The utilisation of deep geothermal reservoirs not only leads to a change in the pore pressure regime, but also to the long-term propagation of a cooling front. These changes in the stress state can lead to seismicity in or around the reservoir. However, the seismicity currently observed is lower than expected. In practice, there appears to be a gradual reduction in the thermally induced stress changes. The CoolStress project aims to investigate how thermally induced stresses develop over the course of production. Best practice recommendations for modelling thermal stresses in hydrothermal geothermal projects are to be developed. In general, thermally induced seismicity is to be better understood to ensure safe operation.

The aim of the work package at TU Darmstadt is to use generic models to investigate the effects of pore pressure and the propagation of the cooling front as a result of cold-water injection in interaction with relevant factors of the reservoir rock. These factors are permeability, thermal conductivity, Young's modulus and its variation, layer changes in the vicinity of the reservoir as well as faults. Generic models are used to investigate the thermo-hydro-mechanical material behaviour.

in preparation