不同沉积微相致密储层的成岩响应及其控储机理——以鄂尔多斯盆地西部延长组为例  

Diagenetic Responses to Delta Front-Lacustrine Depositional Microfacies and Implications for Tight Reservoir Quality Differences in the Yanchang Formation,Western Ordos Basin

作　　者：王乾右 杨威[1,2] 葛云锦 宋岩[1,2] 姜振学[1,2] 罗群[1,2] 左如斯 李耀华 刘聃 张帆 王耀华[1,2] 鲁健康 WANG QianYou;YANG Wei;GE YunJin;SONG Yan;JIANG ZhenXue;LUO Qun;ZUO RuSi;LI YaoHua;LIU Dan;ZHANG Fan;WANG YaoHua;LU JianKang(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,China;Unconventional Oil and Gas Sciences and Technology Institute,China University of Petroleum(Beijing),Beijing 102249,China;Department of Earth,Ocean and Ecological Sciences,University of Liverpool,Liverpool L693GP,UK;Research Institute of Shaanxi Yanchang Petroleum(Group)Co.,Ltd.,Xi’an 710075,China;State Key Laboratory of Marine Geology,Tongji University,Shanghai 200092,China;Oil and Gas Survey,China Geological Survey,Beijing 100083,China;The Institute of Exploration Techniques,Chinese Academy of Geological Sciences,Langfang,Hebei 065000,China)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)非常规油气科学技术研究院,北京102249 [3]利物浦大学地球,海洋与生态科学系,英国利物浦L693GP [4]陕西延长石油(集团)有限责任公司研究院,西安710075 [5]同济大学海洋地质国家重点实验室,上海200092 [6]中国地质调查局油气资源调查中心,北京100083 [7]中国地质科学院勘探技术研究所,河北廊坊065000

出　　处：《沉积学报》2021年第4期841-862,共22页Acta Sedimentologica Sinica

基　　金：中国石油大学(北京)优秀青年学者科研启动基金项目(2462020QNXZ004);国家科技重大专项(2016ZX05034001-005,2017ZX05035002-007);国家留学基金(202009110097)。

摘　　要：沉积微相是影响陆相致密油气储层发育的重要控制因素,不同微相的成岩响应和储层质量不同,制约了储层精细刻画与有利区预测工作。通过岩心、薄片、测井、孔渗、扫描电镜、XRD矿物分析、微米CT和压汞资料,识别了鄂尔多斯盆地西南部延长组三角洲—湖相致密储层8种沉积微相类型,刻画了不同微相在矿物组成、成岩作用、储层物性和孔隙结构方面的差异。结果表明,不同微相储层的压实作用,溶蚀作用和自生绿泥石、伊利石的胶结作用差异明显。水下分流间湾、浅湖泥和半深湖泥储层中黏土和云母等塑性矿物组分含量高,受机械和化学压实影响更大。受大气水渗滤作用和生烃作用影响,水下分流河道,河口坝和席状砂储层中溶蚀孔较为发育。频繁的砂泥互层和湖流侵入导致滩砂体铁方解石胶结大量发育。自生绿泥石和伊利石胶结物的产状具有明显的沉积微相分带性,但不同微相储层的高岭石和硅质胶结差异不大。最后建立了致密储层孔隙连通性系数E和孔隙结构评价系数A,甄别了不同微相储层质量差异,可为储层精细刻画与分级评价提供指导。Depositional microfacies is an important influencing factor in the development of continental hydrocarbonbearing reservoirs.However,the diagenetic responses to the depositional microfacies and their implications for reservoir quality variation remain enigmatic,which limits detailed reservoir description and prediction of the location of high-quality reservoirs.The tight continental reservoirs of the Yanchang Formation in the Ordos Basin were targeted with the aim of clarifying the differences in diagenetic,petrophysical and pore-structural characteristics of tight reservoirs within different microfacies.A multi-methodological approach,involving petrographic assessments,logging evaluations,physical property experiments,digital SEM imaging analyses,3D micro-CT imaging analysis,X-ray diffraction mineral identification and mercury intrusion experiments,was utilized to identify eight delta-front-lacustrine microfacies in this study.The results show that different microfacies reservoirs vary in compaction,dissolution,and clay mineral cementation.Interdistributary bays,shallow lacustrine mudstones,and semi-deep lacustrine mudstones that are rich in plastic clay and mica are those most likely to be affected by physical and chemical compaction.Reservoirs affected by meteoric water percolation and hydrocarbon generation,such as distributary channels,mouth bars and sheet sand reservoirs,are characterized by well-developed dissolution pores.Interbedded sandmud deposits and lacustrine tidal incursions lead to strong ferrocalcite cementation into beach bar sandstones.The occurrence of authigenic chlorite and illite cements displays prominent microfacies zonation;kaolinitic and siliceous cementation show less variation than other diagenetic processes in different microfacies reservoirs.Finally,this study proposes two evaluation parameters:a pore connectivity index,E,and a pore structure evaluation parameter,A,to assist in clarification of the differences in reservoir quality resulting from the range of depositional microfacies.

关 键 词：鄂尔多斯盆地 延长组 致密储层 沉积微相 储层质量 孔隙结构 成岩作用 

分 类 号：TE122[石油与天然气工程—油气勘探]