PROPERTIES OF RESERVOIR GASES - Petroleum Reservoir Fluid Property Correlations - page 20

Standing wrote equations to represent the graphical correlation for gas
viscosity at 1 atmosphere pressure, and Dempsey prepared an equation
to represent the graphical correlation for the ratio of gas viscosity at
pressure and temperature to the gas viscosity at 1 atmosphere pressure. 20
Two similar sets of correlation equations were proposed by Jossi,
Stiel, and Thodos and by Dean and Stiel. 21 Pseudocritical pressures,
pseudoreduced temperatures, pseudoreduced densities, and molecular
weights of the gases are required.
Lee, Gonzalez, and Eakin proposed a set of correlation equations
for gas viscosities as a function of temperature, gas molecular weight,
and gas density. 22 They referenced a similar set of correlations from Lee,
Starling, Dolan, and Ellington. 23
Elsharkawy proposed corrections to the viscosity calculated with the
Lee, Gonzalez, Eakin equations to account for the presence of nitrogen,
carbon dioxide, and heptanes plus. 24
Poling et al. reported a set of correlation equations that require
pseudocritical temperatures and pseudocritical pressures. 25
Londono et al. collected a large set of gas viscosity data and prepared
a new set of gas viscosity correlation equations (their “implicit model”). 26
They started with an equation for gas viscosity at 1 atmosphere pressure
correlated with gas specific gravity and temperature. This was adjusted
to reservoir conditions with another equation based on gas density with
coefficients based on temperature.
Sutton proposed equations that combine the method reported by
Poling et al. with the form of the Lee et al. equations. 27
Evaluation of proposed correlation equations for gas viscosities
The data set compiled by Gonzalez et al. has extensive gas viscosity
measurements for only eight naturally occurring gases. 28 These appear
to be the only reservoir gas viscosity data available in the literature.
Table 2-4 gives a description of these data. They were used to evaluate
the gas viscosity correlation equations. All eight of these gases have gas
compositions indicating that they are dry gases. No gas viscosity data
for gas condensates appear to be available.
Lee, Gonzalez, and Eakin used approximately one-half of these data
to develop their correlation equations. 29 Londono et al. used all of these
data plus a large amount of data from pure component, binary, and
ternary mixtures in preparing their correlation equations. 30 Sutton