珠江口盆地珠一坳陷古近系油气富集规律及下一步勘探策略  

Hydrocarbon enrichment law of Paleogene Zhu1 depression and its next exploration strategy in Pearl River Mouth basin

作　　者：米立军 张向涛 陈维涛 刘培 杜家元 姚佳利 MI Lijun;ZHANG Xiangtao;CHEN Weitao;LIU Pei;DU Jiayuan;YAO Jiali(CNOOC China Limited,Zhanjiang Branch,Zhanjiang,Guangdong 524057,China;CNOOC China Limited,Shenzhen Branch,Shenzhen,Guangdong 518000,China)

机构地区：[1]中海石油(中国)有限公司湛江分公司,广东湛江524057 [2]中海石油(中国)有限公司深圳分公司,广东深圳518000

出　　处：《中国海上油气》2018年第6期1-13,共13页China Offshore Oil and Gas

基　　金："十三五"国家科技重大专项"南海东部海域勘探新领域及关键技术(编号:2016ZX05024-004)"部分研究成果

摘　　要：随着新近系勘探程度的提高,古近系逐步成为珠江口盆地珠一坳陷的重点勘探领域。从珠一坳陷油气成藏的关键地质条件出发,系统梳理古近系油气分布规律,探索其勘探潜力。珠一坳陷不同洼陷油气富集程度差距大,其中裂陷期构造活动强的洼陷易形成欠补偿湖盆,发育富生烃层系、形成富生烃洼陷;两幕裂陷形成了文昌组和恩平组2套烃源岩,其地化特征不同,形成两期油气充注;沉积演化的旋回性决定了三级层序及沉积体系的差异展布,导致不同洼陷储盖条件的差异。盆地格局和洼陷结构影响油气在平面上的展布,其中正常半地堑油气主要富集于缓坡带,低角度及复式半地堑油气在陡坡带、缓坡带均有分布;"源、断、砂"立体输导控制油气在纵向上分段聚集,"源-砂"、"断-砂"组合模式分别导致层内、层间富集的分段性;区域盖层控制规模性油气分布,其分布越稳定,油层数量和规模往往越大。珠一坳陷油气资源丰富,古近系勘探潜力大,下一步应围绕"富洼找优、差异勘探"思路,形成"一洼一突破、一带一油田"格局,并将二级构造带整体纳入勘探视野,连片评价并叠合勘探,重视构造转换带、缓坡带和隆起带等区带,有层次地推动该地区古近系勘探进程。With the increasing exploration degree of Neogene,Paleogene has gradually become a key exploration area of Zhu1 depression in Pearl River Mouth basin.Based on the key geological conditions of hydrocarbon entrapment of Zhu1 depression,hydrocarbon distribution law of Paleogene is systematically studied,and its exploration potential is searched.There is a large gap of hydrocarbon enrichment among different sags of the Zhu1 depression.The sags with strong tectonic activity during the rifting period are likely to form under-compensation lake basins,which develop hydrocarbon-rich strata and become hydrocarbon-rich sags.Two sets of source rocks of Wenchang Formation and Enping Formation were formed during two episodes of rifting with different geochemical characteristics,resulting in two phases of hydrocarbon charging.The cyclicity of sedimentary evolution determines the differential distribution of third-order sequence and sedimentary system,resulting in differences in reservoir-cap conditions between different sags.The basin tectonic style and the sag structure affect the hydrocarbon distribution in the plane.In normal half graben,hydrocarbon is mainly concentrated in the gentle slope zone,while in low angle and compound half graben,hydrocarbon is distributed in both steep slope zone and gentle slope zone.The“source,fault,sand”three-dimensional transmission controls the segmental concentration of hydrocarbon in the longitudinal direction.The“source-sand”and“fault-sand”combination mode leads to the segmental concentration within and between layers,respectively.The regional cap rocks control the large-scale hydrocarbon distribution,and the more stable the distribution is,the larger the number and scale of oil layers are.The Zhu1 depression is rich in hydrocarbon resources,and the exploration potential of the Paleogene is large.The next step exploration should be based on the idea of“seeking priority in rich sags,and adopting specific exploration methods in different regions”to form a pattern of“achievi

关 键 词：珠江口盆地 珠一坳陷 古近系 盆地结构 富烃洼陷 优质相带 勘探策略 

分 类 号：TE121.1[石油与天然气工程—油气勘探]