Productivity enhancement of geothermal wells through fault zones: Efficient numerical evaluation of a parameter space for the Upper Jurassic aquifer of the North Alpine Foreland Basin

Abstract Fault zones (FZ) are major components of geothermal exploration concepts for the Southern German Upper Jurassic aquifer (UJA). Because these sections of possibly favorable hydraulic properties can be hidden in pumping test data, their explorational importance with respect to well productivity is still debated. In this work, the effect of hydraulically active FZ on the well-productivity-index (PI) is quantified in dependency of the UJA parameter space using numerical modeling and the Reduced Basis method. Results suggest that hidden FZ can increase PI significantly, while a hydraulically active FZ thickness of ≥ 100 m is unlikely for the Upper Jurassic aquifer.