串联F-K加相移插值法偏移

本文介绍的偏移成像方法为递归F-K法、相移插值法及串联偏移技术的有效结合,简称CFPI法.该方法中,波场外推采用相移插值法中递归向下延拓方式,而每一延拓层间的成像则用文中给出的常速F-K加剩余速度F-K偏移,通过与横向速度变化有关的插值来实现,该过程用FFT完成.该方法可采用较大的延拓步长速归向下外推与成像.理论分析及实际计算结果比较表明,该算法效率远高于相移插值法偏移.

MIGRATION WITH THE CASCADED F-K PLUS PSPI METHOD

A cascaded F-K plus PSPI (called CFP1) migration which combines the recursive F-K method with the PSPI method by the cascaded migration technique is described in this paper. The calculating efficiency is significantly increased. In this process, the recursive downward continuation in PSPI is used to do the wave field extrapolation, where as the imaging at each step is preformed by a constant velocity F-K migration plus residual velocity F-K migration interpolated according to the lateral variations of velocity. The F-K process can be completed with FFT. The application of cascaded F-K makes the down /ard continuation step size much bigger, that improves the efficiency. Both synthetic and real data show that this method is a F-K migration suitable for steep dips and complex structures with a high speed and a low cost.