基于三维初至波层析反演的莺歌海盆地浅层气云速度精细刻画  

Fine Characterization of Shallow Gas Velocity in the Yinggehai Basin Based on Three-dimensional First Break Wave Tomography Inversion

作　　者：晏红艳 丘斌煌 原健龙 余嘉顺[2] Yan Hongyan;Qiu Binhuang;Yuan Jianlong;Yu Jiashun(Geophysical R&D Institute,Geophysical-COSL,Zhanjiang Guangdong 524057,China;College of Geophysics,Chengdu University of Technology,Chengdu Sichuan 610059,China)

机构地区：[1]中海油田服务股份有限公司物探事业部物探研究院,广东湛江524057 [2]成都理工大学地球物理学院,四川成都610059

出　　处：《工程地球物理学报》2024年第6期1038-1049,共12页Chinese Journal of Engineering Geophysics

基　　金：中海油田服务股份有限公司科研项目(编号:E-23232009,E-23232010,E-23232013)。

摘　　要：针对莺歌海盆地L气田受浅层气吸收衰减的影响,地震数据处理过程中,利用速度拾取或反射波层析等常规方法建立的浅层气云区速度不准,造成浅层气下覆地层同相轴下拉,影响构造解释与储层预测的问题。本文提出了一套基于三维初至波旅行时层析速度反演的解决方案,并对莺歌海盆地L气田实验工区内的三维地震数据进行了处理试验。结果表明:该方案能够比较准确地求取浅层气云区的速度模型,速度精度较常规方法提高9%~15%。用此速度模型进行深度偏移成像,偏移成像道集同相轴平整,偏移叠加剖面成像改善明显,浅层气下覆地层同相轴得到恢复,较好地消除了地震剖面上浅层气下覆地层同相轴下拉现象,为构造解释与储层预测等后续研究提供更加了可靠的地震资料。In view of the influence of shallow gas absorption and attenuation in the L gas field in Yinggehai Basin,the velocity of the shallow gas cloud area established by conventional methods such as velocity pickup or reflected wave tomography is inaccurate in the process of seismic data processing,resulting in the event pull-down of the shallow gas overlying strata,which affects the structural interpretation and reservoir prediction.In this paper,a solution based on three-dimensional first break wave tomography inversion is proposed,and the 3D seismic data in the L gas field experimental area of the Yinggehai Basin are processed and tested.The results show that the proposed scheme can accurately obtain the velocity model of the shallow gas cloud region,and the velocity accuracy is 9%to 15%higher than that of the conventional method.Pre-stack depth migration is carried out by using this velocity model,the imaging gathers are flattened with the event,the imaging stack section is significantly improved,and the event of the shallow gas overlying strata is restored,which can better eliminate the phenomenon of the event pull-down phenomenon of the shallow gas overlying strata on the seismic section,and provide more reliable seismic data for subsequent studies such as structural interpretation and reservoir prediction.

关 键 词：莺歌海盆地 气云区 初至波 层析反演 速度模型 

分 类 号：P631.4[天文地球—地质矿产勘探]