Changes

==Rotating system==

==Rotating system==

The rotating system consists of the [[rotary table]] and the ''[[drill stem]]'' ([[kelly]] [8 in [[:file:Land rig example drawing.png|Figure 1]]], [[drill string]], and [[bit]]). The ''rotary table'' is a square hole in the derrick floor with a [[rotary bushing]] that is used to turn the ''[[kelly bushing]]''(9) and kelly. The ''kelly'' is a square or hexagonal length of pipe that is screwed on the drill pipe and used to convey the rotary movement to the drill string and bit. The ''drill string'' refers to the combination of drill pipe, collars, and other bottom hole assembly components. (For more information on bottom hole assemblies, see [[Wellbore trajectory]].) Attached to the end of the drill collars is the ''bit''. The bit does the actual grinding or cutting of the rock. The style of bit used is dependent on the rock type and drilling conditions. Common [[bit type]]s include drag, tri-cone, insert, PDC, and diamond.

The rotating system consists of the [[rotary table]] and the ''[[drill stem]]'' (kelly [8 in [[:file:Land rig example drawing.png|Figure 1]]], [[drill string]], and [[bit]]). The ''rotary table'' is a square hole in the derrick floor with a [[rotary bushing]] that is used to turn the ''kelly bushing''(9) and kelly. The ''kelly'' is a square or hexagonal length of pipe that is screwed on the drill pipe and used to convey the rotary movement to the drill string and bit. The ''drill string'' refers to the combination of drill pipe, collars, and other bottom hole assembly components. (For more information on bottom hole assemblies, see [[Wellbore trajectory]].) Attached to the end of the drill collars is the ''bit''. The bit does the actual grinding or cutting of the rock. The style of bit used is dependent on the rock type and drilling conditions. Common [[bit type]]s include drag, tri-cone, insert, PDC, and diamond.

The hole is drilled by adding joints or lengths of drill pipe to the end of the kelly. When pipe is added, the hoisting system is used to pick up the kelly so that it hangs from the derrick above the rotary table. ''Tongs'' (large pipe wrenches)(13 and 14) or chains are used to unscrew the kelly from the previous joint of pipe. The kelly is then screwed into a new joint of pipe that has been temporarily stored in the ''mouse hole''(11), a cased opening in the rig floor. The kelly and the new joint of pipe are then screwed on the previous pipe and lowered into the hole so that drilling can resume. When all of the pipe is pulled out of the hole, it is referred to as a ''[[trip]]''. Pulling out part of the drill string, then returning to drilling, is called a ''[[Short trip|short]]'' or ''[[wiper trip]]''. Such trips are performed to verify that the drill string can move through a recently drilled potentially troublesome section of the borehole.

The hole is drilled by adding joints or lengths of drill pipe to the end of the kelly. When pipe is added, the hoisting system is used to pick up the kelly so that it hangs from the derrick above the rotary table. ''Tongs'' (large pipe wrenches)(13 and 14) or chains are used to unscrew the kelly from the previous joint of pipe. The kelly is then screwed into a new joint of pipe that has been temporarily stored in the ''mouse hole''(11), a cased opening in the rig floor. The kelly and the new joint of pipe are then screwed on the previous pipe and lowered into the hole so that drilling can resume. When all of the pipe is pulled out of the hole, it is referred to as a ''trip''. Pulling out part of the drill string, then returning to drilling, is called a ''short'' or ''wiper trip''. Such trips are performed to verify that the drill string can move through a recently drilled potentially troublesome section of the borehole.

==Hoisting system==

==Hoisting system==