Effective wave dispersion and attenuation in three-periodic thin poroelastic layers saturated by two-phase fluids

Wave induced fluid flow (WIFF) in fluid-saturated poroelastic media occurs due to conversion of fast to slow diffusion P-waves at mesoscopic scales, which are much larger than the average pore size and much smaller than the traveling fast P-wave wavelengths. In this work we show that in hydrocarbon reservoirs, where the pore space is saturated by two-phase fluids, capillary pressure and interference betweeen the fluid of the two phases induce additional velocity attenuation and dispersion of seismic waves. We present a Finite Element (FE) procedure to determine the phase velocities and dissipation factors in a three-periodic fine layered poroelastic medium saturated by two-phase fluids. Firstly, the numerical results are compared with those of single-phase effective fluids and then, cases of patchy saturation are analyzed. The results show that residual saturations and wettability influence the effective P-wave phase velocities and dissipation factors.