Comparing the static and dynamic foam properties of a fluorinated and an alpha olefin sulfonate surfactant

To improve the understanding of the influence of oil type and of oil saturation on foam stability and foam generation, core flooding experiments have been performed using three different North Sea oils. The experiments were performed using two surfactants – an alpha olefin sulfonate (AOS) and a fluorinated surfactant (FS-500) – both with and without oil. The dynamic foam stability has been compared with results from static foam tests.Foam was generated by both surfactants in all core flooding experiments both with and without oil.The experiments showed that the surfactants generated foam with similar strengths and stability in both dynamic foam experiments and static foam tests without oil. In the core flooding experiments with residual oil saturation, the AOS surfactant generated weaker foam than that of the FS-500 surfactant.Foam generation with the FS-500 surfactant in core flood experiments seemed independent of the presence of residual oil saturation with respect to foam strength. Foam propagation was significantly delayed, however, in the presence of oil.AOS generated foam with differing foam strengths for the different crude oils in the core flooding experiments. Interestingly, the AOS surfactant showed more rapid foam propagation with, than without residual oil present in the core.The correlation between the static and dynamic foam experiments was poor for the AOS surfactant.