Flow transport in deformable porous matrix with damage

Damage and fracturing in deformable porous matrix are relevant for geological process such as magma-fracturing during melt migration as well as hydrofracturing of crustal rocks for carbon sequestration and shale gas recovery.These fracturing processes are associated with the propagation of a pore-generating damage front ahead of high-pressure fluid injection. Theoretical works are necessary to help better understand flow behavior under deformation with damage. Many researchers have worked on the construction of damage models incorporated with elastic deformation and/or viscous relaxation, which follow the approach of irreversible thermodynamics and assume an additional thermodynamic state variable, such as the density of microcracks controls the materials strength. In our model, we relate microcracks formation and grainsize reduction in the matrix to surface free energy existing at the interface between phases by applying two-phase physics and interface thermodynamic. In cases with both elastic and viscous rheology, our results show that flow transport through porous matrix is more effective with deformational energy being partitioned to surface energy associated with newly created fractures and grain-size reduction/coarsening.