混相条件下油气相渗规律表征

Relative Permeability Law Under Condition of Miscible Phase

为深入研究混相条件下的相渗规律,分析了J·B·N方法和现行两相相对渗透率测定标准,结合混相原理形成了混相条件下的相渗曲线不存在的认识,并提出了混相相渗的表达方法。研究表明,无论是J·B·N方法还是现行的国家标准都在强调参与渗流的两相互不相溶,且渗流过程中两相的性质不发生变化,而混相条件下相渗恰好违背了这一点,导致实验点之间各自孤立,无法连接成线,因此相渗曲线根本不存在。为此提出了使用非混相相渗曲线来表达混相相渗的近似表达法,将混相驱开发过程按照原油中含CO2量的多少分成无数个非混相驱替的阶段,每个非混相驱替过程对应一个非混相相渗曲线,混相相渗就是一系列非混相相渗曲线的组合。该观点的提出是对混相条件的再认识,是气驱技术的深化与发展,对于混相驱数值模拟和方案制定具有重要的指导意义。

For further researching seepage law under the condition of miscible phase, the J·B·N method and standard of two-phase relative permeability measurement were analyzed, and by combining the principle of miscible, this paper realized that relative permeability curve did not exist under the condition of miscible phase, and put forward the expression method of miscible phase relative permeability. Research has shown that, J·B·N method and the current national standards both emphasized that the two phase could not dissolve each other, and the nature of the two phase could not change in the seepage process, but the relative permeability under the condition of miscible phase just violated that, leading to the isolation of each test sites unable to connect into line, so the relative permeability curve did not exist at all. Therefore, this paper put forward approximation method of immiscible phase relative permeability by using immiscible phase permeability curve, in which the stage of miscible flooding development was divided into many immiscible displacement processes according to the CO2 content in crude oil, and each immiscible displacement process corresponded to an immiscible phase relative permeability curve, thus miscible phase permeability was the combination of a series of immiscible phase permeability curve. The view is the re-recognition of miscible conditions, and the deepening and upgrading of gas displacement technology. It has important guiding significance to numerical simulation and development planning for miscible displacement.