Transient Process of Gas Liquid Flow Sealing in Plunger Lift Method

Plunger lift is an economical artificial lift method to solve the liquid loading problem in gas wells. Because of the inevitable annular gap between plunger and tube wall, the liquid above plunger may leak downward and the gas may slip upward during lifting process. How to quantitatively describe the gas-liquid counter-current flow sealing property is still challenging to optimize the plunger lift method. In this paper, a transient physical model is proposed to discribe the gas-liquid flow sealing during plunger lifting process. The physical model is solved by the finite difference method. Combining the similarity experiments, the proposed transient model is verified qualitatively. Both liquid leakage and gas slippage phenomena are considered in the new model which are common in practice. The transient variations of plunger velocity, liquid leakage and stress conditions during plunger lifting process are investigated theoretically and experimentally.