Novel glycerin-based microemulsion formulation for enhanced oil recovery

Among enhanced oil recovery chemical methods, the use of surfactants is cited in many field studies. Microemulsions are systems composed of surfactants that aim to decrease the interfacial tensions between water and oil facilitating their flow in the porous medium. This paper proposes the use of a new microemulsion formulation, based on glycerin as the polar phase for improved oil recovery. The aim is to evaluate if the microemulsion composed of glycerin in the polar phase is as efficient as the microemulsion containing water. The proposed microemulsion was composed of commercial surfactants (DBB-7107 and DBB-7191), isopropyl alcohol, pine oil, and glycerin in substitution of distilled water. The microemulsion was characterized and the recovery tests were conducted with samples of sandstone rock in a core holder. The results showed that the formulation generated a well-defined microemulsion region and presented characteristics typical of microemulsion systems of the water-in-oil type. Recovery tests have shown that microemulsions containing glycerin in the polar phase achieved a recovery factor up to 49% of the residual oil while microemulsions containing water recovered about 36% of the residual oil.