GEOMECHANICAL-HYDRAULIC CHARACTERISATION OF THE RESERVOIR AND ITS OVERBURDEN IN THE NORTH ALPINE FORELAND BASIN, SE GERMANY

In the North Alpine Foreland Basin, SE Germany, the Upper Jurassic carbonates are already being successfully used as a reservoir for hydrothermal geothermal energy. However, the heterogeneous structure of the so-called Malm aquifer means that the rock properties cannot be predicted with a sufficient degree of accuracy. In order to further develop this renewable form of energy production, precise knowledge of the geotechnical parameters of the subsurface serving as a reservoir is absolutely necessary for the realisation of geothermal projects. For this reason, the Geothermal Alliance Bavaria (GAB) research project was established in 2016. In the current second funding period, the reservoir and its overburden are to be characterised geomechanically and hydraulically. For this purpose, an extensive rock mechanics laboratory programme is being carried out on rock samples from existing drill cores of hydrocarbon/research wells and analogue samples from quarries. The parameterisation is done by non-destructive and destructive testing methods. The observed crack progressions are recorded with a high-speed camera. The obtained characteristic values as well as the high-speed camera images serve as input parameters for different scenarios of the numerical crack propagation simulation. The geomechanical reservoir characterisation enables a more precise knowledge of the Malm aquifer and should thus allow geothermal energy in Germany to be used more effectively in the future.

This work has been performed in the framework of the project GAB and is funded by the Bavarian Ministry of Science and Art (StMWK).