A paraffin hydrocarbon, a gas in atmospheric conditions but is easily liquefied under pressure.

It is a constituent of liquefied petroleum gas.

See commercial butane, field-grade butane, normal butane.

Any substance or combination of substances that, when dissolved in water, produces a solution that resists a change in its hydrogen ion concentration on the addition of acid or base.

The random movement exhibited by microscopic particles when suspended in liquids or gases.

It is caused by the impact of molecules of fluid surrounding the particle.

To tighten a threaded connection.

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.