Integrating digitized fracture data in geological 3D models, Upper Carboniferous, Ruhr area, Germany

Subsurface coal-mining in the Ruhr Area provides one of the world´s best documented reservoirs. Mining has been ceased, mine water drainage is gradually reduced and formation water as well as groundwater levels are planned to reach pre-mining levels. Rising mine water levels increase the pore pressure and induce stress changes in the subsurface, which may reactivate natural and/or mining-related faults. Here, we present a geological km-scale 3D model of the Upper Carboniferous of a former mining area in the eastern Ruhr area based on coal seam mappings from the Geological Survey of NRW. This is part of the interdisciplinary FloodRisk project, which aims to enhance the understanding of the geomechanical coupling of increased pore pressure and heterogeneous ground movements. The 3D model integrates multidisciplinary data; e.g. petrophysical parameters obtained from core analysis are integrated to model their spatial distribution with greater confidence in the folded and faulted lithologies. Integration of fractures from t-LiDAR scans of surface analogs provides the basis for discrete fracture network modelling. Fracture analysis reveals four dominant fracture sets characterized by striking orientations of N-S, WSW-ENE, W-E and WNW-ESE with minor sets in between. ... mehr
The model will serve as the basis for future geomechanical simulations such as slip tendency analyses and pore pressure modelling.