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欲实现基于弹性波方程的矢量波场逆时偏移纵、横波独立成像,必须在波场延拓过程中实现纵、横波场的分离,散度和旋度算子分离的纵、横波出现振幅与相位的畸变,导致输出成像结果的振幅失真。本文提出一种在弹性波场延拓过程中实现纵、横波保幅分离的方法,在传统的弹性波方程中加入纵波压力、纵波振动速度和横波振动速度方程,实现纵横波的矢量分解,再对分解后的矢量纵波和矢量横波做标量化合成得到保幅分离的纵、横波场,对保幅分离的纵、横波场应用成像条件,然后实现矢量波场逆时偏移的保幅纵横波成像。该方法可以保证分离后纵、横波的振幅与相位不变;同时,分解后的纵波压力和纵波振动速度可用于层间反射噪音压制和横波极性校正,提高多分量地震资料联合逆时偏移的纵、横波成像质量,从而实现保幅弹性波逆时偏移的目的,为叠前深度剖面应用于叠前反演工作奠定基础。
In order to realize the independent imaging of longitudinal and transverse waves based on elastic wave equation, the vertical and transverse shear waves must be separated in the wave field continuation process. Distortion with phase leads to amplitude distortion of the output imaging result. In this paper, a method of preserving vertical and transverse amplitude-preserving separations in elastic wave field continuation is proposed. In the traditional elastic wave equation, the equations of longitudinal wave pressure, longitudinal wave velocity and shear wave velocity are added to realize the vector decomposition of P- and S- After the decomposition of the vector longitudinal and vectorial shear wave scalar synthesis to obtain the amplitude and amplitude of the separation of the longitudinal and transverse wave fields, the amplitude and amplitude of the separation of the longitudinal and transverse wave fields applied imaging conditions, and then realize the vector wavefield inverse amplitude shift preserving amplitude of the longitudinal and transverse waves Imaging. The method can ensure that the amplitude and phase of the longitudinal and transverse waves remain the same after separation. Meanwhile, the compressional and compressional wave velocities after decomposition can be used for interlayer reflection noise suppression and shear wave polarity correction, and the multi-component seismic data combined with inverse time migration The imaging quality of the longitudinal and transverse waves can be achieved, so as to realize the reverse migration of the amplitude-preserving elastic wave, and lay the foundation for the application of the pre-stack depth profile to the prestack inversion.