Study On The Capacity Of Gas To Carry Liquid In Pipelines

Liquid loading as a common problem in production of gas wells and gathering pipelines,often results in production capacity of gas wells to be limited or even stopped;Pipeline efficiency decreased and pipelines are destoried increased;periodic violent pressure and flow rate fluctuations;pipelines corrosion and many other problems.Most of the existing models of critical gas velocity in vertical wellbore are mainly analyzed by liquid drops.Most models using the parameter of Weber number in determining the droplet diameter size by quantitative analysis,assumed droplet shape before determining the drag coefficient,few studies are focused on the relationship between droplet size and droplet shape.In addition,the capacity of gas to carry liquid is an important factor to analyze the problem of liquid loading in gathering and transportation pipelines,the regulation of which changing with the parameters still need to be explored.To address these issues mentioned above,relevant studies based on the actual project were conducted in this paper.Based on data provided by domestic and foreign literatures,the existing main models of the capacity of gas to carry liquid of gas wells have been compared and analyzed.Also,the adaptability of each model to high or low pressure gas well has been determined.Considering the former people who have not researched the relationship between droplet size and droplet shape,after studying the relationship between droplet size and droplet shape,confirming the expression of drag coefficient expression,then a new model of the critical gas velocity in vertical wellbore has been established.The results of the new model are in good agreement with the field datas of L shale gas well.Then,the adaptability of the new model to the high and low pressure gas well is determined,and the influence of pipe diameter,temperature,wellhead pressure and the different kinds of liquid on the capacity of gas to carry liquid has also been analyzed.Finally,the regulation of which,the capacity of gas to carry liquid,to L shale gas field were analyzed using OLGA software.Many simulations have been conducted to study the effect of terrain,pipeline diameter,inlet mass water content,flow rate and the surrounded temperature on liquid loading.Then the most likely regions of the L shale gas field liquid loading was predicted,which has provided a theoretical basis for the practical production.