Influence of the crude oil resin asphaltene ratio on the stability of oil water emulsions

During the production of crude oil, water/oil emulsions are formed. They ar e stabilized by asphaltenes and resins which are colloidally dispersed in t he crude oil. Asphaltenes consist mainly of polar heterocompounds. It is known that they decrease the interfacial tension between oil and water and form stable inte rfacial films. Both effects favour the formation and stabilization of emuls ions. Crude oil resins consist mainly of hydrocarbons. Their interfacial activity is less than that of asphaltenes, and they are known to peptize the asphal tenes. Their influence on the formation and stability of emulsions in the p resence of asphaltenes is, however, not well understood. This study investigates the influence of resins from different crude oils a s well as of different resin/asphaltene ratios dissolved in decahydronaphth aline as model system on colloidal stability of model oils interfacial tension between model oil and distilled water stability of emulsions formed from model oils and brine effectiveness of demulsifiers viscosity and droplet size distribution of emulsions It was found that (1) the influence of resins in the presence of asphaltene s on the properties of emulsions is independent of the origin of the resins , i.e. of the oil, from which they are obtained, and (2) high resin/asphalt ene ratios decrease the emulsion stability. (C) 1999 Elsevier Science B.V. All rights reserved.