摘要
顺德北凹为珠江口盆地重要的勘探新区,亟需加强沉积充填演化等基础石油条件的研究。综合运用钻井岩性、测井以及三维地震资料,对顺德北凹古近系层序地层、沉积特征和湖盆沉积充填过程进行了研究。研究认为,顺德北凹古近系可划分为1个一级层序、2个二级层序和6个三级层序,发育扇三角洲、辫状河三角洲、滨浅湖、半深—深湖以及浅海5种沉积相类型。经历了初始断陷期、强烈断陷期、断陷晚期、断拗转换早期、断拗转换晚期5大演化阶段,其中文昌组三段初始断陷期具“湖小水浅”的特征,凹陷南北两侧发育小型扇三角洲及辫状河三角洲;文昌组二段强烈断陷期具“湖扩水深”的特征,凹陷广泛发育半深—深湖沉积;文昌组一段断陷晚期具“湖扩水浅”的特征,凹陷南北两侧发育大型扇三角洲及辫状河三角洲;恩平组断拗转换早期具“湖扩海侵”特征,凹陷发育大型辫状河三角洲;珠海组断拗转换晚期开始“全面海侵”,凹陷以浅海沉积为主。明确凹陷发育三套区域储盖组合和一套局部储盖组合,指出恩平组二段辫状河三角洲砂岩与恩平组一段厚层泥岩组成的区域储盖组合成藏优越,是研究区最有利的勘探层系。
Shunde north sag is an important new exploration area in the Pearl River Mouth Basin,and there is an urgent need to strengthen the research on basic petroleum conditions such as sedimentary filling evolution.Based on the drilling lithology,logging,and three-dimensional seismic data,this study delved into the sequence stratigraphy,sedimentary characteristics,and the sedimentary filling process of the Paleogene in the Shunde north sag,Pearl River Mouth Basin.The results show that the Paleogene of the Shunde north sag can be divided into 1 first-order sequence,2 second-order sequences,and 6 third-order sequences,and five kinds of sedimentary facies are recognized,including fan delta,braided river delta,shallow lake,semi-deep and deep lake,and shallow sea.It experiences five major evolutionary stages:initial rifting stage,strong rifting stage,late rifting stage,early rifting-depression transitional stage,and late rifting-depression transitional stage.The initial rifting stage of the third member of Wenchang Formation has the characteristics of“small lake and shallow water”,and small fan deltas and braided river deltas develop on the north and south sides of the sag.The strong rifting stage of the second member of Wenchang Formation has the characteristics of“lake expansion and deep water”,and semi-deep and deep lake sediments widely develop in the sag.The late rifting stage of the first member of Wenchang Formation has the characteristics of“lake expansion and shallow water”,and large fan deltas and braided river delta develops on the north and south sides of the sag.The early rifting-depression transitional stage of Enping Formation has the characteristics of“lake expansion and sea transgression”,and a large braided river delta develops in the sag.The late rifting-depression transitional stage of Zhuhai Formation begins“comprehensive sea transgression”,and the sag is dominated by shallow sea sediments.It is clear that three sets of regional reservoir-cap assemblages and one set of local reservoir-cap assemblage develop in the sag,and it is pointed out that the regional reservoir-cap assemblage composed of the braided river delta sandstone of the second member of Enping Formation and the thick-bedded mudstone of the first member of Enping Formation is superior in reservoir formation,which is the most favorable exploration stratum in the study area.
作者
胡雯燕
刘小燕
万阳
罗威
金秋月
HU Wenyan;LIU Xiaoyan;WAN Yang;LUO Wei;JIN Qiuyue(CNOOC China Limited,Hainan Branch,Haikou,Hainan 570312,China)
出处
《中国海上油气》
2025年第2期118-131,共14页
China Offshore Oil and Gas
基金
国家自然科学基金企业创新发展联合基金重点支持项目“南海北部深水区深层温压场差异性演化对优质储层的控制机理(编号:U24B2016)”
中国海洋石油有限公司“十四五”重大科技项目“南海深水盆地油气运聚成藏分析与突破方向(编号:KJGG2021-0103)”部分研究成果。
关键词
珠江口盆地
顺德凹陷
古近系
文昌组
恩平组
层序地层
沉积特征
充填演化
Pearl River Mouth Basin
Shunde sag
Paleogene
Wenchang Formation
Enping Formation
sequence stratigraphy
sedimentary characteristics
filling evolution
作者简介
第一作者:胡雯燕,女,硕士,工程师,从事石油地质及勘探研究工作。地址:海南省海口市秀英区长滨三路御府国际(邮编:570312)。E-mail:huwy2@cnooc.com.cn。
