东营凹陷中低成熟度富碳酸盐页岩地质特征——以牛庄洼陷沙四段上亚段为例  

Geological characteristics of shale oil enrichment in Niuzhuang sag,Dongying depression

作　　者：张顺[1] 刘惠民[2,3] 张鹏飞 李军亮 刘鑫金[1] 宋晓倩 魏晓亮[1] 王勇 王伟庆 ZHANG Shun;LIU Huimin;ZHANG Pengfei;LI Junliang;LIU Xinjin;SONG Xiaoqian;WEI Xiaoliang;WANG Yong;WANG Weiqing(Research Institute of Petroleum Exploration and Development,Shengli Oilfield,SINOPEC,Dongying,Shandong 257015,China;Sinopec Shengli Oilfield Company,Dongying,Shandong 257000,China;Shandong Provincial Key Laboratory of Unconventional Oil and Gas Exploration and Development,Dongying,Shandong 257015,China;Research Institute of Geophysical Prospecting,Shengli Oilfield Company,SINOPEC,Dongying,Shandong 257022,China)

机构地区：[1]中国石化胜利油田分公司勘探开发研究院,山东东营257015 [2]中国石化胜利油田分公司,山东东营257000 [3]山东省非常规油气勘探开发重点实验室,山东东营257015 [4]中石化胜利油田分公司物探研究院,山东东营257022

出　　处：《中国矿业大学学报》2022年第6期1138-1151,共14页Journal of China University of Mining & Technology

基　　金：国家重点基础研究发展规划(973)项目(2014CB239100);国家科技重大专项(2017ZX05049);国家自然科学基金项目(4217020748);山东省重点研发计划项目(2020ZLYS08);胜利油田分公司科研项目(YKK2115,YKK2214)。

摘　　要：以东营凹陷牛庄洼陷沙河街组四段上亚段页岩层系为研究对象,通过岩心观察描述、X-射线全岩矿物分析、岩石薄片镜下观察、氩离子抛光样品的扫描电镜观察、CT扫描、有机地球化学测试数据分析等技术方法,对页岩进行沉积环境、岩石学特征、成岩作用、储集特征及有机地化特征分析,明确东营凹陷牛庄洼陷沙四上亚段页岩是一套典型的中低成熟度、富碳酸盐矿物页岩,岩相类型多样且垂向变化快,超压缝、溶蚀孔等储集空间类型丰富、含油性好,具有很好的勘探开发前景.研究结果表明:牛庄洼陷沙四上页岩是偏干旱气候、咸水—半咸水、较低能环境的产物,碳酸盐矿物含量较高,以不同结晶形态的(铁)方解石和(铁)白云石为主,两者之和平均值>40%,与有机质和黏土矿物频繁叠置形成韵律层,构成了纹层状泥质灰岩相、纹层状灰质泥岩相以及(纹)层状灰质或泥质白云岩相等可压性较好的主要岩相(组合)类型;受地层水介质及生烃排酸控制的成岩酸碱环境变化,方解石、白云石、黄铁矿、菱铁矿以及石英颗粒边缘等溶蚀、硅质交代碳酸盐矿物以及方解石白云岩化现象较普遍.有机质生烃排酸与碳酸盐矿物溶蚀是最常见的成岩作用,两者耦合形成的成岩、成储优势在灰白色或白色亮晶方解石纹层内部最为显著,形成了储集能力很好的溶蚀孔及微裂缝.核磁测试孔隙度为5.8%~13.7%,富灰和富云页岩总孔隙体积主要由相对较小的孔隙以及1μm以上晶间孔、溶蚀孔和微裂缝提供,宏孔孔径集中在100~600 nm;除了晶间孔和溶蚀孔,页岩层系还普遍发育裂缝,按发育丰度依次为层理缝、生烃超压缝和构造缝等,这些(微)裂缝的发育对页岩油储集、充注、流动和产出有重要作用.较高的地温梯度有利于中等偏低(Ro为0.52%~0.80%)成熟度页岩规模排烃,地面原油密度为0.89~0.93 t/m^(3),埋深越�Taking the upper sub-member of the fourth Member of Shahejie formation in Niuzhuang sag,Dongying sag as the research object,the core observation description,X-ray whole rock mineral analysis,rock thin section microscopic observation,argon ion polishing sample scanning electron microscope observation,CT scanning,organic geochemical test data analysis and other technical methods were adopted.To sedimentary environment in dongying sag,petrology characteristics,diagenesis,reservoir features and organic geochemical analysis,clear rock newchwang sub-sag,the period of shale in dongying sag is a typical low maturity,rich carbonate mineral shale,various types of lithofacies and vertical change fast,overpressure seam,dissolution pore reservoir space types,such as rich,good lubricity,It has a good prospect of exploration and development.Results show that the shale formation in Niuzhuang sag is the product of arid climate,brackish water and lower energy environment.Carbonate mineral content is higher,with different crystallization(iron)in the form of calcite and dolomite(iron),the sum of the average>40%,and the organic matter and clay mineral frequently superimposed form rhythmic,constitute the grain layer argillaceous limestone facies,grain layered grey mudstone facies and stratiform or bedded limy dolomite equal pressure can be good main types of lithofacies(combination).Diagenetic acid-base environment changes controlled by formation water medium and hydrocarbon generation and acid discharge,the dissolution of calcite,dolomite,pyrite,siderite and quartz grain edge,siliceous metasomatism of carbonate minerals and dolomitization of calcite are more common.Hydrocarbon generation and acid discharge from organic matter and dissolution of carbonate minerals are the most common diagenesis in shale closed system.The advantages of diagenetic reservoir formed by the coupling of the two are most significant in the lamina of pale or white sparry calcite,and the dissolution pores and micro-cracks with good storage capacity are formed.

关 键 词：页岩油 成岩 储集 异常超压 裂缝 沙四上亚段 牛庄洼陷 

分 类 号：TE122[石油与天然气工程—油气勘探]