GEOLOGICAL 3D-MODELLING AS EVALUATION TOOL OF CO2-STORAGE SITES - ONE EXAMPLE FROM THE NORTH GERMAN BASIN

The North German Basin as part of the Southern Permian Basin is one of the main sedimentary basins in the European onshore and offshore region with good CO2-storage potential within several stratigraphic intervals. For the German onshore area, a first nationwide overview of suitable reservoir and barrier rocks of the deeper subsurface with regard to CO2-storage has recently been developed by the Federal Institute for Geosciences and Natural Resources (BGR) together with the state geological surveys. This overview led to an areal assessment of general formation availability, depths and thicknesses. More detailed site specific studies, however, are only available at a few locations and more regional and comprehensive investigations on geological structures with their reservoir and seal properties are still needed.

Here we present a 3D-modelling approach to get a better understanding of the regional geologic and structural development, i.e. burial depth as well as different paleo-environmental conditions that affect the quality of reservoir and seal rocks at a certain location. From a selected area in the centre of the northern German Basin a geological 3D-modell has been build based on available surface maps and fault polygons. The model area comprises 30 by 70 km and inhibits 14 stratigraphic horizons from Rotliegend to Quaternary. Secondly, more detailed information on petrophysical properties has been elaborated from 3 boreholes. Based on geophysical logs (GR, Sonic, resistivity and density) and other available data like core descriptions the mineral content (lithology) as well as reservoir characteristic parameters like porosity and fluid content have been determined by petrophysical methods for two potential stratigraphic intervals, i.e. Triassic Buntsandstein and Lower Jurassic. These results will serve as input for further facies and dynamic modelling studies.