水平井段连续携液理论与试验研究

Theory and Experiment on the Continuous Liquid Carrying in Horizontal Wells

在水平井筒中,地层产出的液体由于重力作用在较短的距离内就会沉降在水平井段底部,以液膜的形式沿着井底向气流方向移动,因而水平井段中连续携液临界气速的计算方法与直井段不同。在水平井段中分层流是主导流型,管底液膜厚度相比之下远大于管顶,是导致水平井段积液的主要因素。从水平井段液膜的流动和分布机理出发提出了分层流模型、携带沉降机理模型与Kelvin-Helmholtz波动理论3种水平井段连续携液临界气速的计算模型,并制作水平井段连续携液试验装置进行了试验研究。结果表明,气液界面不稳定波动携液在水平井段连续携液中处于主导地位,可将基于Kelvin-Helmholtz波动理论的临界气速计算式作为水平井段连续携液临界气速的计算公式。

In horizontal wellbores, the produced liquid had very short distances to fall to the +bottom of the wellbore due to gravity. The liquid flowed to the gas moving direction as the form of film. So the computing method of critical gas rate in horizontal sections was different with that of vertical wells. For a horizontal flow, the dominant flow was a stratified flow, the liquid film at the bottom of the tube became progressively thicker compared to the top of the tube, it was the dominant factor that caused liquid loading in horizontal sections. The stratified flow model, the entrainment and deposition mechanism and Kelvin-Helmholtz wave theory were put forward to compute the critical gas rate in view of the flow and distribution mechanisms of liquid film. The experiment facilities were also established to study the continuous liquid carrying in horizontal sections. The experiment results show that the waves on the gas-liquid interface are the dominant reason of liquid carrying in horizontal sections. So this paper suggested the K-H waves theory as the critical gas rate computing model in horizontal sections.