Geological modelling of the Triassic Stuttgart Formation at the Ketzin CO2 storage site, Germany

At Ketzin, about 25 km west of Berlin (Germany), the saline aquifer of the Triassic Stuttgart Formation is used for a carbon dioxide storage research project. The formation is lithologically very heterogeneous, reflecting a complex fluviatile facies distribution pattern. We focused on the development of a primary geological reservoir model as commonly employed for dynamic modelling during the planning and early injection stages of a storage project. Due to the need to capture the complex geometrical structure of the Stuttgart Formation, despite limited availability of exploration data, stochastic modelling techniques were employed. Firstly, we modelled the facies architecture of the reservoir and, secondly, assigned porosity and permeability values to the facies types included in the model. Petrophysical parameters for each facies type were quantified using site-specific porosity histograms and related permeability functions. The comparison of dynamic flow simulation results and well-test interpretations, and furthermore with the first observed monitoring data, helped to focus the modelling work and to adjust monitoring plans. Modelling is understood as an iterative process, both with respect to data arrival and progressively improving the understanding of the reservoir, but also with respect to the problem which the model is being designed to address.