Water-in-crude oil emulsions. Formation, characterization, and destabilization

Abstract

A survey of properties of water-in-crude oil emulsions based on crude oils from the Norwegian Continental Shelf is given. Special emphasis is given to the characterization and the separation of the interfacially active fraction in the crude oil. For this purpose a consecutive adsorption method was developed. Among the interfacially active constituents isolated palmitic acid was identified. — After adsorption all crude oils are incapable of stabilizing water-in-crude oil emulsions. Model emulsions stabilized by the adsorbed fraction show that the original crude oil emulsion stability can be reproduced depending on the stabilization mechanisms. A similar destabilization sequence for model and authentic crude oil emulsions can be obtained when medium-chain alcohols and fatty amines are used as destabilizers. Fundamentally different destabilization mechanisms for these species are proposed.