Analysis And Experiment Study Of Capacity Of Carrying Liquid In Inclined Wellbore

If the formation water produced in the gas well can't be taken out of the wellbore,liquid loading may happen.In order to avoid liquid loading in gas well,it is necessary to ensure that the gas velocity is greater than the minimum gas velocity required to carry formation water,namely the critical gas velocity.Up to now,the understanding of carrying fluid capacity and the critical gas velocity in the inclined section of the gas well are not enough,and there are some disputes,which need to be further studied.In this paper,the liquid carrying capacity of inclined wellbore is studied from three aspects: experiment,theory and application.Firstly,an experimental system for fluid carrying in inclined wellbore was established to observe the phenomenon of fluid carrying and determine the critical gas velocity.Then,the principle of fluid transport in inclined wellbore is analyzed,and the effects of liquid film and droplet on fluid transport under different conditions and their relations are clarified.Finally,a new method for calculating the critical fluid carrying velocity of inclined wellbore is established,and an analytical method for analyzing the fluid carrying capacity of gas well is proposed,and an analytical software is written.The study shows that liquid droplets and liquid film are two important forms of liquid migration in inclined wellbore.The closer the wellbore is to the vertical,the greater the influence of liquid droplets on the critical fluid carrying velocity;on the contrary,the greater the influence of liquid film.Through the analysis of actual gas wells,it is found that the most likely location of generating fluid accumulation is the wellhead,deflecting section and bottom hole,and the above location should be carefully considered in the analysis of gas well fluid carrying capacity.The new method for calculating the critical gas velocity of inclined wellbore and the software for analyzing the fluid carrying capacity of gas well based on this method is meaningful for gas field development.