Characterization of a Deep Fault Zone in Upper Jurassic Carbonates of the Northern Alpine Foreland Basin for Geothermal Production (South Germany)

Abstract

The fractured and karstified Upper Jurassic carbonates of the South German Molasse Basin, the northern foreland basin of the European Alps, constitute the most important reservoir for deep geothermal energy use in Germany. Over the last 15 years more than 20 deep geothermal heating facilities and power plants were successfully installed. Currently, new wells are drilled deeper and nearer closer to the frontal fault of the Alpine fold belt. The new targets are associated with challenging drilling and detailed target determination like damage zones and intersection of faults of Y-shaped graben structures. One of the wells into the deep basin is the well GEN-1ST, drilled into 4.7 km deep dolomitic carbonates. An intensive research program was carried out to determine the permeability structure across the drilled fault zone including vertical seismic profiling, core drilling and logging.