| Plunger gas lift technology is one of the most effective methods to solve the problem of fluid accumulation in gas wells,and it is also an important measure to tap the production potential of water and gas wells to improve oil recovery.With the wide application of inclined well and horizontal well technology,the existence of well bevel angle makes conventional plungers prone to eccentricity,deflection grinding and other problems in the application,resulting in poor sealing performance of plungers,serious liquid leakage,and reduced lifting efficiency of plungers.In order to solve the above problems,a rotating plunger is introduced to enhance the sealing performance through the centering effect of plunger rotation and reduce the influence of plunger eccentricity and bias grinding.In this paper,the turbulent seal rotating plunger is taken as the research object,and the flow characteristics of the fluid flowing through the gap during the gas lifting process of the plunger are studied by combining numerical simulation and experiment,and the optimal structural design of the rotating plunger structure is carried out on this basis.Aiming at the tightness of the turbulent seal rotating plunger,the sealing groove part of the outer wall of the plunger is studied,and the numerical model analysis of the ring groove structure of the plunger is carried out by large eddy simulation according to the groove type,groove depth,groove spacing,groove width and number of grooves,and the results show that the ring groove on the outer wall of the plunger can realize the turbulent sealing effect,improve the pressure difference between the upper and lower surfaces of the plunger,enhance the sealing performance of the plunger,and compare several groove types,among which the turbulent sealing effect formed by the regular trapezoidal groove is the best.Based on the regular trapezoidal groove to carry out the subsequent simulation,through the flow field analysis of the plunger ring groove structure,from the flow pattern,trend and strength of the vortex in the groove,combined with the comprehensive analysis of the parameters of the plunger speed,vortex amount and turbulence dissipation rate,the optimal parameters of the rotating plunger are: the sealing effect is best when the groove depth is 4mm,the groove width is 12 mm,the number of grooves is 14,and the groove spacing is 5mm;The spiral groove is opened in the lower part of the rotating plunger,which can effectively solve the problem of bias grinding of the plunger in inclined wells and horizontal wells,and the numerical simulation analysis of the angle,width and number of spiral grooves shows that the torque generated when the angle of the spiral groove is 40 degrees,the width is 6mm and the number is 6,and the anti-bias grinding effect is the best.Combined with the above simulation results,the verification experiment of numerical simulation is carried out,the sealing performance of the ring groove is studied by the visual experimental device,and the comprehensive analysis of parameters such as pressure and flow rate of the test plunger when hovering is started to verify the reliability of the simulation results. |
