NGWA Air Rotary Drilling Certification
Exam (Exam D) Practice Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
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1. What is the primary purpose of air rotary drilling in groundwater
exploration?
A. To drill through soft soil only
B. To create permanent wells
C. To penetrate unconsolidated and consolidated formations
efficiently
D. To reduce water usage during drilling
Rationale: Air rotary drilling uses compressed air to efficiently remove
cuttings from a variety of formations, making it effective in both
unconsolidated and consolidated formations.
, 2. Which type of drilling fluid is typically used in air rotary drilling?
A. Water-based mud
B. Compressed air or foam
C. Oil-based mud
D. Bentonite slurry
Rationale: Air or foam is used to lift cuttings to the surface and prevent
hole collapse in air rotary drilling.
3. What is the most common method of removing cuttings in air rotary
drilling?
A. Bucket auger
B. Air lift
C. Cable tool percussion
D. Jetting with water
Rationale: Air lift created by compressed air forces cuttings to the surface
efficiently, which is the standard method in air rotary drilling.
4. What is the primary advantage of using dual-wall drill rods?
A. Reduce drilling speed
B. Reduce energy consumption
, C. Provide both air circulation and structural support
D. Eliminate need for casing
Rationale: Dual-wall rods allow air to circulate through the inner tube
while providing structural support through the outer wall.
5. When drilling through unconsolidated formations, what is a common
problem that may occur?
A. Excessive rotation
B. Hole collapse
C. Overheating of the bit
D. Air contamination
Rationale: Unconsolidated formations lack cohesion, making them prone
to caving or collapsing without proper drilling methods.
6. What is the typical range of air pressure used in air rotary drilling?
A. 10–20 psi
B. 20–40 psi
C. 80–150 psi
D. 200–300 psi
Rationale: Air rotary drilling commonly uses 80–150 psi to effectively lift
cuttings while preventing formation damage.
, 7. Which type of bit is most commonly used in air rotary drilling for soft
to medium formations?
A. Diamond bit
B. Roller-cone bit
C. Chisel bit
D. Core barrel
Rationale: Roller-cone bits are versatile and effective in soft to medium
formations for air rotary drilling.
8. What is the main purpose of a stabilizer in air rotary drilling?
A. Increase air pressure
B. Keep the borehole straight and prevent deviation
C. Reduce bit wear
D. Lift cuttings
Rationale: Stabilizers centralize the drill string to minimize borehole
deviation and improve drilling efficiency.
9. Which of the following is a potential hazard specific to air rotary
drilling?
A. Water contamination
B. Compressed air blowout
Exam (Exam D) Practice Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary purpose of air rotary drilling in groundwater
exploration?
A. To drill through soft soil only
B. To create permanent wells
C. To penetrate unconsolidated and consolidated formations
efficiently
D. To reduce water usage during drilling
Rationale: Air rotary drilling uses compressed air to efficiently remove
cuttings from a variety of formations, making it effective in both
unconsolidated and consolidated formations.
, 2. Which type of drilling fluid is typically used in air rotary drilling?
A. Water-based mud
B. Compressed air or foam
C. Oil-based mud
D. Bentonite slurry
Rationale: Air or foam is used to lift cuttings to the surface and prevent
hole collapse in air rotary drilling.
3. What is the most common method of removing cuttings in air rotary
drilling?
A. Bucket auger
B. Air lift
C. Cable tool percussion
D. Jetting with water
Rationale: Air lift created by compressed air forces cuttings to the surface
efficiently, which is the standard method in air rotary drilling.
4. What is the primary advantage of using dual-wall drill rods?
A. Reduce drilling speed
B. Reduce energy consumption
, C. Provide both air circulation and structural support
D. Eliminate need for casing
Rationale: Dual-wall rods allow air to circulate through the inner tube
while providing structural support through the outer wall.
5. When drilling through unconsolidated formations, what is a common
problem that may occur?
A. Excessive rotation
B. Hole collapse
C. Overheating of the bit
D. Air contamination
Rationale: Unconsolidated formations lack cohesion, making them prone
to caving or collapsing without proper drilling methods.
6. What is the typical range of air pressure used in air rotary drilling?
A. 10–20 psi
B. 20–40 psi
C. 80–150 psi
D. 200–300 psi
Rationale: Air rotary drilling commonly uses 80–150 psi to effectively lift
cuttings while preventing formation damage.
, 7. Which type of bit is most commonly used in air rotary drilling for soft
to medium formations?
A. Diamond bit
B. Roller-cone bit
C. Chisel bit
D. Core barrel
Rationale: Roller-cone bits are versatile and effective in soft to medium
formations for air rotary drilling.
8. What is the main purpose of a stabilizer in air rotary drilling?
A. Increase air pressure
B. Keep the borehole straight and prevent deviation
C. Reduce bit wear
D. Lift cuttings
Rationale: Stabilizers centralize the drill string to minimize borehole
deviation and improve drilling efficiency.
9. Which of the following is a potential hazard specific to air rotary
drilling?
A. Water contamination
B. Compressed air blowout
