In previous papers((1,2,3)) the authors described the results of injecting saturated ethane or propane vapours into a scaled two-dimensional model to recover heavy oils and bitumen at or slightly above the reservoir temperature. The results were encouraging; Although the scaled oil production rates were lower than those obtained with SAGD((4)), they showed that it may be possible to recover heavy oils and bitumens economically using this method in conjunction with long horizontal wells. Apart from the low heat requirement inherent in the use of satu rated propane, additional advantages derived from vapex are a partial in Situ deasphalting and a reduction in the content of heavy metals. The resulting oil can be lighter, of a higher quality and better suited for a direct refining. In this paper these ideas are expanded further: a development of a closed-loop extraction is described and a technique for spreading the hydrocarbon vapour underneath the oil bearing payzone is proposed to simulate the performance of a planar well Using this concept the vapour-oil contact is greatly increased and improved production rates are obtained. The paper discusses scaled physical model results for Peace River bitumen and Lloydminster heavy oil. The mechanism involved is believed to be similar to that which was described earlier on rising fingers of liquid solvent((5)). Experiments are presented that show that the rate of mobilization is a function of the areal distribution of the solvent vapour. The results demonstrate that oil production rates exceed those of the SAGD in spite of the fact that no extraneous heat is injected into the reservoir. This strategy may permit the economic production of marginal heavy oil and bitumen reservoirs.