CFD-based research on fixed valve leakage of inclined well pumps

With the growing demand for oilfield development, the use of inclined and directional wells has gradually increased. However, due to limitations in the shaft structure of inclined wells, the efficiency of rod pumping is significantly compromised. To investigate the delayed closure of fixed valves, a numerical model was developed using computational fluid dynamics technology, by combining the standard k–ω turbulence model with the volume-of-fluid multiphase flow model. The SIMPLE algorithm was employed to calculate the valve closing process in inclined well pumps. The delayed closure of the valve ball, caused by changes in the well inclination angle and swabbing parameters (such as sinking pressure, pump diameter, and stroke speed), was investigated. The simulation results showed that inclined well pumps are most effective at inclination angles below the critical angle (which, in this study, was 59.036°). In addition, lower sinking pressures, larger pump diameters, longer strokes, or fewer stroke times can reduce the time taken for valve closure and minimize leakage. As the well inclination angle approaches the critical value, pump valve leakage increases sharply. By quantitatively analyzing the numerical calculation results, we established a fitting relationship for valve ball fall time. This improved the proposed calculation model for pump efficiency in inclined well pumps, offering valuable insights for their practical application.