What is Kelly Rig?

This is the brief explanation of a Kelly rotating system on the rig. Kelly rig is on an old style rigs and  nowadays it is mostly used on land operations. For offshore operation, a top drive system is used instead.

First of all, it is important for new people to look at these images before reading the information below because they show the equipment’s name and where they are on the rig.

(Ref Inage: http://www.cdc.gov/niosh/face/images/03ok034c.jpg)

(Ref Image: http://geologie.vsb.cz/DRILLING/drilling/theory/theory_html_m61697c8b.jpg)

(Ref Image: http://ffden-2.phys.uaf.edu/212_spring2011.web.dir/Dan_Luo/picture/hoisting.png)

The upper end of the drill pipe is screwed onto the saver sub. The saver sub is used to protect and minimize wearr and tear on the threads at the bottom of the Kelly. 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.

A Kelly cock valve is located at the top of a Kelly and it is a safety valve which can be closed to stop back pressure from coming back to damage other surface equipment.

A swivel attached to the hook does not rotate, but at the bottom part it supports the Kelly which is being rotated while drilling.  Drilling mud is pumped from a mud pump to a stand pipe manifold, Kelly hose and then to a gooseneck connection at a swivel.

A rotary table rotates a Kelly bushing and it simultaneously rotates a Kelly and a drill string and a drill bit. A rotary table has two main functions. The first one is to provide rotation to a drill stem and a bit and the second function is to hold slip in order to support the weight of a drill stem when it is not connected to a Kelly.

Generally, a rotary drive consists of  a chain and rotary-drive sprocket. A rotary-drive sprocket is a part of the draw-works. In other rig power systems, an independent electric motor or engine with a direct drive to a rotary table is utilized. For this case, the rotary is normally driven by a drive shaft instead of a chain and rotary-drive sprocket.

A master bushing severs its function as a rotary motion transmission from a rotary table to a Kelly. Additionally, it is a link between a slip and a rotary table.

A Kelly bushing (some people call “rotary Kelly bushing”) engages a master bushing via four pins and rollers inside a Kelly bushing to allow a Kelly to move up or down freely while it is rotated or in a static mode.

This video demonstrates how to make a connection via a Kelly system.

Related Post

Reel Lay Pipeline Installation Method Reel lay method installs offshore pipeline by sending the pipeline from a reel mounted on a special pipeline installation vessel. Instead of connectin...
What is Top Drive System? A top drive is a big motor system which is hoisted in a derrick or mast of a drilling rig. A top drive is a modern rotating system which has been popu...
How to Prevent Well Ballooning This topic will you describe how to prevent well ballooning. There are several items that you can manage in order to prevent or minimize well ballooni...
Two New Efficient Oil Drilling Techniques Two new efficient oil drilling techniques The U.S. increased oil reserves can be attributed to the development of revolutionary technology that has...
Share the joy
  • 1.2K
  •  
  • 3
  •  
  •  
  •  
  •  
  •  
  •  
    1.2K
    Shares
Tagged , , . Bookmark the permalink.

About DrillingFormulas.Com

Working in the oil field and loving to share knowledge.

2 Responses to What is Kelly Rig?

  1. M.Prashant says:

    where to place blind ram & pipe ram in 21-1/4 inch two stack bop.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.