Investigation on phase behavior and emulsion formation in spontaneous imbibition of aqueous surfactant/alkaline solutions

Numerous techniques have been employed in order to enhance oil recovery from oil reservoirs. One of the effective EOR techniques is the surfactant flooding. Surfactant is used to reduce theinterfacial tension between oil/ brine allowing them to mix and being displaced. However, the useof surfactant is not the only way to reduce IFT. Alkaline flooding is one of the useful and economically efficient EOR techniques. This process is a surfactant-aided gravity drainage.The process of using dilute surfactant in alkaline solution has been investigated in this work. Phase behavior experiments were conducted to evaluate the conditions under which oil-in-wateremulsions form. Physical properties of brine-in-oil emulsions in terms of viscosity, surfacetension, interfacial tension, and stability were experimentally studied. Spontaneous imbibition experiments were conducted to investigate the effect of incorporation of alkaline and surfactantinto the aqueous phase. The concentrations of sodium carbonate, as the alkaline reagent, and the synthetic surfactant had important effects on the emulsion quality. Presence of both reagents improved the oil recovery by spontaneous imbibition.

Keywords:

Enhanced Oil Recovery , Imbibition , Emulsion , Flooding , surfactant , Alkaline