Mechanical Analysis And Combination Optimization Of Carbon Fiber And Stell Hybrid Sucker Rod String

Carbon fiber continuous sucker rod has the advantages of light weight,high strength,corrosion resistance,and is widely used in deep,ultra-deep and corrosive wells.The actual failure form of carbon fiber continuous sucker rod is different from that of steel rod.There are two types of transverse fracture and longitudinal split.The transverse fracture damage form is similar to that of steel rod.One is that the axial load is too large,which causes the sucker rod to break horizontally.Second,the alternating axial stress causes transverse fatigue fracture of the carbon fiber sucker rod string;The longitudinal splitting failure form is unique to carbon fiber rods.The longitudinal splitting failure form is more likely to occur when subjected to alternating torque,alternating bending moment,or the combined action of alternating torsion and bending moment.Therefore,the development of carbon fiber continuous sucker rod string dynamics analysis theory and rod string optimization method is of great significance to ensure the safe,reliable and effective operation of the entire carbon fiber and steel hybrid rod string oil production system.This article mainly carries out the following work:On the basis of the suspension point motion law and the plunger liquid load simulation model,a wave equation-based longitudinal vibration simulation model of the hybrid rod column was established,and the simulation model was solved by the difference method to realize the suspension point load and the axial distributed load of the hybrid rod column.And the simulation of the concentrated axial force at the pump end.Considering the influence of the non-uniform axially distributed load on the bending stiffness of the rod string,based on the quasi-static assumption,a simulation model of the in-plane buckling configuration and spatial buckling configuration of the hybrid rod string in the tubing is established.Simulation of the buckling configuration in the tube and simulation of the friction force of the rod and tube.Using the plane buckling configuration and the space buckling configuration as the lateral vibration displacement excitation respectively,the horizontal vibration simulation model of the vertical well hybrid rod string is established;the rope suspension is simplified to the upper boundary of the torsion spring,and the friction between the spiral buckling configuration and the tubing is generated The induced torque is the excitation force,and the torsional vibration simulation model of the hybrid pole-column is established;based on the simulation results of the vibration law of the hybrid pole-column,the multi-axial alternating stress simulation model of the arbitrary cross-section of the hybrid pole-column is established,and the static strength and fatigue strength are calculated.Taking the carbon fiber rod uncompressed,the strength of the carbon fiber rod string and the fatigue strength conditions as the constraints,the highest efficiency of the hybrid rod string pumping system is the optimization objective function,and the swabbing parameters and the combination of the mixed rod are the target design variables.Design a mathematical model.