Liquid Cohesion Induced Particle Agglomeration Enhances Clogging in Rock Fractures

Suspended particle transport is frequently involved in many geophysical processes and subsurface engineering applications. Although common and important, the effect of liquid cohesion on particle clogging has been overlooked in previous studies. We conduct visualized experiments of dilute suspension flow in a rough fracture and find a dramatic enhancement of clogging by a tiny amount of additional immiscible wetting liquid, even at weight percentage ω ≤ 0.5%. An experimental phase diagram of clogging patterns is obtained in the space of secondary liquid content and flow rate. The combined effect of suspension composition and hydrodynamic condition on the clogging behavior is analyzed to explain transitions of clogging regimes. A theoretical model of agglomerate size is proposed to quantify the capillary cohesion effect. This work improves the understanding of fines migration and particle‐clogging behaviors in the subsurface and paves the way for possibility of controlling particle transport and clogging in various applications. Plain Language Summary Suspended particle flow and clogging in rock fractures are involved in many subsurface engineering applications and natural processes. Water‐wet particles dispersed in oil are cohesive and tend to agglomerate, clogging flow channels of crude oil to resist further recovery. Despite being common and important, the effect of liquid cohesion on particle clogging has been overlooked in previous studies. Here, we conduct visualized experiments of dilute suspension flow in a rough fracture. We, for the first time, find a dramatic enhancement of clogging by a tiny amount of additional immiscible wetting liquid, even at a weight percentage as low as 0.1%–0.5%. We obtain an experimental phase diagram of clogging patterns in the space of wetting liquid content and flow rate. The transitions of clogging regimes are explained through the combined control of clogging behavior by the suspension composition and hydrodynamic condition. We propose a theoretical model of agglomerate size to quantify the effect of capillary cohesion induced by the additional wetting liquid. The experimental and theoretical results improve our understanding of suspension flow and clogging behaviors and pave the way for the possibility of controlling particle transport and clogging processes in various applications by adjusting multiphase liquid composition and flowrate. Key Points A tiny amount of immiscible wetting liquid added into dilute suspen