Reliability Prediction Method For Downhole Pumping Pump Life In Pumping Well

The downhole pumping pump is the main lifting equipment in the rod pumping system of the pumping well.In the process of operation,the failure of the pumping pump is serious because of the long-term alternating load,the corrosion of the fluid in the well and the abrasive wear in the crude oil.Pump failures not only increase pump inspection costs,but also reduce crude oil production.Aiming at the problem of serious failure of the pump,this paper focuses on the reliability research of the life of the pump,and provides theoretical guidance for the reasonable use and maintenance of the pump,which is of great significance to reduce the cost of oil production and improve the oil recovery rate.The main research contents of this paper are as follows:The mathematical model of valve ball movement law of pumping pump is established considering the Weil effect,dynamic characteristics of valve ball movement and continuous flow condition of liquid in pump barrel.Based on Matlab,the motion law of the valve ball is simulated,and the motion curve of the valve ball is obtained.The impact velocity between the valve ball and the valve seat and the valve ball and the valve cover is analyzed.Based on ANSYS simulation,the maximum impact stress of valve seat and bonnet was analyzed,and the regression model of impact stress was established.Based on multiphase flow theory and gas variable process theory,the calculation model of liquid pressure in pump barrel was established.Based on S-N curve of materials and linear cumulative damage theory,the reliability calculation model of fatigue life of valve assembly based on Weibull distribution was established.Based on thick-walled barrel theory,the stress analysis and calculation model of plunger and pump barrel is established.Considering the influence of material fatigue performance and equivalent stress of dangerous section,the reliability calculation model of fatigue life of plunger and pump barrel was established.Considering the influence of rod buckling on the contact pressure between plunger pumps,a reliability prediction model for wear life and overall life of plunger pumps was established.Based on different failure modes,the fault types of downhole pumping pump are analyzed,and the fault tree of pumping pump is qualitatively analyzed by using fault tree analysis method.Based on the reliability theory of series system,the life reliability prediction model of pump with Burr distribution is established.