关键词: 超高压气藏, 气体偏差因子, 拟对比压力, 计算方法, 高压物性实验

Abstract: Based on the theory of gas molecule movement and the equation state for fluid,it is proved theoretically that gas deviation factors under the ultra-high pressure are linearly dependent on pseudo-reduced pressure.The calculation result of Dranchuk-Abou-Kassem fitting equation was compared with that of the other fitting equations for high pressure and extra-pressured conditions.The performance of the DAK equation was also identified by experimental data of field gases under ultra-high pressure and by Standing-Katz correlation.The results show that it is possible and practical to generate the deviation factors of gas in ultra-pressure gas reservoirs by extending the application region of DAK equation and linearly extrapolated Standing-Katz correlation when the pseudo-reduced pressure is over 15 in the same area.Furthermore,this linear extrapolation method of Standing-Katz correlation could be applicable to calculate the deviation factors for dry gas,wet gas and gas condensate reservoirs.

Key words: ultra-high pressure gas reservoir, gas deviation factor, pseudo-reduced pressure, calculation method, PVT experiment