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,

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

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:

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

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

Therefore, the absolute permeability is, 0.111 darcys.