基于应力偏量的横波纯应力逆时偏移成像方法  

A reverse time migration method for shear wave pure stress based on stress partial tensor

作　　者：张树奎 杜启振[1,2] 孙文涵 李钊 李向阳[3] 符力耘 ZHANG ShuKui;DU QiZhen;SUN WenHan;LI Zhao;LI XiangYang;FU LiYun(Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China),Qingdao 266580,China;Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266580,China;College of Geophysics,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油大学(华东)深层油气重点实验室,青岛266580 [2]青岛海洋科学与技术国家实验室海洋矿产资源评价与探测技术功能实验室,青岛266580 [3]中国石油大学(北京)地球物理学院,北京102249

出　　处：《地球物理学报》2020年第11期4168-4175,共8页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41930429,41774139);中国石油天然气集团公司科学研究与技术开发项目“深层与非常规物探新方法新技术”(2019A-33)联合资助.

摘　　要：基于弹性波解耦延拓方程的波场分离方法不仅可以得到解耦的纵、横波质点振动速度场,还可以获得纵、横波应力场.针对横波纯应力场在利用单一分量成像时不具有明确物理意义的问题,本文将应力偏张量引入到横波应力场中,基于应力偏量第二不变量构建得到横波应力不变量并将其用于应力场的逆时偏移成像中,获得了可完整表征横波应力场的成像结果.模型试算表明,本文构建的横波应力不变量可以有效利用横波应力张量中的波场信息,并得到准确的弹性逆时偏移成像结果.Both the decoupled P-wave and S-wave particle velocity field and stress field can be obtained through wavefield separation.To investigate the physical meanings of S-wave pure stress field in single component imaging,stress partial tensor is introduced to S-wave pure stress field in this paper.Based on the second invariant of stress partial tensor,S-wave stress invariant is established and applied to stress field reverse time migration,from which the imaging results can completely characterize S-wave stress field.Numerical tests demonstrate that the wave-field information of S-wave stress tensor can be effectively utilized via the established S-wave stress invariant,which contributes to accurate elastic wavefield imaging.

关 键 词：弹性波逆时偏移 横波纯应力场 应力偏张量 应力偏量第二不变量 

分 类 号：P631[天文地球—地质矿产勘探]