石臼坨凸起东段斜坡区油气运移模式与明化镇组下段勘探实践  

Hydrocarbon migration mode and exploration practice of the lower member of Minghuazhen Formation in the slope zone of the eastern Shijiutuo bulge

作　　者：张宏国 王玉秀 付鑫 张震 张靖泽 Zhang Hongguo;Wang Yuxiu;Fu Xin;Zhang Zhen;Zhang Jingze(Tianjin Branch of CNOOC(China)Co.,Ltd.)

机构地区：[1]中海石油(中国)有限公司天津分公司

出　　处：《中国石油勘探》2025年第1期170-179,共10页China Petroleum Exploration

基　　金：中国海洋石油有限公司“十四五”重大科技项目“地层岩性油气藏高效识别与精细评价技术”(KJGG2022-0303)。

摘　　要：渤海湾盆地渤中坳陷石臼坨凸起以新近系明化镇组下段(明下段)成藏为主,凸起低部位斜坡区发育顺向断层,馆陶组输导层油气“过而不留”,明下段勘探成效差。在前期研究基础上,结合丰富的地震、钻井、地球化学资料,对石臼坨凸起东段油气运移路径开展精细分析,明确凸起斜坡区油气运移机制。研究表明,凸起南侧边界断层石南1号断层在馆陶组开启系数大于东营组、明化镇组,上盘凸起斜坡区馆陶组圈闭充满度远大于下盘的陡坡带,控制油气由凹向凸的垂向运移,并优先在馆陶组侧向分流,且凸起区为优势的分流方向。馆陶组输导层的非均质性和坡度控制斜坡区原油汇聚;馆陶组输导层的非均质性为斜坡背景下原油汇聚提供基础,不同物性的砂岩之间形成微观层面“岩性圈闭”;在此基础上,当馆陶组输导脊坡度小于1°时,可形成大量的原油汇聚储集空间,在顺向断层晚期活动配合下,斜坡区馆陶组汇聚的油气可中转至明下段砂体规模性成藏。上述“缓坡汇聚—断层中转”运移新模式突破了顺向斜坡区输导层油气“过而不留”的传统认识,在石臼坨凸起东段斜坡区明下段成功发现秦皇岛27-3亿吨级油田,为渤海湾盆地斜坡背景下源外层系持续勘探提供借鉴。The gas reservoirs were mainly accumulated in lower member of the Neogene Minghuazhen Formation(lower Minghuazhen member)in Shijiutou bulge,Bozhong Sag,Bohai Bay Basin.However,the exploration results were unsatisfactory due to the consequent faults in the slope zone in the lower part of the bulge and the fact of“hydrocarbon passing through without retention”in Guantao Formation transport layer.Based on previous studies,and combined with abundant seismic,well drilling and geochemical data,the hydrocarbon migration path in the eastern Shijiutuo bulge has been analyzed in detail,clarifying the migration mechanism in the slope zone of the bulge.The study results indicate that Shinan No.1 Fault,a boundary fault on the south side of the bulge,had a greater opening coefficient in Guantao Formation than in Dongying and Minghuazhen formations.The hydrocarbon filling degree in traps in Guantao Formation in the bulge slope zone in the upper fault plate was much higher than the steep slope zone in the lower fault plate,controlling the upward hydrocarbon migration from sag area to bulge zone and the lateral diversion in Guantao Formation,with the advantageous diversion direction of the bulge zone.The heterogeneous transport layer in Guantao Formation and slope gradient controlled the oil accumulation in the slope zone,and the microscopic bed plane“lithologic traps”were formed by sandstones with different physical properties.On this basis,when the slope angle of convergent ridge in Guantao Formation was less than 1°,a large amount of reservoir space was formed for oil accumulation.Affected by tectonic activity of consequent faults in the late stage,oil and gas in Guantao Formation in the slope zone migrated to the lower Minghuazhen member sand reservoir and accumulated on a large scale.The above new migration pattern of“hydrocarbon convergence in gentle slope–transit by fault”has broken through the traditional understanding of hydrocarbon“passing through without retention”in the transport layer in the conseq

关 键 词：渤中凹陷 石臼坨凸起 浅层明化镇组油藏 馆陶组输导层 成藏模式 勘探实践 

分 类 号：TE122.3[石油与天然气工程—油气勘探]