(378g) Stability of Oil-in-Water Emulsions of Heavy Crude Under Flowing Conditions

Multiphase transport is a widely used technology for conveying crude oil in the petroleum industry. Due to the inevitable incomplete oil-water emulsification, fluids in pipe often flow in phases of free water and emulsion. Emulsion stability is a decisive index affecting flowing conditions, it can be well characterized by stable water fraction. However, most studies concerning about this critical parameter still rest on the stage of qualitative description. Moreover, the emulsion stability of heavy crude, an enriched promising oil, is scarcely focused. To this end, this paper aims to conduct some quantitative investigations on heavy crude emulsion stability with a unique experimental facility. It mainly consists of a stirred tank with good temperature control, a stirring system equipped with a torque meter and a V-shaped measuring tube. Sensitivity study regarding temperature, salinity, PH value, shear rate, emulsifier dosage, total water fraction of oil-water mixture, as well as mixing condition was executed by measuring the stable water fraction after stirring. It was found that the stable water fraction of heavy crude increases with salinity, PH value, emulsifier dosage and pectin-bitumen content, while decreases with temperature. This might be ascribed to the augment of interfacial active agents and the thickness of interfacial film. Based on the experimental results, we initially proposed a stable water fraction model for heavy crude, applicable in both static and flowing conditions. Verification shows a good agreement between prediction and experiment with average relative errors below 13.3%. Calculating stable water fraction, this model benefits in estimating pipeline flow condition, and further helps to schedule transportation arrangements.