基于Rytov近似的叠前深度偏移方法  

Prestack depth migration method based on Rytov approximation.

作　　者：陈生昌[1] 曹景忠[1] 马在田[1] 

机构地区：[1]同济大学海洋地质重点实验室

出　　处：《石油地球物理勘探》2001年第6期690-697,共8页Oil Geophysical Prospecting

摘　　要：陈生昌 ,曹景忠 ,马在田 .基于 Rytov近似的叠前深度偏移方法 .石油地球物理勘探 ,2 0 0 1,36 (6 ) :6 90～ 6 97本文在频率—波数域和频率—空间域实现了一种基于 Rytov近似的叠前深度偏移方法 ,并在二维空间作了 Marmousi模型炮集数据的处理。通过与 Split- Step Fourier和 Phase- Screen等叠前深度偏移方法的比较 ,我们认为基于 Rytov近似的叠前深度偏移方法不仅在效果上优于前两者 ,而且还能更好地处理速度横向变化。在散射波场的计算中 ,我们使用了一个比 Huang L等 (1999) [3 ] 的方法更稳定的散射波场计算公式 ,扩大了 Rytov近似的应用范围 ,使基于 Rytov近似的叠前深度偏移方法能够适应更剧烈的横向速度变化。In this paper, a prestack depth migration method based on Rytov approximation is carried out in frequency-wavenumber domain and frequency-space domain, and is used to process common shot gather data for Marmousi model in 2-D space. Through comparison with split-step Fourier migration method and phase-screen migration methods, we considered that the prestack depth migration method based on Rytov approximation not only can produce better migration result than previous two methods, but also can better handle lateral velocity variation. During calculation of scattered wavefield, we use a more stable formula for scattered wavefield than that used by Huang L et al. It extends the range of Rytov approximation, and makes the prestack depth migration method based on Rytov approximation can adapt strong lateral velocity variation.

关 键 词：叠前深度偏移方法 Rytov近似 散射波场 速度横向变化 波场外推 GREEN函数 地震勘探 

分 类 号：P631.429[天文地球—地质矿产勘探]