优化15点频率-空间域有限差分正演模拟  

Optimal 15-point finite difference forward modeling in frequency-space domain

作　　者：刘璐[1,2] 刘洪[1] 刘红伟[1] 

机构地区：[1]中国科学院地质与地球物理研究所中国科学院油气资源研究重点实验室,北京100029 [2]中国科学院大学,北京100049

出　　处：《地球物理学报》2013年第2期644-652,共9页Chinese Journal of Geophysics

基　　金：国家自然科学基金重点项目(40830424);国家自然科学基金项目(40674072);国家自然科学基金重点项目(40774069)联合资助;国家油气重大专项(2011ZX05008-006-50)

摘　　要：频率域正演是频率域波形反演的基础,有效快速的正演差分格式可以保证反演结果的精度和效率.本文以用较小的系数矩阵带宽来高效地压制频域正演频散为目标,综合利用加权平均算子、平均加速度项和优化系数三种方法,提出了优化15点差分格式;并且采用压缩存储方式来存放大型系数矩阵,极大地缩小了内存使用量;进而结合最佳匹配层(PML)边界条件,明显地压制了边界反射;最后,通过与前人方法的对比验证,证实了本方法可以在不明显增加计算量的情况下,较好地压制频散.Forward modeling is the fundamental factor of waveform inversion in frequency-space domain. Fast and effective difference scheme can guarantee the precision and efficiency of the results of waveform inversion. In this paper, aiming at suppressing dispersion effectively with a smaller impedance matrix bandwidth in frequency-space domain, we make use of three techniques, weighted averaging operator, averaging the mass acceleration term and optimizing the coefficient, then propose an optimal 15-point difference scheme And we use compressed storage method to store the huge impedance matrix so that significantly decrease the memory consumption. In order to suppress the reflection from the boundary, we apply perfectly matched layer boundary condition. Finally, through the comparison between our difference scheme and the previous methods, it is proved that our method can effectively suppress dispersion without adding too much calculation amount.

关 键 词：15点差分格式 压缩存储 最佳匹配层 加权平均差分算子 

分 类 号：P631[天文地球—地质矿产勘探]