基于抛物线方程的坐标拉伸τ-p变换的P-P、P-SV波分离

分离P-P波和P-SV波最常用的是τ-p变换法, 但是在τ-p域中, P-P波和P-SV波常有重叠部分, 不能很好分离。地震勘探中, 当炮检距小于界面深度时, P-P波和P-SV波的时距曲线方程都可近似为抛物线方程。针对这种情况, 提出了一种基于抛物线方程的坐标拉伸τ-p变换的P-P、P-SV 波分离方法, 该方法首先对地震记录沿空间方向上进行坐标拉伸, 再进行τ-p正变换, 在τ-p域中分离P-P波和P-SV波, 其次对P-P波和P-SV波分别进行τ-p反变换, 实现P-P波和P-SV波的分离。与常规τ-p变换法对比分析表明, 利用该方法能很好地将合成地震记录中的P-P波和P-SV波分离。

Separating P-SV wave from P-P wave by coordinate stretch τ-p transform based on parabolic equation

τ-p transform method is the most effective method for separating P-SV wave from P-P wave, but sometimes P-SV wave overlaps P-P wave and can not be separated completely in τ-p domain. When offset is shorter than interface depth in seismic exploration, the time-distance curve equations of P-SV wave and P-P wave can approximate to parabolic equations. Aiming at this situation, a method to separate P-SV wave from P-P wave by coordinate stretch τ-p transform based on parabolic equation is present. The authors process the seismic records by coordinate stretch along space direction and do τ-p transform at first, and then separate P-SV wave from P-P wave in τ-p domain, and inverse τ-p transform for P-SV wave and P-P wave respectively to separate P-SV wave from P-P wave finally. In contrastwith normal τ-p transform, thismethod can separate P-SV wave from P-P wave completely and effectively.