井筒零液流研究

零液流量气提流动是产水气井中一类独特的持液流动现象，是井筒中长时间积存形成了液柱，而气体流速又不足以将液体带出井筒所致，表现为井筒中存在两相流气提区，而井口处的液体流量为零。其现场意义在于:它相当于积液气井气举排水过程中始喷点的概念。建立了该流动现象的流型划分标准、压降和持液率计算数学模型，并自行设计建立可视化实验台架模拟该物理现象。实验采用先进测试手段采集得到其流型图片以及压降、井口压力、注气量、持液率等数据。通过理论计算与实验数据对比，验证该理论模型的正确性。最后给出算例模拟计算实际气井零液流量气提流动和无滑脱气液两相流动，从而得出规律性认识。该研究成果对于指导严重积液气井气举排水采气设计有着积极意义。

Wellbore zero liquid flow study

Liquid column is formed in the wellbore due to the long-time liquid loading, while the gas flow rate is not so high that the liquid could be carried over the wellbore. As a result, two-phase flow gas lifting area exists in the wellbore, and the liquid flow rate is zero in the well head. The phenomenon is called liquid flow rate being zero, and it is a special flow-pattern of water production gas wells. It matches to point of gas lift. In this paper, the criteria for the classification of flow patterns, the mathematical model for calculating the pressure drop and liquid holdup rate are presented. Also a self-designed visual experiment bench is established to simulate the phenomenon. Advanced testing methods are adopted in the experiment to acquire the photographs of the flow patterns and the data of pressure drop, wellhead pressure, gas injectioin volume, and liquid holdup rate. Through theoretical calculations and experimental data comparison, the theoretical model is proved to be correct. Finally, examples are given to simulate gas flow with zero liquid flow and non-slip gas-liquid two-phase flow of actural gas wells. The research results are useful to drainage design of gas wells with severe liquid loading.