Components Of A Rotary Rig Explained!
1. Mud Pit – A man made pit dug into the earth next to the drilling rig. It is used to house the drilling fluid (mud) or waste materials discarded after the treatment of drilling fluid. Steel tanks are now more commonly in use but are still referred to as ” mud pits”. Mud tank is the preferred terminology used on off shore rigs.
2. Shale Shaker – Or commonly called a shaker. A vibrating mesh-like screen used to separate cuttings made by the drill bit. The diameter of openings in the screen shall be as small as possible to allow 100% of the circulating fluid to pass through, therefore depositing the cuttings directly into the reserve pit.
3. Suction Line – A pipe tube or hose that delivers the fluid form the mud pits to the inlet side of mud pump.
4. Mud Pumps – Or slush pumps. A large, high-pressure, positive displacement pump used to circulate drilling fluid through the circulating system and back to the mud pit. Typically you will see three or more on one site depending on the size and depth of the rig and well bore.
5. Engine Generator sets – are the main source of power on a rig. A combustion engine used to convert heat content of fuel into rotary motion, as well as powering other equipment during the drilling process.
6. Vibration Dampening Hose – The hose which extends from the mud pumps; it is designed to prevent the movement of the pumps from vibrating farther down the line. Left unchecked, these vibrations can damage equipment and will produce a lot of unnecessary noise.
7. Draw Works – This is the hoisting system that every rig uses to raise or lower the travelling blocks and the drill string. It spools off or takes in the drilling line which is attached to the crown blocks and, in turn, the travelling blocks and drill string.
8. Stand Pipe – Drill pipe stood vertically alongside the mast or derrick ready to be added to the drill string.
9. Rotary Kelly Hose – Delivers high pressure drilling fluid to the drill string.
10. Goose neck – A curved join that allows the connection of the rotary kelly hose to the kelly and the swivel.
11. Travelling blocks – Are hung in the centre of the the derrick or mast by the crown blocks and the drilling line via a series of pulleys. It can be raised or lowed using the draw works.
12. Cat Line – The cat line is a separate hoist line powered by the cat head which is located on separate spools on either side of the draw works. The purpose of these lines is to aid with tripping in and tripping out as well as hoisting heavy equipment around the rig floor.
13. Crown Blocks – The crown blocks sit at the very top of the derrick or mast, it is an assembly of sheaves on axles. The drilling line is spooled off the draw works through the crown blocks and eventually to the travelling blocks.
14. Derrick – Don’t get confused between a derrick and a mast they are two different components. The derrick is a tall load bearing structure in the centre of the substructure. The derrick is assembled piece by piece at the rig site. By contrast, the mast is a portable unit which can be raised or lowered as a complete structure when necessary.
15. Monkey Board – Is where the Derrick Man will work during the tripping in and tripping out operations. The monkey board is placed high in the derrick or mast.
16. Drill pipe – Is the pipe used to extend the drill string, they have a male and female threaded connection on each end. Drill pipe is commonly 30ft per length and is hollow to allow the drilling fluid to pass through.
17. Substructure – Often referred to as the drill floor, this is the main structure where all drilling operations take place.
18. Swivel – The swivel is an essential tool hung from the hook on the travelling blocks, it is used to permit rotary motion from the motionless hook to the spinning drill string. The swivel also provides a connection for the rotary hose and a passageway for the drilling fluid into the drill string.
19. Kelly – Normally four or six sided heavy duty steel tubular device suspended from the swivel and connected to the last unit of drill pipe to turn the drill string as the rotary table turns. The Kelly also has a bored passage through it which allows flow of drilling fluid to the drill string and up the annulus. Kellys are normally 54ft or 17m long.
20. Rotary Table – Also known as the turn table. This is the primary component used to rotate the drill string and support the drilling assembly.
21. Rat Hole – The Rat Hole is a hole made into the substructure and lined with pipe, placed just off to the side of the main bore hole. This is where the Kelly is stored during hoisting operations.
22. B.O.P Stack – ”Blow Out Preventer”. In my opinion, this is the most important part off any oil rig. The B.O.P Stack is the assembly of various types of blow out preventer’s installed underneath the substructure. During a kick, these BOPs seal off the well bore to keep pressure down hole rather than allowing it to explode through the substructure.
23. Annular Blow Out Preventer – Part of the B.O.P Stack and the first set of blow out preventers. It is essentially a valve that when manipulated will seal off the annular space between the pipe and the well bore, or if there is no pipe is present the Annular B.O.P will close off the entire bore hole. The Annular B.O.P has a flexible seal that is forced to take on whatever shape is in the bore of the preventer.
24. Ram Blow Out Preventer – The Ram preventer is usually placed below the Annular Preventer. It operates by closing two flat rams completely together, crushing anything between them, and sealing off the wellbore and the drill pipe.
25. Drill String – Is the column of drill pipe, collars and tools connected together to form the drill string. The drill string is what transmits drilling fluid and rotational power from the Kelly and rotary table to the drill bit itself.
26. Drill Bit – The drill bit is the cutting element attached to the very bottom of the drill string. Click here for more on drill bits.
27. Conductor Casing – Also known as Conductor Pipe and Drive Pipe. This is the first string of casing cemented into the bore to prevent softer formations from caving into the well bore. This type of casing also helps conduct the drilling fluid from the bottom of the hole to the surface when drilling starts.
28. Diverter line – A pipe directed at diverting the fluids from a well to a safe location during an unexpected release of fluid.