面向盐下成像的基于波前构建法的高斯波束偏移  

Wavefront-construction-based Gaussian beam migration for subsalt imaging

作　　者：徐海 高正辉[2] 韩复兴[2] 孙章庆[2] 霍守东 苗贺 刘学城 XU Hai;GAO ZhengHui;HAN FuXing;SUN ZhangQing;HUO ShouDong;MIAO He;LIU XueCheng(Research Institute of Petroleum Exploration and Production,SINOPEC,Beijing 102206,China;College of Geoexploration Science and Technology,Jilin University,Changchun 130026,China;Key Laboratory of Petroleum Resources Research,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Sinopec Northeast China Petroleum Bureau,Changchun 130062,China;Geophysical Measuring Exploration Institute of Liaoning Province,Shenyang 110000,China)

机构地区：[1]中国石油化工股份有限公司石油勘探开发研究院,北京102206 [2]吉林大学地球探测科学与技术学院,长春130026 [3]中国科学院地质与地球物理研究所,中国科学院油气资源研究院重点实验室,北京100029 [4]中国石油化工股份有限公司东北油气分公司,长春130062 [5]辽宁物测勘查院有限责任公司,沈阳110000

出　　处：《地球物理学进展》2022年第6期2481-2491,共11页Progress in Geophysics

基　　金：中国石化科技部基金“安第斯项目南区M1薄砂岩油藏开发关键技术”(P20072-2);国家自然科学基金项目(42074150)联合资助。

摘　　要：高斯波束偏移是目前工业上应用最广泛的偏移成像技术之一.但是当处理盐下成像问题时,由于盐体上界面起伏剧烈且盐体与围岩速度差异较大,只有小角度入射的射线才能穿过盐体,从而导致了盐下区域照明较差.通常,采用加密初始射线的方式来缓解这个问题,但这会导致计算时间的剧烈增加.由此,本文提出了基于波前构建法的高斯波束偏移,以保持波前传播过程中射线密度近似恒定.相较于加密初始射线的方式,本文提出的方法是自适应的,对于提高射线的覆盖范围更加有效.此外,本文采用高精度的波前初始化射线追踪技术作为波前构建的方法.Sigsbee2A模型下的应用实例表明,相较于常规高斯波束偏移加密初始射线的方式,本文提出的方法不仅能够获得更好的盐下照明效果,且对计算效率的影响也更小.Gaussian beam migration has been one of the most popular migration imaging techniques in the industry.However,when dealing with subsalt imaging cases,only the rays with small incident angle could pass through the salt body due to the dramatically rugged surface and the existence of large velocity contrast,which leads to poor illumination beneath the salt.In general,a denser sampling of initial rays is adopted to alleviate this problem at the cost of a huge increase of the computational time.We present a Gaussian beam migration method based on the wavefront construction method to keep the ray density approximately constant during the propagation of the wavefront,which is adaptive and more effective to increase the coverage area of rays than the denser sampling of initial rays.In this migration method,the high-precision wavefront-oriented ray tracing technique is employed as the wavefront construction method.The application of the Sigsbee2 A model shows that,compared with the conventional Gaussian beam migration with denser initial rays,the proposed migration method not only achieves better subsalt illumination,but also has less influence on calculation efficiency.

关 键 词：高斯波束偏移 波前构建法 射线追踪 波前初始化射线追踪技术 盐下成像 

分 类 号：P631[天文地球—地质矿产勘探]