“双复杂”条件高精度建模与成像方法——以酒泉盆地窟窿山地区为例  

Research on high precision modeling and imaging with dual-complexity conditions:Taking the Kulongshan mountainous area of Jiuquan Basin as an example

作　　者：肖明图[1] 苏勤[1] 余国祥 李斐[1] 凌越[1] 邵喜春[1] XIAO Mingtu;SU Qin;YU Guoxiang;LIFei;LING Yue;SHAO Xichun(Northwest Branch,Research Institute of PetroleumExploration&Development,PetroChina,Lanzhou,Gansu 730020,China;Qinghai Geophysical Department,BGP Inc.,CNPC,Dunhuang,Gansu 736202,China)

机构地区：[1]中国石油勘探开发研究院西北分院,甘肃兰州730020 [2]东方地球物理公司青海物探处,甘肃敦煌736202

出　　处：《石油地球物理勘探》2020年第S01期41-48,6,共9页Oil Geophysical Prospecting

基　　金：国家科技重大专项“前陆冲断带及复杂构造区地震成像关键技术与构造圈闭刻画”(2016ZX05003-003)资助

摘　　要：窟窿山地区是酒泉盆地主要的油气富集带,近地表结构复杂、地下逆掩冲断构造发育对深层构造准确成像造成极大的挑战。常规浮动基准面建模与偏移方法存在表层静校正不彻底、地表大平滑面不适应剧烈起伏地表、浅层速度建模精度低影响深层偏移归位等三方面问题,使推覆体下盘构造不能准确成像。为此,提出"双复杂"条件高精度建模与成像方法,建立了一套面向"双复杂"区的深度域高精度建模与成像流程。以分区双变静校正为基础,提高表层高频静校正精度;以近地表折射与深层反射融合建模为核心,得到高精度整体速度模型;以真地表小平滑面叠前深度偏移为关键,确保深层构造准确成像。实际资料成像结果表明,新方法提高了冲断构造的成像精度,有效改善了成像质量,验证了"双复杂"条件高精度建模与成像方法的可行性。The Kulongshan mountainous area is rich in oil and gas resources in Jiuquan Basin.It is characterized by both complex in near-surface and overthrust subsurface structures,leading to great difficulties in subsurface accurate imaging.Conventional floating-datum-based prestack migration doesn’t work well in such an area,so that problems such as insufficient static correction,inadequate adjustment of floating datum to severely undulating surface,and inaccurate shallow velocity models affecting the migration accuracy of deeper structures are presented,and the conventional method cannot satisfy the requirement for precise imaging of the overthrust structures.This paper proposes an integration strategy of static correction and depth imaging.Combining with the partitioned double-variable static correction,it can improve the accuracy of high-frequency near-surface static correction.The key technique integrates near-surface refraction inverted velocity with deep reflection inverted velocity reasonably to acquire a highprecision global velocity model,and uses pre-stack depth migration of true surface with small-scale surface smoothing parameters to enhance the deep imaging accuracy.Application of the high-precision depth modeling and imaging processing technique to raw data shows that the method can improve the imaging quality and accuracy of complex thrust structure effectively,proving the superiority and feasibility of the method for high-precision modeling and imaging in complex areas.

关 键 词：真地表小平滑面 双变静校正 “双复杂”条件 融合速度建模 叠前深度偏移 

分 类 号：P618.13[天文地球—矿床学] P631.4[天文地球—地质学]