| The beam pumping unit is the earliest and most widely used pumping unit.It has the characteristics of simple structure and stable working condition,and is widely used in the oil production operation of the Karamay oilfield in Xinjiang.However,the Karamay oilfield is located in the desert and Gobi.It is dry and rainless all year round.The outdoor temperature is extremely high in summer and the temperature difference is large,while the winter temperature is extremely low and the wind and sand are large all year round.In this harsh working environment,the belt,gearbox and pulley device of the conventional beam pumping unit are easily damaged,resulting in the shutdown of the oil well and severely affecting the normal exploitation of the oil field,which has become an urgent problem to be solved in the Karamay oilfield.In order to solve this problem,based on CYJY4-1.5-13HB,a direct-drive beam pumping unit for motor drive is designed and related research and analysis are carried out,and the following research and analysis are carried out:(1)Taking the 4-type motor direct-drive beam pumping unit as the research object,the theoretical formula of kinematics of pumping unit is deduced,the dynamic equation of pumping unit is established,and the variation law of displacement,velocity and acceleration of suspension point is analyzed,the beam swing angle and the link angle range are verified.The results show that the modified motor direct drive beam pumping unit's motion parameters meet the performance requirements.(2)The fluid in the pumping pipe is regarded as the Couette flow,and the energy dissipation function of the oil along the path is derived.The viscous energy consumption along the up and down stroke of the sucker rod is calculated.Considering the influence of the sucker rod coupling and the centralizer,the local energy consumption function of the oil flowing through the coupling and the centralizer is derived.Based on the principle of equal friction work,the theoretical formula of equivalent damping coefficient of sucker rod system is derived,and the influence law of equivalent damping coefficient of sucker rod system is analyzed.The results show that:?When the strength is sufficient,the smaller size of the sucker rod is used to help reduce the local viscous energy consumption.?Reducing the sudden change in the cross-sectional area of the sucker rod coupling and the centralizer has a significant effect on reducing the damping force.(3)Considering the influence of the sucker rod coupling and the thread,the theoretical formula of the rod body deformation,the coupling deformation and the axial tensile deformation of the sucker rod are derived.Based on the equivalent deformation method,the theoretical formula of the equivalent tensile stiffness of the sucker rod is derived.The sensitivity analysis of the equivalent tensile stiffness of the sucker rod is carried out.The results show that:?The equivalent tensile stiffness is less sensitive to the weight of the sucker rod,the length of the rod of the sucker rod,and the length of the coupling,and the equivalent tensile stiffness is more sensitive to the projected area of the threaded rod in the axial direction of the sucker rod.?When calculating the equivalent tensile stiffness of the sucker rod,the influence of the threaded connection is not negligible,and the influence of the thread should be considered in the calculation.(4)Considering the longitudinal vibration of the sucker rod,the physical model of the multi-degree of freedom of the sucker rod-spring-damping system is established.In the generalized coordinate system,the kinetic energy,potential energy and generalized force expression of the system are derived.The dynamic model of the sucker rod column is established.Based on the well condition parameters of Well#5110 in Karamay Oilfield,the computational work diagram of the well is obtained by solving the dynamic differential equations.The results show that:the calculation of the dynamometer and the measured dynamometer are very close.The calculation error of the dynamometer is less than 5%in more than 85%of the cycle;the dynamic model can predict the fulcrum.(5)With the aid of Adams dynamics simulation software,the dynamic simulation model of the 4-type motor direct-drive beam pumping unit was established.The influence law of crank balance weight on crank torque,the influence of tail beam balance weight on crank torque and the effect of compound balance on crank torque are analyzed.With the crank torque as the target parameter,the optimal design of the pumping unit balance parameters is carried out.Finally,the pumping machine movement and the force state of the components under the optimal balance parameters are simulated and analyzed.The results show that:the balance weight has a greater influence on the crank torque.The curve between the maximum crank torque and the balance weight is "V" shape.With the increase of balance weight,the maximum crank torque first decreases linearly,then increases linearly.Overall,the composite balance effect is better than the crank balance and tail beam balance.After the balance structure is optimized,the maximum crank torque is significantly reduced,which reduces the maximum output torque of the direct-drive motor and effectively controls the manufacturing cost of the direct drive motor.In summary,this paper analyzes the performance parameters of the direct-drive beam pumping unit through the kinematics and dynamics theory analysis of the pumping unit,and lays a theoretical foundation for the dynamic simulation of the pumping unit.Based on the study of the equivalent damping coefficient and the equivalent tensile stiffness of the sucker rod,the dynamic analysis of the sucker rod is carried out,and the calculation diagram of the suspended point is obtained.The parameters of the power diagram are calculated as the suspension point load of the pumping unit,the balance structure of the pumping unit is optimized,the maximum crank torque of the pumping unit is reduced,and the manufacturing cost of the direct drive motor is reduced.This research is of great significance for the transformation of the beam pumping unit in the Karamay oilfield,improving the safety and reliability of the pumping unit and increasing the oil recovery efficiency of the oilfield. |
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