Paper Title
Study on Drag Characteristics of Heavy Oil Flowing through Upward Vertical Pipe Under the Action of Aqueous Foam

A new idea is proposed to reduce drag resistance of heavy oil flowing through vertical pipe by injecting aqueous foam. Experiments were conducted in a flow loop, which includes devices for foam generation, injection and the establishment of an annular foam layer. The effects of foam and oil flow rates on pressure gradients along the pipe test section were explored and a corresponding pressure gradient prediction model was established based on a core-annular flow theory. The results indicate that the aqueous foam has a great drag reduction effect in vertical heavy oil pipe flow and a significant drag reduction efficiency was obtained. The predicted values were in good agreement with the experimental data, with relative errors within±20%. Keywords- Heavy oil, Aqueous foam, Vertical pipe, Drag characteristic, Pressure drop predictionv