A Study Of Liquid-carrying Mechanism And Pressure Drop Characteristics Of Gas-liquid Two-phase Flow In Inclined Wells

Liquid loading is a common problem in gas well production process.With the development of gas wells,bottom hole pressure and gas production will continue to decline,and the capacity of liquid-carrying will also decline,until the produced liquid in the well is insufficient to be carried out continuously by the gas flow,and eventually accumulated at the bottom of the well,restraining gas well production and even causing shutdown.Therefore,it is of great significance to accurately predict the critical liquid-carrying flow rate of inclined gas wells and study the variation law of pressure drop in wells for ensuring the safety of gas reservoir production and improving the recovery efficiency.Based on the energy conservation equation,the functional relationship between critical Weber number and droplet deformation parameters is derived.Based on the force balance analysis of liquid-droplet,the critical liquid-carrying flow rate model about liquid droplets of gas wells considering the influence of droplet deformation and deviation angle is established.Compared with other liquid-droplet models,the average absolute prediction error of the new liquid-droplet model is the lowest,which is closer to the actual situation in the field.Based on the force of liquid film in inclined gas wells,a critical liquid-carrying film model for inclined gas wells considering the effect of inclination angle on the thickness of liquid film on the wall of the well is established.Compared with other liquid film models,the average absolute prediction error of the new model is the smallest,which is more consistent with the actual production.In addition,the liquid-droplet model and liquid film model proposed in this paper are further analyzed.Through comparison,it is concluded that when the gas-liquid ratio of inclined gas wells is high,the liquid-droplet model in this paper is closer to the actual value,while when the gas-liquid ratio of gas wells is relatively low,the liquid film model in this paper is more accurate.In this paper,Fluent is used to simulate the pressure drop of gas-liquid two-phase flow in inclined gas wells under different inlet gas velocity,volume liquid holdup and inclination angle.The simulation results show that the gas well pressure drop increases with the increase of inlet gas flow rate,volume liquid holdup and inclination angle when the gas well is in normal production.This paper studies critical liquid-carrying flow rate and the variation of pressure drop with gas flow rate,volume liquid holdup and inclination angle in inclined gas wells,which provides a theoretical basis for dynamic analysis of field gas wells and judgment of liquid accumulation.