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8375433 
Meetings & Symposia 
A preliminary report on oil recovery by high - Pressure gas injectiont 
Whorton, LP; Kieschnick, WF, Jr 
1950 
American Petroleum Institute 
Drilling and Production Practice, API 1950 
247-257 
English 
It is proposed that the injection of gas into oil reservoirs at pressures much higher than those used with conventional gas pressure maintenance will result in considerably higher recoveries. This proposal originated from studies of gas-condensate systems. These studies led to the conclusion that a system containing appreciable amounts of hexane-plus components usually contains high concentrations of intermediates (approximately ethane through heptane). Calculations indicated that a high-pressure natural gas containing these intermediates would evaporate much larger amounts of a typical reservoir oil than a similar gas with low concentrations of these components. Experimental results of batch treatment of oil by gas at high pressure confirmed this. This work also led to the concept of "reservoir volume ratio. This results from the enrichment of the treating gas, which, when subsequently mixed with the virgin oil, is highly soluble and swells the oil to many times its original volume. Experimental work on a dynamic system, in which reservoir fluid was displaced from a porous medium with gases at high pressure, showed that high recoveries could be obtained, up to approximately 90 percent of the oil in place. The recoveries are improved by: 1, high pressures; 2, high concentrations of intermediates in the injected gas; and 3, undersaturation of the reservoir oil at the pressure of displacement. The added recovery of this process over that of low-pressure gas sweep seems to be absent below about 3, 000 psi. The mechanism appears to be explained by the higher mutual solubility of the phases at the higher pressures with the attendant effect of reduction in the difference in viscosity between the displaced and displacing phases. Also, with undersaturated oil the reservoir volume ratio effect is important. © Drilling and Production Practice 1945. All rights reserved.