摘要
凝析气井产能主要受近井区域的渗流动态控制。在近井区域,压力损耗较高,凝析气的流动压力常常会低于露点压力而导致凝析油在此区域逐渐累积;该区域明显地呈低压、高凝析油饱和度、高界面张力和高流速的特征;常规理论过高估计了高凝析油饱和度带来的堵塞效应,却忽视了高流速对凝析油的剥离效应,研究发现高速流动对近井油气相对渗透率的影响并非象常规理解那样简单,而是呈现出综合效应;如何准确理解高速效应的影响,对于凝析气藏渗流动态分析以及生产动态预测有很重要的意义。文章建立了油气两相渗流的定解问题,得到了拟稳态形式的流入动态方程,在三区渗流机理上首次综合考虑了毛管数和非达西效应对相对渗透率的影响,揭示了高速流动下油气相对渗透率变化及油气分布状态新特征,对不同流入动态模型的对比分析表明,该方法较之现有方法更有助于正确预测生产动态,评估气井产能。
Productivity of condensate gas wells is mainly controlled by the percolation performance near the hole. Since the pressure loss is big in the zone near the hole, the flowing pressure of condensate gas is usually lower than the dew-point pressure, which leads the condensate oil accumulating in the zone gradually. The zone has the obvious features of low pressure, high saturation of condensate oil, high interfacial tension and high flowing velocity. The conventional theory over-high estimates the plugging effect caused by the saturation of condensate oil and omits the stripping effect of high flowing velocity to the condensate oil. Study finds the influence of high velocity flow on the relative permeability of oil and gas near the hole is not so simple as we usually think. It is an integrated effect. It is very important for the percolation performance analysis and the production performance prediction of condensate reservoirs how accurately to understand the influence of high velocity effect. The article establishes the definite solution of oil/gas biphase percolation and derives the inflow performance equation under pseudo steady state. The influence of capillary number and non-Darcy effect on the relative permeability is first considered integrally on the percolation mechanism of the three zones. The new characteristics of oil/gas relative permeability variation and oil/gas distribution state are discovered under high velocity flow. With comparison and analysis of different inflow performance models, it is demonstrated the method is more helpful to properly predict the production performance and evaluate the productivity of gas wells than the existing methods.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2005年第2期136-139,共4页
Natural Gas Industry
基金
国家重点基础研究发展规划(973)项目(2001CB209108)资助
关键词
凝析油
凝析气藏
相对渗透率
油气
流入动态方程
凝析气井
气井产能
区域
效应
新特征
Gas condensates
Mathematical models
Mechanical permeability
Natural gas fields
Natural gas well production
Natural gas wells
Oil fields
Percolation (fluids)
Surface tension
