INFLUENCE OF OPERATING CONDITIONS ON LOADS AND FATIGUE STRENGTH IN A ROD COLUMN OF PCP

The relevance of the research is caused by the need to increase the reliability and resource of progressing cavity pumps, used in complicated well operating conditions, since they have low reliability in comparison with electrical submersible pumps, that limits their application. Progressing cavity pumps are used in well conditions characterized by a high viscosity of the pumped fluid (more than 30 mPa·s) and a high content of solid particles in it (the coefficient of suspended particles is more than 500 mg/liter). Experience in operating progressing cavity pumps shows that the reliability of pumping installations depends primarily on the reliability of the rod string. In addition to the torque load required to transfer the rotation from the induction motor to the screw pump, immersed on more than one kilometer from the wellhead, the sucker string experiences tensile loads from the weight of the pump rods and the axial load of the screw pump, as well as bending loads caused by the spatial curvature of the wellbore . The paper proposes the implementation of methodology for calculating the sucker rod columns of progressing cavity pumps with regard to axial, torsional and bending loads in the Python programming language. The proposed method for calculating the rod column of a screw pumping unit takes into account the rod column friction on tubing pipes arising from the Eulerian forces pressing the rods to the pipes due to the spatial curvature of the wellbore. Using software implemented in the python programming language, the authors have made calculations that showed the influence of various complicating factors on the magnitude of the loads on the rod string. As a result of calculations of the fatigue strength of the pump rods, cyclic loads during the rotation of the rods in the local sections of the local curvature of the wellbore was shown. The developed software allows you to take into account the degree of influence of complicated well operating conditions at the design stage, and thus, significantly increase the turnaround time of the rod screw pumping units. The main aim of the research is to assess the influence of various operating factors on the loads acting on the string of pump rods during well operation, as well as on the fatigue strength of the pump rods. Methods. Using software implemented in the python programming language, calculations were performed that showed the influence of various complicating factors on the magnitude of the loads on the rod string. The paper demonstrated the effect of loads on the fatigue strength of sucker rods caused by cyclic loads during rotation of the rods in the areas of local curvature of the wellbore. The developed software allows taking into account the degree of influence of complicating factors at the stage of selecting the layout of a PCP, as well as during operation, and thereby significantly increasing the overhaul period of PCP operation.