In this paper a laboratory study was reported for investigating a method to improve sweep efficiency by applying alkaline flooding for Pelican Lake reservoir. This included interfacial tension measurements, micromodel observatios and channelled sandpack flood tests. In total, 48 flood tests were conducted in channelled sandpacks to evaluate the chemical formulas and injection strategies for Pelican Lake oil. The first 14 sandpack flood tests were carried out to assess the potential of the alkaline flooding for the oil. The results suggested that 0.4 wt% NaOH and 0.2 wt% Na2CO3 was the optimum combination to maximize the oil recovery efficiency in the channelled sandpacks. Based on industry interest in using a NaOH-only slug injection, in the second step 34 flood tests were conducted with the injection of only NaOH solution. For Pelican oil, 0.6 wt% NaOH was the optimum concentration to maximize the oil recovery efficiency (~15% IOIP recovery) in NaOH-only injection. The sandpack flood results obtained in this study showed that formation of water-in-oil dispersion and improvement of sweep efficiency in channeled sandpacks did occur in the tertiary recovery process through the injection of NaOH-only solution.

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