What is the kelly bushing?

Asked by: Crystal Vazquez

1. n. [Drilling] 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.

What is the function of kelly bushing?

Kelly bushing is that elevated device positioned right on top of the rotary table and used to transmit torque from the rotary table to the kelly. The kelly bushing is designed to be the connection between the rotary table and the kelly. The kelly is a 4 or 6 sided steel pipe.

What is the function of Kelly?

The kelly is used to transmit rotary motion from the rotary table or kelly bushing to the drillstring, while allowing the drillstring to be lowered or raised during rotation.

What is the kelly bushing elevation?

Kelly Bushing Height (KB): The height of the drilling floor above the ground level. Many wellbore depth measurements are taken from the Kelly Bushing. The Kelly bushing elevation is calculated by adding the ground level to the Kelly bushing height.

What is a Kelly in oil drilling?

A kelly drive is a type of well drilling device on an oil or gas drilling rig that employs a section of pipe with a polygonal (three-, four-, six-, or eight-sided) or splined outer surface, which passes through the matching polygonal or splined kelly (mating) bushing and rotary table.

How does a kelly rig work?

The Kelly moves through a square or hexagonal opening in the Kelly Drive bushing Kelly Drive bushing mates with a master bushing in the rotary table the rotary table turns the master bushing.

What is a kelly valve?

The kelly-valve is a type of drill stem valve used to prevent flow out of the drill pipe if a kick should occur during a tripping operation.

What is master bushing?

A device that fits into the rotary table to accommodate the slips and drive the kelly bushing so that the rotating motion of the rotary table can be transmitted to the kelly.

How long is a Kelly drilling?

about 40 ft

The Kelly is about 40 ft in length with a square or hexagonal shape and it is hollow throughout in order to transport the drilling mud. Kelly moves freely through a Kelly bushing even though the drill stem is rotated.

What is the difference between Kelly and top drive?

This means that Top Drives can drill about 90 feet before making a connection, whereas with a Kelly System, you will make a connection at about 30 feet deep. Another difference between a Kelly and a Top Drive is that a Top Drive System allows rotation and circulation while back reaming out of a hole.