不同压力下确定凝析气井二项式产能方程的一种新方法

凝析气藏在低于露点压力的情况下，地层中的流体将由单一的气相变成气液两相。这种相态变化对凝析气井产能存在两方面的影响：一是气相流体相对密度降低，其粘度、偏差因子等也随之发生变化；二是重烃液化后吸附于岩石表面并在近井地层中富集，降低了含气饱和度及气相相对渗透率，严重影响了气井产能。从气井二项式产能方程的主要影响因素出发，利用初期凝析气井测试资料获得的二项式产能方程，依据凝析气藏气相流体组成、相对密度、粘度及偏差因子随压力的变化情况，结合凝析气藏油、气相渗实验结果，提出了对初期二项式产能方程系数的修正，便可获得在不同压力下符合凝析气井实际的二项式产能方程，实例验证该方法具有良好的预测效果。

A NEW APPROACH OF ESTABLISHING BINOMIAL DELIVERABILITY EQUATION OF GAS CONDENSATE WELL AT DIFFERENT PRESSURES

Formation fluid of single phase will change into two-phase gas-liquid when pressure of condensate gas reservoir is lower than dew point pressure. This phase change will influence deliverability of condensate gas well in two respects: First, relative density of fluid in gas phase will lower, resulting in relevant changes of its viscosity and Z-factor. Second, heavy hydrocarbons adhere on rock surfaces and accumulate near wellbore after liquefaction, lowering gas saturation and relative permeability of gas phase and seriously influencing deliverability of gas well. The main influential factors of binomial deliverability equation of gas well are analyzed. According to changes of fluid component, relative density, viscosity and Z-factor of gas phase with reservoir pressure and combining with experiment results of oil and gas relative permeability in condensate gas reservoir, the coefficients of binomial deliverability equation, established with initial test data of condensate gas well, are corrected to reflect the real conditions of condensate gas well at different pressures. Case calculation verifies that the new equation can more accurately predict deliverability of condensate well.