Study On Carrying Capacity Of Low Permeability Gas Well With Underground Throttle

Downhole choking technology is widely used in the development of low permeability gas reservoirs in recent years. With the continuous development of gas field, the proportion of water production gas wells increase year by year for water-gas reservoirs.It is very important to predict the liquid ability and judge the gas well effusion.In this paper, considering a certain volumn of water when gas wells with downhole choke are producing, the flowing buttonhole pressure calculation model is established by the methods of average parameters and Cullender-Smith. The computing model of wellbore pressure has been established with Hagedorn-Brown vertical tube air water two phase methods. The temperature model considered the wellbore radial thermal conduction has been built.Perkins model is used to calculate the pressure drop through the throttling mouth. According to the characteristics of the enthalpy values are equal before and after the throttle, and based on the theory of phase equilibrium, suitable model has been built to calculate the chocked temperature dropping values. Paper based on the liquid droplet particle force equilibrium theory, we deduced a new model to predict the minimum flow rate of liquid loading. The universal model considered the effects of droplet deformation and droplet size on the minimum flow rate of liquid loading, and contracted drag coefficient. It used the function relation between the droplet deformation parameters and the critical Weber number to calculate the droplet deformation parameters. The universal model can theoretically explain the reasons why minimum flow rates of various gas fields differ significantly by contracting the existing model and the new model. Finally,100gas wells in the Sulige gas field were taken as example to demonstrate the use of the model.Through the parameter sensitivity analysis on the critical carrying fluid model, analyzed liquid carrying capacity of the gas wells with downhole choke. Through the example analysis of the gas wells in Sulige field, the universal model can predict the gas well effusion and provide the basis for drainage gas recovery.