Question

A brine is used to measure the absolute permeability of a core plug. The rock sample is 4 cm long and 3 cm 2 in cross section. The brine has a viscosity of 1.0 cp and is flowing a constant rate of 0.5 cm3/sec ( cube centimeter per second) under a 2.0 atm pressure differential.

Calculate the absolute permeability.

Answer 1

Answer : The absolute permeability is, 0.111 darcys.

Explanation : Given,

Volumetric constant rate =
`0.5cm^3/s`

Cross section area =
`3cm^2`

Pressure = 2 atm

Viscosity = 1.0 cp

Length of rock = 4 cm

From the Darcy equation we conclude that,

`\text{Volumetric constant rate}=\frac{(\text{Absolute permeability}* A* P)}{\eta * l}`

where,

A = cross section area

P = pressure

`\eta` = viscosity

l = length of rock

Now put all the given values in the above formula, we get:

`0.5cm^3/s=\frac{(\text{Absolute permeability}* 3cm^2* 2\text{ atm})}{1.0cp * 4cm}`

`\text{Absolute permeability}=0.111\text{ darcys}`

Therefore, the absolute permeability is, 0.111 darcys.