity which produces high conductive temperature gradients within the Pierre, Carlisle, Graneros, and Belle Fourche shales (Cretaceous) which cover the region as an insulating layers up to 2 km thick. These high temperature gradients make waters contained in all underlying aquifers potential geothermal resources. Confined groundwater flow regional aquifers generates a large geothermal region in south central South Dakota and north central Nebraska where temperature gradients of the order of 100 K km-1 occur within the insulating shale layer. Confined groundwater flow to the east occurs throughout the regional and created local thermal anomalies where structures cause upward flow.