Abstract

Emulsions of three Saskatchewan heavy oils have been circulated through a laboratory pipeline for periods between 100 to 280 hours. Resistance to flow remained low in tests using an ethoxylated nonylphenol as surfactant and inversion did not occur. The preparation procedure was simple and could be easily adapted to field conditions. Droplet sizes increased continuously with time and the discharged mixture separated rapidly on standing.

Introduction

Transportation of viscous crude oil in emulsion form is a possible alternative to use of viscosity-reducing diluents, drag reducing additives or hot-oil techniques. Since emulsion viscosities are multiples of that of the continuous phase, the high viscosity oil should be dispersed in a low viscosity medium such as water to minimize energy losses during flow. To maintain stability, and in particular to prevent inversion from an oil in water to a water-in-oil emulsion, a surfactant is required if high concentrations of oil in water are to be used. Although the properties of emulsions have been thoroughly studied and the literature is voluminous, as in other applications of surface chemistry it is impossible to make quantitative predictions from the bulk properties of the continuous and dispersed phases. Experimental studies are always required and the role of basic science is to minimize the amount of such work as much as possible. Thus although a few applications and field demonstrations using equipment of commercial scale have been reported 1–2and numerous patents for possible surfactants have been registered, 3–12 tests were necessary to investigate the conditions in which Saskatchewan crude oils might be transported.

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