Annular preventers are the most versatile well control equipment and there are many names referring it as bag preventers, or spherical preventers. The annular preventers are able to seal around several size of drill pipe/drill collar, work string, wireline, tubing, etc. There are some models which can utilize wellbore pressure to provide additional sealing capability.
The annular preventer consists of a body, a cap, a piston and a rubber packing element. The illustration below demonstrates the drawing of an annular preventer.
How the annular preventers work?
Close – When the hydraulic oil is pumped into the extend port, the element inside will be lifted and squeezed the pipe/tubular.
Open – On the other hand, if the hydraulic fluid is pumped into the retract port, the element will be pushed down resulting in releasing the tubular.
The following videos will help you understand how the annular preventer work.
Nowadays, there are several manufactures providing this equipment such as Hydril, NOV (Shaffer) and Cameron. The models available in the market based on the manufactures are listed below:
Hydril – Hydril GL, GX, GK and Annu-Flex

Hydril GL
http://hydrilpressurecontrol.com/pressureControl/BOP/annulars/annular-GL.php

Hydril GK
http://hydrilpressurecontrol.com/pressureControl/BOP/annulars/annular-GK.php

Hydril Gx
http://hydrilpressurecontrol.com/pressureControl/BOP/annulars/annular-GX.php

Hydril Anuflex
http://hydrilpressurecontrol.com/pressureControl/BOP/annulars/annular-Annuflex.php
Cameron – Cameron DL

Cameron DL
http://www.c-a-m.com/forms/Product.aspx?prodID=ecd6ef4e-19dc-4ea9-ad47-94689e36b61c
NOV (Shaffer) – SPHERICAL BOPS

SPHERICAL BOPS
http://www.nov.com/Drilling/Drilling_Pressure_Control/Blowout_Preventers/Spherical_BOPs.aspx
In the market, the annular preventers have wide range of size and operating pressure and you can see from the technical specification from the link that we provide. It is very important that personnel must know how to operate and maintenance the annular preventers properly. Personnel must strictly follow the operating manual to prevent the premature failure.
References
Cormack, D. (2007). An introduction to well control calculations for drilling operations. 1st ed. Texas: Springer.
Crumpton, H. (2010). Well Control for Completions and Interventions. 1st ed. Texas: Gulf Publishing.
Grace, R. (2003). Blowout and well control handbook [recurso electrónico]. 1st ed. Paises Bajos: Gulf Professional Pub.
Grace, R. and Cudd, B. (1994). Advanced blowout & well control. 1st ed. Houston: Gulf Publishing Company.
good job drlingformulas!!:p
I think you just made a mistake in showing the open and close port path way! ( The Red Arrow)
Thanks for your good website
Sorry for my mistake while editing the image. The closing and opening images are corrected already.
I Have always find this website very usefull, specially your daily news letter. Good Job Guys keep up the Good work.
However on this articels (annular preventers) I Think you may have made a small error on you Information on Opening and Closing Port, I think you got it backwards, Opening Shoild be from the top and Closing should be from the Bottom
never the less.. this is a Fine website..
Thank you
The closing and opening images are corrected already.
He guys what is range of anular closing pressure minimum to maximum.is any update
Pradeep,
Each manufacture has their own max and min annular closing pressure therefore the best way to know is to open the specification sheet for your annular BOP.
Regards,
Shyne.
Hi
Where is the API monogram stamped on an annular BOP. is it stamped into the body of the BOP or just attached byan API plate
My best regards
Jim Wight
Typically, you will have the plate on any BOP. I’ve not seen any monogram stamp on the BOP.
Hi;
Is a Hydril GX and GK (13 5/8 x 5 K) element compatable with each?
Regards;
Darcy
Darcy,
I am not sure. You must conslut with the manufacture.
Hi
Annular Upetrom VH is a copy of Hydril GK.
Head packer unit is the same?