Laboratory investigations have been undertaken to assess the suitability of heavy oil-in water emulsions for pipeline transportation. The emulsions contained 65% oil in water and were prepared using polyethoxy nonylphenol surfactants. Two methods were employed for simulating the shear process which accompanies pipeline flow: a bench scale stirred vessel and a rotated pipe toroid. The progress of the emulsions towards inversion, at which point the oil becomes the continuous phase, was followed by measuring the surfactant concentration in the aqueous phase using liquid chromatography. At inversion the surfactant concentration falls below the threshold level required to sustain an oil-in-water emulsion. The experiments showed that the lifetime of the emulsion depends upon the initial surfactant dosage, the solids content of the oil, the intensity of shear and the nature of the shear process. Laminar flow was found to be less desirable than turbulent flow.