共转换点速度分析

Analysis of velocity at common-converted-point.

转换波共转换点相对于共中心点的偏移距离随着纵横波速度比、深度以及炮检距等因素的变化而变化,因此不能采用固定道集的方法进行转换波速度分析,而应当在速度比与深度等因素变化时,速度分析所用的道集也做相应的变化。本文提出了一种随着速度比与转换点深度的变化而动态抽道的转换波速度分析方法,实现了扫描叠加速度、转换点深度与共转换点道集的一一对应。此法应是一种真正意义上的共转换点速度分析技术。经理论模型与实际地震资料验证,表明了该方法的有效性。

The distance of common converted point ( CCP ) of converted wave relative to common mid point (CMP) changes with such factors as ratio of P- and S-wave velocities, depths and offsets ,which can't use fixed gathers to conduct analysis of converted wave velocity ,whereas use different gathers to conduct velocity analysis when ratio of velocities and depths change. The paper presented a method of analysis of converted wave velocities that sorts traces dynamically along with the variation of ratio of velocities and depths of converted points,which realizes the correspondence of sweeping stack velocities and depths of converted points with common converted point gathers. It is shown by theoretical model and real seismic data that the method is effectiveness.