底水凝析气藏循环注气物质平衡方程及应用

Material Balance Equation of Condensate Gas Reservoirs with Bottom Water in Cyclic Gas Injection and Its Application

循环注气开发过程中凝析气藏流体相态特征变化复杂,受注气推进及地层压力分布影响,地层中反凝析液饱和度分布难以用一平均值代替,造成用物质平衡方程方法计算的储量偏差较大,驱动指数不宜计算,不利于循环注气开发效果的评价。而在建立物质平衡方程时引入两相体积系数的概念,可以准确描述流体相态,使物质平衡方程的表达简化。通过实际计算可以看出,应用此方法可以方便、准确地计算凝析气藏动态储量大小,分析储量动用情况,计算凝析气藏各种驱动能量的大小、评价循环注气开发效果。

During the development of condensate gas reservoirs in cyclic gas injection,the variation of phase behavior characteristics was complex because of the influence of injected gas advancement and formation pressure distribution.As of the heterogeneity of formation and the uncertain movement of injection gas,the distribution of condensate saturation was also hard to be predicted.It is impossible to discribe the condensate saturation using an average data,thus a new method of establishing material balance equation is put forward,two phase volume coefficients are introduced.Accordingly,the dynamic reserves,quantity of water drive,drive index are all obtained accurately.