Kirchhoff型偏移反偏移串联地震数据炮检距转换技术  

Conversion of seismic data offset by series Kirchhoff migration and demigration

作　　者：叶云飞 孙建国[3] 刘志斌 张益明 孙文博 仝中飞 YE YunFei;SUN JianGuo;LIU ZhiBin;ZHANG YiMing;SUN WenBo;TONG ZhongFei(South Institute of Jilin University,Guangdong Zhuhai 519090,China;College for Geo-Exploration Science and Technology,Jilin University,Changchun 130026,China;CNOOC Research Institute Company Limited,Beijing 100027,China)

机构地区：[1]吉林大学南方研究院,广东珠海519090 [2]中海油研究总院有限责任公司,北京100027 [3]吉林大学地球探测科学与技术学院,长春130026

出　　处：《地球物理学报》2018年第9期3783-3790,共8页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(41274120);十三五国家重大专项"南海深水区油气勘探地球物理关键技术课题"(2016ZX05026001)联合资助

摘　　要：零炮检距数据在海洋地震资料处理中有很多优势和用途,然而,受海洋水平拖缆地震采集作业方式的限制,接收数据的最小炮检距一般在200m左右,小于该炮检距的数据是无法直接获得的.通常的做法是通过对较大炮检距数据进行动校,通过外推来变相获得零炮检距(包括小炮检距)数据,其外推的精度会受到地震资料信噪比、动校正速度的精度等因素影响,并且保幅性较差.本文通过一种基于Kirchhoff真振幅偏移和反偏移串联的技术,在反偏移过程中改变观测系统,有效实现了大炮检距反射地震数据向零炮检距(包括小炮检距)数据之间的转换,且很好地保持了零炮检距(包括小炮检距)数据的振幅特性.同时,经偏移-反偏移串联处理后,有效压制了地震数据中的随机噪声,地震资料信噪比和成像精度均得到显著提高.Zero offset data has many advantages and applications in marine seismic data processing.However,limited by the marine streamer seismic acquisition method,the minimum offset of received data is generally about 200 meters,and the data with offset smaller than it cannot be obtained directly.The usual approach to get the zero offset data(including small offset data)is by extrapolating larger offset data after NMO correction.Unfortunately,the accuracy of this extrapolation is affected by the signal-to-noise ratio of seismic data and the accuracy of velocity for NMO correction,and this method is difficult to preserve the true amplitude.In this paper,based on the Kirchhoff true-amplitude migration and demigration series technique,in which the observation system is changed during the process of demigration,the zero-offset(including small-offset)data are converted from the large offset seismic data effectively while the amplitude characteristics data are preserved.In addition,after the series processing of migration and demigration,the random noise in seismic data is effectively suppressed and the signal-to-noise ratio and the imaging precision of seismic data are significantly improved.

关 键 词：零炮检距 真振幅 偏移 反偏移 数据变换 

分 类 号：P631[天文地球—地质矿产勘探] P738[天文地球—地质学]