VTI介质多参数地震走时层析成像方法研究.doc

文档介绍：
VTI 介质多参数地震走时层析成像方法研
究#
王光银,刘玉柱,杨积忠,董良国**
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(同济大学海洋与地球科学学院,上海 200092)
摘要:本文基于球谐展开群速度表达式计算走时关于各向异性参数的 Fréchet 核函数,利用
共轭梯度法进行 VTI 介质中多参数联合反演。我们考虑了两种参数化方法。经过理论分析
和数值试验,我们得出:与经典的 Thomsen 参数化方法相比较,垂直慢度,水平慢度,以
及动校正慢度的参数化方法更有利于多参数联合走时层析。为了克服参数在物理上对走时
的不敏感性,我们采用了两步法来做双参数反演,理论模型实验反演得到了与垂直速度精度
相当的。可以将两步法扩展到三步法以同时反演各向异性介质中的三个参数,数值实验展
示了该策略的应用潜力.
关键词:固体地球物理;各向异性介质;Fréchet 核函数;参数化;联合层析;
中图分类号:
Joint inversion of VTI parameters using nonlinear
traveltime tomography
WANG Guangyin, LIU Yuzhu, YANG Jizhong, DONG Liangguo
(Ocean and Earth School, Tongji University, Shanghai 200092)
Abstract: In this paper, we use a nonlinear tomographic method to jointly invert the multiple
parameters in VTI media. It is based on the harmonic series of group velocity to calculate the Fréchet
kernels of traveltime respect to model parameters. Two parameterizations are used. Through
theoretically analysis and numerical experiments, we find that the parameterization of vertical slowness,
horizontal slowness, and NMO slowness is more appropriate for joint traveltime tomography,
compared with the original Thomsen parameterization. To e the physical weak influence of
epsilon on traveltime, a double-round strategy is employed in double-parameter inversion, through
which epsilon as well as vertical velocity is essfully obtained. The extension from double-round t