Emulsification of Indian heavy crude oil using a novel surfactant for pipeline transportation

Abstract The most economical way to overcome flow assurance problems associated with transportation of heavy crude oil through offshore pipelines is by emulsifying it with water in the presence of a suitable surfactant. In this research, a novel surfactant, tri-triethanolamine monosunflower ester, was synthesized in the laboratory by extracting fatty acids present in sunflower (Helianthus annuus) oil. Synthesized surfactant was used to prepare oil-in-water emulsions of a heavy crude oil from the western oil field of India. After emulsification, a dramatic decrease in pour point as well as viscosity was observed. All the prepared emulsions were found to be flowing even at 1 °C. The emulsion developed with 60% oil content and 2wt% surfactant showed a decrease in viscosity of 96%. The stability of the emulsion was investigated at different temperatures, and it was found to be highly stable. The effectiveness of surfactant in emulsifying the heavy oil in water was investigated by measuring the equilibrium interfacial tension (IFT) between the crude oil (diluted) and the aqueous phase along with zeta potential of emulsions. 2wt% surfactant decreased IFT by almost nine times that of no surfactant. These results suggested that the synthesized surfactant may be used to prepare a stable oil-in-water emulsion for its transportation through offshore pipelines efficiently.