天然气工业2026，Vol.46Issue(7)：108-124,17.DOI:10.3787/j.issn.1000-0976.2026.07.009
四川盆地东缘—鄂西地区二叠系吴家坪组富有机质页岩孔隙特征及其主控因素
Pore characteristics of organic-rich shale of the Permian Wujiaping Formation in the eastern margin of Sichuan Basin and western Hubei area and their controlling factors
摘要
Abstract
The second member of the Permian Wujiaping Formation(Wu 2 Member)in the eastern margin of the Sichuan Basin and western Hubei area represents a critical replacement horizon for marine shale gas exploration in South China.However,the low exploration degree and insufficient basic geological research have resulted in a poor understanding of pore development characteristics and their controlling factors,which restricts the sweet spot selection and efficient exploration of shale gas.Focusing on the Wu 2 Member shale in the study area,this paper systematically analyzes the pore characteristics of different shale lithofacies and their controlling factors by means of core observation,thin-section analysis,argon ion polishing-field emission scanning electron microscopy,and low-temperature gas adsorption experiments.In addition,a pore evolution model is established.The following results are obtained.First,the Wu 2 Member shale in the study area was deposited in a slope-deepwater shelf environment.It is characterized by a mineral assemblage of"high silica,moderate carbonate and low clay",high content of brittle minerals,and high organic matter abundance,dominated by Type Ⅱ2 kerogen.Second,there are mainly four types of lithofacies identified in the Wu 2 Member shale,including carbon-rich siliceous shale,carbon-rich mixed shale,high-carbon mixed shale,and medium-to low-carbon calcareous shale.Third,the reservoir space in the Wu 2 Member shale is mainly composed of secondary organic pores,with a small number of intergranular pores,dissolution pores and microfractures.The pore size is dominated by micropores and mesopores.These shale lithofacies exhibit significant heterogeneity,with carbon-rich siliceous shale being the best in pore structure and reservoir performance,while medium-to low-carbon calcareous shale being the worst in reservoir performance.Fourth,the pore development in the Wu 2 Member shale is synergistically controlled by organic matter type and abundance,mineral composition,and diagenesis.High organic matter abundance and brittle mineral support are crucial for the formation of high-quality reservoirs.Mechanical compaction,cementation,hydrocarbon generation from organic matter pyrolysis,acidic fluid dissolution,and clay mineral transformation jointly control the preservation and modification degree of reservoir pores.In conclusion,this study clarifies the development mechanisms of Wu 2 Member high-quality shale reservoirs,and can provide a theoretical basis for shale gas evaluation and sweet spot prediction in the study area.关键词
四川盆地东缘—鄂西地区/吴家坪组/页岩气/孔隙结构/主控因素/孔隙演化模式Key words
Eastern margin of Sichuan Basin and western Hubei area/Wujiaping Fm/Shale gas/Pore structure/Controlling factor/Pore evolution model分类
能源科技引用本文复制引用
杨锐,赵帅,徐建亭,包汉勇,申宝剑,刘皓天,刘计勇,王鹏威,董田,张莉..四川盆地东缘—鄂西地区二叠系吴家坪组富有机质页岩孔隙特征及其主控因素[J].天然气工业,2026,46(7):108-124,17.基金项目
国家自然科学基金项目"四川盆地及周缘二叠系页岩气差异富集机理与分布规律"(编号:U25D9024)、"构造抬升-降温阶段海相深层页岩气赋存状态动态演化过程"(编号:42172157),中国石油化工股份有限公司科研项目"川东地区重点层系页岩气成藏条件与评价技术研究"(编号:P23077),页岩油气富集机理与高效开发全国重点实验室开放基金课题"川东红星地区二叠系优质页岩储层发育机理"(编号:33550000-24-ZC0699-0059),武汉市高层次人才计划青年项目. （编号:U25D9024）
