Reservoir Quality Requirements for Geothermal Developments in Deep Sedimentary Basin

Abstract

Deep sedimentary basins are investigated worldwide for geothermal power and direct-use applications. While low temperature direct use applications are widely developed and in operation, the development of geothermal power generation in the same geological settings had highly variable success rates. The need for temperature above 100-120 °C leads to targeting hydrothermally active faulted areas or more generally greater depth. With depth comes the increase of cost, uncertainties and risk for the project. One specific uncertainty to consider is the quality of the targeted geothermal reservoir. Reservoir quality can vary significantly within a basin or even sub-basin, depending on the local depositional, tectonic and diagenetic history. Reservoir quality impacts the resource volume calculation and the deliverability of the wells which then inform the economic model. In this work, we investigate the impact of the requirements on reservoir quality for the development of power generation in deep sedimentary basins. Specifically, we examine the role of uncertainty in porosity and permeability on the resource and well deliverability calculations and the implication for field development and overall project risk. An application for the Cooper Basin, South Australia is presented.