凝析气藏考虑毛管数和非达西效应的渗流特征

近期的大量理论和试验研究发现,高速流动导致的毛管数和非达西效应对近井油气相对渗透率有显著影响,仅考虑非达西效应无法准确描述油气真实渗流状态。准确理解并考虑这2种效应的影响对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。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。实例分析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,本方法比现有方法更有助于正确预测生产动态,评估气井产能。

Characteristics of Gas Condensate Flow in Porous Media Considering Capillary Number and Non - Darcy Effect

It is found recently in numerous theoretical and experimental researches that capillary number and non-darcy effect caused by high velocity flow has magnificent effect on relative permeability within the immediate vicinity of the well. The classic methods only considering non-darcy effect are impossible to characterize the real flow behavior both gas and condensate accurately. So how to understand and to consider the effects caused by these two effects is important to analyze gas condensate flow and predict production performance. The paper defined a solution problem of two phase flow both gas and condensate and derived the inflow performance relationship equation under pseudo steady state. Based on three zones flow mechanism, the integrated consideration of capillary number and non-darcy effect is firstly presented. Applied analysis showed some new characteristics of gas/condensate relative permeability and distribution under high velocity flow. Comparing with the different inflow performance relationship models, the result indicates that present method is more accurate than classic ones to predict the production performance and to evaluate the productivity.