摘要
从一阶速度—应力弹性波方程出发,基于旋转交错网格,推导了时间二阶精度空间2M阶精度的有限差分离散格式。阐述了递归卷积复频移完全匹配层(CPML)边界条件的原理,建立了一阶速度—应力弹性波高阶差分CPML边界条件的递推公式。开展了CPML边界中关键参数m、κ和α的选取实验,通过分析反射误差分布图,选取了CPML边界条件中最优参数。全局反射误差与波场快照都说明,CPML较PML对隐失波具有更优的吸收性能。基于Matlab平台,编写了基于CPML边界的旋转交错网格弹性波正演模拟程序,应用该程序对各向异性介质及随机介质进行了模拟,得到了弹性波正演剖面记录及波场快照,通过对正演剖面记录及波场快照的分析,可以更清楚地了解弹性波在各向异性介质及随机介质的传播特性,指导非均匀介质中地震勘探资料解释。
On the basis of the first-order velocity-stress elastic wave equation,a finite-difference discretization scheme with 2 M-order accuracy of second-order space accuracy is deduced based on rotational staggered grid.The principle of recursive convolutional complex frequency shift perfectly matched layer（ CPML） boundary condition is expounded,and the recurrence formula of first order velocitystress elastic wave high order difference CPML boundary condition is established. The selection of the key parameter m,and sum of CPML boundary is carried out.By analyzing the distribution of reflection error,the optimal parameters of CPML boundary condition are selected. Both global reflection errors and wavefield snapshots indicate that CPML has better absorption properties than evanescent waves.On the basis of the Matlab platform,a program of elastic staggered forward simulation of rotating staggered grid based on CPML boundary is developed.The program is used to simulate the anisotropic medium and random medium. The seismic wave forward record and wavefield snapshot are obtained.The forward propagation profile and the wavefield snapshots can be used to better understand the propagation characteristics of seismic waves in anisotropic media and random media and to guide the interpretation of seismic exploration data in heterogeneous media.
作者
冯德山
王向宇
FENG De-Shan;WANG Xiang-Yu(School of Geosciences and Info-Physics,Central South Universit;Key Laboratory of Non-ferrous Resources and Geological Detection of Hunan Province,Changsha 410083,Chin)
出处
《物探与化探》
CAS
CSCD
北大核心
2018年第4期766-776,共11页
Geophysical and Geochemical Exploration
基金
国家自然科学基金资助项目(41574116)
中南大学创新驱动项目(2015CX008)
中南大学教师研究基金资助项目(2014JSJJ001)
中南大学升华育英人才计划(2012)
湖湘青年创新创业平台培养对象共同资助项目(2013)
关键词
旋转交错网格
高阶差分法
卷积完全匹配层
各向异性介质
随机介质
正演
rotation staggered grids
high-order difference method
convolutional perfectly matched layer
anisotropic media
randommedia
forward
