IDENTIFICATION OF TYPE OF RESERVOIR FLUID - Petroleum Reservoir Fluid Property Correlations - page 195

are valid. 5 In fact, figure 5-3 validates the distinct transition point of
an initial producing gas-liquid ratio of 3,200 scf/STB for the difference
between volatile oils and gas condensates. The data points on figure 5-3
indicate the laboratory observed dew points or bubblepoints at reservoir
temperature. Virtually all the data above the horizontal dashed line
exhibit dew points, i.e., the reservoir fluids are gases. Virtually all the data
below this line exhibit bubblepoints, i.e., the reservoir fluids are liquids
(oils). There are only two samples with bubblepoints and three samples
with dew points that do not fit this pattern. Thus, an initial producing
gas-liquid ratio of 3,200 scf/STB represents a precise transition from gas
condensates to volatile oils.

5000

4500

4000

3500

3000

2500

2000

10 11 12 13 14 15

Composition of Heptanes Plus In Reservoir Fluid, mole %

Laboratory observed dewpoint Laboratory observed bubblepoint

Fig. 5-3. Volatile oils and gas condensates—what's the difference? Data from 130 reservoir
fluid studies.