Challenges in geothermal reservoir modeling: from applications to future opportunities

The physical processes and their mutual interactions within a geothermal reservoir are highly complex and unique, and can differ significantly from place to place. As a result, each model presents its own challenges. Critical aspects include the identification and integration of relevant geological structures and fluid pathways, appropriate choice of boundary conditions, calibration by means of existing field investigations and also operational management. In this presentation we would like to show the possibilities and challenges of modeling geothermal reservoirs. For this purpose, we present both synthetic and real thermo-hydraulic-mechanical models of different types of geothermal reservoirs and discuss their results.
The geothermal power plant in Soultz-sous-Forêts represents a pioneer for economic use Enhanced geothermal systems (EGS). More than 20 years of research have created a unique database of experimental data that can be used nowadays to calibrate thermo-hydraulic models of the complex fault and fracture network at Soultz and to predict a future sustainable operation. The aquifers of the Upper Rhine Valley or the upper Jurassic in the greater Munich area pose a quite different challenge. ... mehrHere, the combination of matrix permeability, faulted (and in limestones karstified) leads to a vast sensitivity regarding the internal geology, but also partly high flow rates. We present initial results of calibrated thermal-hydraulic-mechanical models of a continuous long-term operation to track changes in the long-term behavior of the reservoir. Finally, we will show how kilometer-scale hydrothermal convection cells can explain thermal anomalies in faulted sandstone reservoirs located in northwestern Germany.