Thermostratigraphic and Heat Flow Assessment of the South Slave Region in the Northwest Territories, Canada

Abstract

: Despite the elevated heat flow known in the Western part of the South Slave Region (Northwest Territories, Canada), a continuous and equilibrium geothermal gradient was never measured in boreholes below the communities where geothermal energy could be developed. This paper aims to predict the geothermal gradient and assess the Earth’s natural heat flow below the communities of Fort Providence, Kakisa, Hay River, and Enterprise. Temperatures from drill-stem test and bottom well logs were corrected for drilling disturbance and paleoclimates. Thermal conductivity and heat generation rate of the geological formations were determined from the literature and with new laboratory measurements. 1D models were developed to evaluate subsurface temperature through the sedimentary formations, based on a thermostratigraphic assessment. Results indicate a geothermal gradient varying from 44.1 ± 10.6 °C km-1 to 59.1 ± 14.9 °C km-1 and heat flow varying from 105.5 mW m-2 to 160.2 mW m-2 below the communities. These estimates are in agreement with the equilibrium geothermal gradients measured in the Cameron Hills, south of the four communities, and used to verify our predictions. Hay River appears to be the most promising community with the highest geothermal gradient estimated to be 59.1 ± 14.9 °C km-1.