预测倾斜气井临界携液流量新模型

目前应用广泛的临界携液流量预测模型大多以垂直井作为研究对象,并未考虑井斜角度对携液的影响,造成倾斜气井临界携液流量预测值与实际情况存在较大偏差。针对倾斜气井是否出现积液问题,基于液滴受力平衡分析,建立考虑液滴形变与井斜角度影响的气井临界携液流量预测新模型。根据能量守恒方程,推导得到临界韦伯数与液滴变形参数的函数关系式。基于椭球形液滴假设,考虑液滴内部流动及液滴形变影响,将邵明望模型计算结果下调15%作为椭球形液滴的曳力系数。结合实例与Turner模型、李闽模型、王志彬模型、杨文明模型和Belfroid模型进行对比分析发现,新模型准确程度较高,计算精度提高14.49%～16.80%,能正确判断气井积液情况,与现场实际情况吻合,可以有效指导气田安全、合理生产。

A new model for predicting critical liquid-carrying flow rate in inclined gas wells

At present, most of the widely used critical liquid-carrying flow prediction models are taking vertical wells as research object, and as we do not consider the effect of deviation angle on liquid-carrying, a large deviation was caused between the predicted value of critical liquid-carrying flow and the actual situation in inclined gas wells. In order to judge whether there is a problem of fluid loading in inclined gas wells, based on the analysis of liquid-droplet force equilibrium theory, a new model for predicting the critical liquid-carrying flow of gas wells was established on the basis of considering the effect of droplet deformation and well deviation angle. According to the energy conservation equation, we deduced the functional formula between critical Weber number and droplet deformation parameters. Based on the hypothesis of ellipsoidal droplet, and considering the influence of droplet internal flow and droplet deformation, the drag coefficient of the ellipsoidal droplet is taken down by 15% of the calculation results for Shao Mingwang model. Compared with Turner model, Li Min model, Wang Zhibin model, Yang Wenming model and Belfroid model, it is found that the new model has a higher accuracy, with an increase of 14.49%~16.80% in calculation accuracy. It can correctly judge the liquid accumulation in gas wells, which is consistent with the actual situation in the field, and can effectively guide the safe and rational production of gas fields.