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Figure 4.5 - Focal flooding: 1 – drilled well

Pattern flooding. Pattern flooding most intense action on
the layer system, which ensures the on-highest rate of
development. In the USSR, flooding was started in 1943 in the
fields of Kazakhstan - Dosor and Makati. This system of flooding
is used to develop reservoirs with very low permeability.
Efficiency pattern flooding depends on the heterogeneity of the
reservoir, the reservoir thickness, viscosity of the oil and the depth
of the deposit. A feature of this system of flooding is the
placement production and injection wells evenly on the area.
Water injection is performed through the injection wells that are
placed with production wells and between them hold the same
distance. Pattern flooding systems used for experimental works to
enhance oil recovery. Pattern flooding can be effectively used in
the early stages of development under good learning geological
feature of the reservoir. In this system producing and injection
wells are placed at the uniform grids. There are four-, five-, seven-,
and nine- systems. Formulas for definition flowrates and validities
for each of these systems.
Selective flooding. Selective flooding is a form of
pattern flooding, which is used in oil fields with significant
heterogeneity as the focal flooding.

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