Page 97 - PVT Property Correlations

Wet Gases Chapter | 4 75

TABLE 4.7 Reservoir Gas Specific Gravity Comparison for the Two
Example Fluids
Method Sample 1 Sample 2
Composition data 0.950 0.780
CGR data 0.997 0.770
Separator data 1.020 0.770
CGR, condensate gas ratio.

TABLE 4.8 Results of z-Factor and Gas Formation Volume Factor for the
Two Example Fluids
Parameter Unit Option Sample 1 Sample 2
From gas 1.503 1.052
composition
z-Factor Dimensionless From CGR 1.510 1.067
From separator 1.549 1.067
conditions
From gas 0.00282 0.00406
composition
Gas formation rcf/scf From CGR 0.00284 0.00412
volume factor
From separator 0.00273 0.00412
conditions

Solution of Problem 2
Using the three reservoir gas specific gravity values obtained for the two
gases, the procedures of the Dry Gases Chapter are followed to compute
pseudocritical pressure and temperature with the procedure of Piper et al.
(1993). The pseudoreduced pressure and temperature are calculated using the
initial reservoir pressure and reservoir temperature. The technique of
Dranchuk and Abou-Kassem (1975) for z-factor calculation is then applied.
The gas formation volume factor is calculated by the equation from the Dry
Gases Chapter. The important results for these calculations are summarized
in Table 4.8.
The variation of the two gases z-factors and formation volume factors are
not significant between the different approaches. The z-factor variation for