Study On The Numerical Simulation Of The Seismic Wave Field In The Two Phase-medium

The two-phase medium theory was introduced in order to more precise description underground contains the fluid porous medium with earthquake project and energy seismic survey thoroughdevelopment. Boit's theory for elastic waves in porous media was established on macroscopic level(Biot, 1956a, b, 1962a, b). The anelastic effects arise from viscous interactions between the fluid and the soild matrix. The following assumptions are used in the theory: (1)Seismic wavelength is large in comparison to the pore size. (2)The deformations are small. (3)The liquid phase is continous, such that pore are connected and the disconnected pore are part of the matrix. (4)The soild matrix is elastic. (5)The medium is statistically isotropic, and gravity forces are neglected.The seismic simulation is the research underground complex medium effective method, the finite element, finite-difference, and pseudospectral methods are usually employed. In the paper, the finite element and the finite-difference method principle, the realization method are introduced importantly. In numerical simulation of wave propagation meda, the imposition of artificial boundaries introduce spurious reflections which will affect the accuracy of numerial sultions. So several boundary conditions are introduced. Based on mastering principles of wave equation forward modeling, many complex medium models suitable to the real fact have been built respectively and subsequently wave equation forward modeling was practiced, The author analyzed forward modeling parameters influence on the modeling accuracy and efficiency but also put forward how to improve the efficiency at the maximum while guaranteeing forward modeling accuracy.The paper analyzed wave equation response to the complicated medium through image of wave field, thus to achieve a better comprehend of wave propagation in complicated structure and continued the subsequent processing and research for the two-phase medium. The result reveals pore fluids and solid/fluid in teraction cans often and harden the rock's matrix. The velocity dispersion and amplitude attenuation of the acousic and elastic waves and cause the compressional wave of the second kind. Orientation of fractures or cracks, periodic sedimentary deposits of rock, and alignment of the stresses cause velocity anisotropy, shear-wave splitting.