石油勘探与开发2025，Vol.52Issue(2)：279-291,13.DOI:10.11698/PED.20240684
陆相富有机质页岩纹层组合特征与页岩油差异富集机理
Lamina combination characteristics and differential shale oil enrichment mechanisms of continental organic-rich shale:A case study of Triassic Yanchang Formation Chang 73 sub-member,Ordos Basin,NW China
摘要
Abstract
The lamina(combination)types,reservoir characteristics and shale oil occurrence states of organic-rich shale in the Triassic Yanchang Formation Chang 73 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 73 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 73.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 spatial superposition of shales with various laminae,the stepwise migration via multi-scale pore and fracture network,and the multi-differentiation in shales with different lamina combinations under the control of organic-inorganic interactions fundamentally decide the differences of shale oil components between shales with different lamina combinations.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Key words
organic-rich shale/lamina combination characteristics/differential enrichment mechanism/shale oil/Chang 73 sub-member/Triassic Yanchang Formation/Ordos Basin分类
石油、天然气工程引用本文复制引用
牛小兵,吕成福,冯胜斌,周钱山,辛红刚,肖月也,李成,淡卫东..陆相富有机质页岩纹层组合特征与页岩油差异富集机理[J].石油勘探与开发,2025,52(2):279-291,13.基金项目
国家自然科学基金项目(42302184) （42302184）
甘肃省基础研究创新群体项目(22JR5RA045) （22JR5RA045）
