基于CUDA转换波Kirchhoff叠前时间偏移反算子假频算法  

Anti-aliasing method of converted-wave Kirchhoff prestack time migration base on CUDA

作　　者：孔选林[1,2] 喻勤[2] 

机构地区：[1]成都理工大学油气藏地质及开发工程国家重点实验室,成都610059 [2]中国石化西南油气分公司勘探开发研究院,成都618000

出　　处：《地球物理学进展》2014年第6期2679-2684,共6页Progress in Geophysics

基　　金：国家科技重大专项课题<四川盆地碎屑岩层系大中型油气田形成规律与勘探方向(二期)>(2011ZX05002-004)子专题<多波地震资料处理软件关键模块研发>(2011ZX05002-004-002)资助

摘　　要：转换波的Kirchhoff叠前时间偏移算法由于受到算子假频的影响,会造成偏移成像质量降低.针对算子假频干扰成像这一问题,必须消除反算子假频的影响.文章对纵波算子假频生产的原理进行分析,避免了转换波反假频复杂公式和转换波参数,从反算子假频的基本公式出发,结合转换波偏移成像的公式进行推导引申,得到了转换波的反算子假频的数学表达式.在算法中利用了奈奎斯特采样定理和基于Z变换的复数数字滤波器设计方法,构建了局部三角形滤波器进行反算子假频处理.在算法实现过程中,创新之处在于利用CUDA的高性能计算能力,设计实现了高性能并行三角滤波算法.通过构建了一个脉冲模型验证了反算子假频算法,算法能够较好的去除脉冲中的算子假频产生的噪音,最后通过实际转换波资料的测试,利用CUDA的高性能计算实现的反算子假频算法,能够快速有效的消除算子假频的影响.Converted-wave Kirchhoff prestack time migration（C-wave KPSTM）is an important technique in Converted-wave processing because it can image accurately in the whole 3D spaceswithout CCP and DMO.As the calculation method of migration is inappropriate,it leads to appearing of operator aliasing.The imaging quality is reduced because of operator aliasing in the C-wave PSTM.To eliminate the imaging effect of operator aliasing,the different from the previous is thatpaperanalyzed how it comes into being in P-wave avoiding the complex formula and the C-wave parameters,and the essence of operator aliasing is that the sampling not meeting the nyquist sampling theorem.The channel space is not dense enough in adjacent data channel,therefore,the remaining difference of migration operator cannot meet the nyquist sampling theorem,and the operator aliasing appeared.In order to meet the nyquist sampling theorem it have to do data interpolation,but the calculation will be huge and unacceptable.Through the analyzing the operator aliasing data,it get a conclusion that the input data processing with operator aliasing filter firstly and then migrating and summingis equivalent to the input data being interpolated and then migrating and summing.In this way the calculation is not increased and need operator aliasing filter only.It starts from the basic formula of operator aliasing of P-wave,and derived by the mathematical formula of C-wave PSTM,and gets the mathematical expression of the operator aliasing in C-wave PSTM.It is clear that it can get maximum frequency of operator aliasing in a time point,when the frequency of input data is lower than the maximum frequency,it can filter the part of aliasing,now the problem turn into a problem of low pass filtering.To design the low pass filter,It designs the complex filter base on Z-transform and nyquist sampling theoremin the algorithm,and built the locally triangle low pass filter for operator aliasing filtering.In the process of implement,The innovation of the paper is thatit completes t

关 键 词：统一计算设备架构 转换波 反假频 算子假频 

分 类 号：P631[天文地球—地质矿产勘探]