Page 399 - Standard Handbook Petroleum Natural Gas Engineering VOLUME2

Production Engineering

PROPERTIES OF HYDROCARBON MIXTURES
This section contains correlation and procedures for the prediction of physical
properties of natural gas and oil. Physical constants of single components are
given in Table 6-1.

Compressibility Factor and Phase Behavlor

The compressibility factor Z is a dimensionless factor independent of the
quantity of gas and determined by the character of the gas, the temperature,
and pressure.
PV
z=-=- MPV
nRT mRT
Field Units SI Unlts
P = absolute pressure psia kPa
V =volume fP ma
n =moles m/M dM
m =mass Ib kg
M = molecular mass Ibhb mole kg/kmole
T = absolute temperature "R K
R = universal gas constant 10.73 [psia 8.3145 [kPa
fWoR Ib mole ms/kmol K]
mole]
p =density slugm3 wm5

A knowledge of the compressibility factor means that the density p is also
known from the relationship

p=- PM
ZRT
Compresslbillty Factor Using the Prlnclple
of Correspondlng States (CSP)

The following terms are used, P, T and V, such that
T
P
p =-, T, =-, v, =- V (6-3)
pc Tc vc
where P, Tr and Vr = reduced parameters of pressure, temperature and volume
P, Tc and Vc = critical parameters of P, T and V from Table 6-1
(tat continued on page 368)

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