Applications for Annual Seals

I use mine once every year.

Why do people insist on making us say these things?

Rephrase my question.

What applications would you use annular seals?

Rabat:

One use for annular seals is in the petroleum industry when oil wells are drilled. The seals are placed at the top of casing string between the casings to prevent pressure from migrating from one annulus to the other. There are several reasons for this: 1) There are different pressure ratings on each string of casings, usually the casing with the lower pressure rating is the outside casing. The smallest is the highest rated. The smallest casing is usually in contact with the highest pressures found in the wellbore and is usually called the production casing. The seal on this string of casing protects the production-intermediate casing annulus from being energized with wellbore pressures. 2) The production tubing-production casing annulus is sometime pressurized with natural gas (or other gas) to be used as gaslift gas (to assist oil prodution). The again, the production casing-intermediate casing annulus is protected by the seal at the top of the production casing string.

By the way, in this application, the seals are located in the well head assembly, otherwise known as the christmas tree.

Other application for annular seals is in hydraulic or pneumatic rams.