TM 5-3820-256-10
d. Air drilling techniques.
NOTE
If the well is to be drilled using air drilling methods, the mud pits need not be used. It will be necessary to
install the drive sleeve.
(1) Position the drive sleeve under the rotary table. Lower the kelly through the rotary table and attach the drive
plate. Lower the plate into the sleeve and rotate the table to screw the drive sleeve into the ground.
Remove the drive plate from the kelly sub and attach a tri-cone bit.
(2)
Operate the hoist drum to lower the kelly so that the bit contacts the ground inside the drive sleeve. Be sure
the kelly bushings are properly engaged in the rotary table. Begin rotation of bit and lower the kelly to put
weight on the bit.
(3)
Operate the air compressor to begin blowing cuttings up away from the bit.
(4)
Operate the water injection pump to inject enough water into the air stream to settle the dust coming out of
the hole.
NOTE
If drilling a large diameter hole (12"), you may need to inject foam into the air stream. (Refer to FM 5-
166 for more information.) (5) If more weight is needed on the bit for drilling, operate the pulldown
system to add the required weight.
(6)
Drill down the kelly. Stop rotation but continue air circulation until cuttings stop coming up.
CAUTION
Do not raise the bit out of the ground with the air compressor operating. The rush of air, dust, and dirt
can cause injury to eyes and skin.
(7)
Operate the hoist drum to raise the kelly partially up the hole; shut off the air compressor before exiting the
hole.
(8)
Add pipe (make connections) just like you would if you were drilling with mud.
e. Percussion drilling.
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