岩矿测试2026，Vol.45Issue(1)：142-159,18.DOI:10.15898/j.ykcs.202506030140
超低渗砂岩微观水驱油及剩余油分布特征研究
Microscopic Waterflooding and Residual Oil Distribution Characteristics in Ultra-Low Permeability Sandstone
摘要
Abstract
The pore structure of ultra-low permeability sandstones is highly complex,with strong wettability heterogeneity,which complicates the characterization of oil-water flow behavior and remaining oil distribution during waterflooding.Current research methods mainly rely on core-scale experimental analysis,which falls short in accurately capturing pore-scale dynamic flow processes in heterogeneous porous media.As a result,the microscopic mechanisms of oil displacement remain inadequately understood.To address this,visual models based on real core samples from ultra-low permeability reservoirs in the Ordos Basin were constructed to conduct waterflooding experiments.Numerical simulations were also employed to investigate the characteristics of oil-water flow and distribution during waterflooding.The results demonstrate that waterflooding in ultra-low permeability rocks exhibits a fingering pattern.Both a reduction in pore throat radius and an increase in heterogeneity lead to decreased oil displacement efficiency.Increasing the injection rate improves oil displacement efficiency in oil-wet rocks by up to 17%,whereas in water-wet rocks,it first increases and then decreases,peaking when viscous and capillary forces reach equilibrium.As rock wettability shifts from strongly water-wet to strongly oil-wet,oil displacement efficiency decreases by 20.2%,and the dominant forms of remaining oil transition from corner and throat types to clustered and interconnected types.Under mixed-wettability conditions,water phase flow paths alter significantly,with the proportion of clustered remaining oil being 17.2%-33.4%higher compared to purely oil-wet or water-wet systems.This leads to lower sweep efficiency and displacement efficiency relative to homogeneous wettability systems.Due to capillary effects,the wettability at the pore inlet plays a decisive role in controlling fluid flow under mixed-wettability conditions.This study provides an important theoretical foundation for the effective development of water injection in ultra-low permeability reservoirs.The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202506030140.关键词
水驱油/剩余油分布/孔隙尺度/润湿性/数值实验Key words
waterflooding/residual oil distribution/pore scale/wettability/numerical experiment分类
能源科技引用本文复制引用
王国环,肖文联,王建宁,宋鹏,郑玲丽,张熙,郑多闻..超低渗砂岩微观水驱油及剩余油分布特征研究[J].岩矿测试,2026,45(1):142-159,18.基金项目
国家自然科学基金项目(51874248) （51874248）
国家科技重大专项项目(SQ2025AAA120126) （SQ2025AAA120126）
西南石油大学青年科技创新团队项目(2018CXTD10) （2018CXTD10）
