波场延拓层速度分析方法

Interval velocity analysis using wave field continuation

根据波场延拓理论和模糊决策理论,本文介绍一种对于层状介质,利用地表 CMP 道集数据自动反演各层的层速度和双程旅行时的层速度反演方法。直接利用波场延拓层速度方法所获得的地下介质层速度与根据 VSP 资料计算所获得的层速度不太吻合,前者通常偏高。文中对影响波场延拓层速度精度的三个主要因素进行了校正,校正后的波场延拓层速度结果与VSP 层速度结果吻合很好。用此法求取层速度的精度高,并具有较强的适应弱反射和抗干扰的能力,是一种很有潜力的技术。

I propose a new interval velocity inversion method which,based on wave field continuation theory and fuzzy decision theory,uses CMP seismic gathers to automatically estimate interval velocity and two-way travel time in layered medium.The interval velocity calculated directly from wave field continuation is not well consistent with that derived from VSP data,the former is usually high- er than the latter.Three major factors which influence the accuracy of interval velocity from wave field continuation are corrected,so that the two kinds of in- terval velocity are well consistent.This method brings better interval velocity, adapts weak reflection waves and resists noise well.It is a feasible method.