To cease work on a well which is non-productive, to plug off the well with cement plugs and salvage all recoverable equipment. Also used in the context of field abandonment.

Accumulation - Pressure increase over the maximum allowable working pressure of the vessel allowed during discharge through the pressure-relief device.

A combination of oil and acid or water and acid under high pressure used to separate or fracture hard limestone formations.

To treat oil-bearing limestone or other formations, using a chemical reaction with acid, to increase production. Hydrochloric acid or other acid is injected into the formation under pressure. The acid etches the rock, enlarging the pore spaces and passages through which the reservoir fluids flow. The acid is then pumped out and the well swabbed and put back into production.

Actual flow capacity is the flowing capacity determined by measurement.

Adjusted set pressure - Vacuum or gauge pressure at which under test stand conditions (atmospheric back pressure) valves commence to lift

An industrial gas turbine. The design of which is derived from aerospace turbines, generally between 10-50 megawatts.

AEx - North American NEC 505 Explosion protected Equipment.

AHTS is an abbreviation within shipping for - Anchor Handling Tug Supply Vessel

A method of rotary drilling that uses compressed air as its circulation medium. This method of removing cuttings from the well bore is as efficient or more efficient than the traditional methods using water or drilling mud; in addition, the rate or penetration is increased considerably when air drilling is used. However, a principal problem in air drilling is the penetration of informations containing water, since the entry of water into the system reduces its efficiency.