Page 382 - Fundamentals of Reservoir Engineering

NATURAL WATER INFLUX 317

2) Material Balance Calculation

F = N p (B o + (R p - R s)B g)

E o = ((B o - B oi) + (R si - R s)B g)

Time F E o F/E o W e/E o W e/E o
(years) (MMrb) (rb/stb) (MMstb) (r eD = 10) (r eD = 5)
1 12.124 .0268 452.4 142.9 140.9
2 30.761 .0574 535.9 234.5 223.8

3 52.826 .0.923 5.72.3 286.7 260.3
4 79.798 .1411 565.5 297.2 253.5
5 105.964 .1881 563.3 314.8 251.3
6 132.292 .2380 555.8 326.2 243.8
7 157.080 .2862 548.8 338.2 236.8
8 179.177 .3299 543.1 352.5 231.2
9 196.654 .3630 541.7 373.6 229.7
10 210.743 .3895 541.1 396.4 229.1
TABLE 9.6

The plot of F/E o versus W e/E o, fig. 9.15, shows that the trend deviates below the
theoretical 45° line after the first year. This indicates that the correct value of r eD should
be somewhat smaller. The calculation has therefore been repeated with r eD=5.

3) Calculation of W e for r eD = 5.

Values of We for r eD=5 are listed in table 9.7. These have been calculated using the W D
values listed in column 5 of table 9.4.