Seismic signatures of reservoir transport properties and pore fluid distribution

The effects of permeability, frequency, and fluid distribution on the viscoelastic behavior of rock are investigated. Wave-induced squirt fluid flow is considered at two scales: (1) local microscopic flow at the smallest scale of fluid-saturation heterogeneity and (2) macroscopic flow at a larger scale of fluid-saturated and dry patches. The important results of the theoretical modeling are: (1) a hysteresis of acoustic velocity versus saturation resulting from variations in fluid distributions, and (2) two peaks of acoustic wave attenuation - one at low frequency (caused by global squirt-flow) and another at higher frequency (caused by local flow). -from Authors