基于矢量波场分离的TI介质逆时偏移

基于两步法分离各向异性矢量波波场,第一步,将各向异性波动方程进行相似变换(使其具有明确直观的运动学和动力学特征),使其投影在各向同性方向上;第二步,各向异性介质传播算子波场分离基础上的波形校正,将投影于各向同性方向上的波场校正回各向异性方向上,最终达到各向异性波场分离的结果。笔者首先对VTI介质进行试算,以证明其可行性;此外,将地表数据进行分解,即所采集到的多分量地震数据在进行偏移成像之前先进行数据分解,得到纯净的qP波数据、qSV波数据以及qSH波数据,通过地表数据的分解将成像过程变成一个可控过程,通过对地表数据输入的控制得到我们所希望的成像结果分量,可以减少无谓的计算;对Hess模型正演炮记录进行了数据分解,并对其进行了逆时偏移成像以验证理论的可行性。

Reverse-time migration for TI medium based on vector wavefield separation

Two?step separation was conducted for anisotropy vector wavefield.The first step is to make the anisotropic elastic wave equa?tion in the polarization direction of the projection isotropic so that it has clear and intuitive kinematic and dynamic characteristics;the second step is to calculate anisotropic medium propagator wavefield separation waveform correction based on the correction of the projec?ted direction of the wavefield in the isotropic direction back to the anisotropic direction, and ultimately the anisotropic wavefield separa?tion can be achieved.First of all,the test of VTI media proves its feasibility.In addition,the authors put forward the surface data decom?position,namely,data decomposition is conducted for collected multicomponent seismic data before the migration imaging.In order to get the pure qP wave,qSH wave and qSV wave data the authors conducted the surface data input control to obtain the satisfactory imaging results of components and make imaging decomposition of the surface data performed in a controlled process,thus reducing unnecessary computation.The authors conducted decomposition of Hess forward modeling shot record data and reverse?time migration imaging.