A Comparison of Slug and Wave Characteristics in High Pressure Flow with Multiphase Models

Flow models for multiphase transport of oil and gas mixtures in pipelines need to be qualified against high pressure experiments using hydrocarbon fluids. Experiments performed at low gas densities (low pressures) are often considered to be too far from actual pipeline conditions to be used for model validation. Experimental facilities for multiphase flows at realistic production conditions have therefore been an important part of the experimental work at Statoil, and a range of experiments have been made with fluids from offshore oil fields. Experimental results for flows with large amplitude waves and liquid slugs are reported here, together with comparisons with closure relations from the literature. High pressure gas-liquid flows easily develop waves at the interface which sometimes results in the formation of slugs flow given sufficiently large liquid flow rates. A comparison of the observed flow regime with flow regime predictions using OLGA was made for two combinations of pressure and temperature. A viscous crude was chosen for the experiments and both turbulent and laminar flows were observed. Time series from liquid fraction measurements have been analysed in order to extract propagation speed and frequency. Closure models from the literature for propagation speed and frequency were compared with the high pressure experimental data.