resulting in decreased energy consumption and increased Experiments were performed to study bitumen film rupture and bitumen recovery, is the impetus for undertaking a systemdisplacement on model surfaces. Bitumen film on a glass plate atic study of the mechanisms involved in oil-water displacewas found to thin down and rupture in the presence of water ment on a solid surface. Such mechanistic understanding can having a high pH; whereas on a polytetrafluoroethylene surface, also help in other applications such as in situ recovery of film rupture did not take place. Experimental results on the rate petroleum using water flooding or enhanced-oil-recovery of bitumen/water contact line displacement on a glass surface are processes used to displace oil from the pores of a reservoir also reported. A thin coating of bitumen on a glass surface re-
(2). The treatment of beaches exposed to oil spills entails tracted spontaneously in the inward radial direction upon exposure to an aqueous environment. The initially circular bitumen the use of dispersants to produce a stable oil-in-water emuldisk was reshaped into a spherical droplet. The time variation of sion upon agitation with water (3). The use of sand for the the apparent dynamic contact angle of bitumen on the glass sursinking of oil slicks on the surface of sea water has also face was measured at different pH and temperature. Finally the been reported. Here sand is dredged up from the sea bed equilibrium contact angle of the bitumen on the glass surface was and fluidized with water and additives to separate oils (4).
also measured. The bitumen displacement rate on the glass plate
In each of the above situations, it is necessary to know is higher at lower pH and the corresponding equilibrium contact (i) whether water can displace oil from the sand particles angle is smaller. The rate of bitumen displacement increases with and (ii) how quickly the displacement process takes place.
a decrease in the initial bitumen volume. The water temperature Preferential wetting by water occurs if the free energy per has minimal effect on the equilibrium contact angle; however, it unit area of water/sand interface is less than the free energy has a significant influence on the bitumen displacement rate through changes in the bitumen viscosity. The displacement of a per unit area of the oil/sand interface. If this occurs, oil is three-phase contact line is modeled using a simple force balance released from the sand surface and separation of oil and sand at the contact line. The experimentally measured dynamic contact can take place. The rate of disengagement of the bitumen angle is predicted well by the proposed model. The dynamic confrom the oil sands ore depends on the following sequential tact angle predictions by other contact line displacement models steps: (i) thinning and rupture of the bitumen film which is were compared with the experimental data. The practical implicapresent as a coating on the sand surface in the presence of tions of these results for bitumen extraction from oil sands are water, (ii) displacement of the bitumen/water interface and discussed.