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1) surface water (from rivers and lakes);
2) upper water horizons;
3) water formation of oil-bearing horizons;
4) lower water horizons.
Only a few cases of water supply sources may be eligible
for flooding without preparation. In most cases, have to start
preliminary preparation of water.
In water treatment, depending on the need to perform the
following steps: 1) remove the oil; 2) aeration; 3) sterilization; 4)
stabilization of water; 5) coagulation; 6) defending; 7) filtering.
The suitability of water used for injection into reservoirs
usually determined in the laboratory by filtering water through the
core. Water is considered suitable for injection into reservoirs if
the permeability of the core remains constant. Reliable data on the
quality of water used for flooding and about the optimum pressure
at the line injection can only be the result of water injection test
into oil deposits.
The injected water into deposit pose the following
requirements:
1. Water must not enter into a chemical reaction with
formation waters, because of the possible loss of sediment and
pore sealing layer.
2. The number of solids in water should be small because it
can lead to contamination of the wellbore zone and loss
acceleration of well. The content of impurities in the water taken
from the experience of pumping water.
3. Water shall not contain impurities hydrogen sulphide and
carbon dioxide, in order not to cause corrosion of the surface and
underground equipment.
4. Injected water should not cause swelling of clay particles,
leading to clogging of pores in the reservoir and fracture wellbore
zones.
5. Water used for injection should be subjected to biological
treatment cultivation from microorganisms.

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