Page 316 - Standard Handbook Petroleum Natural Gas Engineering VOLUME2

Fluid Movement in Waterflooded Reservoirs 283

Table 5-39
Areal Sweep Efficiency at Breakthrough (M = 1)
Type of pattern E,, % 12791 E,, % [2771*
Direct line drive (d/a = 1) 57.0 57
Direct line drive (d/a = 1.5) 70.6 -
Staggered line drive 80.0 75 (d/a = 1)
5-spot 72.3 68-72
7-spot 74.0 74-82
9-spot diagonal/directional rate
0.5 49
1 54
5 69
10 78
~ ~ ~ ~
From Reference 133.
Based on summary of data presented by Craig.
are very useful. Recently, Fassihi [291] provided correlations for the calculation
of areal and vertical sweep efficiencies. For these correlations of areal sweep,
the data of Dyes, Caudle, and Erickson [281] were curve-fitted and the resulting
equation was:
'-

= [a, ln(M + as)+ a,]f, + a4 In(M + a,)+ as (5-220)
E,

where E, is the -areal sweep efficiency which is the fraction of the pattern area
contacted by water, M is the mobility ratio, and the coefficients are as listed in
Table 5-40 for the 5-spot, direct line drive, and staggered line drive. These
coefficients are valid both before and after breakthrough, and apply to mobility
ratios between zero and ten, which is within the range observed in many
waterfloods. For the 5-spot pattern, these values of E, are generally higher than
in later experiments, and a correction has been suggested by Claridge [292] that
should be multiplied by the E, from the Dyes et al. data:

E, = EPPd
{M0.5 -[(M - 1)(1- Ep/V,)]0.5}' (5-221)

Table 5-40
Coefficlents in Areal Sweep Eff lclency Corretatlons
Coefficient 5-SpOt Direct line drive Staggered line drive

a, - 0.2062 - 0.3014 - 0.2077
a2 - 0.0712 - 0.1568 - 0.1059
- 0.511 - 0.9402 - 0.3526
a3
a4 0.3048 0.3714 0.2608
a5 0.123 - 0.0865 0.2444
a, 0.4394 0.8805 0.3158
From Reference 291.