Modelling permeability and stimulation for deep heat mining
Permeability is the decisive reservoir property for the economic success of geothermal operations as it determines the flow rates that can be achieved when circulating fluid to mine heat from the reservoir. However, at the depth of deep geothermal reservoir targets, permeability is typically too low for commercial circulation rates and therefore requires enhancement by (hydraulic) stimulation. There is currently no quantitative theory that can predict by how much reservoir permeability may be enhanced during stimulation at a given site. This uncertainty is one of the major investment risks in the future development of deep geothermal energy in Switzerland. In addition, seismicity induced by hydraulic stimulation is the biggest technical and societal acceptance risk. Our project develops and applies novel numerical simulation techniques for the quantification of permeability enhancement during hydraulic stimulation, its spatial evolution during reservoir development, and the seismicity-related processes of fault slip during stimulation.
The project is part of the National Research Programme "Energy Turnaround" (NRP 70) founded by the SNSF.