Utilizing geothermal energy from enhanced geothermal systems as a heat source for oil sands separation: A numerical evaluation

Abstract

Burning natural gas to heat water for oil sands separation is and energy and carbon-intensive process. This study presents a COMSOL Multiphysics simulation model that comprehensively investigates the feasibility of utilizing geothermal energy from enhanced geothermal systems (EGSs) as a heat source for oil sands separation. The simulation model was built with discrete fractures and was verified with analytical results. The results demonstrate that a doublet EGS performs better than a triplet EGS for heat production, because a doublet system has more uniform flow distribution and longer flow paths. The heat production performance of an EGS can be improved by decreasing the injection temperature or creating more fractures and wider fracture apertures to increase the injection flow rate in a deeper geothermal reservoir. By adjusting the parameters of water, fractures, and the geothermal reservoir, the theoretical model shows that a doublet EGS can provide hot water (≥60 °C) for 30 years, thus saving 957.35 × 106 m3 of natural gas and reducing 1.96 × 106 tonnes of greenhouse gas emissions. This study provides a rational approach for evaluating potential EGS projects in future to provide hot water for oil sands separation.