| Abstract: | The viscosities of natural gases have ben correlated as a function of composition, temperature, and pressure. Six equations are presented which express the viscosity of natural gases in terms of average molecular weight, reduced temperature, reduced pressure, reduced volume, reduced density, composition, and viscosities of the pure components. It was found that the viscosities of natural gases can be expressed over a wide range of temperature and pressure in terms of the viscosities of their components. Coefficients for Eakin's equation have been redetermined for methane, ethane, propane, and n-butane and similar coefficients for nitrogen, carbon dioxide, iso-butane, n-pentane, and n-heptane are presented for the first time. A total of 345 viscosity measurements were made for ten lean natural gases over a range of pressures from 1000 to 10,000 psig and temperatures from 77°F to 400°F. 145 data points are also presented for seventeen rich condensate gas samples which have not been published elsewhere, along with 121 measurements taken from the literature. Average deviations of from 8.8 to 13.8% were obtained for the six different equations developed from the 611 data points. These correlations are substantially more accurate than previously available procedures, and cover a much wider range of composition. |
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