基于Rytov近似的叠前深度偏移方法

本文在频率一波数域和频率一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。

Prestack depth migration method based on Rytov approximation.

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.