Optimization Analysis of Parameters for Carbon Fiber Composite Sucker Rod Pumping Systems Based on Finite Element Method

Carbon fiber composite sucker rods represent a technological innovation in oil production systems, exhibiting excellent performance. This sucker rod not only improves oil production efficiency and reduces accidents, but also saves energy and lowers the operating costs of oil wells. However, the working conditions of the carbon fiber composite sucker rod oil extraction system are relatively complex. The carbon fiber composite sucker rod body adopts a symmetrical structure formed by one-time solidification of three layers of fiber (carbon/glass fiber) materials, requiring the use of steel sucker rods in combination, and the impact of various system parameters is not fully understood. This paper focuses on the carbon fiber composite sucker rod as the research object, analyzing the external loads of the carbon fiber composite sucker rod oil extraction system. It also establishes a mechanical model of carbon fiber composite sucker rods, adopts a new finite element modeling method for sucker rod pumping systems, conducts transient dynamic analysis on the lifting motion of carbon fiber composite sucker rods in oil wells, and optimizes system parameters. The example verifies the rationality and feasibility of the finite element model. The results show that the higher the dynamic viscosity of crude oil, the more polished rod dynamometer cars tend to approach a “parallelogram”, and the polished rod load becomes more stable during the lifting process. With larger strokes, the maximum polished rod load increases, the longitudinal vibration amplitude of the carbon fiber composite sucker rod increases, and the load variation becomes more unstable. As the number of strokes increases, the maximum polished rod load and the pump plunger stroke length both increase, leading to higher pump efficiency, but the fluctuation amplitude of the polished rod dynamometer cars also increases, which affects the stability of the sucker rod’s lifting motion. When the carbon fiber sucker rod ratio exceeds 0.5, the difference between the self-weight and polished rod load initially decreases, then increases. As the carbon fiber sucker rod ratio increases, the pump plunger stroke length gradually decreases, and pump efficiency declines.