毛细管数效应对凝析气井流入动态的影响

凝析油析出是凝析气藏开发中普遍存在的现象, 因而常表现出与干气流入动态不同的特性。理论和现场应用表明, 直接利用干气或折算方法进行凝析气井动态预测会带来较大的误差。其原因是忽略了反凝析液对凝析油气相对渗透率的影响。利用凝析气相态理论和闪蒸计算方法, 考虑流体相态和组分的变化以及凝析气井的表皮系数, 引入稳态理论的两相拟压力函数, 考虑毛细管数效应对凝析油气体系相对渗透率的影响, 建立了拟稳态条件下的凝析气井流入动态预测方法。实例应用表明, 采用考虑毛细管数效应的凝析油气两相拟稳态流入动态方程, 弱化了凝析油的堵塞作用, 有助于正确评估凝析气井的产能, 准确把握凝析气藏的动态特征。

The Influence of Capillary Number Effect on Inflow Performance in Condensate Gas Well

Condensate dropout is widely existent in development of condensate gas pool, usually different from gas inflow performance. The theoretical study and field application indicate that big error will occur when predicting condensate gas performance by just using dry natural gas or converting method for the reason that the influence of retrograde condensed liquid on relative permeability of condensate oil and gas is normally ignored. This paper establishes the prediction method for inflow performance of condensate gas well under condition of pseudosteady state by using the theory of condensate gas phase state and flashing method, with consideration of changes of fluid phase behavior and composition as well as skin factor of condensate gas well, along with consideration of the influence of capillary number effect on relative permeability of condensate oil and gas system by using steady state theory and two phase pseudo-pressure functions. The case study shows that the equation for two phase pseudosteady state inflow performance with consideration of capillary number effect can be helpful to properly estimate the productivity of a condensate gas well and correctly recognize the behavior of a condensate gas pool through weakening the effect of retrograde condensation.