摘要
通过三维地震、钻井资料的综合分析,结合区域海平面升降特征的研究认识,建立琼东南盆地乐东凹陷梅山组T-R层序格架,并详细论述了梅山组海底扇沉积体系演化过程,认为琼东南盆地在中新世存在五期规模较大的海侵-海退旋回事件,乐东凹陷主要碎屑物源方向经历由早期海南隆起向晚期越南方向的迁移过程,在凹陷内部形成展布方向、规模存在差异的三期大型海底扇沉积。结合区域油气成藏要素研究,认为梅山组海底扇砂岩受到后期黄流组中央峡谷切割,在整体“泥包砂”沉积背景下形成梅山组海底扇-黄流组水道砂岩复合型岩性圈闭,并通过底辟、裂隙沟通乐东凹陷深部崖城组烃源岩,形成“下生上储”型岩性油气藏。在此认识指导下,针对梅山组海底扇-黄流组水道砂岩复合型岩性圈闭钻探获得成功,新增探明天然气储量约为100×108 m^(3)。
T-R sequence framework of Meishan Formation in Ledong Sag,Qiongdongnan Basin was established and its evo⁃lution process of submarine fan deposits was discussed in detail according to the comprehensive analysis of 3D seismic and drilling data,combined with the rising and falling characteristics of regional sea level.Results reveal that five large-scale transgression-regressive cycle events happened in the study area during the middle Miocene,and the source of main clastic materials in Ledong Sag migrated from Hainan Uplift in the early stage to Vietnam in the late stage.During this process,three stages of large submarine fan deposits with different distribution directions and scales were formed in Ledong Sag.Combined with the controlling factors of regional oil and gas accumulation,it is believed that the submarine fan sandstone of Meishan Formation was cut by the central Canyon of Huangliu Formation in the late period;the composite lithologic traps of Meishan Formation submarine fan-Huangliu Formation channel sandstone were formed under the overall mud-sand sedi⁃mentary background,which communicated with deep source rocks of Yancheng Formation through diapirs and fractures,forming“lower generation and upper reservoir”type lithologic reservoirs.Under the guidance of this understanding,the composite lithologic traps of Meishan Formation submarine fan-Huangliu Formation channel sandstone have been success⁃fully drilled,with proved natural gas reserves of nearly 100×108 m^(3).
作者
李安琪
胡林
王真真
李胜勇
李明
LI Anqi;HU Lin;WANG Zhenzhen;LI Shengyong;LI Ming(Zhanjiang Branch,CNOOC,Zhanjiang City,Guangdong Province,524057,China)
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2021年第2期76-84,共9页
Petroleum Geology and Recovery Efficiency
基金
国家科技重大专项“大型油气田及煤层气开发”子课题“莺琼盆地高温高压天然气富集规律与勘探开发关键技术”(2016ZX05024-005)。
关键词
海底扇
重力流
岩性圈闭
层序格架
琼东南盆地
submarine fan
gravity flow
lithologic trap
sequence framework
Qiongdongnan Basin
