Monitoring the behaviour of anionic polymer-anionic surfactant stabilized foam in the absence and presence of oil: Bulk and bubble-scale experimental analyses

The present study aims at monitoring the bulk and bubble-scale behaviour of anionic polyacrylamide-sodium dodecyl sulphate stabilized foam in the absence and presence of oil. Dynamic stability tests provided results indicating that polymer increases the foam dynamic stability and decreases the drainage. Oil slows down the drainage rate of polymer-surfactant foam. In the absence of oil, foam is drained gradually/smoothly whereas remarkable fluctuations are evident in drainage graphs when oil is present. The Hele-Shaw cell was employed to conduct bubble-scale as well as statistical analyses on how foam texture is influenced by a polymer-surfactant system and hydrocarbon. Bubble-scale analyses, taken right after foam generation in the absence of oil, revealed that foam bubble sizes and their standard deviation increase by polymer concentration. The coefficient of variation of foam bubble sizes drops with polymer concentration in the absence/presence of oil, meaning the growth of foam texture uniformity. Oil increases the bubble size diversity in the foam texture. Disproportionation/Ostwald ripening is hindered by increasing the foam bubble distribution uniformity by adding polymer to the foaming solution. At polymer concentrations higher than 13 x 10(-4) g/g, a polymer-surfactant mixture generates foam in the presence of oil as stable as foam in the absence of oil, while at the polymer concentrations lower than 7 x 10(-4) g/g, bubbles are highly unstable when oil is present. Results of this study help to gain a better understanding about the extent to which polymer could enhance the foam stability in bulk/bubble-scale, which might be applicable for enhanced oil recovery operations.