ABSTRACT
Water-in-oil mixtures were grouped into four states or classes: stable, mesostable, unstable, and entrained water. Only stable and mesostable states can be characterized as emulsions. These states were established according to lifetime, visual appearance, complex modulus, and differences in viscosity. Water-in-oil emulsions made from crude oils have different classes of stability as a result of the asp haltene and resin contents, as well as differences in the viscosity of the starting oil.
In this paper a new numerical modelling scheme is proposed and is based on empirical data and the corresponding physical knowledge of emulsion formation. The density, viscosity, saturate, asphaltene and resin contents are used to compute a class index which yields either an unstable or entrained water-in-oil state or a meso-stable or stable emulsion. A prediction scheme is given to estimate the water content and viscosity of the resulting water-in-oil state and the time to formation with input of wave-height.