Page 1 of 33
NGWA - Air Rotary EXAM 150 QUESTIONS
AND CORRECT ANSWERS LATEST UPDATE
THIS YEAR
QUESTION: Hole cleaning and penetration rates will vary with air rotary. What factors affect
cleaning and penetration? - ANSWER-Air Pressure and Volume
Formation Type
Bit Type and Condition
Drilling Fluid/Injection
Drill Pipe Size and Depth
Cutting Size and Volume
QUESTION: Why is information concerning the geology important in proper grouting of
unconsolidated formations? - ANSWER-Permeability of the Formation
Stability of the Formation
Formation Pressure
Groundwater Flow
1
, Page 2 of 33
Formation Composition.
QUESTION: When would you gravel pack a well? - ANSWER-When the formation is
unconsolidated, to prevent sand or fine material from entering the well, and to enhance water
flow by stabilizing the borehole
QUESTION: What formations are best to use a soft tri-cone bit? - ANSWER-clay, sand, or shale.
QUESTION: What functions must a drill pipe perform to drill unconsolidated formations? -
ANSWER-Transmit torque
circulate drilling fluid/air
support drill string weight
maintain borehole integrity
QUESTION: When would you use heavy drill collars? - ANSWER-to add weight on the bit,
stabilize the drill string, and prevent buckling in deep or hard formations.
2
, Page 3 of 33
QUESTION: Explain how chip catchers can aid in formation logging? - ANSWER-help collect
cuttings for accurate formation logging by preventing loss of samples during drilling, ensuring
representative data.
QUESTION: How does bit design vary with geology? - ANSWER-varies by formation hardness,
with softer formations needing wider teeth and harder formations requiring tougher, more
durable materials.
Q; What precautions must be used when sand seams are encountered in air rotary drilling in
unconsolidated formation? - ANSWER-1. Reduce Air Pressure
2. Use of Foam or Polymers
3. Monitor Cuttings
4. Casing Advancement
5. Slow Drilling Rate
QUESTION: How are samples obtained in air rotary drilling in unconsolidated formations? -
ANSWER-Continuous Sampling of Cuttings:
Split-Spoon Sampling
3
, Page 4 of 33
Drilling Fluids/Polymers
QUESTION: Heavy steel casing would best be used in what rotary process? - ANSWER-best used
in the air rotary process for stabilizing unconsolidated or collapsing formations.
QUESTION: What air compressor checks must be made daily? - ANSWER-Oil level
filters
belts
air pressure
leaks
QUESTION: What type of drill bit maintenance can be done in the field? - ANSWER-Cleaning
inspecting for wear
sharpening teeth
replacing damaged parts
4
NGWA - Air Rotary EXAM 150 QUESTIONS
AND CORRECT ANSWERS LATEST UPDATE
THIS YEAR
QUESTION: Hole cleaning and penetration rates will vary with air rotary. What factors affect
cleaning and penetration? - ANSWER-Air Pressure and Volume
Formation Type
Bit Type and Condition
Drilling Fluid/Injection
Drill Pipe Size and Depth
Cutting Size and Volume
QUESTION: Why is information concerning the geology important in proper grouting of
unconsolidated formations? - ANSWER-Permeability of the Formation
Stability of the Formation
Formation Pressure
Groundwater Flow
1
, Page 2 of 33
Formation Composition.
QUESTION: When would you gravel pack a well? - ANSWER-When the formation is
unconsolidated, to prevent sand or fine material from entering the well, and to enhance water
flow by stabilizing the borehole
QUESTION: What formations are best to use a soft tri-cone bit? - ANSWER-clay, sand, or shale.
QUESTION: What functions must a drill pipe perform to drill unconsolidated formations? -
ANSWER-Transmit torque
circulate drilling fluid/air
support drill string weight
maintain borehole integrity
QUESTION: When would you use heavy drill collars? - ANSWER-to add weight on the bit,
stabilize the drill string, and prevent buckling in deep or hard formations.
2
, Page 3 of 33
QUESTION: Explain how chip catchers can aid in formation logging? - ANSWER-help collect
cuttings for accurate formation logging by preventing loss of samples during drilling, ensuring
representative data.
QUESTION: How does bit design vary with geology? - ANSWER-varies by formation hardness,
with softer formations needing wider teeth and harder formations requiring tougher, more
durable materials.
Q; What precautions must be used when sand seams are encountered in air rotary drilling in
unconsolidated formation? - ANSWER-1. Reduce Air Pressure
2. Use of Foam or Polymers
3. Monitor Cuttings
4. Casing Advancement
5. Slow Drilling Rate
QUESTION: How are samples obtained in air rotary drilling in unconsolidated formations? -
ANSWER-Continuous Sampling of Cuttings:
Split-Spoon Sampling
3
, Page 4 of 33
Drilling Fluids/Polymers
QUESTION: Heavy steel casing would best be used in what rotary process? - ANSWER-best used
in the air rotary process for stabilizing unconsolidated or collapsing formations.
QUESTION: What air compressor checks must be made daily? - ANSWER-Oil level
filters
belts
air pressure
leaks
QUESTION: What type of drill bit maintenance can be done in the field? - ANSWER-Cleaning
inspecting for wear
sharpening teeth
replacing damaged parts
4
