Page 378 - Fundamentals of Reservoir Engineering

NATURAL WATER INFLUX 313

PRESSURE
(psia)
p =2740
2700 i
2620

2500 p =2500
1
2395
2300 p =2290
2
2199
2100 p =2109
3
2029
p =1949
4
1900
1883
p =1818
5
1760
1700 p =1702
6
1655
p =1608 1571
7
1500 p =1535 1507
8
p =1480 1460
9
p =1440
10
1300
0 1 3 4 5 6 7 8 9 10
TIME (years)

Fig. 9.14 Reservoir pressure decline approximated by a series of discrete pressure
steps; exercise 9.2

Interpreted Data

Fig. 9.14 shows a more detailed graph of the continuous pressure decline which has
been approximated by 10 annual pressure steps, as described in the text. The
magnitude of the ∆p's can be calculated, using equs. (9.15) and (9.16), as shown in
table 9.2.