油气地质与采收率2025，Vol.32Issue(5)：55-68,14.DOI:10.13673/j.pgre.202403047
粉砂岩储层致密化成因研究
Densification mechanism of siltstone reservoirs:A case study of lower Triassic M Formation in Western Canada Sedimentary Basin
摘要
Abstract
The tight siltstone reservoirs of the lower Triassic M Formation in the Western Canadian Basin are rich in oil and gas resources,but it has a series of problems such as fine grain size,low porosity and permeability,complex sedimentary and diagenesis processes,large differences in rock fabric between layers,and strong vertical and horizontal heterogeneity,resulting in low accuracy in geological sweet spot prediction and difficulties in oil and gas exploration and development.To better understand the reservoir characteristics and achieve efficient development,research on the restoration of the reservoir densification process should be deepened.Based on the core description and thin section analysis,X-ray diffraction,scanning electron microscopy,and high-pressure mercury injection were comprehensively used to determine the reservoir pore development characteristics and diagenetic types of the three main layers of the lower Triassic M Formation in the study area.On this basis,the evolution process of diagenesis-reservoir formation was further clarified,and the causes of reservoir densification were divided.The results show that the pores in the tight siltstone reservoirs of M Formation are dominated by residual intergranular pores and dissolution pores,and the pore throat radius is concentrated between 10 and 150 nm,which belongs to tight siltstones with ultra-low porosity and ultra-low permeability.The diagenesis types are dominated by compaction,cementation,and metasomatism.The present diagenesis falls between the middle stage A and middle stage B.The dissolution is relatively developed in the LE layer.Due to the influence of sedimentary environments,the processes of porosity variation in the three main layers differ greatly.LC layer is dominated by compaction-based porosity reduction,supplemented by carbonate cementation-based porosity reduction.In the LE layer,carbonate cementation is the main factor of porosity reduction,and dissolution has improved the reservoir properties.LG layer has a higher shale content,and early compaction is the primary mechanism for porosity reduction.Based on the diagenesis and porosity variation,the causes of densification in the LC,LE,and LG layers are classified as primary mixed origin,secondary cementation origin,and primary fine-grained origin,respectively.关键词
致密粉砂岩储层/成岩作用/成岩—成储匹配关系/致密化过程/西加盆地Key words
tight siltstone reservoir/diagenesis/diagenesis-reservoir formation matching relationship/densification process/Western Canadian Basin分类
能源科技引用本文复制引用
薛子鑫,朱强,刘仁静,姜振学,李冬梅,李孝刚,马晓昌,李长海..粉砂岩储层致密化成因研究[J].油气地质与采收率,2025,32(5):55-68,14.基金项目
国家自然科学基金面上项目"海相富气页岩低阻成因及其对含气性的控制机理"(42072151)、"混积页岩储层多尺度孔—缝系统对页岩油赋存及可动性的控制"(42272137),中国石化集团科技部项目"加拿大致密凝析气藏富液区效益开发技术及应用"(JP25054). （42072151）
