渤海湾盆地沧东凹陷孔二段页岩层系不同岩性储层结构特征  

Shale Oil Reservoir Structure Characteristics of the Second Member of Kongdian Formation in Cangdong Sag,Bohai Bay Basin

作　　者：赵贤正[1] 陈长伟[1] 宋舜尧[1] 杨飞[1] 王晓东[1] 冯建园[1] 刘建青[1] 孙鹏[1] 何振铎[1] 马忠梅 Zhao Xianzheng;Chen Changwei;Song Shunyao;Yang Fei;Wang Xiaodong;Feng Jianyuan;Liu Jianqing;Sun Peng;He Zhenduo;Ma Zhongmei(Dagang Oilfield Branch of China National Petroleum Corporation Ltd.,Tianjin 300280,China)

机构地区：[1]中国石油大港油田分公司,天津300280

出　　处：《地球科学》2023年第1期63-76,共14页Earth Science

基　　金：国家重点研发计划项目(No.2020YFA0710504);中国石油勘探与生产分公司重点科技项目(No.2022KT1002);中国石油天然气股份有限公司科学研究与技术开发项目(Nos.2019E-26,2021DQ0508)。

摘　　要：为进一步明确湖相页岩层系优势储集岩性,聚焦页岩油甜点、提高水平段甜点钻遇率,增加水平井页岩油产量,利用沧东凹陷孔二段G108-8井494.29 m岩心,3000余块次薄片、扫描电镜、核磁共振、压汞和全岩X衍射等数据,系统分析页岩层系中碳酸盐岩、砂岩和泥页岩孔隙类型、结构及非均质特征.结果表明:长石、石英和有机质对储集空间发育具有建设性作用,方解石、黏土和方沸石矿物是储集空间发育的不利因素,白云岩化作用虽在一定程度上改善了碳酸盐储层结构,但白云岩类微晶、泥晶纳米级晶间孔隙储集、渗流条件较差,页岩层系优势储集岩性主要包括砂岩、纹层型页岩和裂缝型白云岩3种类型;纹层型页岩储层基质储集、渗流相对较好,富长英质矿物纹层内残余粒间孔、溶蚀孔之间连通性较好,压裂改造后人工裂缝与基质孔缝形成复杂缝网结构,具备稳产能力,是页岩油主力产层.根据新认识,将钻探箱体聚焦到8~10 m厚纹层状长英质页岩段,GY5-3-1L、GY5-1-9H两口井首年单井累产油超1.0×10^(4)t,桶油成本下降到65美元,实现了湖相页岩油效益开发.In order to further clarify the dominant reservoir lithology of lacustrine shale strata,focus on sweet spots,improve the drilling encounter rate of sweet spots in the horizontal section,and increase the shale oil production of horizontal wells,this paper comprehensively uses the 494.29 m core of Well G108-8 in the second member of Kongdong Sag,more than 3000 sub-sections,scanning electron microscopy,nuclear magnetic resonance,mercury intrusion and whole-rock X-ray analysis data to systematically analyze the carbonate rock,sandstone and shale pore types,structures,and heterogeneity.The results show that feldspar,quartz and organic matter have a constructive role in the development of reservoirs.Calcite,clay and analcite minerals are unfavorable factors for the development of reservoir space.Although dolomitization has improved carbon to a certain extent,dolomite-like microcrystalline,micrite nano-scale intercrystalline pore storage and poor seepage conditions,the dominant reservoir lithology of shale oil mainly includes feldspar lithic sandstone,laminar type shale and fractured dolomite.Laminar shale has various types of reservoir space,and the residual intergranular pores and dissolution pores in the laminae rich in felsic minerals have good connectivity.Artificial fractures form complex fracture network structure with the matrix pores and fractures,and has the ability to stabilize production,which is the main production layer of shale oil in the second member of the hole.The newly implemented horizontal well focuses the drilling box to the 8-10 m thick layered felsic shale interval,wells GY5-3-1L and GY5-1-9H produced more than 1.0×10^(4) t of oil per well in the first year,and the cost per barrel of oil dropped to US$65,realizing the profitable development of lacustrine shale oil.

关 键 词：渤海湾盆地 沧东凹陷 孔二段 页岩油 储层 孔隙结构 石油地质学 

分 类 号：P618.13[天文地球—矿床学]