井下有积液气井的产气剖面解释方法研究

An Interpretation Method for Gas Production Profile of Gas Wells with Standing Liquid

气井内最常见的是气水两相流动。当井底有积液时,气体携带积液连续流向井口,其所携带的积液由于重力影响在井筒下部上下循环流动,这一现象会造成对井内流体的产量解释误差很大。目前国内外常用的漂流模型、滑动模型、均流模型等均不能描述这种特殊情况。基于此,在测试仪器已无法解决该问题的情况下,利用浮力射流理论提出了井筒中局部积液段气液两相流动的概化模式。应用多相混合物模型对井筒中的气液两相紊流运动进行了数值计算,其中雷诺应力采用标准k-epsilon紊流模型和壁函数方法封闭。在计算区域的进口处给定均匀来流速度,在出口引入压力边界条件。计算结果验证了气体射流推动积液运动和形成积液自循流的模式。根据计算结果修正各分层产水量的计算方法,为储层评价和工程作业提供了一种全新的途径。

Generally, gas ＆ water flows simultaneously in gas wells. However, interpretation for downhole fluid output may be in error when gas carried standing fluid recycles in well bore with standing fluid available. Methods applied home and abroad such as drift model, sliding model and monophasic fluid model can not illustrate the above mentioned phenomena. A new conceptual model for two-phase flow（gas and water） in partial interval with standing liquid in well bore is worked out in terms of buoyancy jet flow theory. Numerical computation is performed for turbulent flow of gas and water phases in well bore with multiphase mixture model in which standard k-epsilon turbulent model is taken as Reynold stress and sealed with wall function method. Uniform incoming fluid flowing velocity is set for entry of computation region and pressure boundary condition is inducted for outlet. The computation results verified that gas jet drives standing fluid and generates standing fluid circulation, computation methods for water yielding of separate zone are modified with computation results. It is proved to be a new approach for reservoir evaluation and engineering service.