MAST & DERRICKS
Overview
The rig’s mast is a strong tower that supports the equipment attached to the traveling block & hook. Crew members sometimes use the words “mast” and “derrick” interchangeably. In reality, a mast stands independently on the rig floor and is raised as a single piece unit. In the old days, rig owners used a lot of derricks. A standard derrick as it’s called, is usually bolted together. It has four legs, beams and girds, or cross braces. Unlike the mast, the derrick cannot be lowered or raised as a single unit. Today masts are much more common than derricks.

Mast
Manufacturers usually weld and pin the mast together for easier to assembly or disassembly. A self-erecting mast may be a Cantilever type, a folding type, or a telescoping type.
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Transporting Mast: Once take a look at some of the alternative ways that heavy roading here can be used to transport a mast to the land rig well site. These transport methods can be used in terrain that’s fairly flat and open, like desert. Here you see a mast together with the substructure being towed in the upright position. Here is another mast being towed with its substructure. However, this one is being towed in a horizontal position. Once it’s at the well location, it will be raised up into position using the drawworks. This mast is also being towed in a horizontal position, but its substructure is towed separately. The mast will have to be mounted and raised on the substructure once it arrives at the well location.

Height & Capacity
A mast or derrick is tall, normally having a clear height from 100 to 160 ft (30-50 m). They’re also strong; they’re able to support static weights ranging from 275,000 pounds to 31/4 million pounds (or 125,000 to 1.5 million kg). A rig’s mast must be tall enough to allow crew members to set back drill pipe, tubing and other tubulars they pull out of the hole during a trip out. It also has to be tall enough to allow the driller to raise the traveling block above the height of the derrick man’s monkey-board.


Stands
With the traveling block high in the mast, and the elevator at the derrick man’s position on the monkey-board. The derrick man sets back drill string elements or stands. Most rigs pull three-joint stand of drill pipe and drill collars. A three-joint stand is three made-up joints of drill pipe or collars. Small rigs may pull two or even one joint stand. In rare cases, a really large rig may pull four-joint stand. Regardless of the number of joints, pulling pipe in stands instead of a single joint at a time speeds up the tripping process.

Crown Walkaround (Water Table)
The working platform at the top of the derrick or mast that permits access to the crown block is called the walkaround. It is also called the water table.

Monkey-board
The monkey-board is the derrick man’s working platform when crew members pull pipe or run it back into the hole. The derrick man sets stands of pipe back into a finger board, a platform with projections that holds the top of the pipe in place as it stands in the mast.

Stabbing Board
A stabbing board is similar to the monkey-board. It is a small platform in the mast or derrick about 30-40 ft (or 9-12m) above the rig floor. A drilling crew member, usually the derrick man, works on the platform when running casing or tubing. The derrick man guides the top of the casing or tubing from the stabbing board. The crew member calls the stabber, adjust the stabbing board’s height with a hydraulic, electric or air-powered motor. The height varies depending on the length of the casing or tubing being made up and running into the hole.

[TOOL BOX]
Here is a picture of a rig. When you’re given a rig component, click on the photo where the component is located.

SUBSTRUCTURE
Overview
The substructure is a rugged set of beams. It supports the mast or derrick and the heavy hoisting & rotating equipment. It also supports the drilling tubulars on the rig floor. It must be high enough to accommodate the blowout preventer stack underneath the rig floor.

V-Door, Pipe Ramp & Catwalk
Crew members hoist pipe and equipment from the catwalk up to the rig floor by raising it up the pipe ramp. They hoist it onto the rig floor through the V-door.

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The V-Door takes its name from the early days of the oil -----. On old standard derricks, this opening looked like a large up side down “V”. The name’s stuck, even though today the opening may not look much like a “V”.