川西北线束三维地震成像攻关及勘探意义  

Application of swath 3D seismic imaging to northwestern Sichuan Basin: Implications for prospecting

作　　者：韩嵩[1] 梁瀚[1] 关旭[1] 陈骁[1] 冉崎[1] Han Song;Liang Han;Guan Xu;Chen Xiao;Ran Qi(Exploration and Development Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610041,China)

机构地区：[1]中国石油西南油气田公司勘探开发研究院

出　　处：《天然气勘探与开发》2018年第3期7-13,共7页Natural Gas Exploration and Development

基　　金：中国石油天然气股份有限公司重大科技专项"西南油气田天然气上产300亿立方米关键技术研究与应用"(编号:2016E-0604)

摘　　要：四川盆地西北部双鱼石构造的地表地质条件及地下构造变形复杂,地震采集资料品质差,难以准确落实其北西山前复杂带的构造,无法在上古生界取得进一步的勘探突破。因此,2016年新采集了线束三维地震数据,在该地震采集成果的基础上开展了处理、解释联合攻关,形成了适合川西北部"双复杂"特点的地震叠前偏移成像处理解释技术:(1)结合露头信息、微测井及地质认识,形成基于大炮初至反演约束层析静校正技术;(2)基于小平滑面出发,利用近地表速度模型,形成地表、地下速度融合技术;(3)基于VSP测井约束的非线性层析成像技术。结果表明:运用上述技术,线束三维地震数据资料品质得到较大改善,在攻关处理剖面上准确刻画了(1)号断层展布及上古生界下盘断点,新发现该断层逆掩下盘发育的上古生界隐伏构造,且该断层向北西山前复杂带迁移,使该地区栖霞组有利勘探区域由早期的2 000 km^2扩大至3 000 km^2。In Shuangyushi structure,northwestern Sichuan Basin,not only complicated surface geological condition but also subsurface structural deformation bring about seismic data with poor quality,which makes it difficult to accurately confirm the piedmont complex belt in northwestern Shuangyushi structure.As a result,the Upper Paleozoic in this basin has not been made an exploration breakthrough.In this study,seismic processing and interpretation were carried out jointly based on swath 3D seismic data acquired in 2016.And some pre-stack migration imaging technologies,which are suitable for northwestern Sichuan Basin with features of"double complex",were developed,including(1)the constrained tomographic static correction technique established through first-break inversion and based on outcrop data,microlog,and geological understanding,(2)the surface and subsurface velocity merging technique developed by near-surface velocity model and based on topography with little smoothing,and(3)the nonlinear tomography technique based on VSP logging constraints.Results show that,after their application,the quality of swath 3D seismic data quality is greatly improved;the distribution of No.1 Fault and the Upper Paleozoic footwall breakpoints are characterized and identified precisely on the processing profile;an Upper Paleozoic buried structure developed at the thrust footwall of No.1 Fault is newly recognized;this fault migrated towards the piedmont complex belt;and the favorable exploration area of Qixia Formation in this basin is expanded to 3 000 km2 from previously predicted 2 000 km2.

关 键 词：微测井 VSP 小平滑面 速度融合 非线性层析成像 隐伏构造 

分 类 号：P631.4[天文地球—地质矿产勘探]