Mesoscopic fluid flow simulation in double‐porosity rocks

Abstract

A discrete Fourier transform algorithm is designed to simulate mesoscopic fluid flow(MFF) in double‐porosity rocks. Double‐porosity equations with MFF are derived. Results from pseudo‐spectral simulation show MFF transfers fast P waves and the first kind of slow P waves' energy to the second kind of slow P waves, and the Biot diffusive mode significantly attenuates the second kind of slow P waves' energy. We use a novel approach with a numerical grid method to solve the double‐porosity wave equations. We conclude that the wavefield's attenuation should be attributed to a two‐step mechanism: (1) MFF and (2) macroscopic Biot diffusion. Numerical estimations have shown that MFF in the double‐porosity model can produce a high attenuation (0.32DB/10 m, 1/Q = 0.1083) in the seismic band (50 Hz).