Environmental Engineering Reference
In-Depth Information
Production well
Injection well
Figure 5.14
Schematic of model reservoir (Christie and Blunt, 2001) and well locations
different cases were considered and developed in the oil recovery graph:
(i) only pressure gradient was applied to the reservoir, (ii) electrical gradi-
ent was superimposed on top of pressure gradient (i.e. both pressure and
electrical gradients were applied to the reservoir).
As observed in figure 5.15 (a), after 100 days, the water has gradually
displaced oil toward the production well, but most sections of the reser-
voir are still filled with oil. The fractional flows of oil and water are 1 and 0
respectively, which means all of the production at this stage is oil and the
water has not reached the production well yet. Looking at the oil recovery
changes versus water injected pore volumes, only about 5% of the original
oil in the reservoir has been extracted. Also, there is no discernible differ-
ence in the oil recovery between the two cases of with and without applied
electrical gradient after 100 days. This is attributed to the fact that most of
the reservoir is still filled with oil and the water saturation has not reached
the minimum value to activate the EO flow of water and consequently the
contribution of EO generated viscous drag of oil.
After about 650 days, the water has reached the production well and
the fractional flow of water drops while that of oil increases at the same
time as observed in figure 5.15 (b). At this stage, the water is displacing
the oil in most parts of the reservoir and only about 25% of the original
oil is recovered. As observed in the oil recovery profile, the contribution
of applied electrical gradient is about 4% increase in the oil recovery after
700 days. After 2500 days, the water has filled most parts of the reservoir
and the fractional flow of water is about 0.9 and that of oil is about 0.1 as
observed in figure 5.15 (c). About 50% of the original oil in the reservoir is
recovered with the combined gradient application, to which the contribu-
tion of applied electrical gradient is about 7% increase in the oil recovery.
Search WWH ::
Custom Search