High throughput and high GOR (gas-to-oil ratio) favor foam formation. Foams are made up of bubbles (lamellae) stabilized by surfactants, either naturally

occurring surfactants (resins, asphaltenes, naphthenic acids, etc.) or added production chemicals such as some film-forming corrosion inhibitors. It is the Marangoni effect, mass transfer on or in a liquid layer due to surface tension differences, that stabilizes foams.3 Viscosity has also been found to play a major role in determining whether a crude oil will foam under experimental conditions.4