陆相富有机质页岩纹层组合特征与页岩油差异富集机理--以鄂尔多斯盆地三叠系延长组长7_(3)亚段为例  

Lamina combination characteristics and differential shale oil enrichment mechanisms of continental organic-rich shale:A case study of Triassic Yanchang Formation Chang 7_(3) sub-member,Ordos Basin,NW China

作　　者：牛小兵[1,2] 吕成福 冯胜斌[5] 周钱山 辛红刚[5] 肖月也 李成[5] 淡卫东[5] NIU Xiaobing;LYU Chengfu;FENG Shengbin;ZHOU Qianshan;XIN Honggang;XIAO Yueye;LI Cheng;DAN Weidong(National Engineering Laboratory for Exploration and Development of Low Permeability Oil&Gas Fields,Xi’an 710018,China;PetroChina Changqing Oilfield Company,Xi’an 710018,China;Northwest Institute of Eco-Environmental Resources,Chinese Academy of Sciences,Lanzhou 730000,China;Key Laboratory of Petroleum Resources Exploration and Evaluation,Gansu Province,Lanzhou 730000,China;Research Institute of Exploration and Development,PetroChina Changqing Oilfield Company,Xi’an 710018,China;University of Chinese Academy of Sciences,Beijing 730099,China)

机构地区：[1]低渗透油气田勘探开发国家工程实验室,西安710018 [2]中国石油长庆油田公司,西安710018 [3]中国科学院西北生态环境资源研究院,兰州730000 [4]甘肃省油气资源勘探与评价重点实验室,兰州730000 [5]中国石油长庆油田公司勘探开发研究院,西安710018 [6]中国科学院大学,北京730099

出　　处：《石油勘探与开发》2025年第2期279-291,共13页Petroleum Exploration and Development

基　　金：国家自然科学基金项目(42302184);甘肃省基础研究创新群体项目(22JR5RA045)。

摘　　要：通过对鄂尔多斯盆地三叠系延长组7段3亚段(简称长7_(3)亚段)富有机质页岩的纹层(组合)类型、储集特征和页岩油赋存状态等开展系统研究,揭示不同纹层组合约束下页岩油赋存的主控因素;并结合页岩油微运移表征及评价方法,从接力式供烃、阶梯式运移、多级分异的角度深入探讨页岩油差异富集机理和富集模式。研究表明:①长7_(3)亚段页岩主要发育无纹层型(泥岩)、砂质纹层、凝灰质纹层、混合纹层和富有机质纹层等5类主要纹层组合。②不同纹层组合页岩储集空间存在明显差异,砂质纹层和凝灰质纹层页岩中大量发育的粒间孔、溶蚀孔及生烃增压缝等多尺度孔缝系统构成液态烃赋存的主要场所。③各类纹层组合页岩中页岩油的赋存和分布受有机质丰度、储集性、热演化程度、矿物组成及纹层规模共同控制,砂质、凝灰质纹层等刚性纹层组合页岩的微纳米孔缝中以游离态的轻质组分为主,而有机质、黏土矿物及骨架矿物颗粒表面则以吸附态的重质组分为主。④长7_(3)亚段不同纹层组合页岩间发生了明显的页岩油微运移,整体呈现出富有机质纹层页岩→凝灰质纹层页岩→混合纹层页岩→砂质纹层页岩→泥岩的阶梯式运移特点。⑤多种类型纹层页岩空间叠置关系控制下有机质的“接力式”供烃、多尺度孔缝网络的“阶梯式运移”及不同纹层组合页岩中“有机-无机相互作用”控制下的“多级分异”是导致页岩油在不同纹层组合页岩间油组分差异性的根本原因。The lamina(combination)types,reservoir characteristics and shale oil occurrence states of organic-rich shale in the Triassic Yanchang Formation Chang 7_(3) sub-member in the Ordos Basin were systematically investigated to reveal the main controlling factors of shale oil occurrence under different lamina combinations.The differential enrichment mechanisms and patterns of shale oil were discussed using the shale oil micro-migration characterization and evaluation methods from the perspectives of relay hydrocarbon supply,stepwise migration,and multi-stage differentiation.The results are obtained in five aspects.First,Chang 7_(3) shale mainly develops five types of lamina combination,i.e.non-laminated(mudstone),sandy laminae,tuffaceous laminae,mixed laminae,and organic-rich laminae.Second,shales with different lamina combinations are obviously different in the reservoir space.Specifically,shales with sandy laminae and tuffaceous laminae have a large number of intergranular pores,dissolution pores and hydrocarbon generation-induced fractures.The multi-scale pore and fracture system constitutes the main place for liquid hydrocarbon occurrence.Third,the occurrence and distribution of shale oil in shale with different lamina combinations are jointly controlled by organic matter abundance,reservoir property,thermal evolution degree,mineral composition and laminae scale.The micro-nano pores and fractures in the shales with rigid laminae represented by sandy laminae and tuffaceous laminae mainly host free light components,while the surfaces of organic matter,clay minerals and skeleton mineral particles are dominated by adsorbed heavy components.Fourth,there is obvious shale oil micro-migration between shales with different lamina combinations in Chang 7_(3).Generally,such micro-migration is stepwise in a sequence of shale with organic-rich laminae→shale with tuffaceous laminae→shale with mixed laminae→shale with sandy laminae→mudstone.Fifth,the relay hydrocarbon supply of organic matter under the control of the spat

关 键 词：富有机质页岩 纹层组合特征 差异富集机理 页岩油 长73亚段 三叠系延长组 鄂尔多斯盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]