| Migration and trapping of light non-aqueous phase liquids (LNAPLs) in heterogeneous porous media was examined using two two-dimensional finite-element numerical models, with partial to full hysteresis. Modelling LNAPL migration in the Nordegg fractured sandstone aquifer necessitated modifications to the conceptual model to allow for numerical implementation. Results illustrate LNAPL is constrained in the fracture network by capillarity. Migration occurs both up and down dip, spreading laterally and vertically away from the source. The Hermite Collocation method employed cannot accurately represent three-phase flow in fractured porous media.;Porous media simulations illustrate LNAPL migrating laterally along the water table, and spreading vertically downward as the water table falls. The water table properties affect the extent of lateral and vertical migration, and subsequently the trapped distribution. Lenses are shown to act as either capillary barriers or sinks for LNAPL, depending on the contrast between water saturation across the lens interface. |
