声波方程逆时偏移中的无分裂PML吸收边界条件  

Non-splitting PML Absorbing Boundary Conditions in Reverse-time Migration of Acoustic Waves

作　　者：王鹏飞[1] 何兵寿[1] 

机构地区：[1]中国海洋大学海底科学与探测技术教育部重点实验室,山东青岛266100

出　　处：《工程地球物理学报》2015年第5期583-590,共8页Chinese Journal of Engineering Geophysics

基　　金：国家自然科学基金项目(编号:41174087;41204089);国家科技重大专项项目(编号:2011ZX05005-005);863计划项目(编号:2013AA064201)

摘　　要：逆时偏移是当前地震资料处理的前沿技术,吸收边界条件是逆时偏移技术的重要组成部分。目前,业界常用的基于波场分裂思路的完全匹配层PML(Perfectly Matched Layer)吸收边界条件在改善边界吸收效果和改进偏移成像质量方面发挥了巨大作用,但这种方法需要在边界处为分裂后的各个分量开辟额外的内存空间,且需要分边角处理,增加了逆时偏移技术的内存负担和计算开销。为了减少内存负担和提高计算效率,首先从双程声波方程出发,推导了声波方程的无分裂PML吸收边界条件,然后给出该边界条件下波动方程逆时延拓的数值实现过程。理论分析和模型实验结果得到:无分裂PML边界条件具有与分裂算法相同的边界吸收效果,并且基于无分裂PML的逆时偏移算法效率更高,更便于程序代码的编写和GPU(Graphic Processing Unit)的并行实现。Reverse-time migration（RTM） is the most advanced technology in seismic data process, and absorbing boundary conditions are the essential part in RTM. Currently, the PML based on splitting wave field is widely used in seismic data process. It improves the imaging result. However, PML based on splitting wave field needs to split the velocity and stress fields, which results in additional memory and extra computing in edge and angle. Therefore, based on the two-way acoustic wave equation, PML absorbing boundary conditions are improved. At the beginning, non-splitting PML absorbing boundary conditions are deduced based on two-way acoustic wave equation. Then, the numerical algorithm steps of RTM extrapolation are provided based on non-splitting PML. Finally, Model tests and theoretical analysis indicate that non-splitting PML has the same good boundary absorbing effect as splitting PML, but RTM,based on non-splitting PML, is more efficient and more easily for code programming and GPU transplanting.

关 键 词：逆时偏移 吸收边界条件 无分裂完全匹配层 计算效率 

分 类 号：P631.5[天文地球—地质矿产勘探]