The distillation mechanism in steam displacement of oil

During steam drive recovery of oil a thin zone of high volatile oil concentration is formed between the upstream hot steam region and the downstream cold liquid region containing water and the oil at its initial composition. Distillable components, coinjected or stripped from the oil remaining in the upstream steam region, are transported and build up this region. The existence of this zone is responsible for the high recovery of oil from the steam zone. This paper investigates the growth and the stability of this zone, for the case when relatively small amounts of volatile oil are present. We show that this zone is described by ODE's typical of traveling waves. The growth and stability are illustrated numerically. Our results suggest that steam drive recovery can be improved by the pre-injection of a small slug of volatile oil.