What is the difference between porosity and permeability?

Porosity refers to the measure of the void spaces within a rock or any other porous media, such as soil. In other words, it is the amount of empty space between the solid particles in a geological medium. Porosity is usually expressed as a percentage, indicating the ratio of the volume of void spaces to the total volume of the material.

Permeability, on the other hand, is the measure of a geological medium's capability to transmit fluids, such as water, oil, or gas, through the interconnected pore spaces (voids) within the material. It is usually measured in units called Darcy or milliDarcy (1 Darcy = 0.987 μm²).

Both porosity and permeability are essential properties that control the flow of fluids through rocks and other porous media. While porosity determines the amount of fluid that a medium can potentially store, permeability defines how readily a fluid can move through the pore spaces.

The main differences between porosity and permeability are as follows: 1. Porosity is the measure of void spaces or the amount of empty space within a geological medium, whereas permeability is the measure of the medium's ability to allow fluid flow through its interconnected void spaces. 2. Porosity is expressed as a percentage, whereas permeability is often measured in units called Darcy or milliDarcy. 3. Porosity focuses on the storage capacity of a porous medium, while permeability evaluates the ease of fluid movement through the medium. In summary, porosity and permeability are two different properties relating to the void spaces within geological media. Porosity quantifies the amount of empty space or storage capacity, and permeability measures the ease of fluid flow through the interconnected pore spaces of the medium.