Abstract: Fine particle migration widely exists in two-phase flow processes in both nature and engineering fields, such as pollutant migration, remediation, as well as oil and gas production. However, the effects of particle-induced blockage in porous media on two-phase flow remain unclear. Utilizing a self-developed three-dimensional visualization experimental platform, this study conducted a series of two-phase displacement experiments with different flow rates and pore sizes in a porous medium, and systematically investigated the transport and clogging behavior of fine particles and their subsequent effects on two-phase flow dynamics. The results reveal that particle-induced pore clogging during two-phase flow is governed by the synergistic control of flow rate and pore size. At low flow rates, pore size has minimal impact on clogging. However, at high flow rates, pore size becomes the dominant factor. By analyzing the spatial distribution of residual fluids, the study clarified the relationship between pore clogging and fluid connectivity: more significant clogging leads to a more discrete distribution of the residual wetting phase and reduced fluid connectivity. Additionally, the experiment also revealed the controlling mechanism of blockage on displacement pressure and displacement efficiency during two-phase flow. The findings are expected to provide important theoretical insights and practical guidance for optimizing two-phase flow process and improving energy recovery efficiency.

Key words: porous medium, fine particle, pore clogging, two-phase flow, connectivity characteristic