Applications of the boundary absorption using a perfectly matched layer for elastic wave simulation in poroelastic media
完全匹配层吸收边界在孔隙介质弹性波模拟中的应用

In numerical modeling of elastic wave propagation in a porous medium, artificial boundaries should be treated so that they have minimum effects on elastic wave simulations. In this paper, a high-order velocity-stress staggered-grid finite-difference scheme, with a perfectly matched layer (PML) absorbing boundary condition, was firstly proposed for simulating wave propagation in poroelastic media. The construction of perfectly matched layer was discussed in detail, and the implementation of high-order finite-difference scheme of the PML boundary conditions was also studied. The numerical results were validated by using analytical solutions in a homogeneous model. The paper demonstrated the performance of PML for body waves with various incident angles and various absorbing thicknesses. Also, free surface Rayleigh waves are investigated for their absorptions. The PML was compared with two kinds of absorption boundary conditions to confirm the efficiency of the PML. Our numerical results show that, the PML can efficiently absorb or reduce outgoing waves, not only for body waves, but also for surface waves. The PML method is one of the best absorption boundary conditions for porous elastic wave modeling. Our algorithm will play an important role for investigating elastic wave response of inhomogeneous porous media, especially for studying borehole sonic logging response of heterogeneous porous media.