Investigation of downward flow is relevant due to the downward inclination of transport lines, injection of chemicals and CO2 as part of Enhanced Oil Recovery (EOR) operations. Furthermore, carbon capture and underground storage often require transporting and injecting CO2 mixtures within two-phase flow regions. Despite its practical relevance, downward two-phase flow remains one of the least studied areas of multiphase flow with limited experimental data and modeling gaps. Available experimental data indicates that commonly used mechanistic models and commercial simulation tools often fail to accurately predict key flow parameters of interest. This presentation provides an experimental study of low-viscosity oil-air flow, with physical properties close to liquid and gas CO2, in downward inclined pipes. Experimental data covers a wide range of operational conditions and includes flow pattern, liquid holdup, pressure gradient and wall-liquid shear stress. Experimental results are compared with the commonly used commercial software, based on mechanistic models. A detailed analysis is presented for stratified flow, the most frequently observed flow pattern in downward inclinations.
Speaker: Gulnur Uali, Researcher at the Tulsa University Fluid Flow Projects
Moderated by Mark Zheng, Program Chair, SPE Flow Assurance Technical Section
Hosted by SPE Flow Assurance Technical Section on 22 April 2026