Modelling the Injection of CO2 Enriched Groundwater into a Low-Temperature Fractured Rock Siliciclastic Reservoir at the German GECO Demo Site in Bochum

To investigate the potential efficiency of CO2 storage in a low temperature sedimentary reservoir the German GECO demo site in Bochum, located in the Upper Carboniferous, was chosen. Understanding of transport paths during the planning of the demo site is complicated by heterogeneities in the subsurface and a widespread branching mine dewatering system. Numerical groundwater flow and transport modelling was used to characterise and investigate the potential of the Bochum Upper Carboniferous subsurface. Based on the extensive mining situation in the Ruhr area within a complex geologic setting a stepwise modelling concept was developed. The concept comprises three scales with an increasing level of detail. This paper provides an overview of the numerical modelling performed starting at the conceptional model followed by the geological, groundwater flow and reservoir modelling.