一种基于广义绕射叠加的深度域偏移成像方法

A Depth Migration Imaging Method Based on Generalized Diffraction Stack

广义绕射叠加偏移方法通过波动方程数值解来表示Green函数,从而实现Kirchhoff型偏移。但是在地震正演模拟中,广义绕射叠加偏移使用的Dirac脉冲存在无限带宽,难以使用有限差分法来计算。为了克服这个问题,本文在广义绕射叠加偏移的基础上进行改进,对震源项进行分解,利用波动方程数值解来表示有限带宽Green函数,从而实现Kirchhoff型偏移。模型试验结果表明,该方法有效可行,能够解决复杂地质条件的成像问题。

The method of generalized diffraction stack migration expresses the Green func-tion by the numerical solution of the wave equation, thus realizing the Kirchhoff-type mi-gration. However, in the seismic forward modeling, the Dirac pulses used in the general-ized diffraction stack have infinite bandwidth, which is difficult to calculate by using the fi-nite difference method. In order to overcome this problem, based on the generalized diffrac-tion stack, this paper decomposes the source term and uses the numerical solution of the wave equation to represent the band - limited Green＇s function to realize the Kirchhoff - type migration. The model test results show that the method is effective and feasible to solve the problem of imaging of complex geological conditions.