Page 121 - PVT Property Correlations

Gas Condensates Chapter | 5 99

Pressure
temperature

R (Initial producing CGR) R (Initial producing CGR)
vi
vi
2 Stages 3 Stages full
T sep and P sep T sep and P sep 1st, 2nd
Gas Sp.Gr Sep. Gas Sp.Gr Sep. 1st, 2nd
ST API ST API

Pd from Pd from
Pd unknown Pd known
basic inputs composition

Properties:
OFVF
GFVF
R s
R v

FIGURE 5.8 Flow chart for MBO PVT properties’ calculations for gas condensates. MBO,
modified black oil.

Accurate description of the behavior of gas condensate reservoirs below dew
point pressure is important, as the economic value of the gas decreases with
reservoir depletion. This decrease is due to the fact that gas becomes leaner
with less producing CGR. The following sections discuss the properties
required for engineering gas condensate reservoir fluids.

Dew Point Pressure

Dew point pressure can be estimated at any temperature from the dew point
correlations of Appendix B, Gas Correlations Formulae. Several correlations
are available and these require either the surface gas specific gravity or gas
composition. All dew point correlations use surface information except
Alzahabi et al. (2017) correlation, which uses the compositional information
from downhole fluid analyzer tools to calculate dew point pressure.