Skip to main content
Open Access Publications from the University of California

Influence of injection-induced cooling on deviatoric stress and shear reactivation of preexisting fractures in Enhanced Geothermal Systems


Cold water injection into a hot, fractured, geothermal reservoir may trigger shear activation of pre-existing fractures that can help to enhance reservoir permeability, but may also result in unwanted seismicity. In this paper, we investigate through numerical modeling of a hypothetical geothermal reservoir how injection-induced cooling may influence the potential for shear activation, paying special attention to the evolution of deviatoric stress under various stress regimes. In each case, we consider either a reservoir with homogeneous hydraulic properties or the presence of a more permeable fracture zone intersecting the injection well. This fracture zone is either oriented in the maximum (SHmax) or minimum (Shmin) horizontal stress direction. Our main finding is that depending on the configuration, injection-induced cooling stresses can favor or prevent shear reactivation of the preexisting fracture, and this effect can vary temporally and spatially.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View