有限差分—虚谱混合法逆时地震偏移  

Finite difference-pseudo-spectral hybrid approach for reverse time seismic migration

作　　者：张建国[1] 王山山[1] 

机构地区：[1]成都理工大学地球物理学院,四川成都610059

出　　处：《油气地球物理》2016年第1期17-21,共5页Petroleum Geophysics

摘　　要：有限差分法由于其算法简单、计算速度快等优点被广泛应用于地震偏移,但由于使用差分计算空间导数,计算精度相对不高,而虚谱法作为高阶有限差分的极限,其计算精度比较高,可使用较大网格且精度也能得到保证。本文将有限差分法和虚谱法相结合,形成逆时偏移的一种混合计算方法。该方法在一个空间坐标方向使用交错网格有限差分算法,在另外一个空间坐标方向使用虚谱算法,在兼顾精度的情况下,提高计算速度和减少占用内存,使其整体综合性能有所提高。模型逆时偏移结果表明,有限差分—虚谱混合法具有较高的成像精度,是一种有效的偏移方法。The finite difference method （FDM） is widely used in seismic migration due to its adv- antages of simple algorithm and high computation efficiency, but the finite difference approach accuracy of spatial derivative is not high. The pseudo-spectral method （PSM） as the limit of the high order finite difference approach, its calculation accuracy of spatial derivative is high. As using less nodes of grid, the precision can still be guaranteed. In this paper, we propose a hybrid scheme based on the finite difference method and pseudo-spectral method for reverse time migration. In the hybrid method, the spatial derivative in one of the space coordinates is approximated using the high-order staggered grid FDM, while in other coordinates are approximated by staggered PSM. The hybrid method takes account of the accuracy, calculation speed and memory consumption three aspects, so that comprehensive performance of the method has improved. The numerical example shows that the finite difference-pseudo-spectral hybrid method has higher imaging accuracy, and is an efficient seismic migration method.

关 键 词：有限差分 虚谱法 混合法 逆时地震偏移 

分 类 号：P631.4[天文地球—地质矿产勘探]