Numerical Simulations of Liquid Leakage and Gas Channeling for Plunger Lift

Plunger lift is one of the commonly used processes for liquid extraction and gas production in gas wells. Owing to the gap between the plunger and the tubing wall, liquid leakage and gas channeling during the lifting process are inevitable. Liquid leakage reduces the amount of lifted liquid, and gas channeling is not conducive to the complete utilization of formation energy. Furthermore, the gas that breaks through the gap into the top of the plunger also hinders plunger movement. To address this problem, we used CFD to simulate plunger movement in the tubing and analyzed the influence of various factors, such as plunger velocity, pressure difference between the upper and lower ends, and plunger diameter, on liquid leakage and air channeling. The results indicated that when the plunger rises and drains the liquid, the plunger velocity increases, the leakage between the plunger and the tubing increases, and the gas channeling volume decreases. When the pressure difference between the upper and lower ends of the plunger increases, leakage loss is reduced. The larger the plunger diameter, smaller the interval between the plunger and the tubing, and smaller the less leakage loss. The results of the study validate the influencing factors of plunger lift leakage and gas channeling, optimizing the plunger structure and improving the efficiency of plunger lifting.