A new prediction model for the critical gas velocity of liquid-carrying in horizontal gas wells
The phenomenon of liquid loading in gas wells is the backflow and accumulation of fluid in the wellbore.It is one of the serious production problems in gas wells.It can lead to reduced production and even production shutdown.The ability to predict fluid accumulation in gas wells is important for ensuring positive production and optimizing related production processes.In order to take appropriate countermeasures to prevent the occurrence of fluid accumulation in a timely manner,it is crucial to accurately predict and identify the accumulation points.In this paper,indoor experiments were conducted using an air-water mixture in a 60 mm diameter pipe with 0.2 MPa and 0.5 MPa pressure at 0～90° inclination angles.The variation of the critical gas flow rate at different angles,pressures and liquid volumes was analyzed.As the angle increases,the critical gas velocity first increases and then decreases.The inclined section is the most difficult well section to carry fluid.55° inclination angle is the most difficult angle to carry fluid.Based on the analysis of fluid film forces.Considering the inhomogeneous distribution of the liquid film on the wall of the inclined gas well,SHEKHAR's equation for the maximum liquid film thickness distribution is used.Considering the balance of droplet load and liquid film entrainment in the gas core,a new critical liquid-carrying prediction model for inclined gas wells was developed.The new model is compared with LUO model,BARNEA model and LIU model using experimental data and field data.The model calculates the best agreement with the field data with an accuracy of 91％.It shows that it has better performance than other fluid accumulation prediction models.The new model can be used for the judgment of horizontal gas well liquid loading.
gas wellcritical gas flow rateliquid loadingliquid film thickness
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