30,000 pullback rating can be used as an additional
A split centralizer and pipe-handling system located
on the ITWD worktable is used to break and make drill
pipe connections, to support the drill string during pipe
handling, to provide a centralizer bushing for the drill
string, and to aid in setting casing and making casing
joint. The centralizer is a split design consisting of a rear
section welded to the main frame and a removable
forward section. The forward section is held in place by
two pins and can be manually swung out or detached to
facilitate setting large diameter casing or surface pipe.
The forward section is removed during transport and
stored on top of the worktable. The centralizer
accommodates various sizes of split bushings to adapt
to a number of drill pipe, casing, and down-hole-drilling
A hydraulically powered breakout wrench is also
mounted on the worktable. This wrench is used with a
manual holding wrench (used to support the drill string
and stop rotation) to make and break pipe and casing
Top-Head Drilling Operations
All personnel assigned to drill with the ITWD
should thoroughly read and understand the operators
manual before proceeding with any drilling operations.
Additionally, SAFETY IS PARAMOUNT over all
actions performed during drilling operations.
In general, you proceed to set up the rig as follows:
Move the rig into position on the selected site. Use the
hydraulic outriggers to level the rig and take the weight
of the rig off the axles. Ensure adequate overhead
clearance; then raise and lock the derrick.
For the top-head drilling rig proceed with the
1. Attach the centralizer half to the worktable.
2. Install the centralizer bushings.
3. Place the bottom holding wrench in position.
4. Dope (lubricant for threads) the top-head
spindle sub threads.
5. Lower the hoist and attach the hoist plug.
6. Raise the top-head.
7. Dope the tri-cone bit threads (down-
hole-drilling hammer treads if hammer drilling).
8. Manually thread the bit into the bit sub.
9. Wrap the mud flinger around the bit sub.
10. Dope the hoist plug threads and thread into the
11. Raise the bit sub with the hoist and insert into
the centralizer bushing.
12. Insert the holding wrench to the support bit sub;
close the forward half of the centralizer and pin it shut.
13. Remove the hoist plug from the bit sub.
Installation of the Drill Pipe:
1. Slide the drill pipe sling over the drill pipe.
2. Attach the hoist cable to the drill pipe sling and
hoist the drill pipe into position over the bit sub.
3. Lower the top-head into position with the
rotation on slow.
4. Tighten all connections and raise the drill
slightly off the holding wrench and remove the holding
Rotary Mud Drilling:
1. The mud pits for top-head drilling are dug and
designed, as shown in figure 9-10.
2. Connect the suction hose to the mud standpipe.
3. Place the suction hose into the mud pit and
connect the hose to the mud pump inlet.
4. Set the engine speed to the manufacturers
recommendations and open the mud pump valve.
5. Control the mud flow by adjusting the mud
6. While drilling, adjust the top-head drive spindle
rotation and pulldown speed and monitor the mud pump
stand pressure to avoid a plugged drill bit or loss of
7. Upon completion of the hole, place the suction
hose in a source of clean water and flush the drill pipes
Rotary Air Drilling:
1. Lower the bit to within 4 inches of the ground,
and connect the flushing line to the air compressor.
2. Turn on the compressor, open the air valve, and
set the engine speed at the speed recommended by the
3. Set the pulldown regulator to a minimum and
start the top-head drive spindle rotation, and set the
pulldown speed to LOW.