基于两相流模型的直井动态排积液方法研究——以大牛地气田为例

The Research of Dynamic Liquid Discharge and Holdup Methods in Vertical Wells Based on Two Phase Flow Model

有效排出积液对低压低产气井的稳产保产具有重要意义。针对目前大牛地气田直井积液状态无动态监测手段、排液方法相对粗糙的缺陷进行排积液方法研究。首先基于两相流的形成与转换机理,结合环状流、过渡流、段塞流、泡状流4种流态的特征,定义了无积液、井壁积液、井筒积液、井底积液4种积液状态;其次,通过对比实际产量与各流态的形成边界以及临界携泡流量的大小关系,将4种积液状态的气井进一步细分为8类,并将泡沫排水、提产带液、降压带液等排水方法进行组合,制定了针对性的8类排积液方法;最后,实例分析证明该方法在现场应用中取得了良好的效果。

The effective liquid discharge was important for stabilizing production in low-pressure and low-yield gas wells.In allusion to the problem that there was no dynamic liquid monitoring method and liquid discharge method was relatively rough in vertical wells of Daniudi Gas Field,the methods of liquid discharge and holdup were studied.First,based on transformation mechanism of two-phase flow and combined with four kinds of characteristics of liquid flowing such as annular flow,transition flow,slug flow,bubble flow,4 kinds of liquid holdup states such as no liquid holdup,liquid holdup in wellbore,borehole liquid holdup and downhole liquid holdup were defined.Secondly,by comparing the relationship between the actual production,the boundary formed each liquid flow state and size of critical liquid carrying capacity,the gas wells with 4 kinds of liquid holdup were divided into eight kinds,the methods of water drainage with foam,liquid carrying capacity,pressure reduction with liquid were combined.finally,the case study shows that the method applied in the field achieves good effect.