气井连续携液临界产量的计算方法

NEW MODEL OF THE CRITICAL LIQUID CARRYING FLOW RATE FOR GAS WELLS

针对产水气井的实际生产状况,运用流体力学相关理论,对气井连续携液临界产量的计算方法进行了深入研究,分别提出了高气液比携液临界产量模型和低气液比携液临界产量模型。在高气液比携液临界产量模型中,液滴存在形式为圆球形,模型推导中充分考虑了井筒内流动状态的变化,采用与Turner经典液滴模型相同的力学分析方法,得到了针对不同雷诺数范围的临界产量计算公式,使经典液滴模型在理论上更加完善。在低气液比携液临界产量模型中,以Hagedorn和Brown井筒压力计算方法为基础,定义了理论持液率、实际持液率的概念和计算方法,并通过整个井筒内理论和实际持液率的对比来确定低气液比条件下气井连续携液临界产量,解决了低气液比条件下携液临界产量的确定方法问题。现场应用结果表明,这种方法能准确预测气井连续携液的临界产量,对气井合理生产制度的制定有一定的指导意义。

In the process of production, the gas well brings the liquid bottom hole to the surface. Through the comprehensive investigation and valuation on the existing model by applying the knowledge of hydrodynamics, a new critical liquid carrying flow rate model for gas wells at high GLR (gas liquid ratio) and low GLR is brought out, which can predict the minimum flow rate for the continuous removal of liquids from gas wells accurately. At high GLR, the model still adopts the forces balance concept of drop model, but was derived by adopting mechanical analysis same as that of Turner drop model considering flow variation within wellbore, which gained different critical production formula by considering different Reynolds' Number and perfected classical drop model theoretically. At low GLR, based on Hagedorn and Brown's method of wellbore pressure calculation, the concept and calculation method of theoretical and actual liquid hold-ups are defined, and the continuous liquid carrying critical production at low GLR is determined by comparing theoretical and actual liquid hold-up rates. The field application indicates the good match between the computation results of the method and actual production data, providing a useful tool for developing reasonable gas well production program.