Influence of Fracture Orientation on Particle Transport in Water-Saturated Fractured Chalk: Experimental and Modeling Approaches

Abstract

The role of fracture orientation on particle transport in a water-saturated fractured chalk sample was investigated. Transport experiments were performed with different fracture orientations using kaolinite particles and dissolved fluorescein under different flow velocities. The experimental data were fitted to a model based on the advection–dispersion equation. The transport parameters were conducted and correlated to the flow velocity and the fracture orientation. The results revealed that an increase in fracture orientation vertically leads to earlier breakthrough curves and a higher recovery. The increase in the fracture orientation reduces the particle–fracture surface interaction. Fracture orientation has a negligible effect on the transport of fluorescein. Kaolinite particles are transported faster than fluorescein at all fracture orientations due to the size-exclusion effect. Particle dispersion is more important for greater orientations since particles can sample the entire flow velocity. Further investigations on particle size are necessary to understand in-depth the impact of fracture orientation on particle dispersion. As the fracture orientation increases, the probability of particle collision with the fracture surface decreases, leading to a decrease in the filtration coefficient. By using experimental methods, this study contributes to the advancement of understanding the effect of fracture orientation on the transport of particles.