Formation of fluid heavy oil-in-water emulsions for pipeline transportation

Abstract The diverse factors affecting the viscosity of a surfactant stabilized viscous crude oil-in-water emulsion for pipeline transportation were studied. The study discloses that the stability of the oil-in-water emulsion stabilized by a nonionic surfactant Nonyl Phenol Ethoxylate increases as the surfactant concentration increases with a subsequent decrease in the crude-oil–water interfacial tension (IFT). Increasing the oil content and the speed of mixing of the emulsion resulted in an increased emulsion stability. Fresh water and synthetic formation water were used to study the effect of aqueous phase salinity on the stability and viscosity of the emulsion. Surfactant dissolved in synthetic formation water was utilized to find out the possibility of injecting the surfactant into a well bore to effect emulsification in the pump or tubing for the production of heavy crude oils as oil-in-water emulsion. The effective viscosity of a viscous Egyptian crude oil (Geisum crude oil) decreased when it was emulsified with water in the presence of a nonionic surfactant in the form of an oil-in-water emulsion. It was possible to form stable emulsions with synthetic formation water characterized by a low dynamic shear viscosity. This will enhance the production of viscous crude oils by injecting surfactant dissolved in formation water to affect downhole emulsification. Further, the produced crude oil-in-water emulsion is characterized by its low effective viscosity which will facilitate its pipeline transportation to the refiner.