Fractured rock hydromechanics: from borehole testing to solute transport and CO2 storage

Abstract

The interaction between mechanical deformation and fluid flow in fractured rock gives rise to a host of coupled hydromechanical processes, which form the basis of a number of interesting research questions with practical implications. This paper will first discuss these processes in general, describing two numerical models that have been developed to analyse these processes. Then, four very different studies will be presented to illustrate the richness of this field. The first study has to do with borehole injection testing to determine fracture parameters and how hydromechanical effects will modify test results. The second study is on stress changes (caused by stress release) in rock near a tunnel during excavation, which cause significant changes in fluid pressures in the region. The third study is on the relationship between mechanical effects and flow anisotropy and channelling in a rock block with a fracture network. The fourth study pertains to the hydromechanical effects associated with deep CO2 injection and storage. These examples serve to demonstrate the various interesting research problems in fractured rock hydromechanics. In the coming years, we expect intensified activity and further advances in this exciting field of research.