轴对称各向异性介质波动方程深度偏移的对称非平稳相移方法  

Wave equation depth migration with symmetric non-stationary phase shift method in axi-symmetrical anisotropic media

作　　者：刘礼农[1] 陈小宏[2] 张剑锋[1] 刘洪[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]中国石油大学(北京),北京102249

出　　处：《地球物理学报》2007年第1期277-284,共8页Chinese Journal of Geophysics

基　　金：中国科学院知识创新工程项目(KZCX1-SW-18);中国石油天然气集团公司物探重点实验室(GPKL0406)资助

摘　　要：由所建立的三维qP波相速度表示式出发,导出并解析求解各向异性介质中的频散方程,得到三维各向异性介质中的相移算子,进而将以相移算子为基础的对称非平稳相移方法推广到各向异性介质,发展了一个三维各向异性介质的深度偏移方法.文中使用的各向异性介质的速度模型与现行的各向异性构造的速度估计方法一致,将各向同性、弱各向异性及强各向异性统一在一个模型中.所建立的各向异性介质对称非平稳相移波场延拓算子可以同时适应速度及各向异性参数横向变化;文中给出的算例虽然是针对二维VTI介质的,但所提出的算法同样适用于三维TI介质.A 3-D dispersion equation for the transversely isotropic media with a tilted symmetry axis is derived from the qP wave phase velocity expression. The anisotropic phase shift operator can be obtained with the vertical wavenumber, which is analytically solved from the dispersion equation. Then the symmetric nonstationary phase shift wave equation depth migration method in isotropic media is extended to anisotropic media. The macro velocity model used for describing anisotropic media is consistent with the current velocity estimation method and can simultaneously accommodate the isotropy, weak anisotropy and strong anisotropy. The symmetric non-stationary phase shift extrapolation operator can accommodate transverse variation of velocity as well as the anisotropic parameter. Although a 2-D VTI example is present in the paper, the proposed algorithm can be used in 3-D TI media as well.

关 键 词：波动方程 各向异性介质 相移算子 对称非平稳相移延拓算子 

分 类 号：P631[天文地球—地质矿产勘探]