波动方程叠前深度偏移角度道集求取方法  

Angle domain common-image gather calculation based on wave equation prestack depth migration

作　　者：张广智[1] 常德宽 王一惠 印兴耀[1] 陈怀震 李海亮[2] 

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]中国石油勘探开发研究院西北分院,甘肃兰州730020 [3]中国石油华北油田公司地球物理勘探研究院,河北任丘062552

出　　处：《石油地球物理勘探》2016年第3期529-536,416-417,共8页Oil Geophysical Prospecting

基　　金：国家"973"项目(2014CB239201;2013CB228604);国家油气重大专项(2011ZX05014-001-010HZ)资助

摘　　要：针对常规直接转换法和直射线叠前时间偏移(PSTM)法提取的角度道集无法满足地质构造复杂地区的AVA分析与反演精度的问题,研究基于共炮检距道集波动方程保幅叠前深度偏移方法,提取角度域共成像点道集。首先,对地震数据进行叠前深度偏移得到炮检距域共成像点道集;其次,在频率—波数域对炮检距域共成像点道集利用快速插值映射法抽取角度域共成像点道集。通过与直接转换法和直射线PSTM法提取的角度道集比较,分析不同方法求得的角度道集信息的准确性和AVA特征。数值试算和实际资料处理结果表明:共炮检距道集波动方程保幅叠前深度偏移方法求取的角度道集的振幅相对保真,角度范围更广,更适用于AVA分析。Angle-domain common image gathers(ADCIGs)extracted by the conventional conversion method and the straight-ray PSTM method cannot meet the requirements of both AVA analysis and inversion in geologically complicated areas.In this paper we put forward an amplitude-preserved wave equation prestack depth migration based on common offset gathers to extract ADCIGs.First,we process seismic datasets with prestack depth migration to obtain offset domain common image gathers.Then in the frequency-wavenumber domain,angle domain common image gathers are extracted with fast interpolation from offset domain common image gathers.Finally we analyze AD-CIGs information and AVA properties calculated by both the direct transform method and the straight-ray line PSTM method.Both numerical experiments and real data tests show that ADCIGs obtained by the proposed approach have larger angle range and better amplitude,and are more suitable for AVA analysis and inversion.

关 键 词：深度域角度道集 AVA分析 保幅波动方程偏移 

分 类 号：P631[天文地球—地质矿产勘探]