Definition – What does Annular Blowout Preventer (Annular BOP) mean?
Annular Blowout Preventer is a large valve that is used to control the well fluids. The sealing element in this kind of valve resembles the large rubber donut which mechanically squeezes inward and seals the drill string, open hole, casing, pipe or any non-cylindrical object like the Kelly. It is efficient in maintaining a seal around drill pipes even when it rotates during the drilling process. The Annular Blowout Preventer can seal a variety of pipes of different sizes unlike the ram blowout preventer.
Petropedia explains Annular Blowout Preventer (Annular BOP)
The Annular Blowout Preventer works on the principle of a wedge to shut in the well. It consists of a rubber seal which is donut-like and is called elastomeric packing unit, which is strengthened with steel ribs. Most of the blowout preventer stacks consist of at least one Annular Blowout Preventer at top of the stack and one or more ram blowout preventers below. The preventer performs following functions:
- It seals the annular between the casing, tubing, and drill pipes.
- It seals the hole when drill pipes, casing or tubing are out from the hole.