Mechanism Simulation And Structure Optimization Of Rotary Sealing Plunger In Directional Well

Abstract

Aiming at the problems of eccentric wear and poor sealing performance of conventional gas well plungers in directional wells, a CFD-based optimized design has been adopted for the key structures of the rotary dynamic seal plunger, and a mathematical model of liquid discharge of rotary dynamic seal plunger has been established. The working mechanism of key structures like spiral groove and jet hole on the plunger has been clarified. The parameters of the spiral grooves have been optimized, with the spiral angle of 30°, the groove width of 6mm, and the groove number of 8; and the number of injection holes has been optimized at 12 through orthogonal experimental design. The results of laboratory verification experiments show that the optimized plunger structure successfully realizes the rotating liquid discharge, with the deviation between running and rotation speed of the plunger and the numerically simulated speed below 10%. Based on the indoor experimental research and field application, it can be concluded that the theoretical analysis method can accurately characterize the liquid drainage mechanism of the rotary dynamic seal plunger. The optimized rotary dynamic seal plunger is suitable for the gas well dewatering process of inclined wells with an inclination angle of less than 60°.

Keywords

• directional well
• numerical simulation
• plunger
• rotary dynamic seal
• verification experiment