A device attached to the catshaft of the drawworks that is used as a power source for unscrewing drill pipe; usually located opposite the driller’s side of the drawworks.

See cathead.

Any inexperienced worker or “hand”.

See boot sub

Abbreviation: barrels per day.

1.

A hole made by drilling or boring; a wellbore.

2.

The wellbore itself, including the openhole or uncased portion of the well.

Borehole may refer to the inside diameter of the wellbore wall, the rock face that bounds the drilled hole.

A device set in tubing, particular collars, to facilities the landing of pressure bombs (recorders).

A device with a restricted opening placed in the lower end of the tubing to control the rate of flow.

See choke.

A closed pressure vessel with a furnace to burn coal, oil, or gas, used to generate steam from water.

1.

The pressure at the bottom of a well.

2.

The pressure, usually measured in bar at the bottom of the hole.

This pressure may be calculated in a static, fluid-filled wellbore with the equation:

bhp = p g h

where p (rho) is the fluid density in kg/m3, g is gravity in m/s2, and h is the vertical depth of the well in meters.

Abbreviation: blowout preventer.

Water occurring in a producing formation below the oil or gas in that same formation.

Controls, usually located near the driller’s position on the rig floor, that are manipulated to open and close the blowout preventers.

See blowout preventer.

The assembly of blowout preventers installed on a well

1.

The emptying or depressurizing of material in a vessel.

2.

The material thus discarded.

The discharge pipe from a well being drilled by air drilling.

The blooey line is used to conduct the air or gas used for circulation away from the rig to reduce the fire hazard as well as to transport the cuttings a suitable distance from the well.