联合波束分解和球面角度分解的绕射波成像  

Diffraction imaging based on beam decomposition and spherical angle decomposition

作　　者：李才 吕丁友 张德龙 肖广锐[1] 王玉秀 于卓 LI Cai;LYU Dingyou;ZHANG Delong;XIAO Guangrui;WANG Yuxiu;YU Zhuo(CNOOC Ltd.Tianjin Branch,Tianjin 300459,China;China University of Petroleum(Beijing),Beijing 102249,China;Schlumberger Technology Services(Beijing)Co.,Ltd.,Beijing 100016,China)

机构地区：[1]中海石油(中国)有限公司天津分公司,天津300459 [2]中国石油大学(北京),北京102249 [3]斯伦贝谢科技服务(北京)有限公司,北京100016

出　　处：《石油地球物理勘探》2025年第1期127-136,共10页Oil Geophysical Prospecting

基　　金：中海石油(中国)有限公司“七年行动计划”重大科技专项课题“渤海油田上产4000万吨新领域勘探关键技术”(CNOOC-KJ-135ZDXM36TJ08TJ)资助。

摘　　要：断层、盐丘、溶洞、裂缝等非均质体作为重要的勘探目标,在地震波场中多表现为极其复杂的绕射波响应特征,因此高分辨率的绕射波成像对油气勘探开发具有重要意义。文中构建了一种基于波束分解和球面角度分解的绕射波成像分离与强化流程,可以在成像后进行,可适用于不同的偏移算法,且避免了偏移前分离绕射波由于数据量大带来的庞大计算量。首先,对偏移数据进行从大到小不同尺度子束的串联计算,再经过多轮次迭代得到初步分离的绕射波场;然后,基于球面角度分解,形成指定地层倾角范围的道集,即DIP(Dip Image Partitions)道集;最后计算DIP的振幅包络属性和相似度并应用于初步分离的绕射波场,进而得到高分辨率的绕射波成像体。该流程首次应用于渤海湾中生界潜山内幕成像,提高了潜山内幕小尺度地质不连续体的识别精度。Heterogeneous bodies such as faults,salt domes,karst caves,and fractures,as important targets in current structural and lithologic exploration,usually act as extremely complex diffractions on seismic records.Therefore,high-resolution diffraction imaging is of great significance for oil and gas exploration and development.This study proposes a diffraction imaging separation and enhancement workflow based on beam decomposition and spherical angle decomposition,which can be applied after imaging.This method is compatible with different migration algorithms and avoids the substantial computational load associated with pre-migration diffraction separation due to massive data volumes.Firstly,a sequential computation of sub-beams at varying scales,from large to small,is applied to the migrated data,followed by multiple iterations to achieve the preliminary separation of the diffraction wavefield.Subsequently,spherical angle decomposition is used to form gathers within specified stratigraphic dip ranges,which are referred to as dip image partition(DIP)gathers.Finally,the amplitude envelope attributes and similarity of the DIP gathers are calculated and applied to the preliminarily separated diffraction wavefield,which results in a high-resolution diffraction imaging volume.This workflow is applied for the first time to the imaging of the Mesozoic buried hill interiors of Bohai Bay,significantly improving the resolution for identifying small-scale geological discontinuities within the buried hill structures.

关 键 词：绕射波分离 波束分解 球面角度分解 倾角分解道集 相似度计算 绕射波成像强化 

分 类 号：P631[天文地球—地质矿产勘探]