气井携液临界气流速计算新模型

A New Model to Calculate Critical Velocity for Liquid Loading in Gas Wells

罗程程 李楠 刘永辉 曹光强 叶长青

LUOChengcheng LINan LIUYonghui CAOGuangqiang YEChangqing

油气藏地质及开发工程全国重点实验室·西南石油大学, 四川 成都 610500 中国石油勘探开发研究院, 北京 海淀 100083 中国石油西南油气田公司工程技术研究院, 四川 成都 610017

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China Research Institute of Exploration and Development, PetroChina, Haidian, Beijing 100083, China Engineering Research Institute, Southwest Oil & Gas Field Company, PetroChina, Chengdu, Sichuan 610017, China

准确预测气井积液时机并提前采取合理排采措施可有效降低积液带来的风险。现有积液预测模型缺乏与气井积液特征对比分析，导致适应性较差。为此，开展了可视化物理模拟实验，分析了不同气流速下液膜流动规律，基于液膜流动特征，定义了新的积液临界点；基于液膜层受力分析，建立了携液临界气流速机理模型。研究结果表明，液膜反转后，液体并不会在井底聚集，而是以液体波动形式向上带液，液膜反转越严重，波动越明显；液膜反转时井筒流动相对稳定，与气井积液时所表现的特征不符，导致其计算携液临界气量值偏大；将液膜层流层向上和向下流动流量相等定义为积液临界点能够更好地捕捉气井积液动态；新模型在不同影响参数条件下均与液膜模型呈现良好的对应关系，在公开发表文献中的实例井数据中预测精度最高。模型能够为气井积液判断提供参考。

Accurately predicting the liquid-loading timing in gas wells and taking reasonable corresponding deliquification technologies in advance can effectively reduce the risk of liquid loading. Existing liquid-loading prediction models lack comparative analysis with liquid-loading features in gas wells, resulting in poor adaptability. Therefore, visual experimental tests were carried out to study the flowing behavior of liquid film at different gas velocities, a new criterion of liquid-loading initiation was defined subsequently. Based on the force balance of liquid film, an analytical model of critical gas velocity for liquid loading was established. And the following research results were obtained. First, the liquid does not accumulate at the bottom of the pipe when the liquid film reverses and travels upward as instead liquid waves. The more serious the liquid film reversal is, the more obvious the fluctuation is. Second, when the liquid film reverses, the flow is relatively stable in the pipe, which is not consistent with the features of liquid loading in gas wells, leading to the prediction of critical gas velocity in liquid-reversal criterion too conservative. Third, it captures the liquid-loading dynamics in gas wells when liquid-loading criterion is defined as the equal liquid flow rate of upward and downward in the laminar liquid film. Fourth, the new model has a good changing trend with the liquid-film model at different affecting parameters, and its prediction accuracy is the highest against the published well data in the literature. In conclusion, the new model can be used to judge liquid loading in gas wells.

10.11885/j.issn.1674-5086.2023.08.13.31