Experimental Investigation of Effective Factors on Foam Stability of Surfactant Solution in the Presence of Co-Solvent and its Effect on Oil Recovery

Foam injection for the purpose of Enhanced Oil Recovery (EOR) process is one of the approaches of chemical EOR. In this method, in addition to using the surfactant, other chemical additives are used to achieve ultralow IFT which result in mobilizing the residual oil of the primary and secondary recovery stage. Foam generation causes to achieve the mobility ratio of less than 1, and then the foam generation improves volumetric sweep efficiency. In foam flooding, foam stability is one of the determining parameters for increasing oil recovery. Generating the most stable foam is one of the subjects of the recent researches on this kind of EOR process in stand point of selection of type and concentration of chemicals. In this study, effects of salinity, surfactant concentration, and the type and the concentration of co-solvent were investigated on foam stability. Optimized stability was gained in different co-solvents. This optimum was used in flooding process to investigate its effect on oil recovery. Butyric acid and 1-butanol were two used co-solvent. The most stable foam was resulted from the samples which utilized butyric acid as co-solvent. Maximum oil recovery of 44% of OOIP has observed in solution with 1-butanol as co-solvent, which is not displaced by water flooding. Moreover, observing the maximum oil recovery validates the efficacy of this technique.