International Valves

API 16A Annular bop

A Blowout Preventer (BOP) is a large, specialized valve or similar mechanical device, used to seal,
control and monitor oil and gas wells to prevent blowouts, the uncontrolled release of crude oil
and/or natural gas from a well. They are usually installed in stacks of other valves.

An Annular Blowout Preventer can close around the drill string, casing or a non-cylindrical object,
such as the kelly. Drill pipe including the larger-diameter tool joints (threaded connectors) can be
“stripped” (i.e., moved vertically while pressure is contained below) through an annular
preventer by careful control of the hydraulic closing pressure. Annular blowout preventers are
also effective at maintaining a seal around the drillpipe even as it rotates during drilling. Annular
BOPs are typically located at the top of a BOP stack, with one or two annular preventers
positioned above a series of several ram preventers. Annular preventers have only two moving
parts, piston and packing unit, making them simple and easy to maintain relative to ram

The Annular BOPs manufactured by our company features a compact structure, which can seal
Kelly, drill pipe sub, drill collar, and various shapes and sizes of cable. Meanwhile, the annular
BOP can provide fixed pressure control during running and retrieving drill pipes.

Detailed Specifications:

Product Name: Annular Blowout Preventer (BOP)
Nominal Bore: 7-1/16″, 11″, 13-5/8″, 20-3/4″, 21-1/4″
Material: AISI 4130 (Forged)
Main Parts: Upper Housing, Body, Piston, Retainer Ring, Packing Unit and Wear Ring.
Top & Bottom Connection: Flanged or Studded
Standards Applied: API Spec 16A, NACE MR0175
Pressure Rating: 2000 PSI to 10000 PSI
Material Class: AA, BB, CC DD, EE, FF
Temp Class: L, P, R, S, T, U, V
Operating Temperature: -18deg – 121deg
Paint Color: Red or Customzed
Performance Requirement: PR1, PR2
Product Specification Level: PSL1, PSL2, PSL3, PSL4
Application: Well Drilling, Well Control


Annular BOP can be spherical or conical. Spherical BOP can be completed