Effect of Oil Polarity on Surfactant Foam Properties at Bulk and Macroscopic Scale

Abstract Recent studies on oil-foam interaction using different types of oil were limited to the aspect of alkane chain length, density and viscosity of crude oil. However, oil polarity toward foam stability to predict the significant variable of the foam half-life and its evaluation in macroscopic oil displacement is still elusive in literature. In this study, the effect of oil polarity on foam properties at bulk and macroscopic scales was investigated. The effect of electrolytes on surfactant foam stability was studied. Subsequently, the foam stability in the presence of polar and non-polar oil was determined. Thereafter, the macroscopic oil displacement efficiency of surfactant foam was evaluated. Finally, a multivariate linear regression analysis was used to predict the significant variable of the foam half-life. The results indicate that cocamidopropyl betaine (CAPB) foam had better stability under the influence of oil polarity, with a half-life decrease of 8% in hexane oil compared to 86% by sodium dodecyl sulfate (SDS). Moreover, SDS foam flooding recovered 10% additional oil compared to 5% CAPB foam. However, oil recovery in the presence of pyridine decreased oil recovery of SDS and CAPB foam flooding to 6% and 3%, respectively. Likewise, mobility reduction factor (MRF) of SDS foam decreased by 74% compared to 39% by CAPB foam. However, both MRF of SDS and CAPB foam drop drastically by 81% and 90%, respectively in the presence of pyridine compared to hexadecane. Finally, the multivariate regression analysis indicates that surfactant is the most significant variable with a P value below 0.0001. The R2 proportion of variation in the response attributed to this model was 0.81, with a root mean square estimation of 5.2386.