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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.

Tight sandstone, with severe diagenesis and complex pore structure, differs greatly from conventional sandstone in terms of rock electrical parameters. In subsurface rock electrical experiments, various electrical parameters are confounded and can only be analyzed qualitatively. The lack of quantitative analysis for each individual electrical parameter presents a challenge for the evaluation of oil and gas saturation in tight sandstone. Based on the 2D pore‐throat model and the features of pore structure in the tight sandstone of the Penglaizhen and Shaximiao Formations in the upper and middle Jurassic of the Western Sichuan Depression, this paper presents 3D micro pore‐throat models for three types of tight sandstone. It proposes a finite element‐based rock electrical simulation method to analyze the influence of pore structure parameters, such as throat radius and throat tortuosity, on electrical parameters such as resistivity, formation factor, and cementation index quantitatively. The research revealed the following results: (1) Throats of tight sandstone usually have lamellar or curved lamellar shapes that are slender and narrow. The lamellar throat used in the proposed pore‐throat model is more consistent with the features of tight sandstone than the tubular throat used in the original model. (2) The throat determines the conductivity of tight sandstone. The throat parallel to the electric potential has the greatest influence on conductivity, and the throat perpendicular to the potential has the least influence. (3) In tight sandstone grades I to III, as the porosity decreases, the formation factor increases and the cementation index decreases. (4) The results of the rock electrical simulation are consistent with the results of the rock electrical experiment, which indicates that the proposed rock electrical simulation method of tight sandstone is effective and accurate.

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