Environmental Engineering Reference
In-Depth Information
All simulations have been made on a three-dimensional model. Figures 14.9 and
14.10 show that the reservoir compaction reduces GOR and WOR of equations
[14.22] and [14.23] at the surface, hence there is higher oil recovery. It must be kept
in mind that compaction at reservoir level implies surface subsidence, as shown in
Chapter 7. The average pressure drop
versus
production time for different values of
Young's modulus is shown in Figure 14.11. This indicates that the reservoir rock
compaction, which occurs during oil production, has reduced the average pressure
drop in the reservoir system. Hence the simplifying assumption of rigid rocks may
give the wrong results.
4000
E = .9631E+10
E = .9631E+08
E = .9631E+06
2000
0
0
100
200
300
400
Production time (days)
Figure 14.9.
Gas
−
oil ratio (GOR, equation [14.22]) versus time for different reservoir rocks
(redrawn with permission from [LEW 98b])
40
E = .9631E+10
E = .9631E+08
E = .9631E+06
20
0
0
100
200
300
400
Production time (days)
Figure 14.10.
Water cut (WOR, equation [14.23]) versus time for three different reservoir
rocks (redrawn with permission from [LEW 98b])
