18 July 2017

Active Heave drawworks

A drawworks with an advanced controls system and additional power to provide the heave compensation of the string on a floating vessel instead of the traditional […]
18 July 2017

Adiabatic accumulator system

An accumulator system is regarded as adiabatic when the pressure change is fast enough that no significant heat is transferred between the outside environment and the […]
18 July 2017

Adjustable choke

A choke in which the position of a conical needle, sleeve, or plate may be changed with respect to their seat to vary the rate of […]
18 July 2017

Air drilling

A method of rotary drilling that uses compressed air as the circulation medium. The conventional method of removing cuttings from the wellbore is to use a […]
20 October 2021

Air pressure vessel (APV)

Pressure vessels are enclosed containers designed for the purpose of holding gas or liquis at a different pressure than the surrounding air pressure.
18 July 2017

Air-actuated

Powered by compressed air, as are the clutch and the brake system in drilling equipment. See choke.
18 July 2017

Anchor deadline

Means of holding the deadline to the derrick or substructure. Usually this is the primary element of the weight indicator.
18 July 2017

Angle of deflection

In directional drilling, the angle, expressed in degrees, at which a well is deflected from the vertical by a whipstock or other deflection tool.
25 July 2017

Annular blowout preventer

A type of BOP that uses a shaped elastomeric sealing element (“packing element”) to seal the space between the tubular and the wellbore or an open […]
18 July 2017

Annular space

(also “annulus“) The space surrounding a cylindrical object within a cylinder. The space around a pipe in a wellbore, the other wall of which may be […]