Mechanism of viscosity reduction in viscous crude oil with polyoxyethylene surfactant compound system

Surfactant can be used to form stable oil-in-water emulsion and reduce the viscosity of viscous crude oil. The mechanism of viscosity reduction was studied for nonionic surfactant alkylphenol polyoxyethylene (9) ether (APE-9) compound systems. The results showed that the viscosity reduction of viscous crude oil by water-insoluble alkylphenol polyoxyethylene (4) ether (APE-4) was higher than sodium dodecyl sulfate (SDS, anionic surfactant) and dodecyl dimethyl betaine (BS-12, amphoteric surfactant) in the binary compound system. The viscosity further decreased by ethanolamine. The interfacial tension (IFT) study showed that when the reduction in IFT was the highest, the viscosity reduction was the highest.