Modelling Reservoir Stimulation in Enhanced Geothermal Systems
Fluid injection in deep wells is a basic procedure in geothermal permeability enhancement. The retrieved changes of Pressure and Temperature are subsequently considered as sources of incremental stress and strain changes, using the elastic model from COMSOL Multiphysics®, which are then converted to Coulomb stress changes on favoured faults, taking into account also the background regional stress. In this work, we first upgrade this kind of procedure to evaluate the permeability enhancement obtained in the stimulation process. A commonly accepted interpretation involves the activation of electro-kinetic processes. SP anomalies observed above the Soultz-sous-Forets geothermal reservoir while injecting cold fresh water have been modelled from the retrieved fluid fluxes, using the Electric Currents interface in COMSOL Multiphysics®.