Page 37 - Standard Handbook Petroleum Natural Gas Engineering VOLUME2

Basic Principles, Definitions, and Data 25

0
n
3 300
2 0.5 0.6 0.7 0.8 0.9 I .O 1.1 1.2
GAS GRAVITY (air = I)

Figure 5-20. Pseudo-critical properties of natural gases [3].

[28] for compressibility of an undersaturated 6il in Figure 5-21 can be used in
a similar fashion as previously discussed for cg. Pseudo-critical temperature and
pressure can be estimated from Figure 5-22 or 5-23. With the pseudo-reduced
compressibility from Figure 5-2 1, oil compressibility can be estimated:

C" = - (5-15)
CPr
P PC
For conditions below the bubblepoint, dissolved gas must be taken into account.
In the absence of laboratory data, the changes in R, and Bo with changes in