Interdisciplinary fracture network characterization in the crystalline basement: a case study from the Southern Odenwald, SW Germany

Abstract. The crystalline basement is considered a ubiquitous and almost inexhaustible source of geothermal energy in the Upper Rhine Graben (URG) other regions worldwide. hydraulic properties basement, which are one key factors productivity power plants, primarily controlled by hydraulically active faults fractures. While most accurate situ information about general fracture network obtained from image logs deep boreholes, such data generally sparse costly thus often not openly accessible. To circumvent this problem, an outcrop analogue study was conducted with interdisciplinary geoscientific methods Tromm Granite, located southern Odenwald at northeastern margin URG. Using light detection ranging (lidar) scanning, characteristics were extracted total five outcrops; these additionally complemented lineament analysis two different digital elevation models (DEMs). Based on this, discrete (DFN) developed to calculate equivalent permeability tensors under assumed reservoir conditions. influences parameters, as orientation, density, aperture mineralization, investigated. In addition, extensive gravity radon measurements carried out area, allowing fault zones naturally increased porosity be mapped. Gravity anomalies served input for stochastic density inversion, through areas potentially open identified. A laterally heterogeneous characterizes highest natural permeabilities expected pluton margin, due influence large shear zones.