Current popular models for calculating critical liquid-carrying flow rate for directional gas wells are established based on vertical wells without considering the influences of deviation angle on liquid-carrying.Now more and more directional wells and horizontal wells are deployed in coal-bed methane recovery

but the current vertical well-based models cannot accurately predict the critical liquid-carrying flow rate of these wells.To solve this problem

we performed study based on Turner calculation model with impacts of deviation angle integrated.Analysis of the force balance of spherical droplets reveals that the liquid drops do not always rise up along the central line but fall off slowly on the tubing wall and finally glide up along the tubing.According to Newton’s friction law

we calculated the friction force between the tubing wall and liquid drop

and rebuild a new model to predict critical liquid-carrying flow rate for directional gas wells.Finally

on the basis of the Turner model

we derived correction factors which are related to the friction coefficients and the deviation angles.The practical application shows that this calculation method has higher precision.