Water-in-crude oil emulsions from the Norwegian continental shelf 11. Ageing of crude oils and its influence on the emulsion stability

摘要

The stability of water-in-oil emulsions based on some North Sea crude oils has been studied with particular emphasis on the effects of ageing, i.e. exposure of the crude oils to air (and light). It is clearly demonstrated that the interfacial tension of a crude oil towards formation water decreases substantially as a result of ageing. This seems to be caused by the formation of various oxidation products, mainly carbonyl compounds. In addition, the water-in-oil emulsions in general become more stable. However, in some cases a reversal of this trend has been observed, indicating that oxidation products still with high interfacial activity but having less beneficial film properties are formed in the later stages of the ageing process.