共聚焦点叠前深度偏移速度估计方法研究

Prestack-Depth-Migration velocity analysis method based on the CFP method

基于共聚焦点技术可以将叠前深度偏移分为激发聚焦与接收聚焦两个过程,通过逆时聚焦算子的作用实现.由速度模型驱动逆时聚焦算子的更新,合成DTS面板,根据等时原理,通过DTS面板中时移曲线的曲率变化来交互的更新速度场.但是当地下介质稍为复杂的情况下,从面板中拾取分析点对应的时移曲线变得非常困难.针对这个问题,本文通过对分析点在限定深度和速度范围内合成的DTS面板零时刻振幅进行叠加,由其值的变化来确定分析点的合理位置及上层介质速度.

Based on the CFP technology, for each subsurface gridpoint, prestack migration may he written in terms of two focusing steps, focusing in detection and focusing in emission. The focusing is done by a focusing operator and the output is DTS panel. In the traditional process of velocity updating , picking up the curvature of the DTS curve is necessary. But if the subsurface is much more complicated, it may be impossible to determine the curve corresponding to the gridpoint. In this paper, we synthesize DTS panel in an appropriate range using different velocities and loca- tions, and stack the amplitude of zero time. Then are determine the correct velocity and location of the considered gridpoint by comparing the values.