NGWA - Air Rotary EXAM STUDY GUIDE
2026 COMPLETE QUESTIONS WITH
CORRECT DETAILED ANSWERS ||
100% GUARANTEED PASS
<RECENT VERSION>
1. What precautions must be used when sand seams are encountered in air
rotary drilling in unconsolidated formation? - ANSWER ✔ 1. Reduce Air
Pressure
Use of Foam or Polymers
Monitor Cuttings
Casing Advancement
Slow Drilling Rate
2. How are samples obtained in air rotary drilling in unconsolidated
formations? - ANSWER ✔ Continuous Sampling of Cuttings:
Split-Spoon Sampling
Drilling Fluids/Polymers
3. 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
,4. 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
Formation Composition.
5. What are some measures to keep wear down on the kelly bar? - ANSWER ✔
maintain alignment, use lubricants, inspect regularly, apply optimal weight
on the bit, and select suitable drilling fluids.
6. How can storage co-efficients be measured in unconsolidated formations? -
ANSWER ✔ using aquifer tests, where water levels are monitored in
observation wells during pumping, allowing for the calculation of storage
based on changes in water levels over time.
7. Assuming you have drilled down to rock and set the casing, what viscosity
mud should you have for continuing the drilling? Explain. - ANSWER ✔ 30
to 50 centipoise
8. What can change rates of penetration in rock formations? - ANSWER ✔
rock hardness, bit design, weight on bit, rotary speed, fluid properties, and
the presence of fractures or faults
9. After continuing into rock formations the centrifugal mud pump starts
cavitating. What should you do? - ANSWER ✔ reduce the pump speed,
check for any blockages in the suction line, ensure proper mud levels in the
pit, and verify that the mud viscosity is appropriate
, 10.What causes differential sticking? How can you best control against it
happening? - ANSWER ✔ Differential sticking occurs when a drill pipe gets
stuck against the walls of the borehole.
11.maintain proper mud weight, ensure good hole cleaning to prevent cuttings
buildup, monitor for pressure changes, and use drilling techniques that
minimize contact between the pipe and the borehole wall
12.What are bentonite materials? - ANSWER ✔ Bentonite materials are clay
minerals rich in montmorillonite, known for their absorbency and swelling
properties, commonly used in drilling fluids and various industrial
applications.
13.Gel-strength refers to what property in drilling fluid? - ANSWER ✔ the
ability of drilling fluid to develop a gel-like consistency when at rest, which
helps prevent the settling of solids and supports the weight of the drill string
during pauses in drilling.
14.Two holes drilled with mud rotary in the same rock formations have
different penetration rates. Explain the probable causes. - ANSWER ✔
variations in bit type, weight on bit, rotary speed, drilling fluid properties,
hole cleaning efficiency, and the presence of fractures or other geological
inconsistencies.
15.How do you measure high solids in drilling muds? What methods are used to
control solids build up? - ANSWER ✔ measured using centrifuges to assess
density and cuttings volume, while control methods include regular
monitoring, using shale shakers and centrifuges for removal, adding fluid
loss additives, and maintaining proper circulation rates.
2026 COMPLETE QUESTIONS WITH
CORRECT DETAILED ANSWERS ||
100% GUARANTEED PASS
<RECENT VERSION>
1. What precautions must be used when sand seams are encountered in air
rotary drilling in unconsolidated formation? - ANSWER ✔ 1. Reduce Air
Pressure
Use of Foam or Polymers
Monitor Cuttings
Casing Advancement
Slow Drilling Rate
2. How are samples obtained in air rotary drilling in unconsolidated
formations? - ANSWER ✔ Continuous Sampling of Cuttings:
Split-Spoon Sampling
Drilling Fluids/Polymers
3. 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
,4. 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
Formation Composition.
5. What are some measures to keep wear down on the kelly bar? - ANSWER ✔
maintain alignment, use lubricants, inspect regularly, apply optimal weight
on the bit, and select suitable drilling fluids.
6. How can storage co-efficients be measured in unconsolidated formations? -
ANSWER ✔ using aquifer tests, where water levels are monitored in
observation wells during pumping, allowing for the calculation of storage
based on changes in water levels over time.
7. Assuming you have drilled down to rock and set the casing, what viscosity
mud should you have for continuing the drilling? Explain. - ANSWER ✔ 30
to 50 centipoise
8. What can change rates of penetration in rock formations? - ANSWER ✔
rock hardness, bit design, weight on bit, rotary speed, fluid properties, and
the presence of fractures or faults
9. After continuing into rock formations the centrifugal mud pump starts
cavitating. What should you do? - ANSWER ✔ reduce the pump speed,
check for any blockages in the suction line, ensure proper mud levels in the
pit, and verify that the mud viscosity is appropriate
, 10.What causes differential sticking? How can you best control against it
happening? - ANSWER ✔ Differential sticking occurs when a drill pipe gets
stuck against the walls of the borehole.
11.maintain proper mud weight, ensure good hole cleaning to prevent cuttings
buildup, monitor for pressure changes, and use drilling techniques that
minimize contact between the pipe and the borehole wall
12.What are bentonite materials? - ANSWER ✔ Bentonite materials are clay
minerals rich in montmorillonite, known for their absorbency and swelling
properties, commonly used in drilling fluids and various industrial
applications.
13.Gel-strength refers to what property in drilling fluid? - ANSWER ✔ the
ability of drilling fluid to develop a gel-like consistency when at rest, which
helps prevent the settling of solids and supports the weight of the drill string
during pauses in drilling.
14.Two holes drilled with mud rotary in the same rock formations have
different penetration rates. Explain the probable causes. - ANSWER ✔
variations in bit type, weight on bit, rotary speed, drilling fluid properties,
hole cleaning efficiency, and the presence of fractures or other geological
inconsistencies.
15.How do you measure high solids in drilling muds? What methods are used to
control solids build up? - ANSWER ✔ measured using centrifuges to assess
density and cuttings volume, while control methods include regular
monitoring, using shale shakers and centrifuges for removal, adding fluid
loss additives, and maintaining proper circulation rates.
