Study On Mechanical Behavior Of Sucker Rod Of A Beam Pumping Unit

In oil fields production at home and abroad,the beam pumping unit is an artificial lifting method commonly used at the moment,which accounts for more than 70% of all the lifting methods.In the past five years,Sinopec has conducted energy consumption tests for more than 20000 oil wells in its oilfield enterprises,and its average system efficiency is less than 30%.Because the matching degree of the running mode between the beam pumping unit motor and the load law is low,the deformation of the sucker rod is larger and the stroke loss is caused,which is one of the reasons for the low efficiency of the system.It is of great significance to study the dynamic process of sucker rod of beam pumping unit for improving pumping efficiency and saving energy and reducing consumption of beam pumping system.In this paper,a mechanical model is set up in two stages of the upper and lower strokes of the sucker rod in a complete stroke cycle.The force analysis and the deformation analysis are carried out.The differential equation is derived.The finite element method is used to determine the displacement,velocity,acceleration and load of each node of the sucker rod in the beam pumping unit.A special calculation program is compiled,and the motion relationship between the top and bottom ends of the sucker rod is summarized through a lot of trial calculations.In order to improve the effective stroke of the bottom hole pump,the optimized bottom hole motion law and load law are used as the bottom constraint conditions to solve the motion law of the sucker rod,and the motion law of the top light rod is calculated and converted into the speed distribution of the motor as the control speed of the motor operation.The field test is carried out on 4 production wells in an oil field with this technique,and its application results are verified.The result of the test proves that the application of the motor running mode in this paper has significant effect on increasing production,saving energy and improving the efficiency of the beam pumping unit.