CFD Numerical Simulation Study Based on Plunger Air Lift

Abstract

To study the movement law of a plunger air lift and liquid discharge efficiency, this paper observes the plunger movement and leakage through indoor experiments, based on which the CFD method is applied to establish a numerical model with the same experimental conditions, and compares the simulation results with the experiments, verifies the feasibility of the CFD simulation, and optimizes the structure of the plunger, and researches the change rule of the bottom-hole pressure and the wellhead pressure in a 200 m long wellbore. The results show that the error between CFD simulation and experimental data is 12.5%. When the depth of the plunger groove is 10 mm, the width of each groove is 10 mm, and the number of grooves is 12, the leakage is minimal; in addition, to ensure the smooth lifting of the plunger, it is necessary to control the wellhead pressure and keep the pressure difference with the bottom of the well. When the wellbore pressure is 10 MPa, the wellhead pressure should be no more than 7 MPa, and when the wellbore–wellhead pressure difference is kept at a certain level (7 MP), the plunger cannot continue to move up when the wellhead pressure is more than 18 MP, so it is necessary to control the wellbore pressure as it cannot be too big and increase the wellbore–wellhead pressure difference as much as possible. The above study of the plunger lifting law provides a reference basis for the determination of the above research plunger process parameters.