Downhole adaptive constant-flow steam injection valve

Aiming at the problem of uneven steam flow distribution caused by steam injection pressure fluctuations and inconsistent formation suction capacity during heavy oil thermal recovery, this study proposes a downhole adaptive constant-flow steam injection method. This method achieved adaptive control of steam flow through the dynamic synergistic effect of a critical-flow Venturi nozzle, a float, and a spring. We studied the dynamic characteristics inside the adaptive constant-flow steam injection valve through theoretical analysis. The relationship equation between float displacement and pressure difference across the inlet and outlet was derived, and key parameters such as spring elastic coefficient and maximum stroke were calculated. Subsequently, based on the computational fluid dynamics method, through the combination of static and dynamic numerical simulations, the flow field distribution characteristics and dynamic response characteristics during the operation of the steam injection valve were analyzed. The results show that when the steam injection volume is 30 t/d, within the pressure difference range of 0.8–1.9 MPa, the float moves within a range of 0–16 mm, and the flow rate fluctuation is controlled within approximately ±10%. Finally, laboratory experiments verified the reliability of the numerical simulation method and further confirmed the capability of achieving constant flow control through the adaptive movement of the spring-float mechanism inside the steam injection valve. This study provides a new approach for downhole steam distribution flow control technology in heavy oil thermal recovery wells and holds significant engineering application value.