Abstract: The main purpose of this work is to derive an analytic formula describing pseudo-steady state flow of gas-condensate under reservoir condition and consider correctly the effect of condensate on well deliverability.Liquid dropout naturally occurs with reservoir depletion below the dewpoint,which differs from dry gas. It is unresolved to account for the effect of condensate on deliverability.Condensate is generally viewed as an immobile phase so that the dry gas flow equation is frequently used to analyze gas condensate well productivity and testing.An accurate evaluation of well productivity and testing is extremely important for the planning and development of gas condensate reservoir.Therefore,there is the strong need to develop a new and rigorous equation to express more closely the gas-condensate flow in porous media.In this paper,the foregoing problem is expected to be resolved.On the basis of the detailed description of flow performance of gas condensate,a definite solution problem of gas condensate two phase flow is formulated. Subsequently the corresponding analytic formula is derived under pseudo steady state.The detailed solution procedures are described.Then a more representative and rigorous overall deliverability equation desired is obtained through introduction of non-Darcy flow.Additionally,the calculation methods of the parameters (two phase pseudopressure integral and two phase non-Daccy flow factor D) involved in the equation and the calculating example are discussed briefly.The calculated results show that the binomial equation used in the dry gas condition is unsuitable for modelling deliverability of gas condensate well due to its overpredictions.

Key words: gas condensate well, two-phase flow, deliverability equation, non-Darcy flow, pseudo-pressure integral, condensate blockage

摘要： 主要目的是推导描述凝析油气渗流的拟稳态解析式,以便在分析凝析气井产能时能正确反映凝析油的影响.凝析油的析出是凝析气藏衰竭过程中普遍存在的现象,此现象是凝析气与干气最本质的区别,但如何考虑凝析油的影响仍然是一个未曾得到圆满解决的难题.通常,在凝析气井产能与试井分析中几乎都把凝析油视为非流动相而直接应用干气渗流方程,但由于凝析油在近井区域因饱和度高会形成油气两相流,使得常规的分析方法一直受到质疑与批评.因此,极需发展一个新的精确的方法来表示孔隙介质中的凝析油气两相流.本文试图解决这一难题.本文在详细描述凝析油气渗流特性的基础上,建立了凝析气藏油气两相流的定解问题,从而求得了拟稳态形式的解析解,文中给出了推导解析解的详细过程.通过引入非达西流修正项,最后得到凝析油气两相流更完善的、新的综合产能方程.此外,还讨论了该方程参数(两相拟压力积分和两相非达西流系数积分)的计算方法及算例.算例表明,用干气二项式方程将过高地估计凝析气井产能,因而是不适合的.

关键词: 凝析气井, 油气两相流, 产能方程, 非达西流, 拟压力积分, 凝析油堵塞