倾斜界面PS转换波速度比和倾角提取的差值谱方法

Difference Spectrum Method of Extracting Velocity Ratio of PS Converted Wave and Interface Dip

首次提出了采用差值谱同时提取转换波速度比和界面倾角的方法。对于倾斜界面的PS转换波地震数据,获取界面上介质的纵横波速度比和反射界面的倾角,是转换波地震数据后续一系列处理流程的关键。通过预设速度比和倾角抽取CCP共转换点道集,并对其进行速度比谱计算,将速度比谱中获得的速度比估算值与预设值作差,在一定范围内改变速度比和倾角值,得到多个速度比差值,最后生成分别以速度比和倾角为坐标的二维差值谱,通过分析差值谱提取纵横波速度比和界面倾角。该方法能够同时对2个未知参数进行提取,获得的结果误差较小,可以为转换波后续处理提供可靠依据。

For seismic data of converted wave on the dipping interface PS,extracting the velocity ratio of vp/vsand the dip of the reflecting interface is critical for the processes of converted wave seismic data.In this paper,we first distill CCP gather of common conversion point by apreset velocity and dip.Second,we get the estimated value of velocity ratio via spectrum calculation,and obtain the difference between the preset velocity ratio and the estimated velocity ratio.Once again,in a certain range we get a lot of the differences on different velocity ratios and dips.Finally,we set up the 2Ddifference spectrum according to the differences of velocity ratios.This method can simultaneously extract the two unknown parameters,and the precise results is prepare for the converted wave subsequent processing.