Particle migration is a pore-scale process that fundamentally controls pore-structure evolution and seepage behavior in granular porous media. This study investigates fine particles migration in coarse-grained sediments and its effects on pore structure and permeability by combining low-field nuclear magnetic resonance (LF-NMR) experiments with coupled CFD–DEM simulations. The evolution of fine particles migration rate, porosity variation, and permeability was analyzed under different fluid injection velocities and fines concentrations. Higher injection velocities accelerate fines initiation and early-stage migration by increasing hydrodynamic drag forces, whereas their influence diminishes at later stages due to pore-structure confinement and localized particle retention. At a constant injection velocity, increasing fines concentration suppresses early fines mobilization owing to enhanced interparticle interactions and pore throat blockage. As seepage continues, progressive fines release and export enlarge pore space and enhance permeability. Spatial analyses reveal that fines migration is governed by localized retention and rearrangement within pore throats. Within the investigated parameter ranges and timescales, system evolution is dominated by internal erosion and pore unclogging rather than sustained macroscopic clogging. These results provide mechanistic experimental–numerical insight into fines migration and seepage stability in granular porous media, with direct relevance to hydrate-bearing sediments and other fine-sensitive geological systems.
Li et al. (Tue,) studied this question.