Page 209 - PVT Property Correlations

Chapter 8

Low Gas Oil Ratio Oils

Low gas oil ratio (GOR) oils are black oils that contain a low amount of
solution gas. They have low bubble point pressures that may never be
reached in the reservoir under practical operating conditions. These oils pro-
duce with low GOR that can be considered constant (since the reservoir pres-
sure remains above the bubble point pressure for nearly the entire life of the
reservoir). Low GOR oils are not necessarily heavy oils as they sometimes
have reasonably low viscosity and can flow easily under normal conditions
of temperature. Despite the low GOR, these oils may have high stock-tank
oil API gravity. Fig. 8.1 shows a plot of bubble point pressure versus total
producing GOR for oil samples collected from worldwide origin and repre-
senting different types of oils (each point represents an oil sample with full
PVT report).
Fig. 8.1 shows that the bubble point pressure is proportional to the initial
solution GOR. It also shows that the bubble point pressure is generally below
1000 psia for oils with solution GOR less than 150 scf/STB. At these levels
of low GOR, the field measurements of gas production may not be available.

FIGURE 8.1 Bubble point pressure versus solution GOR for oil samples. GOR, gas oil ratio.

PVT Property Correlations. DOI: https://doi.org/10.1016/B978-0-12-812572-4.00008-4
© 2018 Elsevier Inc. All rights reserved. 183