摘要
弹性波逆时偏移是一种高精度的复杂构造地震成像方法.然而,在传统的基于矩形网格离散化的逆时偏移中,介质界面通常会产生畸变.另外,因使用双程波动方程进行波场延拓,其产生的反射波会在成像过程中产生偏移假象.为解决这些问题,本文提出了一种拟空间域弹性波方程高阶交错网格有限差分格式,并给出了差分格式的稳定性条件,进而实现了高精度的拟空间域弹性波方程有限差分逆时偏移.模型实验表明,若在计算拟空间域采样间隔时引入速度界面信息,则拟空间域弹性波方程高阶交错网格有限差分逆时偏移能够避免常规弹性波方程逆时偏移中弯曲界面形态畸变问题;此外基于该方法进行波场延拓时可有效压制弯曲界面的假散射现象,并能有效压制层间反射波,因此可以减少剖面上的偏移假象,从而显著提高成像的质量.
Reverse Time Migration(RTM)is a high precision seismic imaging method for complex structures.However,in conventional RTM based on rectangular mesh discretization,the medium interfaces are usually distorted.Furthermore,reflected waves generated by wavefield extrapolation based on the two-way wave equation can result in artifacts in seismic imaging.To overcome these problems,a high-order finite-difference scheme and stability condition for the pseudo-space elastic wave equation are derived,and then a high-precision finite-difference reverse time migration based on the pseudo-space elastic wave equation is realized.Results of model experiments show that the proposed reverse time migration of the pseudo-space wave equation can systematically avoid the interface distortion problem when the velocity interfaces are considered to compute the pseudo-space intervals.Moreover,this method can effectively suppress the false scattering of curved interfaces and internal reflections during wavefield extrapolation,thereby reduce migration artifacts of the profile and significantly improve the quality of migration imaging.
作者
张晓波
宋鹏
刘保华
谭军
李金山
ZHANG XiaoBo;SONG Peng;LIU BaoHua;TAN Jun;LI JinShan(College of Ocean Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,China;Laboratory for Marine Geology,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266061,China;College of Marine Geosciences,Ocean University of China,Qingdao 266100,China;National Deep Sea Center,Ministry of Natural Resources,Qingdao 266237,China)
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2022年第12期4816-4831,共16页
Chinese Journal of Geophysics
基金
国家自然科学基金项目(42106072)
山东省自然科学基金(ZR2020QD071)
青岛海洋科学与技术试点国家实验室山东省专项经费“问海计划”项目(2021WHZZB0700)
泰山学者攀登计划项目(tspd20161007)联合资助.
关键词
拟空间域
弹性波方程
交错网格
有限差分
逆时偏移
Pseudo-space-domain
Elastic wave equation
Staggered-grid
Finite-difference
Reverse Time Migration(RTM)
