From a scientific but also from an operator's point of view, the observation of falling injection pressures in some of the installations running for several years was a surprise. This was the reason for SWM (Stadtwerke München GmbH) to approach ERDWERK and IWC in 2011 to investigate the geothermal plant Sauerlach for positive and negative effects on reservoir behavior with regard to long-term operation.

The main focus of ERDWERK's work was to evaluate the triplet operation by means of thermal-hydraulic simulation. Thus, the conditions of a further operation were examined under the specification of a well failure, which took into account the long-term changes in the permeability and temperature developments at the previous injection wells.

Predicted pump flow and changed delivery temperatures supported the decision-makers in assessing the economic risk in order to take countermeasures for optimized operation if necessary.