Developing a K-value equation for predict dew point pressure of gas condensate reservoirs at high pressure

Abstract

This paper proposed a new empirical K-value equation is developed to calculate dew pressure for gas condensate reservoirs. This equation is applicable in the wide ranges of composition, temperature, and pressure by considering the effect of composition via two equations for normal boiling point and critical temperature of the mixture. The range of dew pressure, temperature, heptane plus mole fraction, methane mole fraction, N₂ mole fraction, CO₂ mole fraction, and H₂S mole fraction are fallen into 2666.7-9655 Psia, 40-350.87 °F, 0.0021-0.213, 0.3344-0.9668, 0-0.4322, 0-0.0864, and 0-0.942 respectively. As an important point, the proposed equation has any adjustable parameters, in addition, this equation indicates that in order to predict of dew pressure of gas condensate reservoirs, trial and error was not needed and therefore, computational speed increases beyond the accuracy. Moreover, the accuracy is validated by comparing against the experimental data of 81 gas condensate reservoirs samples from published literature and the results of Wilson, Whitson, and Ghafoori equations. Compared to the experimental data, the absolute average deviations of dew pressure calculations for the proposed equation, Wilson, Whitson, and Ghafoori were 7.6%, 97.6%, 99.4%, and 94.9% respectively.

Keywords

Dew point pressure / Gas condensate reservoirs / K-value / Wilson

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