龙马溪组页岩不同显微形态有机质成因及其勘探潜力探讨  

Discussion on the Genesis and Exploration Potential of Different Microscopic Forms of Organic Matters in the Longmaxi Formation Shale

作　　者：刘振庄 白名岗[2,3] 杨玉茹 张聪[2,3] 王向华 陈娟[1,2] 谢婷 方立羽 秦丽娟 LIU Zhen-zhuang;BAI Ming-gang;YANG Yu-ru;ZHANG Cong;WANG Xiang-hua;CHEN Juan;XIE Ting;FANG Li-yu;QIN Li-juan(School of Energy Resources,China University of Geosciences(Beijing),Beijing 100083,China;The Key Laboratory of Unconventional Oil&Gas Geology Center,China Geological Survey,Beijing 100029,China;Oil&Gas Survey Center,China Geological Survey,Beijing 100029,China)

机构地区：[1]中国地质大学(北京)能源学院,北京100083 [2]中国地质调查局非常规油气地质重点实验室,北京100029 [3]中国地质调查局油气资源调查中心,北京100029

出　　处：《岩矿测试》2020年第2期199-207,共9页Rock and Mineral Analysis

基　　金：“十三五”国家科技重大专项项目(2016ZX034003-006)

摘　　要：有机质是页岩中最重要的组分,有机孔更是页岩气重要的储集空间,以扫描电镜为主流的微观分析检测技术成为页岩研究的重要手段,目前对有机质的综合研究正逐步成为页岩气勘探开发研究的重要内容。本次研究选取四川盆地及其外围龙马溪组富有机质页岩,采用氩离子抛光非镀膜样品,利用低电压近距离工作状态,对样品进行了高分辨率场发射扫描电镜检测,观察、总结了有机质显微形态,并依据其内部结构及组成特征对其生烃及储集能力进行了探讨。检测结果揭示:龙马溪组富有机质页岩中有机质主要有三种显微形态,分别是结构型沉积有机质、分异型交生有机质和填隙型运移有机质。结构型沉积有机质形成于沉积及早期成岩演化阶段,保留了部分生物结构特征或沉积定向构造;分异型交生有机质与黏土矿物交互生长并经历演化分异作用,形成了类似于岩浆岩中的“花岗结构”;而填隙型运移有机质形成于晚成岩有机质高演化阶段,为液态烃充填于自生矿物晶间,其周边矿物具有自形特征。龙马溪组页岩以填隙型运移有机质和分异型交生有机质为主,二者都发育丰富的有机质孔隙(孔径10~300nm),是龙马溪组页岩优质的生气母质,并具有优质的储集性能。研究结果为我国海相龙马溪组页岩气生成理论及勘探开发评价提供了较深层次的微观信息。BACKGROUND:Organic matter is the most important component in shale,and organic pore is an important reservoir space of shale gas.Scanning electron microscope(SEM),the mainstream microscopic analysis and detection technology,has become an important means of shale research.The comprehensive study of organic matter is gradually becoming an important part of shale gas exploration and development.OBJECTIVES:To summarize the microscopic morphology of organic matter in organic shale of the Longmaxi Formation and discuss its hydrocarbon generation and reservoir ability according to its internal structure and composition characteristics.METHODS:The organic shale of the Longmaxi Formation in Sichuan Basin and its periphery were polished with argon ion,and the samples were examined by high resolution field emission scanning electron microscope under the condition of low voltage and close working distance.RESULTS:There were three main microscopic forms of organic matter in the organic shale of the Longmaxi Formation,which were structure-type sedimentary organic matter,differentiated symbiotic organic matter and interstitial migration organic matter.The structural sedimentary organic matter formed in the stage of sedimentation and early diagenetic evolution,and retained some biological structure characteristics or sedimentary directional structure.Differentiated symbiotic organic matter interacted with clay minerals and underwent evolutionary differentiation,forming a‘granitic structure’similar to that in magmatic rocks.On the other hand,the interstitial migration organic matter was formed in the high evolution stage of late diagenetic organic matter,and the liquid hydrocarbon filled in the intergranular of authigenic minerals,and the surrounding minerals had euhedral characteristics.The shale of the Longmaxi Formation was dominated by organic matter pores-rich interstitial migration organic matter and differentiated symbiotic organic matter,which were the high-quality gas parent materials of the Longmaxi Formation shale,

关 键 词：龙马溪组页岩 高分辨率场发射扫描电镜 不同显微形态有机质 成因及来源探讨 生烃及储集性能 

分 类 号：P619.227[天文地球—矿床学] P575.2[天文地球—地质学]