Masts (drilling rig) Information
Masts are portable load-bearing structures used to support and position the drill string. Masts perform a similar function to that of derricks, but are typically pre-assembled and mounted on a frame, whereas derricks are anchored to the corners of a substructure.
Masts can be classified into several different groups:
- Cantilevered masts are widely used due to their ease of transport and rigging. The mast is anchored at one end and raised into position using the draw-works.
- Bootstrap masts are used when space is limited. The mast is assembled vertically on the rig floor. Draw-works or hydraulic cylinders are used to raise each section sequentially inside the base of the mast after the boot and top sections are in place.
- Telescopic masts make use of several hoisting cables actuated by the draw-works or a winch. As the hoisting equipment is actuated, each section of the mast successively raises into position from within the previous section until the mast is fully extended.
- Folding masts use fold back bracing to allow stacking of the mast sections during transport. The reduced cube is best suited for export and long-distance travel.