Accessing Preferential Foam Flow Paths in 2D Micromodel Using a Graph-Based 2-Parameter Model

This study uses experimental data of pore-scale foam flow inside a high-complexity network to fit a graph-based model describing preferential flow paths based on characteristics of the porous medium. Two experiments, with equal gas fractions but varying injection rates, are modelled in parallel. Proposed paths are solution paths to the k-Shortest Paths with Limited Overlap (k-SPwLO) problem, applied to a graph representation of the porous medium with edge weights representing throat properties. A 1-parameter model, based on throat radius only is tested before integrating a second parameter, describing the alignment of the pores surrounding the throat with respect to injection pressure gradient. The preferential paths in both experiments vary in quantity and in the specific zones described. As such, fitted models characterizing preferential paths for either experiment show separate dependencies to structural parameters. Overall, the graph-based framework was able to capture many high-flow zones in various model parameter combinations, perhaps as consequence of the relatively spiked throat size distribution of the model. The optimized model for the high injection rate experiment markedly shows a non-zero dependence to the pore alignment to pressure gradient as well as throat size, whereas the lower injection rate experiment was best fitted to a model that made sole use of the throat radius.