Study on the combination of the annular jet pump and static mixer to improve the fluid-carrying capacity of gas wells

Aiming at the problem that the suction chamber of the gas-driven jet pump has insufficient mixing of the power gas and the sucked fluid leading to efficiency reduction, this study proposes to effectively combine the static mixer with the annular jet pump and design a new type of annular jet pump and apply it to the gas wells to improve the fluid recovery capacity. Numerical simulations based on the gas–liquid two-phase flow model are carried out for a conventional annular jet pump (CAJP) and a new annular jet pump (NAJP). The reliability of the simulation results is verified by gas–liquid two-phase flow experiments, and the differences between the two in terms of velocity, pressure loss, and turbulent kinetic energy are analyzed. Meanwhile, the validity of NAJP is verified, and the effects of different structures such as static mixer torsion angle, suction chamber angle, and area ratio on the performance of NAJP are analyzed. The results show that NAJP enhances the degree of mixing between the sucked fluid and the power gas through the cyclonic effect created by the static mixer compared with CAJP. It results in a 10.6% year-on-year increase in the velocity of the sucked fluid, a 3% year-on-year increase in the pressure drop, and a 12.2% year-on-year increase in efficiency. NAJP can significantly improve the fluid-carrying performance. With a mixer angle of 210°, a suction chamber angle of 21°, and an area ratio of 1.77, the NAJP achieves an efficiency of 39.7%, which is a year-on-year increase of 7.3% compared to the structure under the same conditions before optimization. This study lays a foundation for the determination of the optimal design scheme of the annular jet pump and at the same time can provide theoretical and technical support for researchers in related fields.