Characterization of the geomechanical properties of a reservoir rock from an integrated analysis of borehole data

Abstract

The importance of the reservoir characterization for addressing a broad range of geomechanics-related problems and the limitation of the deep core data necessitates tools to characterize the mechanical properties indirectly from borehole data. The novel approach of integrating various borehole and hydraulic data of the Soultz-sous-Forêts EGS field proposed in this study enables a characterization of the deep crystalline rock with respect to their role in affecting the failure processes during stimulation. Three zones in the reservoir are proposed based on the inherent structures present in a set of geophysical logs of GPK4 well. The occurrence of abundance fractures and breakouts in the two-mica granite indicate that this zone is weaker than the massive porphyritic granite. In between, a transition zone is identified by its high clay content. On the top of this, the slip tendency of all minor and major fractures in each zone is estimated. As most of the EGS target the crystalline rock, the understanding of the lithological controls on seismicity in granitic rock is crucial for the future development of the EGS