压缩三维走时表提高克希霍夫偏移计算效率
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摘要
地震波走时是克希霍夫叠前深度偏移的重要参数。三维克希霍夫偏移成像由于需频繁读取大数据量的走时表文件,所以计算效率不高。这里提出一种通过压缩三维射线追踪走时表,来提高克希霍夫偏移计算效率的方法:首先规划一个具有规则网格控制点并覆盖所有走时表点集的最小长方体区域,然后以三维三次B样条函数为插值基函数进行最小二乘法曲面体拟合,求出规则网格控制点的数值并以数组形式存储入内存,采用稀疏化存储进一步节省了内存空间。在偏移成像时,再由这些规则网格控制点的数值,使用线性插值公式解编出走时表。实际资料算例验证了该走时表压缩方法不仅近似精度高,计算稳定度高,计算效率高,而且由于省去了频繁进行大数据量走时表文件的读写操作,所以克希霍夫偏移的计算效率提高了二倍以上。
Travel time of seismic waves is an important parameter of Kirchhoff migration. In process of 3-D Kirchhoff migration, the enormous travel time table file is frequently read, which leads to a fairly low calculation efficiency. A method is proposed to improve the computing efficiency of 3-D Kirchhoff migration by compressing the ray tracing traveltime table: At first,a smallest rectangle region in 3-D space with regular grids is constructed, where all the travel time data points are included. Then, the 3-D cubic B-spline function is used to fit a cuboidal surface which covers all the 3-D scattered travel time data, and the values of the finite regular grids can be calculated using least square method and are stored into memory in terms of an array. Compressed sparse column method is used to save more space. When the scattered travel time data are needed by migration, they can be decompressed by liner interpolation of 3-D B-spline function. Application to real seismic data shows that the traveltime compression method can not only compress travel time data with high approximate accuracy, stable calculation result, high calculation efficiency, but also improve the numerical efficiency of Kirchboff migration by twice because the enormous travel time table file neednt be frequently read any more.
Travel time of seismic waves is an important parameter of Kirchhoff migration. In process of 3-D Kirchhoff migration, the enormous travel time table file is frequently read, which leads to a fairly low calculation efficiency. A method is proposed to improve the computing efficiency of 3-D Kirchhoff migration by compressing the ray tracing traveltime table: At first,a smallest rectangle region in 3-D space with regular grids is constructed, where all the travel time data points are included. Then, the 3-D cubic B-spline function is used to fit a cuboidal surface which covers all the 3-D scattered travel time data, and the values of the finite regular grids can be calculated using least square method and are stored into memory in terms of an array. Compressed sparse column method is used to save more space. When the scattered travel time data are needed by migration, they can be decompressed by liner interpolation of 3-D B-spline function. Application to real seismic data shows that the traveltime compression method can not only compress travel time data with high approximate accuracy, stable calculation result, high calculation efficiency, but also improve the numerical efficiency of Kirchboff migration by twice because the enormous travel time table file neednt be frequently read any more.
引文
[1]郭洪升,陈俊良.地震数据实时自适应压缩方法研究[J].地震学报,1989,11(1):68.
[2]张军华,仝兆岐.用小波变换法定量压缩地震数据[J].石油大学学报:自然科学版,2003,27(5):29.
[3]王喜珍,滕云田,高孟潭,等.基于整数小波变换的地震数据压缩[J].地震学报,2004,26(增刊):116.
[4]余平,马小虎,陈恒金.基于提升小波的地震数据压缩编码算法[J].苏州大学学报:工科版,2009,29(1):7.
[5]AVERBUCH A Z,METER F,STROMBERG J O,etal.Vassiliou,Low bit-rate efficient compression forseismic data[J].Institute of Electrical and ElectronicsEngineers Transactions on Image Processing,2001,10:1801.
[6]BERNASCONI G,VASSALLO M.Efficient data com-pression for seismic-while-drilling applications[J].IEEE Transactions on Geoscience and Remote Sensing,2003,41:687.
[7]WU R S,WANG Y.Seismic data compression using a-dapted local cosine transform and its effect on imaging,61st Meeting[E].European Association of Geoscien-tists and Engineers,Extended Abstracts,2003.
[8]GIANCARLO B,VITTORIO R.High-quality compres-sion of MWD signals[J].Geophysics,2004,69:849.
[9]CABDèS E J,DEMANET L.The curvelet representationof wave propagators is optimally sparse[J].Communica-tions on Pure and Applied Mathematics,2005,58:1472.
[10]CHENG G,ZHANG B.Compression storage and solu-tion of large sparse matrix[J].Progress in Geophysics,2008,23:674.
[11]关履泰,覃廉,张健.用参数样条插值挖补方法进行大规模散乱数据曲面造型[J].计算机辅助设计与图形学学报,2006,18(3):372.
[12]毛可飞,路辉.基于多层B样条的海底地形生成方法[J].计算机仿真,2005,22(4):222.
[13]夏爱生,胡宝安,申楠公,等.系数矩阵为带状大型稀疏矩阵线性方程组解法研究[J].军事交通学院学报,2007,9(1):83.
[14]成谷,张宝金.反射地震走时层析成像中的大型稀疏矩阵压缩存储和求解[J].地球物理学进展,2008,23(3):674.
[15]陈英时,吴文勇.采用多波前法求解大型结构方程组[J].建筑结构,2007,2(9):138.
[2]张军华,仝兆岐.用小波变换法定量压缩地震数据[J].石油大学学报:自然科学版,2003,27(5):29.
[3]王喜珍,滕云田,高孟潭,等.基于整数小波变换的地震数据压缩[J].地震学报,2004,26(增刊):116.
[4]余平,马小虎,陈恒金.基于提升小波的地震数据压缩编码算法[J].苏州大学学报:工科版,2009,29(1):7.
[5]AVERBUCH A Z,METER F,STROMBERG J O,etal.Vassiliou,Low bit-rate efficient compression forseismic data[J].Institute of Electrical and ElectronicsEngineers Transactions on Image Processing,2001,10:1801.
[6]BERNASCONI G,VASSALLO M.Efficient data com-pression for seismic-while-drilling applications[J].IEEE Transactions on Geoscience and Remote Sensing,2003,41:687.
[7]WU R S,WANG Y.Seismic data compression using a-dapted local cosine transform and its effect on imaging,61st Meeting[E].European Association of Geoscien-tists and Engineers,Extended Abstracts,2003.
[8]GIANCARLO B,VITTORIO R.High-quality compres-sion of MWD signals[J].Geophysics,2004,69:849.
[9]CABDèS E J,DEMANET L.The curvelet representationof wave propagators is optimally sparse[J].Communica-tions on Pure and Applied Mathematics,2005,58:1472.
[10]CHENG G,ZHANG B.Compression storage and solu-tion of large sparse matrix[J].Progress in Geophysics,2008,23:674.
[11]关履泰,覃廉,张健.用参数样条插值挖补方法进行大规模散乱数据曲面造型[J].计算机辅助设计与图形学学报,2006,18(3):372.
[12]毛可飞,路辉.基于多层B样条的海底地形生成方法[J].计算机仿真,2005,22(4):222.
[13]夏爱生,胡宝安,申楠公,等.系数矩阵为带状大型稀疏矩阵线性方程组解法研究[J].军事交通学院学报,2007,9(1):83.
[14]成谷,张宝金.反射地震走时层析成像中的大型稀疏矩阵压缩存储和求解[J].地球物理学进展,2008,23(3):674.
[15]陈英时,吴文勇.采用多波前法求解大型结构方程组[J].建筑结构,2007,2(9):138.
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