Laboratory experiments have been conducted to investigatethe use of propane as a steam additive to enhance productionof 13.5API oil from Morichal field, Venezuela. The maincomponent of the apparatus is an injection cell into which istamped a sand mix consisting of sand, water, and oil.Thermocouples placed in the cell enable tracking of the steamfront. The cell pressure is set at 50 psig, while superheatedsteam at 160C is injected at 5 ml/min cold-water equivalentat the top of the cell. Produced liquid is collected from thebottom of the cell, and after emulsion-breaking treatment, oiland water volumes are measured.Experimental runs have been conducted in which thepropane:steam mass ratio is varied from 0:100 (steam only) to5:100. A run using 5:100 nitrogen:steam mass ratio has alsobeen made to evaluate the contribution of convective heat tooil production. The main findings of this research (derivedfrom four runs with consistent operating conditions) are asfollows. First, the propane:steam mass ratio of 5:100accelerates the start and peak of oil production by 20 % and 13% pore volume steam injected (cold-water equivalent),compared to steam injection alone. In the field, this couldtranslate into significant gain in discounted revenue andreduction in steam injection costs. Second, oil recoveriesappear to be similar in all cases, 63 % - 70 % OOIP. Third,the start of production is practically the same for 0:100 and1:100 propane:steam ratio and for 5:100 nitrogen:steam ratio,indicating probably a minimum propane:steam ratiorequirement. Fourth, oil production acceleration in the 5:100propane:steam case is probably caused by ?dry distillation?.Last, convective heat transfer at any of these low (5:100)ratios appears to be of secondary importance. Researchcontinues to better understand the mechanism and thereaftermodel the production of oil under steam-propane injection.
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