Study Of Gas Wellbore Flow Dynamics In The Masian Area

The wet gas transmission process has become the main form of oil and gas gathering pipeline in China,and with the exploitation of gas fields,water from gas wells is an inevitable phenomenon,which will make the gathering pipeline accumulation of liquid and gas well bore accumulation phenomenon become the most common and more difficult problem in the exploitation and transportation of natural gas.At the initial stage of liquid accumulation,foam is one of the commonly used drainage measures,which is now widely used in gathering pipeline and gas well drainage process,and gas wells in the Masian area are no exception.In order to clarify the flow law of gas wellbore with liquid accumulation,this paper will take gas wells in the Masian area as the research object and use a combination of indoor simulation experiments and theoretical analysis to study the wellbore flow dynamics,and the main work of the paper is as follows:(1)Experiments on gas-liquid two-phase tubular flow at different well slope angles,different gas-liquid volumes and different tubing diameters are conducted using air and water to determine the variation patterns of gas-liquid two-phase flow pattern,liquid-carrying volume,pressure drop and critical liquid-carrying flow rate,and to qualitatively give the influence mechanism.(2)With reference to the characteristics of foam carriage,experiments on gas-water bubble three-phase flow at different well slope angles,different gas-liquid volumes,different tubing diameters and different bubble concentrations were conducted with the use of foaming agent in the field to determine the changes in gas-water bubble three-phase flow pattern,liquid-carrying capacity,pressure drop and critical foam-carrying flow rate after the addition of foaming agent,and to compare the changes in flow pattern,liquid-carrying capacity,pressure drop and critical liquid-carrying flow rate before and after the addition of foaming agent.(3)Based on the measured experimental data,the existing gas-liquid two-phase flow conversion limits were verified and the final gas-liquid two-phase flow conversion pattern was determined,based on which the gas-water bubble three-phase flow conversion limits were established and the final flow conversion pattern was obtained;based on the existing gas-liquid two-phase flow and gas-water bubble three-phase flow pressure drop calculation models,a new pressure drop calculation model was established after reconsidering the changes in the liquid/gas holding rate,and through verification It is found that the errors are within 15%,which meet the requirements of engineering calculation.(4)Based on the experimental data of the measured critical fluid/bubble,the most difficult fluid-carrying angle and the easiest fluid-carrying foamer concentration were analyzed,and the critical fluid/bubble flow rate calculation method was established after considering the effects of droplet deformation and foamer concentration,and the model was evaluated and verified by selecting the actual wells in the Masian area.