[HSC05-P04] Modeling of fracture-permeability of soft rocks for CCUS technologies
Keywords:soft rocks, fracture permeability, modeling
To model precisely the process of fluid flow transport within such reservoirs, relationship between fluid transport and geomechanical response in the whole regime pre- and post-fracturing of deformation including shear-fracturing and post slipping should be well addressed.
The purpose of this study is to examine experimentally permeability changes in low-permeable rocks during deformation, shear-fracturing, and post-failure slipping depending on changes in effective pressures, which assumes that permeability changes in fracturing rocks in the course of CO2 injection under conditions of geological storage of CO2.
Our results demonstrated that the obtained stress-strain curves showed different trends on each types of low-permeable rocks tested, and particularly, harder mudstones (e.g. shale, slate) had a significantly more slowly change in permeability compared to softening mudstone, as effective pressure decreases. In terms of modeling of fracture permeability, in pre-failure regime, the obtained fitting curves based on permeability change as a function of volumetric strain showed a harmony with previous literature data related to dilatancy. Whereas, our predicted model in post-failure regime could not be explained fully by a conventional model of fracturing permeability including normal stress, and fracture aperture.