Interfacial Interaction of Cationic Surfactants and Its Effect on Wettability Alteration of Oil-Wet Carbonate Rock

Abstract

Oil recovery by water flooding from carbonate reservoirs is considered ineffective because of the capillary forces in naturally fractured oil-wet carbonate formations. Surfactant solutions are often recommended to enhance the oil recovery by both wettability alteration and reduction of interfacial tension (IFT). In this study, the effects of cationic surfactants from the trimethylammonium bromide (CnTAB) family, viz., C10TAB (BTAB), C15TAB (DTAB), C16TAB (TBAB), and C19TAB (CTAB), on the surface tension, IFT, and wettability alteration of a carbonate rock along with adsorption of the surfactant on the carbonate rock were investigated. Different analyses, including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDAX), and Fourier transform infrared spectroscopy (FTIR), were conducted to study the mechanism for wettability alteration of the oil-wet carbonate surface. Results demonstrated that, among the four surfactants used, C15TAB and C19TAB presented a ...