NGWA - Study Guide - Air Rotary/NGWA - STUDY GUIDE – WITH
VERIFIED AND WELL ANALYZED ANSWERS
What precautions must be used when sand seams are encountered in
air rotary drilling in unconsolidated formation?
1. Reduce Air Pressure
2. Use of Foam or Polymers
3. Monitor Cuttings
4. Casing Advancement
5. Slow Drilling Rate
How are samples obtained in air rotary drilling in unconsolidated
formations?
Continuous Sampling of Cuttings:
Split-Spoon Sampling
Drilling Fluids/Polymers
Hole cleaning and penetration rates will vary with air rotary. What
factors affect cleaning and penetration?
Air Pressure and Volume
Formation Type
Bit Type and Condition
Drilling Fluid/Injection
Drill Pipe Size and Depth
Cutting Size and Volume
Why is information concerning the geology important in proper
grouting of unconsolidated formations?
Permeability of the Formation
Stability of the Formation
Formation Pressure
Groundwater Flow
Formation Composition.
,When would you gravel pack a well?
When the formation is unconsolidated, to prevent sand or fine
material from entering the well, and to enhance water flow by
stabilizing the borehole
What formations are best to use a soft tri-cone bit?
clay, sand, or shale.
What functions must a drill pipe perform to drill unconsolidated
formations?
Transmit torque
circulate drilling fluid/air
support drill string weight
maintain borehole integrity
When would you use heavy drill collars?
to add weight on the bit, stabilize the drill string, and prevent buckling
in deep or hard formations.
Explain how chip catchers can aid in formation logging?
help collect cuttings for accurate formation logging by preventing
loss of samples during drilling, ensuring representative data.
How does bit design vary with geology?
varies by formation hardness, with softer formations needing wider
teeth and harder formations requiring tougher, more durable
materials.
Heavy steel casing would best be used in what rotary process?
best used in the air rotary process for stabilizing unconsolidated or
collapsing formations.
What air compressor checks must be made daily?
Oil level
filters
belts
air pressure
leaks
, What type of drill bit maintenance can be done in the field?
Cleaning
inspecting for wear
sharpening teeth
replacing damaged parts
Differential sticking of drill pipe can be prevented by what methods?
Use higher mud flow
reduce drill string contact
maintain proper mud weight.
What common fishing tool are used in rotary drilling?
Overshot
spear
fishing magnets
junk baskets
Regular maintenance of the rotary swivel consists of what?
Lubrication, checking for leaks, inspecting bearings, and replacing
worn seals.
What methods are used to clean the hole of cuttings in air rotary
drilling in unconsolidated formations?
Airflow, foam injection, and polymer use.
How does air pressure change as the hole deepens?
must increase as the hole deepens to maintain effective cuttings
removal.
What are the advantages and disadvantages of high pressure air
rotary drilling in unconsolidated formations?
Advantages: Faster drilling, efficient cuttings removal.
Disadvantages: Risk of formation collapse, loss of circulation,
potential for blowouts.
How does cost per foot air rotary compare with mud rotary in
unconsolidated formations?
VERIFIED AND WELL ANALYZED ANSWERS
What precautions must be used when sand seams are encountered in
air rotary drilling in unconsolidated formation?
1. Reduce Air Pressure
2. Use of Foam or Polymers
3. Monitor Cuttings
4. Casing Advancement
5. Slow Drilling Rate
How are samples obtained in air rotary drilling in unconsolidated
formations?
Continuous Sampling of Cuttings:
Split-Spoon Sampling
Drilling Fluids/Polymers
Hole cleaning and penetration rates will vary with air rotary. What
factors affect cleaning and penetration?
Air Pressure and Volume
Formation Type
Bit Type and Condition
Drilling Fluid/Injection
Drill Pipe Size and Depth
Cutting Size and Volume
Why is information concerning the geology important in proper
grouting of unconsolidated formations?
Permeability of the Formation
Stability of the Formation
Formation Pressure
Groundwater Flow
Formation Composition.
,When would you gravel pack a well?
When the formation is unconsolidated, to prevent sand or fine
material from entering the well, and to enhance water flow by
stabilizing the borehole
What formations are best to use a soft tri-cone bit?
clay, sand, or shale.
What functions must a drill pipe perform to drill unconsolidated
formations?
Transmit torque
circulate drilling fluid/air
support drill string weight
maintain borehole integrity
When would you use heavy drill collars?
to add weight on the bit, stabilize the drill string, and prevent buckling
in deep or hard formations.
Explain how chip catchers can aid in formation logging?
help collect cuttings for accurate formation logging by preventing
loss of samples during drilling, ensuring representative data.
How does bit design vary with geology?
varies by formation hardness, with softer formations needing wider
teeth and harder formations requiring tougher, more durable
materials.
Heavy steel casing would best be used in what rotary process?
best used in the air rotary process for stabilizing unconsolidated or
collapsing formations.
What air compressor checks must be made daily?
Oil level
filters
belts
air pressure
leaks
, What type of drill bit maintenance can be done in the field?
Cleaning
inspecting for wear
sharpening teeth
replacing damaged parts
Differential sticking of drill pipe can be prevented by what methods?
Use higher mud flow
reduce drill string contact
maintain proper mud weight.
What common fishing tool are used in rotary drilling?
Overshot
spear
fishing magnets
junk baskets
Regular maintenance of the rotary swivel consists of what?
Lubrication, checking for leaks, inspecting bearings, and replacing
worn seals.
What methods are used to clean the hole of cuttings in air rotary
drilling in unconsolidated formations?
Airflow, foam injection, and polymer use.
How does air pressure change as the hole deepens?
must increase as the hole deepens to maintain effective cuttings
removal.
What are the advantages and disadvantages of high pressure air
rotary drilling in unconsolidated formations?
Advantages: Faster drilling, efficient cuttings removal.
Disadvantages: Risk of formation collapse, loss of circulation,
potential for blowouts.
How does cost per foot air rotary compare with mud rotary in
unconsolidated formations?
