A special device that, when fitted in to the master bushing, transmits torque to the kelly and simultaneously permits vertical movement of the kelly to make hole.

It may be shaped to fit the rotary opening or have pins for transmitting torque.

Also called

A kind of tank of filter used to separate oil and water.

An entry of water, gas, oil, or other formation fluid into the wellbore during drilling.

It occurs because the pressure exerted by the column of drilling fluid is not great enough to overcome the pressure exerted by the fluids in the formation drilled.

If

A slot in the edge of the barge hull of a jackup drilling unit over which the drilling rig is mounted and through which drilling tools are lowered and removed from the well being drilled.

The heavy steel member, three-, four-, six-, or eight-sided, suspended from the swivel through the rotary table and connected to the topmost joint of drill pipe to turn the drill stem as the rotary table turns.

It has a bored passageway that permits fluid

To overcome pressure in a well by use of mud or water so that surface connections may be removed.