Correlation between interfacial tension bump and optimal crude oil dehydration
Résumé
In the presence of a large excess of asphaltenes in oil phase, an interfacial tension anomaly (a small bump of the order of 1 mN/m), is found to correspond to the optimum formulation where the fastest water-in-oil emulsion breaking is observed. This correspondence, also observed for other systems, indicates that strong interaction should occur between asphaltenes and demulsifiers. Therefore, the optimum formulation would correspond to a situation where there is enough demulsifier to remove the asphaltenic interfacial gel by orogenic displacement, but not too much to cause adsorption of large asphaltenic/demulsifier complexes which would slow down emulsion drainage.