# Air Permeability - Air Permeability The principle of the...

This preview shows pages 1–4. Sign up to view the full content.

A ir P ermeability The principle of the test is that air is drawn through a specified area of fabric. The rate of airflow is adjusted until a specified pressure difference between the two fabric surfaces ( face and back ) is achieved. The airflow is measured and the air permeability is calculated. Permeability needs to be measured, either directly ( using Darcy's law ) or through estimation using empirically derived formulas. A common unit for permeability is the Darcy (D), or more commonly the millidarcy (mD).

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
(1 Darcy 10 −12 m 2 ) Other units are cm 2 and the SI m 2 . Permeability is part of the proportionality constant in Darcy's law which relates discharge ( flow rate ) and fluid physical properties ( e.g. viscosity ) , to a pressure gradient applied to the porous media. For a rock to be considered as an exploitable hydrocarbon reservoir without stimulation, its permeability must be greater than approximately P A L q K
C lassification o f P ermeability A bsolute P ermeability

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern