Study on the Liquid-Holding Rate Law of Gas–Water–Foam Three-Phase Flow in a Wavy Pipe

As a common method for liquid drainage in wave-shaped pipelines, foam drainage has been used in gas-gathering pipelines in various oil and gas fields. One of the common problems encountered in wave-shaped foam drainage pipelines is the inaccurate prediction of the liquid retention rate. This issue makes it difficult to predict liquid accumulation points, which affects gas output efficiency, causes pipeline corrosion, and generates natural gas hydrates. To clarify the liquid-holding rate law of wavy foam drainage pipelines is studied. In this study, through experiments to verify the accuracy of the numerical simulation method, we investigate the easiest liquid accumulation points and the liquid-holding rate of wave-shaped foam drainage pipelines, with factors such as inlet gas velocity, inlet liquid velocity, import and export differential pressure, undulation angle, and inlet temperature change rule. Among them, the error between the numerical simulation results and the experimental results is 4.68%. Finally, after considering the influence of the aforementioned factors on the liquid retention rate of wave-shaped pipelines, a new liquid retention rate calculation model for wave-shaped pipelines with foam drainage is established by introducing dimensionless numbers, such as gas-phase velocity coefficient, liquid-phase velocity coefficient, and angle correction coefficient. The method is compared with the results of previous research, and the error is within 15%. The model has a simple form and high calculation accuracy, providing a theoretical basis for pipeline inspectors to predict liquid accumulation conditions and reasonably adjust production schedules.