坐标拉伸后的线性拉冬变换法波场分离

Wave field separation by linear Radon transform after coordinate stretch

本文介绍了如何在叠前对各种波场进行分离的方法。该方法以水平层状介质情况下的反射波时距方程为出发点，对叠前炮集或CMP道集记录在时间一炮检距域进行坐标拉伸处理，然后进行线性拉冬变换，变换后的波场因速度和T0时的不同而分布于不同位置，因此在变换域可以很容易地将不同波场分离开来；之后，再通过逆变换将各种波场分别交换到时间-炮检距域，这样波场就得到了较完全的分离。该方法在对弹性波炮集二分量合成记录的处理中得到了理想的处理效果，成功地对P波波场、PSV转换波波场和P波二次反射波场进行了分离。由于该方法是以反射波的双曲线特征及速度差异为基础的，因此可适用于与反射波有关的任意叠前波场分离。

The method for prestack separation of wave fields is described here. Thismethod involves the time--distance equation of reflection wave in layered medium,and coordinate stretch processing of prestack shot--trace gathers or CMP trace gathers is made in time--offset domain. Then the linear Radon transform is conducted.Because the wave fields after transform have different velocities and T, times, theyare distributed on different positions; thus they will be easily separated in transform domain. Then the various wave fields are respectively transformed into time offset domain by inverse transform, so the wave fields will be separated quite completely.Satisfied processing results have been achieved in processing two component elastic--wave synthetic seismograms. p--wave fields I PSV--converted wave fields andp--wave secondary reflection wave field are separated off successively. Because thismethod is based on hyperbolic characteristics and velocity contrast of reflectionwaves, it is applicable to the separation of arbitrary prestack wave fields relatedwith reflection waves.