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Technical characteristics of the closed type sampler PSS-300
(ВПП-300) are following: the working pressure is 30 MPa; the
working temperature is 100 °С; the volume of the sample of oil taken
3
out of the well is 300 сm ; diameter is 38 mm; the length is 1800 mm;

the mass is not bigger than 9 kg.
The advantages of the bottom hole sampler of flowing type BS-
3M (ПД-3М) are it’s simplicity and the reliability in operation. The

main disadvantage of this sampler is considerable variation of time

delay.

10.2.2 Peculiarities of the oil bottom hole sampling

There are the samplers which are used for lifting the samples up
from the flowing and gas-lift wells and from pumping wells (through

the annular space).
Flowing samplers are recommended for lifting the samples of oil
up from the wells with high productivity and in the case of low

viscosity of oil. In the case of high viscosity of oil and low
productivity of well there are difficulties at oil sampling by flowing
devices. These difficulties are connected with the complexity of

the displacement of the mixture which entered the sampler before
with the bottom hole sample. The reason for it is the changeability
of the sampler’s entrance holes plugging. That is why for high
viscosity oil sampling from the wells with low production rates

closed type samplers are used. The devices of this type are put down
to the bottom hole with the closed valves (the valves are opened on
the bottom hole). It allows to take the most reliable sample of oil.

It is better to take out the downhole oil samples at the beginning
of the field development.
The technique (method) of sampling depends on the field
drive. If the formation pressure exceeds the saturation pressure

considerably, sampling the quality sample does not cause difficulties.
If bottom-hole pressures are lower than the saturation pressure
when gas is released from oil only in the bottom-hole formation zone,

then before sampling, it is necessary to change the production
conditions of the well thus, that the bottom-hole pressure at the new
production conditions exceeds the saturation pressure. So for

sampling the high-quality sample of oil it is necessary that the single-

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