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Edge flooding. Edge flooding is used for developing
small deposits of oil reserves. Maintenance of pressure by edge
flooding is effected by injecting water into special wells located
outside the drainage boundary or the oil-bearing contour (external
WOC) on a distance 100-1000 m (Fig. 4.2).

3
/
1
/

2
/
4

Figure 4.2 – Edge water flooding: 1 – external oil-bearing
contour (external WOC); 2 – internal oil-bearing contour (internal
WOC); 3 – injection wells; 4 – production wells

Inasmuch as water injection creates an artificial external
drainage boundary in closer proximity to the producing zone, we
have the question about concerning the optimal distance between
the injection and recovery wells. Increasing the distance between
the injection and recovery wells is good practice because the high-
pressure gradients, what create near the injection wells don`t affect
for shape of the drainage boundary and don`t cause fingering.
However, if the distance between recovery and injection wells is
more than 1.5-2 kilometers, the artificial drainage boundary is not
very effective.
Now is a water flooding is rare.

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