Abstract: Dense Non-aqueous Phase Liquids (DNAPLs) are common pollutants in groundwater. Understanding the migration mechanisms is of great significance. To explain the effect of wettability of porous media on the flow rate and residual saturation of DNAPL in the experiment, we simulated the DNAPL migration via solving the basic fluid mechanics equations at pore scale and reproduced the
behaviors similar to the experimental results. The results show that the multi-interface model can better explain the migration mechanism and reproduce a phenomenon similar to the laboratory scale. The falling speed is affected by both advancing interface and rear interface while the residual saturation is mainly determined by the rear interface. In addition, we demonstrate that the effect of wettability on motion works through the heterogeneity of porous media.

Key words: DNAPL, pore-scale, wettability, migration characteristics