Liquid Leakage Model in Plunger Lift

Gas well effusion is an important cause of low production and a common problem in the later production period. It seriously threatens the stability of gas well and even causes the shutdown, which greatly reduces the recovery rate of gas field. Plunger lift with the advantages of simplicity, reliability and economy is widely used in gas well effusion. Liquid leakage is an important problem that causes the inefficiency and even failure of the deliquification. Based on the Navier-Stokes equation for annular gap flow, a new liquid leakage model of plunger lift during the deliquification considering pressure loss of plunger-tubing annulus is established. The fourth-order complex Simpson formula to simplify the leakage volume and render it more practical. The analysis of simulated data using Gupta et al. indicates that the liquid leakage rate averages around 1% during the upward movement of the plunger. Additionally, considering the upward movement of the plunger, the resulting leakage volume greatly impacts the plunger's discharge efficiency. The velocity and flowrate of liquid leakage are quantified, which accurately simulate the liquid loss during the plunger gas lift process and predicting gas well productivity and optimizing plunger lift parameters. It not only helps to accurately characterize the leakage process during the dynamic process of plunger gas lift, but also can be used in the design of plunger structure, description of gas well effusion and evaluation of plunger lift.