Figure 9-7.-Hoisting plug.
performs tasks, such as racking the steel pipe, screwing
the hoisting plug, and handling the drill pipe or casing.
The floor hand records the information on the drill log,
records cutting samples, maintains the mud pits, and
maintains all work tools and equipment on the deck of
the rig.
All crew members must wear protective clothing or
equipment, such as hardhats, gloves, safety shoes, and
safety belts. When wearing hard hats, the derrick hand
and any other crew member working overhead should
wear chin straps to keep the hard hat from dropping on
personnel below. Also, while working in the mast, crew
members should attach their tools securely to the safety
belt by means of line. Before ascending, they should
clean their shoes of all mud and inspect footholds for
grease. No crew member should wear loose or flapping
clothes. Gloves should be worn for protection when
handling wire rope. Safety shoes with reinforced tops
will protect toes from being crushed.
Kelly-Drive Rotary Drilling Operating
Principles
The basic components of a kelly-drive rotary
drilling rig are the derrick and hoist, kelly, turntable,
drill pipe, bit, and pump (fig. 9-6).
The drill pipe comes in lengths that are joined
together, as the depth of the well increases. The top joint
of the drill pipe is connected to the kelly, which is a
splined hollow shaft, that passes up through the
turntable and kelly bushing. This bushing is grooved to
fit the splines on the kelly. When rotated by the turntable,
the kelly is free to move up and down. The pump forces
a mixture of clay and water through the kelly and drill
pipe.
A water swivel, suspended from above, is attached
to the top of the kelly. It allows the kelly, drill pipe, and
bit to rotate with the driving mechanism. The water
swivel and kelly are raised and lowered by a cable that
runs from the swivel over the sheave at the top of the
derrick down the kelly drum. The kelly drum brakes and
wire rope control the pressure and rate of feed to the bit
by holding off or applying the weight of the drill pipe.
The accessories of a kelly-driven rotary drilling rig
include the hoisting plug, slips, drill collar, kelly sub,
and casing. The hoisting plug (fig. 9-7) is the connecting
link between the hoisting line and the drill pipe. It
swivels so that the drill pipe is free to turn while being
hoisted. The slips (fig. 9-8) are used to hold the drill pipe
when it is being moved in or out of the hole while a joint
is removed or added. The slips are circular wedges made
in two or four pieces and fastened together in sets or
pairs. Teeth on the inside of each slip grip the outside of
the drill pipe. The slips are tapered in such a manner that
when set around the drill pipe and pulled into the
turntable, they grip the drill pipe securely. The drill
Figure 9-8.—Slips.
9-7
