Pore-scale gas–water flow in rock: Visualization experiment and simulation

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.