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VA – GP - OA: Numerical Multiphase PTA
p 18/29
Figure
24: Production phase for R=5,000 ft, k=100 mD
GOR Analysis
We have seen that although the loglog plot exhibits some oscillations during the production
phase, its global trend can be interpreted in terms of fluid mobility. Let us now focus on the
evolution of the produced GOR.
For mild depletion (R=50,000 ft, k=100 mD), we have seen that the expansion of the gas
bubble in the vicinity of the well was leading to strong oscillations on the pressure derivatives
(Figure 18). These oscillations also appear on the GOR, as shown on Figure 25. This is a direct
consequence of the transient nature of the flowing composition downstream of a saturation
front cell, as was explained in section 3.2 (Figure 19). Note that the vertical scale was greatly
increased in order to magnify this effect on Figure 25.
Figure 25
: Evolution of the rates during production phase (R=50,000 ft, k=100 mD)
0.01
0.1
1
10
100
1000
10000
Time [hr]
100
1000
10000
3600
4100
4600
Pressure [psia]
0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000
Time [hr]
10000
10040
Liquid rate [STB/D]
15090
15140
15190
Gas rate [Mscf/D]
Liquid rate
Gas rate
Simulated qo
Simulated qg