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LABORATORY EXPERIMENT № 3

DETERMININATION OF ABSOLUTE PERMEABILITY

COEFFICIENT OF ROCKS (CORES) FOR GAS
BY MEANS OF GC-5 (ГК-5) DEVICE

3.1 The objective of the experiment is: to study the concepts
of permeability of rock, permeability coefficient and to determine
the absolute permeability coefficient of the rock sample for gas.

3.2 Definitions

Permeability is a property of rock to transmit fluid (liquid or gas)

under pressure difference. There are three types of permeability:

absolute, effective and relative permeability.
Absolute permeability is permeability of the porous medium
for the fluid (liquid or gas) which is chemically inert relatively to the

porous medium under condition that it is completely saturated (100 %
saturated) with this fluid. Effective permeability is permeability of

the porous medium for the fluid (liquid or gas) under condition that

the porous medium is occupied by more than one fluid. Relative
permeability is the ratio of effective permeability of the porous

medium for a particular fluid at a particular saturation to absolute
permeability of the porous medium for this fluid at total saturation.

Absolute permeability is the property of rock and it does not
depend on the properties of filtered liquid or gas if there is no

interaction of fluid with rock. The magnitude of effective permeability
depends not only on physical properties of rocks but also on the

degree of saturation of pore space by liquids or gas and on their

physical and chemical properties.
Permeability is also classified by the type of fluid which flows
through the porous medium. There is rock permeability for liquid
(water, oil) and for gas (natural gas, air).

To determine absolute permeability, gas (natural gas, air, N , He)
2
is usually used. It was established that when liquid flows in the porous
medium its permeability is influenced by physical and chemical
properties of liquid (clay particles swell in water, resins plug pores).

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