Page 194 - PVT Property Correlations

168 PVT Property Correlations

Solution of Problem 1
The correlation inputs are
GOR 5 600 scf/STB as Separator GOR.
For calculating the Stock-Tank GOR

Separator pressure 5 200 psig
Separator temperature 5 75 F

Stock-tank API 5 40.4
Separator gas Sp. Gr. 5 0.82.
Reservoir temperature 5 217 F

Note: Stock-tank API gravity and separator gas gravity are used for cal-
culation of both the stock-tank GOR and other black-oil fluid properties.

Stock-tank GOR 5 147 scf/STB (from Valko and McCain, 2003
correlation)
Total GOR 5 747 scf/STB.

Problem 2—Calculation of PVT Properties for a Black Oil

A PVT report on a representative fluid sample is available for the fluid in
Problem 1. Use the correlation input data of Problem 1 to estimate bubble-
point pressure from selected correlations of the ones given in Appendix A,
Oil Correlations Formulae (Standing, 1947; Al-Marhoun, 1988; and McCain,
1991). Compare the calculated bubble-point pressure to the measured value
of 2635 psia.
Also calculate oil formation volume factor, solution GOR, oil density, oil
viscosity, and oil compressibility using Standing (1947), Al-Marhoun (1988),
and latest McCain correlations (when applicable) at the bubble-point pres-
sure, and compare the calculated values to the actual measured values from
the PVT report:
Measured values from the PVT report are given below.
Oil formation volume factor 5 1.48 rbbl/STB
Solution GOR 5 780 scf/STB
Oil density 5 41.0 lb/ft 3
Oil viscosity 5 0.373 cp
Oil compressibility 5 18.8E 26 psi 21

Solution of Problem 2
Separator GOR 5 600 scf/STB. At the given separator conditions, the stock-
tank GOR is estimated to be 127 scf/STB from Valko and McCain (2003)
correlation (Appendix A: Oil Correlations Formulae).