The risk of fluid-injection-induced fault reactivation in carbonate reservoirs: an investigation of a geothermal system in the Ruhr region (Germany)

Abstract In this study, we investigate the potential for fluid-injection-induced fault reactivation and induced seismicity risk during simultaneous injection-extraction operation in a theoretical geothermal doublet system carbonate reservoir Ruhr region. Using coupled three-dimensional thermo-hydro-mechanical approach, probability of injection-induced rupture. We perform sensitivity study assuming variability matrix permeability, injection/production flow rates, well placement options, rock thermal properties, evaluate influence thermally stresses. The ruptured areas were calculated based on Coulomb friction law notion that shear slip is controlled by ratio to effective normal stresses acting pre-existing plane weakness situ stress field configuration. Ruptured intrinsically not critically-stressed environment, using location-specific empirical correlations, used compute local moment magnitudes earthquakes. Based conclude that, long-term, thermally-induced play dominant role greatly increase likelihood seismicity. We, therefore, propose minimum safe distance between an injection should be primarily radius plume generated expected lifetime system. Results from provide valuable insights development future deep systems region other reservoirs worldwide.