凝析气藏各区渗透率及半径确定方法

摘要

凝析气藏开采过程中,凝析油的析出会堵塞地层孔隙,降低储层的气相渗透率,导致凝析气藏出现两区或三区分布,甚至出现多区分布.凝析气藏多区分布的不稳定试井双对数曲线特征与复合地层的曲线特征相似.基于试井理论,运用不稳定试井双对数解释曲线,得出了凝析气藏各区的渗透率计算公式,提出了凝析气藏各区半径的求解公式.通过实例计算,并将其结果用数值模型进行验证,表明该方法可靠,可以更加详细准确地描述反凝析范围及程度,为凝析气藏的高效开发以及后期改造提供了依据.%In the course of condensate gas reservoir production, because of the separation of condensate oil, the formation pores and fractures are blocked, thus the gas permeability of the reservoir will be reduced and two or three blocks of condensate gas reservoir will result in, and even more multiple-block distribution will happen. The characteristics of log-log plots of the non-stabilized well test of the above distribution are as similar as those of the curves of composite formations. On the basis of well test theory, by using the interpreted log-log curves of non-stabilized well test, the permeability calculating formula of each block of condensate gas reservoir is obtained and furthermore the solution-seeking formula of the radius of the each block is also established. Through the calculation of case history and the verification of numerical simulation model for the above results, the method is proven to be reliable and can more accurately and soundly describe the size and the degree of the above retrograde. Finally the method provides the evidence for the high-efficiency development and later treatment of the condensate gas reservoir.