摘要
本文介绍一种基于τ-P变换的新的叠后深度偏移方法。这一方法是在均匀介质条件下根据波动方程推导出的。其基本思想是:在τ-p域中,当波场分解为它的平面波成分时,改变其τ、p值,再通过τ-p反变换回到深度域中,从而完成了地下界面的偏移归位。 方法所需的计算时间基本是与完成τ-p正、反变换所需时间相同,是一种快速的偏移方法。它可用于任意形状的地下界面,甚至在强干扰背景的条件下,也能提高资料的信噪比和改善信号的连续性。这一方法是在深度域中进行τ-p变换,故它能适应速度存在纵、横变化的地区。为了论证本方法的效果,本文给出了不同的正演理论模型和偏移结果的例子。
This paper introduces a new depth migration method based on the τ-p transform. This, new τ-p migration method (τpDM) is derived from the wave equation for a homogeneous medium. The essential part of this method is to change the values of T and P, as the wave field is decomposed into its plane-wave components in the τ-p domain. Then, the τ-p depth migration is completed, as it returns to x-z domani by τ-R inverse transform.The computation time needed for the τ-p migration method is comparable to that for the calculation of a forward and inverse τ-p transform.This method is capable of dealing with any subsurface geometry. Moreover, the method can enhance the S/N ratio of the data, and improve the coherence of the signal even in the presence of strong random background noise. The method can be applied to the area where the velocities change horizontally and vertically. The reasion is that the present method is in the x-z domain, but not in x-t domain. This is an advantage for the depth migration.We have given several synthetic examples of both depth migration and forward modelling. The results for all synthetic models using TpDM are satisfactory. As with most other migration methods, the success of TpDM depends on the correct migration velocity function used. We have discussed this effect of the migration velocity in this paper.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
1989年第5期569-579,共11页
Chinese Journal of Geophysics
关键词
深度偏移
Τ-P变换
地震勘探
Depth migration, τ-p forward and inverse transform, Migration velocity, Energy coefficient.
