Abstract

Laboratory studies have been made to determine the quantity of oil that may be recovered by application of a solvent flood after water flooding. It was found that substantially all of the oil remaining after water flooding could be recovered by subsequent flooding with a petroleum solvent.

By fractionation and recirculation of the produced effluent it may be possible to reduce the solvent requirements by a factor of two or three.

Introduction

Previous studies have indicated that the oil recovery from porous media may be substantially increased by the injection of miscible fluids. Everett, Goochand Calhoun have suggested that a high recovery could be obtained by displacing reservoir crude with miscible liquids. Results of the study made by Kennedy indicate that the production of oil from depleted oil reservoirs may be substantially increased by the injection of liquefied petroleum gas. Kennedy'slaboratory tests were made using a sand-filled oxygen bottle to simulate a reservoir. The sand was saturated with oil and then flooded with propane. Some of the recoveries obtained by this method were as high as 98per cent indicating that most all of the oil may be obtained by L.P.G. injection.

Offering a and Van der Poel have presented information on the oil to be recovered by circulation of kerosene as a solvent through porous media. They conducted scale model experiments. The study included viscosity ratios of the crude oil to the kerosene from near 1.5 to 5,000. It was found that the oil recovery at breakthrough when flooding with kerosene as a solvent, was equal to those obtained in water flooding at the same viscosity ratio. However, after breakthrough occurred it was found that by flooding with the kerosene [a miscible liquid] the flood becomes much more efficient than the water flood and as a result considerably more oil could be recovered by using the solvent flood than by using the water flood.

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