二维VTI介质qP波斜率层析方法

斜率层析属于立体层析的一种特殊情况,在通过运动学反偏移重建立体层析数据空间的过程中,会出现炮检点位置和旅行时信息已经匹配而地表射线参数水平分量(以下简称地表px参数)无法匹配的情况,这时可利用px残差完成对速度模型和反射点坐标的更新。将各向同性介质中的斜率层析方法推广到二维VTI介质qP波情形,利用地表px参数关于三个各向异性参数的偏导数建立了二维VTI介质qP波斜率层析线性方程组,基于该线性方程组和典型理论数据实施了二维VTI介质qP波斜率层析反演。研究结果表明,VTI介质中的运动学偏移/反偏移与二维VTI介质qP波斜率层析线性方程组相结合,可以实现二维VTI介质的各向异性参数重建,为VTI介质的参数建模提供了一条新的途径。

Slope tomography is a special kind of stereotomography.In the process of reconstructing stereotomographic data-space using kinematic demigration,there will be cases in which source and receiver positions and travel time information have been matched,while the horizontal components of the surface ray parameter (hereinafter referred to as the surface px parameter) cannot be matched.In this case,only the residual of px will be used to update the model space.In this paper,the slope tomography,commonly used in isotropic media,is extended to the qP-wave in 2D VTI media.A linear system of qP-wave slope tomography in 2D VTI media was established based on the Frechet derivatives of the surface px parameters with respect to three anisotropic parameters.Using the proposed linear equations,the slope tomographic inversion of the qP-wave in 2D VTI media was implemented based on typical synthetic data.Numerical testing showed that the anisotropic parameters of VTI media could be well reconstructed by combining the kinematic demigration in VTI media with the 2D qP-wave slope tomography algorithm proposed in this paper.This provides an alternative approach for parameter estimation of VTI media.

国家自然科学基金面上项目(编号:41874118,41574098)资助。