MRI study of non-aqueous phase liquid extraction from porous media.

Magnetic resonance imaging is used to investigate, at the pore scale, the dissolution and mobilisation of discrete non-aqueous phase liquid (octanol) ganglia trapped within porous media by capillary forces, by a mobile aqueous phase. Dissolution is observed to be described by a mass-transfer limited model. Mobilisation of entrapped ganglia commences at lower flowrates when a surfactant is introduced into the mobile aqueous phase.