The Wettability Alteration Behavior of Cationic Gemini Surfactants on Oil-aged Mica Mineral Surfaces

Abstract

Abstract The wettability of oil reservoir rock will affect the oil recovery efficiency by reducing the capillary force. A Gemini cationic surfactant containing double dodecyl chains and two quaternary ammonium headgroups was synthetized and used as a new wetting alteration agent. This paper focuses on the wettability alteration of Gemini cationic surfactants on oil-aged mica mineral surface. The results of contact angle data show that Gemini cationic surfactant have great wettability to alter oil-aged mica surfaces to mid-wetting even weakly water-wet. The adsorption morphology by atomic force microscopy shows that the degree of wettability alteration is mainly dependent on the coverage areas of surfactant molecules. Gemini surfactant formed monolayer on oil-aged mica surface and the monolayer has the trend to from a compact film with increasing concentration. Compared with the single chain surfactant, Gemini surfactant has stronger ability to alter oil-aged surfaces. Considering the flooding experiment in lab results, this Gemini surfactant might be a good choice to be used in chemical flooding.