VSP数据的逆时偏移

REVERSE-TIME MIGRATION OF VERTICAL SEISMIC PROFILING (VSP) DATA

据逆时偏移的基本思想,首次引用傅氏变换和差分法相结合的方法(FDM)数值求解全声波方程,实现对垂直地震剖面(VSP)记录数据的波场外推。同时,利用射线方程实现对震源的向下延拓。从而解决了非零井源距VSP数据的偏移。 所用方法对地下界面倾角较大、速度横向变化没有限制,因而适应于地下构造比较复杂的地质情况。此外,还可用于地面地震记录的迭前深度偏移。

Basing on the idea of reverse time migration, the article for the first time, realizes wavefield extrapolation of the recorded data of the vertical seismic profiling (VSP) by using the method of combining fourier traslation with finite difference (FDM) to solve numerically the total sound wave equation. Meanwhile, down-extrapolation of the seismic source is achived by using the ray equation. Thus the VSP dadum migration of the non-zero offset is solved.As the method, would be limited by bigger dip interfaces and velocity changing in the horizontal direction, it cf.n be used to those places where underground strctures are complex. In addition, the method csn be used to prestacked migration of the surface saismic records.