Abstract

Due to its low cost, excellent injected performance and good blocking capacity for high permeability zones, polymer/gel enhanced foam flood has been proven as an efficient method to improve oil recovery. This paper presents an optimization study of the slug size of polymer enhanced foam (preformed foam) and a study of gel-enhanced foam on oil recovery and high permeability zone blocking for a Saskatchewan heavy oil. A series of sandpack tests with different slug sizes are conducted to investigate the oil recovery performance of polymer enhanced foam flood. The experimental results indicate that, by considering the foam flood efficiency, the optimal slug size of polymer enhanced foam flood is 1.5 PV in this study. For gel enhanced foam flood, the single-sandpack tests suggest that the gel enhanced foam flood and extended waterflood can still significantly improve the oil recovery (up to 24.1%) after polymer enhanced foam flood; the parallel-sandpack test indicates that gel-foam can efficiently promote the oil recovery in the lower permeability layer by modifying the injection profile. In summary, gel enhanced foam can be used as the fourth recovery method for heavy oil reservoirs after initial waterflood and polymer enhanced foam flood.

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