REFLECTION AND TRANSMISSION OF INHOMOGENEOUS WAVES AT THE PLANE INTERFACE BETWEEN TWO DISSIMILAR SWELLING POROUS HALF-SPACES

The present work deals with the reflection and transmission phenomena of inhomogeneous plane harmonic waves striking obliquely at the plane interface between two dissimilar swelling porous half-spaces saturated with immiscible fluids. Two problems have been considered: (i) when an inhomogeneous dilatational wave is made incident at the interface; (ii) when an inhomogeneous shear wave is made incident at the interface. Appropriate boundary conditions for an impermeable interface between the dissimilar porous half-spaces are formulated. Equations providing the amplitude ratios and explicit expressions for the partitioning of incident energy among various reflected/transmitted waves have been presented. A numerical simulation is conducted for reservoir rock (sandstone) saturated with gas (CO2)-water mixture in the lower half-space and Massillon sandstone permeated by an air-water mixture in the upper half-space. The variations of the amplitude ratios and corresponding energy ratios against the angle of incidence and frequency parameter have been illustrated graphically. It has been verified that during reflection/transmission phenomena, the sum of energy ratios is equal to unity at each angle of incidence.