ON PRESSURE WAVES IN SATURATED FRACTURED POROUS MEDIUM WITH DAMAGEABLE MATRIX

Abstract

A double-porosity model of single-phase flow induced by depression in fractured porous medium with damageable matrix is proposed. The development of small-scale fracturing leads to an increase in the permeability of matrix blocks and the intensification of mass transfer between subsystems of the double-porosity medium. By analyzing the inequality of dissipation, the thermodynamically consistent governing relations and the equation for evolution of the damage parameter in the matrix are derived. For the obtained system of equations, an initial-boundary value problem is formulated and solved numerically that models coupled processes of fluid flow, fracture, and changes in the stress-strain state in a loaded half-space with double porosity, which was initially in equilibrium under abnormally high pore pressure. Development of the damaged zone accompanying the pressure wave is analyzed. Two types of damage zone development are shown to exist. Choice between these solutions depends on the parameters of the medium.