Oil and Gas Glossary

kelly

The heavy steel, pipe-like, four- or six-sided member suspended from the swivel through the rotary table and connected to the top-most joint of drill pipe which turns the drill stem as the rotary table turns. It has a bored passageway that permits fluid to be circulated into the drill stem and up the annulus, or vice versa. Sometimes called kelly joint.

kelly bushing

An adapter that serves to connect the rotary table to the kelly. The kelly bushing has an inside diameter profile that matches that of the kelly, usually square or hexagonal. It is connected to the rotary table by four large steel pins that fit into mating holes in the rotary table. The rotary motion from the rotary table is transmitted to the bushing through the pins, and then to the kelly itself through the square or hexagonal flat surfaces between the kelly and the kelly bushing. The kelly then turns the entire drillstring because it is screwed into the top of the drillstring itself. Depth measurements are commonly referenced to the KB, such as 8327 ft KB, meaning 8327 feet below the kelly bushing.

kerogen

A solid organic material which yields petroleum-type hydrocarbons on heating and distillation

key-seat

A crevice or groove in the formation wall of the well bore or a split in casing in which a survey cable can become wedged. Most likely to occur at "dog legs" in deviated boreholes.

kick

An eruption or flow of drilling mud from a wellbore resulting from the entry of formation fluids, oil, gas, or water into the borehole. Such entry occurs when the pressure in the borehole does not counterbalance the pressure in permeable formation.

kill a well

To circulate water and mud into a completed well before starting well-servicing operations