Abstract The characteristics of pore-scale two-phase flow are of significance to the effective development of oil and gas resources, and visualization has gradually become one of the hot spots in the research of pore-scale two-phase flow. Based on the pore structure of rock, this research proposed a microscopic glass etching displacement experiment and a Navier–Stokes equation based finite element simulation to study the pore-scale gas–water two-phase flow. Then, this research conducted the proposed methods on the type I, type II and type III tight sandstone reservoirs in the Penglaizhen Formation of western Sichuan Basin, China. Results show that the outcomes of both the microscopic glass etching displacement experiment and the finite element simulation are by and large consistent. The water distributed in the large pores is displaced, and the trapped water mainly exists in the area induced by flow around high-permeability pores, perpendicular pores and disconnected ends of pores. The microscopic glass etching displacement experiment is conducive to better observing the phenomenon of a viscous finger-like breakthrough and air jumps in migration flows in narrow throats, while the finite element simulation has the advantages of cost effectiveness, easy operation and strong experimental reproducibility.

中文翻译：

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岩石中孔隙尺度的气水流动：可视化实验与模拟

摘要 孔隙尺度两相流特征对油气资源的有效开发具有重要意义，可视化逐渐成为孔隙尺度两相流研究的热点之一。本研究基于岩石的孔隙结构，提出了微观玻璃蚀刻置换实验和基于纳维-斯托克斯方程的有限元模拟，研究孔隙尺度的气水两相流。然后，本研究对四川盆地西部蓬莱镇组I型、II型和III型致密砂岩储层进行了研究。结果表明，微观玻璃蚀刻位移实验和有限元模拟的结果基本一致。分布在大孔隙中的水被置换，圈闭水主要存在于高渗透孔隙、垂直孔隙和孔隙不连通端周围的流动诱导区域。显微玻璃蚀刻位移实验有利于更好地观察窄喉道迁移流中出现粘性指状突破和空气跳跃现象，而有限元模拟具有成本效益高、操作简便、实验重现性强等优点。