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 […]

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

National trade association that is the major standards-development and advocacy organization for the oil and gas industry.

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

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

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 […]

See Annular blowout preventer.

(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 […]

Difference between bottomhole pressure (BHP) and choke pressure due to friction; a function of flow rate, hole geometry, surface roughness, fluid properties.

An arched, inverted-trough configuration of folded rock layers. Compare Syncline.

The measure of the density of gravity of liquid petroleum products in the United States; derived from relative density in accordance with the following equation: API […]

See Driller’s chair.