Localization and characterization of hydrothermal alteration zones in a geothermal reservoir and their significance for rock mechanics

The present thesis introduces a method to localize hydrothermally altered zones in a crystalline geothermal reservoir. On the basis of synthetic clay content logs, the geomechanical significance of clay zones is demonstrated. It is shown that clay zones reduce the rock strength, thus creating aseismic slips on fractures and affecting the evolution of induced seismicity. The results of the thesis highlight the importance of hydrothermal alteration for hydro-mechanical reservoir characterization.