考虑液滴变形和流动条件的气井连续携液预测新方法

A new prediction approach for continuous liquid carrying in gas wells considering droplet deformation and flowing conditions

关键词:  临界携液流量  高度湍流  曳力系数  液滴变形  井底积液

Key words:  critical liquid-carrying flow rate  highly turbulent flow regime  drag coefficient  liquid-droplet deformation  liquid loading

摘要:

Turner模型和李闽模型是国内外气田现场应用广泛的临界携液流量模型,二者均没有考虑流动条件对携液气量的影响,将曳力系数取为常数,而高度湍流区雷诺数的变化对曳力系数影响较大,从而使模型的计算结果与现场实际数据吻合度较低。基于这一问题,考虑液滴变形对携液气量的影响,并引入GP模型计算高度湍流区液滴的曳力系数,建立了基于高度湍流条件下的气井临界携液流量模型。新模型提出了一种简化的液滴变形参数计算方法,并考虑了高度湍流区曳力系数随雷诺数的变化。将新模型与Turner模型、李闽模型进行对比和验证,结果表明,新模型的预测结果与气井实际数据吻合最好,可以准确预测高度湍流条件下气井临界携液流量,对于气井的合理配产具有指导作用。

Abstract:

Most widely used critical liquid-carrying flow prediction models are Turner model and Li Min model. They both do not consider the influence of flow conditions on the liquid carrying in gas wells and assume the drag coefficient to be a constant. However, the variations of Reynolds number has a great influence on the drag coefficient in highly turbulent flow region, the discrepancies of the two models calculation with actual data exist. Aiming at this problem, considering the effect of drop deformation on the minimum critical flow rate and introducing GP model calculating the drag coefficient in highly turbulent flow regime, a new prediction model for continuous liquid-carrying in gas wells was established. The new model simplifies the calculation of droplet deformation parameters and considers the variations of the drag coefficient with Reynolds numbers in highly turbulent flow region. The new model is compared with Turner model and Li Min model, and validated with the actual data. The results show that the new model provides the prediction results in best coincidence with the actual state of gas wells. In conclusion, critical flow rate of gas wells in highly turbulent flow region can be predicted accurately by the new model, which has a guidance for gas production planning.