湖相混积岩系同沉积淋滤作用识别标志与优质储层形成机理:以石臼坨凸起陡坡带Q29和Q36构造沙一、二段为例  

Meteoric Leaching Evidences, Diagenetic Model and Its Geology Significance in Mixed Rock of Steep Slope Zone of Shijiutuo Uplift

作　　者：卢欢 王清斌 牛成民 杜晓峰 宋章强 冯冲 Lu Huan;Wang Qingbin;Niu Chengmin;Du Xiaofeng;Song Zhangqiang;Feng Chong(Bohai Petroleum Research Institute,Tianjin Branch of China National Offshore Oil Corporation Limited,Tianjin 300459,China)

机构地区：[1]中海石油(中国)有限公司天津分公司渤海石油研究院,天津300459

出　　处：《地球科学》2020年第10期3721-3730,共10页Earth Science

基　　金：国家科技重大专项(No.2016ZX05024-003);中海石油(中国)有限公司科技项目(No.YXKY-2018-KT-01)。

摘　　要：石臼坨凸起陡坡带Q29和Q36构造中深部储层是渤海最大的湖相碳酸盐岩和扇三角洲碎屑岩的混合沉积,这一亿吨级油气田的发现,刷新了碎屑岩储层最厚、单层油层最厚、测试产能最高纪录.通过岩心观察、薄片鉴定、碳氧同位素分析、元素分析等多种分析手段,认为同沉积大气水淋滤作用,对石臼坨凸起陡坡带混积岩系优质储层的形成起到了至关重要的影响.通过对岩石学标志和元素地球化学标志的分析认为,大气水淋滤作用的主要包括两个过程,一是同沉积淋滤作用下,砾石段产生的选择性溶蚀孔、粒内缝、碎屑高岭石;二是沉积后暴露下,碳酸盐岩段产生的垂直岩溶缝、悬垂状白云石、示顶底构造.在此基础上,提出了大气水淋滤作用的模式,可分为成岩作用差异明显两个成岩带,即大气水渗流带和大气水潜流带,并进一步总结了各带内部的成岩特征和演化模式.QHD29-2 E and Q36 structure is so far the largest fan delta siliciclastic and lacustrine carbonate mixed deposits in the first and second members of Shahejie Formation in Paleogene system of Bohai Bay area,which breaks record of maximum reserve scale of siliclastic-carbonate mixed reservoir,the maximum thickness of single oil-bearing layer,and the highest tested productivity in Bohai Sea area.In our recent research,based on comprehensive analysis of rock core,rock slice observation,carbon and oxygen isotope analysis and trace element analysis,it is found that meteoric water leaching diagenesis is the major factor for high reservoir quality forming in the mixing deposition of steep slope zone of Shijiutuo uplift.Petrographical and geochemical evidences of meteoric waters process are identified.It includes 2 processes:dissolution pores,integranular fissures,terrigenous kaolinite in conglomerates during syndepositional process,and vertical karst fissures,geopetal structure in carbonates during subaerial exposure.The meteoric leaching process could be divided into 3 stages,including provenance,transportation and beach bar periods.Finally,the meteoric diagenetic model of mixed deposits in the slope zone is established.Meteoric diagenesis takes place primarily in two formation zones:the vadose zone and the phreatic zone.The diagenetic feature and evolution model of each zone are also concluded.

关 键 词：石臼坨凸起 沙一、二段 混积岩系 同沉积大气水淋滤 成岩模式 沉积 

分 类 号：P574.2[天文地球—矿物学]