Atomic Force Microscopy (AFM) Investigation on the Surfactant Wettability Alteration Mechanism of Aged Mica Mineral Surfaces

摘要

In this study, the mica samples aged in crude oil were treated by two types of surfactants: Triton X-100 and C_(16)TAB, to find the mechanisms of wettability alteration. The contact angle measurements were conducted stepwise to check the wettability alteration of the mica surfaces. Atomic force microscopy (AFM) topographies and phase images were obtained and used to investigate the effects of aging in crude oil and surfactant treatment of the mica surface. The results show that the solution of Triton X-100/brine changes the wettability of the mica surface aged in crude oil to water-wet; however, the solution of C_(16)TAB/brine alters the aged mica surface to more oil-wet conditions. Fractal measurement was used to check the AFM images for quantitative assessment of the surface roughness for wettability alteration investigation. Two different mechanisms proposed here are the surface cleaning and the surfactant adsorption for Triton X-100 and C_(16),TAB, respectively.