中国近海古近纪碎屑岩储层特征与溶蚀作用规律  

The Rules of Reservoir Characteristics and Dissolution of Paleogene Clastic Rocks in Offshore China

作　　者：吴克强 谢晓军 廖计华 韩雅坤 Wu Keqiang;Xie Xiaojun;Liao Jihua;Han Yakun(CNOOC Research Institute Co.,Ltd.,Beijing 100028,China)

机构地区：[1]中海油研究总院有限责任公司,北京100028

出　　处：《地球科学》2023年第2期385-397,共13页Earth Science

基　　金：国家“十三五”科技重大专项(No.2016ZX05026);中海石油(中国)有限公司重大科研生产项目“中国近海富烃凹陷深层(含潜山)大中型油气田勘探方向”(No.2019KT-SC-22)。

摘　　要：随着中国近海浅层(新近系为主)勘探程度日益增加,中深层(古近系为主)特别是始新统和渐新统是未来油气勘探的重要领域之一.然而,针对中国近海中深层碎屑岩储层特征及溶蚀作用规律尚缺乏系统研究.基于大量新钻井、物性数据及多种分析测试等,以辽中凹陷、西湖凹陷和白云凹陷为靶区,系统阐明了中国近海古近纪碎屑岩储层岩石学特征、物性及孔隙类型,分析并总结了其溶蚀作用规律.研究表明:中国近海古近纪砂岩储层岩石类型以长石岩屑砂岩或岩屑长石砂岩为主,同一凹陷不同构造的岩性差异明显,不同层位石英、岩屑含量略有变化;储层物性主体为中低孔-低渗,中-高孔渗储层主要发育在辽中凹陷沙一-二段和白云凹陷珠海组上段;孔隙类型均以次生孔隙为主,原生孔隙仅在西湖凹陷平湖斜坡北侧、辽中凹陷沙四段和白云凹陷珠海组上段较为发育.溶蚀作用整体以酸性流体对长石、连生方解石和部分岩屑的溶蚀为主.辽中凹陷不同构造溶蚀作用差异明显,受浅埋深火山岩母岩与中深层刚性母岩控制的砂岩储层溶蚀作用显著,而西湖凹陷西斜坡平湖组一段-平湖组三段则为早期连生方解石溶蚀,白云凹陷溶蚀作用主要为长石的高岭石化和高岭石的伊利石化.研究旨在为中国近海古近纪碎屑岩储层勘探开发提供借鉴.With the increasing exploration degree of shallow formations(mainly Meogene) in offshore China, middle-deep buried formations(mainly Paleogene), especially the Eocene and Oligocene, is one of the important exploration targets in the future.However, there is still a lack of systematic research on the characteristics and dissolution of the middle-deep clastic reservoirs in offshore China. In this paper, Liaozhong sag, Xihu sag and Baiyun sag were taken as target areas. Based on a large number of new drilling, physical property data and various tests, the petrological characteristics, physical property and pore types of paleogene clastic reservoirs in offshore China were systematically elucidated, and their dissolution regularities were analyzed and summarized.The results show that the Paleogene sandstone reservoirs in offshore China were mainly composed of feldspar-lithic sandstone or lithic-feldspar sandstone. Different structures and lithology varied significantly in the same sag, and the content of quartz and lithic varied slightly in different layers. The reservoir was mainly medium-low porosity and low permeability, and medium-high porosity and permeability reservoirs are mainly developed in the first and second member of Shahejie Formation and the upper member of Zhuhai Formation of Baiyun Sag. The primary pores only developed in the north of Pinghu slope in Xihu Sag, the fourth member of Shahejie Formation in Liaozhong Sag and the upper member of Zhuhai Formation in Baiyun Sag. The dissolution of feldspar,calcite and part of fragments was mainly by acidic fluid. The dissolution in Liaozhong Sag varied markedly between different formations, with significant dissolution in sandstone reservoirs controlled by shallow-buried deep volcanic host rocks and mediumdeep rigid host rocks, while the West Slope of the Xihu Sag showed early succession calcite dissolution in a section of the Pinghu Formation and three sections of the Pinghu Formation, and the Baiyun Sag dissolution was mainly kaolinization of feldspar and i

关 键 词：中国近海 古近纪碎屑岩 储层特征 溶蚀作用 深层勘探 石油地质 

分 类 号：TE122.3[石油与天然气工程—油气勘探]