Question

How do you calculate absolute permeability from the darcy equation?

Answer 1

Absolute permeability:

1. It is a measurement of a fluid's ability to pass through porous rock.
2. When there is complete permeability. It is considered that a rock's pore spaces contain just one kind of fluid.
3. The relative permeability of a rock is then determined using the absolute permeability value, which assumes synchronous fluid flow in the rock's pore spaces.

Step 1: Absolute permeability from the darcy equation:

1. The Darcy equation, which is given as Darcy's equation for linear flow below, is the one that is most frequently used in oil and gas fields to determine permeability in porous media:
   $\Rightarrow \mathrm{q}=-\frac{\mathrm{Ka}}{\mathrm{\mu }}\frac{∆\mathrm{p}}{∆\mathrm{L}}$
2. In a laboratory experiment, viscosity is passed through a core sample at a predetermined flow rate and differential pressure in order to estimate the absolute permeability of a fluid.
3. Once all the requirements have been met, the absolute formula equation shown above is used to get the permeability value. Figure1 depicts this experiment's straightforward setup.

Step 2: Further solution of darcy equation for absolute permeability,

When stated in field units, the above-written Darcy Equation formula for absolute permeability becomes,

$\Rightarrow \mathrm{q}=-1.127\times {10}^3\frac{\mathrm{kA}}{{\mathrm{\mu B}}_0}\frac{∆\mathrm{p}}{∆\mathrm{L}}$

Where,$\mathrm{q}$= flow rate,$\mathrm{k}$= permeability,$\mathrm{A}$= cross-sectional area to flow,$\mathrm{\mu }$= viscosity,$∆\mathrm{p}$= pressure difference,$∆\mathrm{L}$= Length of the fluid path