应用τ-p域矢量旋转的地震数据波场分离  

Seismic wave field decomposition method based on vector rotation in τ-p domain

作　　者：张婧 张文栋 张铁强 孙鹏远 苑益军[2] 李建峰 ZHANG Jing;ZHANG Wendong;ZHANG Tieqiang;SUN Pengyuan;YUAN Yijun;Li Jianfeng(Research&Development Center BGP,CNPC,Zhuozhou,Hebei 072751,China;School of Geophysics and Information Technology,China University of Geosciences(Beijing),Beijing100083,China)

机构地区：[1]中国石油集团东方地球物理公司物探技术研究中心,河北涿州072751 [2]中国地质大学(北京)地球物理与信息技术学院,北京100083

出　　处：《石油地球物理勘探》2020年第1期46-56,5-6,共13页Oil Geophysical Prospecting

基　　金：中国石油天然气集团有限公司科学技术开发项目“深层与非常规物探新方法技术”之子课题“弹性波高斯束偏移技术研究”(2019A-3309)资助.

摘　　要：高保真的弹性波波场分离已成为多波多分量地震勘探中的关键处理流程。常规波场分离方法可归纳为基于波场的运动学特征和基于波场的动力学特征两大类。前者在空间域或τ-p域对纵、横波波场进行分离,后者则侧重于计算不同波型的偏振特性,但二者均受制于各自的局限性,难以达到理想的分离效果。将波场的动力学与运动学特征相结合,文中提出一种基于τ-p域矢量旋转的波场分离方法。即以近地表纵波速度作为波场分离的关键参数,在τ-p域下对地震波数据的垂直分量与水平分量进行极性旋转,根据不同波型的偏振特性,实现将P-P波与P-SV波分离到各自的偏振方向上的目的。针对层状介质模型、MarmousiⅡ模型及实际地震资料的试算处理结果表明,该方法比传统方法能更精准地分离P-P波和P-SV波,解决了能量异常、波场混叠及空间假频等难题,分离后的波场保幅性较好。High-fidelity elastic wave field decomposition has become a key processing step in multi-wave and multi-component seismic exploration.Conventional wave filed decomposition methods can be classified into two categories,kinematic methods and dynamic methods.Kinematic methods decompose the wave filed into P-P wave field and P-SV wave field inτ-p domain or in spatial domain.Dynamic methods focus on obtaining polarization characteristics of different types of wave.However,neither of them can achieve ideal decomposition results because of their inherent limitations.Motivated by the idea of combining both kinematic and dynamic characteristics of the wave field,a wave field decomposition method based on vector rotation inτ-p domain was proposed in this paper.It takes near-surface velocity as the key parameter of wave field decomposition,and applies polarity rotation to the vertical and horizontal components of seismic wave field inτ-p domain.According to the polarization characteristics of different types of wave,it decomposes seismic wave field into P-P wave field and P-SV wave field to the corresponding polarization directions respectively.Model tests were carried out based on layered medium model and MarmousiⅡmodel,and the method was also applied to real seismic data.The results demonstrated that the method can separate P-P wave and PSV wave more accurately compared with conventional methods.It avoided energy anomaly,wave field aliasing and spatial aliasing,and preserved amplitude well after wave field decomposition.

关 键 词：多波多分量 波场分离 Τ-P变换 矢量旋转 

分 类 号：P631.44[天文地球—地质矿产勘探]