Simulation of a sucker rods string rotation during operation in curved and directional wells

DOI: 10.24412/2076-6785-2023-5-78-83

Abstract
The paper considers a model of a sucker rod string in a curved two-branch wellbore. The effect of dogleg severity on rod breakage has been determined. The values of natural oscillation frequencies and resonant frequency of the system as a function of geometric shapes and dimensions of a curved section have been obtained in the course of the research. The mass of the eccentric disk significantly affects the angular speed. The bench tests have proved the restoring force on centralizer strips, as well as the values of loads on the strips depending on the movement of the outer pipe when the centering degree is reached. Conclusions and recommendations on application of new centering devices have been presented.

Materials and methods
Materials: progressive cavity pumping unit, eccentric disk, wellbore, centralizer with a bearing functions, vertical test bench with electric motor and frequency converter, horizontal test bench SITs-2 with a pipe simulator, vertical test bench SITs-2 for spring centralizers.
Methods: simulation, mathematical model of rod rotation deviating from the axis, determination of the frequency of natural torsional oscillations of rods and resonant oscillations.

Keywords
progressive cavity pump, directional wellbore profile, sucker rod string, reduced disc, moment of inertia, rigidity, number of revolutions