Measurement and Prediction of Slug Characteristics in Three-Phase Flows

This paper describes experimental and modelling studies of three-phase (oil-water-gas) flows in a 77.92mm diameter horizontal tube. Measurements were made of pressure gradient and of the spatial and temporal distribution of the contents of the respective phases. Phase content measurements were made using gamma- and X-ray systems capable of discriminating between the two liquid phases. Data were obtained for the time averaged liquid phase hold-ups and, by conditional sampling, the holdup in the bodies of the slugs. Data were also obtained on slug initiation and on the evolution of slug frequency along the (37m) channel. Slug evolution was found to be very different in water-continuous and oil-continuous systems. To predict the flows, the slug capturing methodology developed previously at Imperial College was extended to the prediction of gas entrainment in the liquid slugs. Here, the two-fluid model framework was retained for the three-phase flows by writing a single momentum equation for the combined liquid phases, taking account of the relative motion of the phases using a drift-flux model. Excellent agreement was obtained between the predictions and the experiments.