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Implicit Z-factor Correlations @model for the natural gas in the wide range of pseudo-reduced temperature 

LaTeX Math Inline
body--uriencoded--1.0 < T_%7Bpr%7D \leq 3.0
 and pseudo-reduced pressure 
LaTeX Math Inline
body--uriencoded--0.2 \leq P_%7Bpr%7D \leq 30

and also a specific range of

LaTeX Math Inline
body--uriencoded--0.7 < T_%7Bpr%7D \leq 1.0
 and
LaTeX Math Inline
body--uriencoded--P_%7Bpr%7D < 1.0
Explicit  natural gas viscosity correlation:

LaTeX Math Block
anchor
z
mu
alignmentleft
Z = \frac{0.27 \, P_{pr}}{y \, T_{pr}}
LaTeX Math Block
anchory
alignmentleft
1 + T_1 \, y +T_2 \, y^2 + T_3 \, y^5 + T_4 \, y^2 \, (1+ A_8 \, y^2) \
\mu_g = K \cdot \exp \left( 
- A_8
X \, 
y^2
\rho_g^Y 
\right)
- \frac{T_5}{y} = 0





LaTeX Math Block
anchor
A
K
alignmentleft
T_1
K = 
A_1 +
T^{1.5} \cdot \frac{
A_2 }{ T_{pr} } + \frac{A_3 }{ T_{pr}^3
9.379 + 0.01607 \, MW_g}{209.2 + 19.26 \, MW_g +T}
LaTeX Math Block
anchor
B
X
alignmentleft
T_2
X = 
A_4
3.488 + \frac{
A_5
986.4}{
T
_{pr
} 
} LaTeX Math Block
anchorD
alignmentleft
T_3 = \frac{A_5 \, A_6 }{T_{pr}}
+ 0.01009 \, MW_g
LaTeX Math Block
anchor
E
Y
alignmentleft
T_4
Y = 
\frac{A_7 }{T_{pr}^3} LaTeX Math Block
anchorE
alignmentleft
T_5 = \frac{0.27 \, P_{pr} }{T_{pr}}
 2.447 - 0.2224 \, X

where

LaTeX Math Inline
body

ZZ-factor

LaTeX Math Inline
bodyT

fluid temperature

\mu_g

cpDynamic gas viscosity 

LaTeX Math Inline
body

--uriencoded--

T

_%7Bpr%7D = T/T_%7Bpc%7Dpseudo-reduced temperature 
(or reduced temperature

°RankineNatural Gas Temperature 

LaTeX Math Inline
body

--uriencoded--T_%7Br%7D in case of pure substances)

\rho_g

g/ccNatural gas density

LaTeX Math Inline
body

--uriencoded--T_%7Bpc%7D

 pseudo-critical temperature 
(or critical temperature 

LaTeX Math Inline
body--uriencoded--T_%7Bc%7D
 in case of pure substances)

LaTeX Math Inline
bodyP

fluid pressure

LaTeX Math Inline
body--uriencoded--P_%7Bpr%7D = P/P_%7Bpc%7D

pseudo-reduced pressure 
(or reduced pressure 

LaTeX Math Inline
body--uriencoded--P_%7Br%7D
 in case of pure substances)

LaTeX Math Inline
body--uriencoded--P_%7Bpc%7D

 pseudo-critical pressure 
(or critical pressure 

LaTeX Math Inline
body--uriencoded--P_%7Bc%7D
 in case of pure substances)

and

...

LaTeX Math Inline
bodyA_1 = 0.31506237

...

LaTeX Math Inline
bodyA_2 = -1.0467099

...

LaTeX Math Inline
bodyA_3 = -0.57832729

...

LaTeX Math Inline
bodyA_4 = 0.53530771

...

LaTeX Math Inline
bodyA_5 = -0.61232032

...

LaTeX Math Inline
bodyA_6 = -0.10488813

...

LaTeX Math Inline
bodyA_7 = 0.68157001

...

LaTeX Math Inline
bodyA_8 = 0.68446549


The model range and statistical metrics:

Application range


Temperature100 °F ÷ 340 °F

Pressure100 psi ÷ 8,000 psi
Accuracy


AAPE2.7%


See also

...

Petroleum Industry / Upstream / Subsurface E&P Disciplines / Fluid (PVT) Analysis / Fluid (PVT) modelling / Dynamic fluid viscosity / Dynamic fluid viscosity @model

See also

Natural Science / Physics /Thermodynamics / Natural Gas Viscosity / Z-factor Correlations @modelgas viscosity correlations

Reference

...

Lee, A. L., Gonzalez, M. H., & Eakin, B. E. (1966). The Viscosity of Natural Gases. Journal of Petroleum Technology, 18(08), 997–1000. doi:10.2118/1340-PA (https://doi.org/10.2118/1340-PA)

...