Drop size and concentration profile determination in petroleum emulsion separation

Abstract

Stable emulsions of brine in crude oil were destabilized using a polymeric surfactant demulsifier and were studied during mixing and settling. After emulsion preparation and aging, demulsifier was added and the drop growth was measured using photomicroscopy. Phase separation was monitored using gamma-ray absorption. Aged emulsions exhibited less drop growth during mixing and slow separation; however, the age of an emulsion cannot always be controlled. Increased demulsifier concentration and longer mixing time after demulsifier addition both lead to a larger final drop size and faster separation. Optimizing the mixing conditions under which demulsifier is added to an emulsion could reduce the separation time, although these conditions would be system-specific. The drop size after demulsifier addition was an important indicator of subsequent emulsion separation behaviour.