Modelling of a novel progressive cavity pump with a special internal compression process used in oil wells

Abstract

As a submersible pump, the progressive cavity pump is used to pump fluids from oil wells, and plays a crucial role in determining the oil production. In order to improve the fluid pressurization process and increase the outlet pressure of the progressive cavity pump, a novel all-metal progressive cavity pump (AMPCP) with gradually reducing closed working cavities and variable clearances between its rotor and stator was proposed in this study, so the working processes contain a special internal fluid compression process during operation for petroleum lift. A pair of new rotor and stator with variable clearances were designed, and a novel AMPCP was proposed. Furthermore, the changing law of clearances between the rotor and stator along the axial position of the rotor was studied and controlled, and equations of both their cross-sectional profiles of the rotor as well as stator and the flow area of the AMPCP were derived. The working process including the special internal fluid compression process of the proposed AMPCP and the fluid flows were analyzed by numerical simulations, and the distributions of its internal pressure fields and velocity fields were obtained. Study results show that the proposed AMPCP has a higher outlet pressure and a smaller axial leakage speed than the conventional progressive cavity pump with constant clearances for the same values of other parameters, and the internal compression process of the AMPCP will contribute to increasing the discharge pressure. The research content has important reference value for improving the comprehensive performance and increasing its scope of applications for the oil artificial lift.