凝析气藏水平气井倾斜段油–气–水三相携液规律研究

The Study on the Liquid-Carrying Behavior of Oil-Gas-Water Three-Phase Flow in the Inclined Section of a Horizontal Gas Well in a Condensate Gas Reservoir

摘要: 凝析气藏在开发过程中，随着地层压力的降低，会出现凝析油，这使得井筒中的油气水三相的相态变化与流动规律变得更加复杂，增大气井携液难度。为了深入理解该过程中的相态变化规律，本文采用VOF耦合水平井模型对水平气井倾斜段中油气水三相流动进行数值模拟，研究了不同倾斜角、流速、含气率下油–气–水三相在水平气井倾斜段中的流动特性，并分析这些参数对于油气水三相流体在倾斜段中分布、流动形态及相互作用的影响。模拟结果表明：随着流速的增大，出现的泡状流向分层流转变，随着含气率的增大，出现泡状流–分层流–段塞流转变，随着倾斜角的增大，流型由波状流–段塞流–分层流的连续转变。值得注意的是，通过模拟还发现，当倾斜角大于45˚时，油相趋向在管道底部聚集，这一现象有可能会增加油相沉积的风险。

Abstract: In the development of condensate gas reservoirs, as the formation pressure decreases, condensate oil appears, which complicates the phase changes and flow patterns of the oil-gas-water three-phase system in the wellbore, increasing the difficulty of liquid carrying in gas wells. To gain a deeper understanding of these phase changes, this paper uses a VOF-coupled horizontal well model for numerical simulation of the oil-gas-water three-phase flow in the inclined section of a horizontal gas well. The study examines the flow characteristics of the oil-gas-water three-phase under different inclination angles, flow rates, and gas contents, and analyzes the impact of these parameters on the distribution, flow patterns, and interactions of the three-phase fluids in the inclined section. Simulation results indicate that with increasing flow rate, the flow pattern transitions from bubbly flow to stratified flow; with increasing gas content, the transition is from bubbly flow to stratified flow to plug flow; with increasing inclination angle, the flow pattern changes continuously from wavy flow to plug flow to stratified flow. Notably, the simulation also reveals that when the inclination angle exceeds 45˚, the oil phase tends to accumulate at the bottom of the pipe, which may increase the risk of oil phase deposition.