Abstract:

The cohesion effect induced by liquid bridges between particles, which promotes particle aggregation, is widespread in both natural environments and engineering applications. Understanding the migration and clogging processes of particles in fractured media under the influence of capillary-cohesion is crucial for advancing particle transport knowledge. Through visualization experiments and seepage calculations, the processes of capillary-cohesive particle migration and clogging are studied. A phase diagram of clogging patterns in the space of capillary-cohesion and flowrate is proposed. Experimental results show that capillary- cohesion induces particle agglomeration, increasing effective particle diameter and significantly enhancing fracture clogging. Stripe-like clogging patterns occur at high flow rates, while complete clogging patterns or entrance sealing patterns occur at low flow rates. Hydrodynamic analysis reveals that fluid velocity distributions control the growth of clogging stripes and the change in residual flow channels in the complete clogging patterns. Furthermore, Smoluchowski theory effectively describes the linear growth behavior of clogging stripes over time. These findings elucidate the mechanism of capillary-cohesive particle migration and clogging in rock fractures, providing theoretical and technical guidance for evaluating and controlling particle transport in fractured media.

Key words: capillary-cohesion, fracture seepage, particle migration, clogging