Application of Seismic and Geomechanical Approaches in Defining Geothermal Targets in the German Molasse Basin

Abstract

Geothermal energy exploitation of the Upper Jurassic carbonates underlying the South German Molasse Basin is challenging due to its heterogeneous geological and structural characteristics (karst, fault zones, fractures, and lithofacies). Our approach is based on analyzing depth migrated 3D seismic data for mapping reef growth and areas of intensified karstification, as well as borehole data for correlation and calibration. A 3D facies model created by three seismic attributes displays the distribution of chaotic/massive and laminated/bedded facies of the Upper Jurassic carbonates. Geomechanical-geometrical considerations constrain the in situ stress state and the maximum horizontal stress orientation which found to be matching with the regional in situ stress field and observed open fracture orientation. The integration of these methodologies minimizes exploration risks related to the heterogeneous permeability distribution within the Upper Jurassic carbonates. They derive their validity from nearby projects results, well data, and geological observation, where the ease of their application decreases the overall exploration costs for the development of geothermal projects in the Molasse Basin.