Method Study Of Wavefield Numerical Simulation In Two-Phase Medium Based On The Reformulated BISQ Mechanism

Compared with the one-phase media, the two-phase media is closer to reality. The two-phase media theory which fully consideres the medium structure, fluid special nature, partial characteristic and the overall effect relations can obviously reflects the relation of seismic information and rock mechanical property. It can describe the actual stratal configuration and the stratum nature accurately so as to meet the actual needs of exploration in more and more complex oil gas reservoir naturally.Both of the Biot-flow and Squirt-flow are important mechanisms for the fluid flow in the two-phase media. The BISQ equation including both mechanical mechanisms can reflect the propagation law of seismic wave. But the BISQ model formula is complex and not good in practice. The reformulated BISQ model formula is simple and convenient for computation. The simulation result can reflect the wave-field propagation characteristics of two-phase media exactly and effectively.Based on the Biot theory and BISQ theory, this paper derives first-order velocity-stress equations of reformulated BISQ theory and numerically stimulates using high-order staggered-grid finite-difference. The results are further analyzed. The influence of physical parameters, such as porosity, coefficient of viscosity, permeability and coupling density on seismic wave propagation law are respectively researched to obtain the propagation law in two-phase media. Besides, the method of high-order staggered-grid finite-difference described in this paper shows good simulation effect, high precision, high efficiency and strong practicalbility.