Development of a thermo-hydraulic 3D model of the deep carbonatic Malm aquifer in the Munich region (Germany) with special emphasis on a 3D seismic survey

Abstract

The mutual interference of several geothermal doublets and the relationship of seismic and hydraulic parameters were the focus of the joint research project “Geothermal characterization of karstic-fractured aquifers in Greater Munich, Germany (2008-2011)”. Thirteen doublets and triplets in production or under construction in the Munich region (Germany) provided important data for the development of a hydrogeological model (HGM). On the basis of the HGM a numerical thermo-hydraulic 3D model was generated in order to describe the hydraulic and thermal situation at the end of 2011 and to forecast the effects for the proposed lifetime of the geothermal power plants. The processing and interpretation of the 3D seismic survey in the area of Unterhaching (27 km2) could provide indications of potential hydraulic conductive zones, especially tectonic structures and different facies. After 50 years of operation thermal effects will be limited to the near surrounding area of the injection wells. In this period hydraulic influences on neighbouring doublets will be in most cases of small significance. Sometimes higher interferences will occur when injection wells are situated very close together or high injection rates or low hydraulic conductivities prevail. The numerical model represents a decision support for the optimized and sustainable hydrogeothermal usage of the Malm aquifer for the region of Munich.