# Geophysics : compute the permeability of a 3D Porous medium

Has somebody documented the values entered as inputs and the outputs? What units do they have? How to convert them to SI units?

What values are you talking about?

In what unit is the permeability output displayed?

You mean in the tutorial? It is in lattice units. To convert units you may want to look at the chapter 7 of the book https://www.springer.com/gp/book/9783319446479

From the book, “The lattice constant deltax is the distance between neighbouring lattice nodes in physical units (in m)”. Does this depend on the input dataset resolution or has some default values in Palabos? This is my actual doubt. If its value is equal to the distance between two pixels, then my outputs are way out of bounds.

there is no default value. it does depend on your resolution. say your domain in SI is 10^{-2}m and you have 50 lattice nodes delta x = 10^{-2} / 50.

When using the permeability code, everything you give is in lattice units. so you have to do the conversion by hand depending on your geometry.