Using Oil & Gas Borehole Data to Unlock the Geothermal Potential of the Dogger Sandstone in the North German Basin

Abstract

In Germany, the geothermal development takes place at different speeds regionally. Compared to the Molasse Basin in South Germany, the North German Basin is just at the beginning of its geothermal exploration. The project “Warm-Up” aims to evaluate the geothermal potential in the North German Basin and to promote its geothermal development. One target for detailed investigations are the sandstones of the Dogger. This Jurassic reservoir with nearly full extent in the North German Basin was a worthwhile target for the Oil Industry based on its reservoir quality and its oil content. A large volume of data, including geological and lithological one, with special focus on hydraulic data, porosity-permeability relationships and their links to the facies have been evaluated. Where core data is not available, the extraction of hydraulic properties from well logs is necessary. Different methods for deriving porosity and permeability from well logs are tested and checked against core data. If hydraulic test results are available the comparison of those in-situ data to logging and core measurements is of crucial importance. In reality, a full set of logging, core and test data is only available in a few wells, despite the large effort, taken by the hydrocarbon industry in the past. Therefore, it is important to develop workflows, that allows the prediction of the productivity of the Dogger sandstones in areas with fewer data and to reduce the exploitation risk. Companies like local municipal utility or majors can utilize this knowledge to unlock the geothermal potential of the North German Basin.