Performance study of self‐excited oscillatory cyclone drainage tool to improve the efficiency of natural gas well drainage and gas recovery

Abstract

AbstractThe accumulation of fluid in the wellbore of a natural gas well can seriously affect the production of the well and can even lead to the well flooding and stopping production. The conventional cyclone tool has low kinetic energy, serious energy loss and short effective distance of spiral flow in the process of gas well drainage and gas recovery, thus affecting the efficiency of gas well drainage and gas recovery. In response to the above problems, this paper proposes a new cyclonic drainage solution combining self‐excited oscillating pulse jet and cyclonic flow. The liquid‐carrying air flow through the oscillating chamber forms a large vortex ring and the flow pattern squeezes the central air flow inwards, allowing the return vortex at the wall to develop effectively, increasing the return vortex velocity and increasing the velocity at the centre of the squeezed pulsating flow. In this paper, based on theoretical analysis and experimental research, the numerical simulation results are compared with the various drainage performance of conventional cyclone tools. The results show that the pressure drop and critical fluid‐carrying velocity of the cyclone section are significantly reduced, and the average tangential velocity of the cyclone section and the effective action distance of the cyclone tool are significantly increased, indicating that the new cyclone tool can improve the fluid‐carrying capacity of gas wells by changing the flow pattern of the gas–liquid medium without increasing energy consumption.