Slow waves propagation in BISQ poroelastic model

The slow compressional wave (P2-wave) in porous media based on BISQ model is investigated. The low-frequency approximate expression for velocity and attenuation of P2-wave is presented. Compared with Biot model, BISQ model predicts that the attenuation of P2 waves is very large at low frequency and decreases with increasing characteristic squirt flow length (R), the velocity low-frequency limit is not zero and decreases with increasing R, variation of the ratio of pore fluid-displacement to bulk-displacement is similar to that of attenuation and its phase is different from that of Biot model. The seepage flow induced by P2 wave at the fluid-porous media interface is larger than that of Biot model. For the sake of contrast, the properties of the fast compressional wave are also presented. Two conclusions are induced from the BISQ model: there is no squirt mechanism in inviscid fluid-saturated porous media and there is no dynamic compatibility phenomenon in viscid fluid-saturated porous media.