Page 47 - PVT Property Correlations

Reservoir-Fluid Classification Chapter | 2 27

43,478 scf/STB primary separator gas oil ratio
20% C7 1 mole %
1.2% C7 1 mole %
Fluid with field stock-tank oil gravity of 53 API and initial produc-

ing gas oil ratio of 5440 scf/STB
Fluid with API gravity of 17 and oil-formation volume factor at the
bubblepoint pressure of 1.01 bbl/STB
2.5 Identify the fluid type for the following fluid samples based on the
given compositional data and initial producing gas-oil ratio.
Sample 1 Sample 2 Sample 3 Sample 4 Sample 5
5.6 5.13 7.65 0.92 0.01
CO 2
0.6 0.67 0.27 0.22 0.35
N 2
C1 68.21 75.28 84.11 58.77 34.61
C2 7.1 8.19 5.79 7.57 4.12
C3 3.89 3.99 1.19 4.09 1
iC4 0.8 0.7 0.18 0.91 0.75
nC4 1.7 1.5 0.26 2.09 0.49
iC5 0.7 0.5 0.09 0.77 0.43
nC5 0.8 0.6 0.07 1.15 0.21
C6 1.51 0.72 0.07 1.76 1.62
C7 1 9.2 2.66 0.32 21.75 56.3
C7 1 MW 242 140 157.7 227 276
GOR, scf/STB 5000 3300 120,000 1489 300
2.6 Consider an existing producing gas reservoir whose initial reservoir
pressure is 5000 psi. Initial producing gas oil ratio is 99,000 scf/STB.
Identify the fluid type. Also, assess if there could be any expected liquid
dropout in the reservoir or on the surface.
2.7 Well X (shown below) is a discovery well in a field in north Africa. It was
discovered in 2012 and has production data given in the following two fig-
ures. The produced stock-tank liquid was initially yellowish with gravity
of 55 API.