预测天然气斜井临界携液流量新方法

A new approach for predicting critical liquid-carrying flow rate in directional gas wells

关键词:  临界携液流量  井底积液  修正系数  天然气斜井  曳力系数

Key words:  critical liquid-carrying flow rate  liquid loading  correction coefficient  directional gas well  drag coefficient

摘要:

目的 Turner模型和李闽模型是现场应用比较广泛的气井携液模型,二者是以直井为基础建立的,且假定曳力系数为定值,没考虑井斜角和曳力系数对临界携液流量的影响。为了准确预测天然气斜井临界携液流量,分析了天然气斜井中液滴的受力情况,建立了预测天然气斜井临界携液流量新模型。方法 该模型考虑了雷诺数变化对曳力系数的影响,对比不同曳力系数计算模型的精确度,优选出Barati模型计算天然气斜井中液滴的曳力系数,推导了该模型相对于Turner模型的修正系数,并给出了修正系数表。结果 通过实例将新模型与Belfroid模型、杨文明模型和李丽模型进行比较,结果表明,新模型计算结果与现场数据吻合最好,准确率为94.6%。结论 新模型可用于对天然气斜井积液的判断。 

Abstract:

Objective Turner model and Li Min model are widely used critical liquid-carrying flow prediction models in the fields. They are established on the basis of vertical wells, and the drag coefficient is assumed to be a constant value, the effect of deviation angle and drag coefficient on critical liquid-carrying flow rate are not considered. In order to accurately predict critical liquid-carrying flow rate of directional gas wells, the force of liquid drop in directional gas wells is analyzed, a new model for predicting critical liquid-carrying flow rate of directional wells is deduced. Methods The influences of Reynolds number variation on the drag coefficient are considered, in this model, the accuracy of different drag coefficient calculation models are compared, the Barati model is selected to calculate the drag coefficient of droplets in directional gas wells. The correction coefficient of this model relative to the Turner model is derived, and the correction coefficient table is given. ResultThe new model is compared with Belfroid model, Yang Wenming model and Li Li model by the field cases. The results show that the new model provides the calculation results in best coincidence with the actual data of gas wells, and the accuracy is 94.6%. Conclusion The new model can be used as a guidance for predicting liquid loading of directional gas wells.