Point-by-point method of determining contact angles from dynamic Wilhelmy plate data for oil/brine/solid systems

The wetting behavior of crude-oil/brine/rock systems can have a dominant effect on processes by which oil is recovered from underground reservoirs. A working knowledge of the crude-oil/brine/solid interactions that govern wetting behavior is needed. Application of the dynamic Wilhelmy plate technique to a variety of wettability conditions induced by adsorption from crude oil shows that the conventional method of determining advancing and receding contact angles from force-distance records is not always applicable. A point-by-point interpretation is presented and applied to a variety of situations. These include slippage of the three-phase line of contact and time-dependent wetting phenomena related to adsorption kinetics. For such complex wetting conditions, direct observation of the behavior of the three-phase line of contact is a necessary part of ensuring that interpretations of the force-distance record are reasonable.