Evaluation of energy extraction from a geothermal resource in central Alberta, Canada using different well configurations

Abstract

Geothermal energy harvesting offers a clean option for energy generation with nearly zero greenhouse gas emission. However, due to the lack of understanding of geothermal resource characterization (geological properties and distributions), optimal well placement and operation for energy generation, and energy return on energy invested, geothermal development has been slow. Recently, geothermal energy extraction is drawing attention for its global potential due to environmental concerns about carbon-intensive energy generation from fossil fuels. Here, we examine a potential case of geothermal energy extraction from a sandstone, moderate temperature, low permeability geothermal resource in Central Alberta, Canada, which has not been simulated before. We construct a detailed earth model of dimensions 1,000 m by 1,000 m horizontally and 2,800 m vertically from the surface to the geothermal reservoir using well log data. Heat losses along the wells are taken into account. From detailed geological modelling and thermal reservoir simulation, we demonstrate that different well configurations affect energy extraction from the geothermal resource. The results show that energy produced to energy invested ratio ranges from 1 to 6 GJ/GJ depending on the well configuration, operating rate, and permeability of the reservoir. The outcomes from the research suggest that geothermal development in Alberta will require careful design and operating strategy to yield useful energy returns.