Geomechanical Investigation of High Priority Geothermal Strata in the Molasse Basin, Bavaria, Germany

Abstract

Due to the increasing use of geothermal energy in Bavaria, Germany, over the last years, the practical experience in geothermal plant operation for heat and power generation has shown an evident need for research. Especially questions related to deep geothermal energy need to be answered, and the risk of geothermal exploration in the Molasse Basin and the crystalline rocks in the northern part of Bavaria should be reduced to optimize reservoir engineering. The Molasse Basin, extending along the northern flank of the Alps, represents an alpine foreland basin. Situated south of Munich, the basin offers ideal conditions for the use of hydrothermal geothermal energy. The petrothermal potential in crystalline rock is focused in the northern part of Bavaria. The development and use of this future technology initially requires extensive research but has outstanding future potential. In this context, the determination of rock mechanical parameters is indispensable for the subsequent modelling of hydrothermal and petrothermal reservoirs. For this purpose, laboratory tests were conducted using drilling samples as well as analogue samples from quarries. Based on the results of these experiments a database has been created. This database improves the knowledge of the mechanical properties of representative rock types. Furthermore, the database improves the knowledge about detection of a local stress field, which has major impact on the hydraulic system of the geothermal reservoir. The outcome of this research should increase profitability and minimize risk of geothermal projects.