A Pressure-Drop Model for Oil-Gas Two-Phase Flow in Horizontal Pipes

The accurate prediction of the pressure distribution of highly viscous fluids in wellbores and pipelines is of great significance for heavy oil production and transportation. The flow behavior of high-viscosity fluids is quite different with respect to that of low-viscosity fluids. Currently, the performances of existing pressure-drop models seem to be relatively limited when they are applied to high-viscosity fluids. In this study, a gas-liquid two-phase flow experiment has been carried out using a 60 mm ID horizontal pipe with air and white oil. The experimental results indicate that viscosity exerts a significant influence on the liquid holdup and pressure drop. At the same gas and liquid volume, both the liquid holdup and pressure drop increase with an increase in the viscosity. Combining two existing models, a modified pressure drop method is developed, which is applicable to horizontal pipes for different viscosities and does not depend on the flow pattern. This new method displays a high accuracy in predicting the new experimental data presented here and other published data in literature.