TM 5-3820-256-10
NOTE
The primary and secondary mud pits have a limited capacity. As the hole is drilled, the circulation
system requires more and more fluid to continue circulation. Add water as necessary to ensure the
pump always has an ample fluid supply.
(b)
Lower the bit to the ground surface. Start the mud pump and use minimum throttle at first. Start the rotary
table rotation. Allow the weight of the kelly and the table rotation to drill several feet of hole. If the weight
of the kelly is not enough to penetrate the earth, apply pulldown pressure.
NOTE
When starting the hole, stop the table rotation occasionally and, using a level vertically against the kelly,
check that the hole is being drilled straight down and is not drifting. It may be necessary to "fine-tune"
the rig's leveling jacks.
(c)
Drill the kelly all the way down. Just before the kelly has completed its full travel, stop pulldown (if being
used), then stop table rotation. Do not stop the mud pump circulation at this time; allow ample circulation to
raise all the cuttings out of the hole. Then raise the kelly a few feet off the bottom of the hole. Stop the
mud pump.
(d)
Raise the kelly until the top of the bit sub extends above the top of the rotary table. Install the break-out
fork on the bit sub and lower the kelly. Use the break-out tong to break the bit sub from the kelly. Unscrew
the kelly, raise and retract it into the mast.
(3) Add a drill collar.
(a)
Install the hoisting plug in the drill collar. Use the auxiliary drum line to lift the drill collar above the bit sub
being held in the rotary table.
WARNING
Be careful when picking up and handling drill collars and drill pipe. Be sure you do not damage the
threads by setting the open end directly on the ground. Use thread protectors when handling drill collars
and pipe joints.
(b)
Lower the drill collar onto the bit sub.
(c)
Rotate the rotary table to connect the drill collar to the bit sub. Lift the drill string slightly and remove the
break-out fork. Lower the drill collar into the hole until the top of the collar extends just above the rotary
table.
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