The importance of the third dimension on transport through saturated porous media: case study based on transport of particles

Abstract

The present study involves transport experiments in a three-dimensional, heterogeneous porous medium. Latex particles and chloride are utilized as tracers in an artificially constructed porous medium consisting of a heterogeneous mixture of glass beads. Data collected include chloride breakthrough, particle breakthrough, and particle concentrations remaining within the medium (determined through destructive sampling at the end of the experiment). The chloride breakthrough curve showed substantial dispersion, an indication of mixing among a number of different flow lines (the mixing occurred in the outflow reservoir). The outflow counts of latex particles showed that particles were successfully transported across the length of the medium. The destructive samples showed a complex distribution of particles remaining within the medium which was correlated with the structure of the medium, particularly with the high-permeability pathways. Comparison of the results from this experiment with results from previously published results from two-dimensional media demonstrate that the successful transport of particles across the medium is a direct result of connectivity of high-permeability paths in the third dimension. This observation is consistent both with the distribution of trapped particles and with numerical analysis of the flow field.