Gas bubble nucleation kinetics in a live heavy oil

Abstract

The current primary production of heavy oil and bitumen is highly dependent on the development of ‘foamy oil’, heavy oils containing dispersions of long-lived bubbles of gas. The nucleation and initial growth of these bubbles are key elements of the behavior of foamy oils. The tremendous levels of supersaturation associated with the expansion of live heavy oils within a porous medium can generate large numbers of small bubbles. Colloidal and interfacial science techniques were used to develop a kinetic model of the nucleation and initial coalescence of gas bubbles from the live oil. Expanding a live, heavy oil within a porous medium in laboratory experiments allowed the pressure deficit driving bubble formation to be quantified. The kinetic model and experimental data were used to calculate critical bubble radii, spacing and saturation. The large number of small bubbles predicted by the kinetic model provides an explanation for the pressure deficit observed in the volume expansion experiments. A significant amount of energy is spent on the creation of new interfaces.