| :The object of seismology is mainly to understand the subsurface, and its complex physical properties. With the development of seismological theory, geophysicists are increasingly focusing on application of seismic method. Therefore, a variety of medium has been well studied, from homogeneous to heterogeneous, from elastic to non-perfect elastic, from single phase to multiphase phase, from isotropic to anisotropic. Through theoretical research and experimental measurements, anisotropy of the earth medium has been confirmed. That is the reason why an increasing number of geophysicists pay a lot attention to the anisotropy medium. It has very important theoretical significance and applicable value in oil-gas exploration and understanding anisotropy as well as structure of the underlying medium.Application of reverse-time migration to the seismic observed data and, at the same time, separating S and P wave field from the seismic observed data based on elastic wave equation, independent profile of single S and P wave field can be obtained. Due to the velocity of P wave is higher than that of S wave, the imaging profiles we obtain have different velocity structure. Depending on the profiles, truthful velocity distribution of underground medium is determined. In anisotropic medium, P wave and S wave couple with each other, so it is hard to separate them using divergence and curl operators. So there is a need of developing a method to separating the above wave field in anisotropic medium.The paper uses the high-order staggered-grid finite difference method to simulate wave field in VTI media with high accuracy, and studies the constraints on Thomsen parameters and influence of Thomsen parameters on the various types elastic wave field. This paper researched characteristics of wave field operator and verified that the operator is determined by elastic coefficient. In the end, by studying different models, it proved the correctness and feasibility of the wave-mode separation methods. |
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