| Dual
Rotary Drilling Method
Our
dual rotary rig can handle difficult formations without
the use of casing hammers, under-reamers or drilling
mud. Because the drives are independent, the bit drill
can drill inside, flush with, or ahead of the casing
depending on the type of overburden encountered.
- In situations where
heaving is a factor or sample accuracy is important,
- the casing is advanced
ahead of the drill bit for hole stability and
minimal cross-contamination of cuttings.
|
Dual
Rotary System
"Heavy Formation"
Casing advances
ahead of drill bit.
|
- In situations where
boulders are encountered, the drill operator can
stop the casing rotation, and continue
- through the boulder
with a drill string. Once a pilot hole is
established in the boulder, the operator begins
rotating the casing again, and it follows the drill
string through the boulder.
-
- This "pilot
hole" technique combines with the rotation of
the casing to deliver an uncommonly straight
borehole. Once the desired casing depth is achieved,
the dual rotary drill continues drilling like a
conventional top-drive air drill.
|
Dual
Rotary System
with "boulder encountered"
Drill bit leads casing straight through cobbles and
boulders.
|
