Mesoscopic fluid flow simulation in double-porosity rocks

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).