1|Page
NGWA - Study Guide - Air Rotary|| 2026 Latest Update
With Complete Solutions||Verified Exam!!!
What purpose does a Kelly saver sub serve? - ANSWER-
A Kelly saver sub protects the Kelly from excessive wear
by absorbing the torque and stress during drilling
operations.
What type of lubrication system is used for DHH drilling? -
ANSWER-a mist or oil injection lubrication system to
reduce wear and cool the hammer mechanism.
Explain these terms: misting. dusting. - ANSWER-Misting:
Injecting water or fluid into the air stream to control dust
and cool the bit.
Dusting: Drilling without sufficient fluid, resulting in
excessive dust and potential bit overheating.
What is a surfactant? When is it needed? - ANSWER-
Reduces surface tension; needed to create foam in drilling
fluids for effective cuttings removal.
Explain the difference between high and low pressure air
rotaries. - ANSWER-High-pressure air rotary: Faster
drilling, better cuttings removal, used in hard formations.
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Low-pressure air rotary: Slower drilling, more controlled,
used in softer or unstable formations.
Explain the difference between high and low volume air
rotaries. - ANSWER-High-volume air rotary: Moves more
air, better for deep holes or large cuttings removal.
Low-volume air rotary: Moves less air, suited for shallow
holes or smaller cuttings.
How much pressure of air does it take to life 100 ft of
water? Explain. - ANSWER-It takes 43.5 psi to lift 100 feet
of water because water pressure increases by about 0.435
psi per foot of depth. Therefore, 100 feet × 0.435 psi/ft =
43.5 psi.
What are some advantages and/or disadvantages of the
top head and table drive system? - ANSWER-Top head
drive:
Advantages: Direct torque, better control, less drill string
wear.
Disadvantages: More expensive, complex maintenance.
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Table drive:
Advantages: Simpler, lower cost.
Disadvantages: Less control, higher drill string wear.
Why is it important to keep the bit in gauge? - ANSWER-
ensures proper hole diameter, prevents well collapse, and
maintains drilling efficiency.
How is the DHH drill bit sharpened? - ANSWER-by
grinding the worn or rounded edges of the bit's cutting
surfaces, usually with specialized grinding tools.
How could a crooked hole be corrected using air rotary? -
ANSWER-using stabilizers, reducing weight on the bit,
and adjusting the drilling angle.
Explain various methods for setting casing using air rotary
equipment. - ANSWER-Driving: Use a hammer or rig to
drive the casing down.
Rotating: Rotate the casing into place using the drill rig.
Pushing: Use the rig's hydraulic system to push the casing
down.
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What could cause lost circulation in air rotary drilling? -
ANSWER-Fractured formations, porous zones, or high-
pressure air forcing fluids into surrounding formations.
How are air rotary rigs sized? - ANSWER-air compressor
capacity (CFM/PSI)
drilling depth capacity
mast height.
If up hole velocities decrease, what could be the probable
cause? - ANSWER-Reduced air pressure
blockage in the air stream
increased hole diameter.
What can be added to water to aid in drilling with mud
rotary? - ANSWER-Bentonite, polymers, and surfactants
to improve viscosity, stabilization, and cuttings removal.
In using mud rotary in unconsolidated formations, what is
the relationship of speed in RPMs and feeds? - ANSWER-
In mud rotary drilling for unconsolidated formations, higher
RPMs require lower feeds to avoid collapsing the
NGWA - Study Guide - Air Rotary|| 2026 Latest Update
With Complete Solutions||Verified Exam!!!
What purpose does a Kelly saver sub serve? - ANSWER-
A Kelly saver sub protects the Kelly from excessive wear
by absorbing the torque and stress during drilling
operations.
What type of lubrication system is used for DHH drilling? -
ANSWER-a mist or oil injection lubrication system to
reduce wear and cool the hammer mechanism.
Explain these terms: misting. dusting. - ANSWER-Misting:
Injecting water or fluid into the air stream to control dust
and cool the bit.
Dusting: Drilling without sufficient fluid, resulting in
excessive dust and potential bit overheating.
What is a surfactant? When is it needed? - ANSWER-
Reduces surface tension; needed to create foam in drilling
fluids for effective cuttings removal.
Explain the difference between high and low pressure air
rotaries. - ANSWER-High-pressure air rotary: Faster
drilling, better cuttings removal, used in hard formations.
,2|Page
Low-pressure air rotary: Slower drilling, more controlled,
used in softer or unstable formations.
Explain the difference between high and low volume air
rotaries. - ANSWER-High-volume air rotary: Moves more
air, better for deep holes or large cuttings removal.
Low-volume air rotary: Moves less air, suited for shallow
holes or smaller cuttings.
How much pressure of air does it take to life 100 ft of
water? Explain. - ANSWER-It takes 43.5 psi to lift 100 feet
of water because water pressure increases by about 0.435
psi per foot of depth. Therefore, 100 feet × 0.435 psi/ft =
43.5 psi.
What are some advantages and/or disadvantages of the
top head and table drive system? - ANSWER-Top head
drive:
Advantages: Direct torque, better control, less drill string
wear.
Disadvantages: More expensive, complex maintenance.
,3|Page
Table drive:
Advantages: Simpler, lower cost.
Disadvantages: Less control, higher drill string wear.
Why is it important to keep the bit in gauge? - ANSWER-
ensures proper hole diameter, prevents well collapse, and
maintains drilling efficiency.
How is the DHH drill bit sharpened? - ANSWER-by
grinding the worn or rounded edges of the bit's cutting
surfaces, usually with specialized grinding tools.
How could a crooked hole be corrected using air rotary? -
ANSWER-using stabilizers, reducing weight on the bit,
and adjusting the drilling angle.
Explain various methods for setting casing using air rotary
equipment. - ANSWER-Driving: Use a hammer or rig to
drive the casing down.
Rotating: Rotate the casing into place using the drill rig.
Pushing: Use the rig's hydraulic system to push the casing
down.
, 4|Page
What could cause lost circulation in air rotary drilling? -
ANSWER-Fractured formations, porous zones, or high-
pressure air forcing fluids into surrounding formations.
How are air rotary rigs sized? - ANSWER-air compressor
capacity (CFM/PSI)
drilling depth capacity
mast height.
If up hole velocities decrease, what could be the probable
cause? - ANSWER-Reduced air pressure
blockage in the air stream
increased hole diameter.
What can be added to water to aid in drilling with mud
rotary? - ANSWER-Bentonite, polymers, and surfactants
to improve viscosity, stabilization, and cuttings removal.
In using mud rotary in unconsolidated formations, what is
the relationship of speed in RPMs and feeds? - ANSWER-
In mud rotary drilling for unconsolidated formations, higher
RPMs require lower feeds to avoid collapsing the
