Effect of NaCl and MIBC/kerosene on bitumen displacement by water on a glass surface

Abstract

Experiments were conducted to study the effect of NaCl and MIBC/kerosene surfactants on bitumen displacement by water on a glass surface. A thin coating of bitumen on a glass surface displaced spontaneously in the inward radial direction upon exposure to an aqueous environment containing salt and surfactants. The initially circular bitumen disk took the shape of a spherical droplet. The time variation of the dynamic contact angle and the static contact angle of bitumen on the glass surface were measured and compared with the results available without salt. The dynamic and static contact angles decreased above a certain NaCl concentration for a particular pH, e.g. 16 000 ppm of NaCl at pH 8.2. For the same condition, the dynamic contact angle of bitumen decreased with increasing pH. Furthermore, the static contact angle is also decreased with increasing pH. When combined with a surfactant (MIBC/kerosene mixture is added in the presence of NaCl) the static contact angle restored to a value close to that of a no-salt case. A previously proposed mathematical model based on lubrication approximation for bitumen displacement is discussed. The dynamic contact angle predicted by the model is compared with experimental data for high salt and surfactant concentrations at pH 8.2. The implication of the experimental results to the Hot Water Bitumen Extraction Process is discussed.