VTI介质中波场分离算子特征研究

Wave field separation operator characteristics in the VTI media

垂直轴对称横向各向同性(VTI)介质弹性波逆时偏移成像在每一步波场外推过程中都需要对纵、横波进行分离,以获得各自独立的qP波、qSV波成像剖面,因此纵、横波的分离效果决定了最终成像剖面的质量。本文针对纵横波波场分离过程中最为关键的分离算子进行了研究,分析了VTI介质中基于交错网格有限差分法波场外推过程中qP波、qSV波分离算法及波场分离算子的形态特征和影响因素。结果表明,VTI介质波场分离算子的中间部分取决于算子的阶数,两侧部分则体现了VTI介质的各向异性特征。

In reverse-time migration in vertical transverse isotropy media,we need to separate S-and P-wave fields from seismic data based on elastic wave equation to separately get qS wave field and qP wave field.Thus seismic imaging quality depends on this separation.We mainly discuss in this paper qSand qP-wave separation algorithms and operators using staggered-grid finite difference method in the VTI media.It concludes that the central part of the operators in field separation in the VTI is determined by the order of accuracy,while its outer parts show characteristics of VTI anisotropy.