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The absolute pressure at the entrance of the rock sample P is
1
determined by the equation (3.4). The absolute pressure at the exit of

the sample P is equal to atmospheric pressure P . Atmospheric
atm
2

pressure is measured by barometer. Volumetric flow rate of gas (air)
under atmospheric pressure Q gas s.c. is determined by the following
equation:
V gas
Q gas s.c.  , (3.6)

3
where V is volume of gas (air), m ;  is the time of air passing
gas
through the sample, s.

3.4 Procedure and calculations

3.4.1 Measure the length and the diameter of the core and insert it
into the core holder.
3.4.2 Switch on the compressor and wait for stable air filtration

through the rock sample for 5 – 6 minutes.
3.4.3 Conduct the experiment. It is necessary to put 6 – 7 regimes
with different pressures and note the surplus pressure at the inlet of

/
core holder P and the time of air passing through the sample  for
1
each regime.
Note the volume of gas (air) which pass through the rock sample.

Calculate inlet absolute pressure P by the equation (3.4) and the
1
volumetric flow rate of gas (air) under atmospheric pressure Q gas s.c. by

the equation (3.6).
Note the temperature of air under conditions of the experiment.

3.4.4 Put the results of experiments into table 3.1.

3.4.5 Calculate permeability coefficient for gas (air) k рer.g. for each

regime by the equation (3.5) and the average permeability coefficient
for gas (air).

2
3.4.6 Draw the graph of dependence Q  P ( f 2  P (for control
)
gas s.c. 1 2
of the linearity of the flow).
3.4.7 Viscosity of air under different temperatures is given in

table 3.2.
3.4.8 Draw the conclusion.

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