两相采油指数与单相采油指数的关系及其应用

RELATION BETWEEN TWO-PHASE PRODUCTIVITY INDEX AND SINGLE PHASE PRODUCTIVITY INDEX AND ITS APPLICATIONS

溶解气驱油藏或饱和油藏计算油井最大理论产量公式中的采油指数，应是油井在井底流压高于饱和压力下生产的采油指数，即单相采油指数，只有知道单相采油指数才能获得油井的最大理论产量。实际上，当井底流压低于饱和压力时，井筒附近存在两相流动，油井有一个两相采油指数。研究表明，两相采油指数与单相采油指数之间存在一定关系，本文导出了它们之间的关系式，以及两相采油指数公式，并通过实例说明其应用。

The productivity index used to calculate the maximum theoretical production of oil well in solution gas drive reservoir and saturated reservoir is single phase productivity index that means the flowing bottomhole pressure of oil well is higher than bubble point pressure. When flowing bottomhole pressure is lower than bubble point pressure, two-phase flow will appears nearby the wellbore,and then two- phase productivity index exists. Research results show that two - phase productivity index has something to do with single phase productivity index. This paper presents the reation between them and the computing method of two-phase productivity index and introduces its applications by examples.