横向各向同性介质弹性波多分量叠前逆时偏移  

Multicomponent prestack reverse-time migration of elastic waves in transverse isotropic medium

作　　者：杜启振[1,2] 秦童[1,2] 

机构地区：[1]中国石油大学(华东)地球资源与信息学院,东营257061 [2]中国石油大学中国石油天然气集团公司物探重点实验室,北京102249

出　　处：《地球物理学报》2009年第3期801-807,共7页Chinese Journal of Geophysics

基　　金：新世纪优秀人才支持计划(NCET-07-0845);国家高技术研究发展计划(2006AA06A202);中国石油天然气集团公司石油科技中青年创新基金(05E7028);中国石油天然气集团公司物探重点实验室开放基金(GPKL0802)

摘　　要：随着油气勘探程度的提高,隐蔽油气藏在增储上产方面起到了重要作用,因此发展基于各向异性介质的多分量偏移方法是非常必要的.本文基于横向各向同性(VTI)介质,从二维弹性波速发-应力方程出发,通过在时间上的二阶差分和空间上的交错网格高阶差分对方程进行离散,得到弹性波交错网格高阶差分的多分量逆时偏移算子.在激发时间成像条件的应用过程中引入 Poynting 矢量进行成像并消除逆时偏移所引起的低频干扰.在此基础上实现了 VTI 介质中二维弹性波叠前多分量逆时深度偏移.理论模型的偏移处理表明,该方法能够对地层进行准确成像,并可以消除逆时偏移所引起的低频噪声.With the development of exploration in the mature exploration areas, the subtle trap is playing a dominant role. So, joint migration of multieomponent in anisotropic media is the key technology. This paper provided a full 2-D elastic prestaek reverse time depth migration algorithm for common-source multieomponent data from VTI media. Extrapolation used the coupled anisotropic velocity stress equation for variable velocity solved with a high order staggered grid finite-difference scheme in space and a second-order finite-difference scheme in time. A new imaging condition combined excitation-time imaging condition with Poynting vector was proposed to remove low-frequency artifacts. The algorithm was illustrated by application to synthetic data. The results show that this approach produces clear images and can remove lowfrequency noises.

关 键 词：成像条件 Poynting矢量 多分量 逆时偏移 交错网格 VTI介质 速度-应力方程 

分 类 号：P631[天文地球—地质矿产勘探]