NGWA - STUDY GUIDE - AIR ROTARY
EXAM WITH COMPLETE SOLUTIONS
What precautions must be used when sand seams are encountered in air rotary drilling
in unconsolidated formation? - ANS1. 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? -
ANSContinuous 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? - ANSAir 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? - ANSPermeability of the Formation
Stability of the Formation
Formation Pressure
Groundwater Flow
Formation Composition.
When would you gravel pack a well? - ANSWhen 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? - ANSclay, sand, or shale.
What functions must a drill pipe perform to drill unconsolidated formations? -
ANSTransmit torque
circulate drilling fluid/air
support drill string weight
maintain borehole integrity
, When would you use heavy drill collars? - ANSto 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? - ANShelp collect cuttings for
accurate formation logging by preventing loss of samples during drilling, ensuring
representative data.
How does bit design vary with geology? - ANSvaries 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? - ANSbest used in the
air rotary process for stabilizing unconsolidated or collapsing formations.
What air compressor checks must be made daily? - ANSOil level
filters
belts
air pressure
leaks
What type of drill bit maintenance can be done in the field? - ANSCleaning
inspecting for wear
sharpening teeth
replacing damaged parts
Differential sticking of drill pipe can be prevented by what methods? - ANSUse higher
mud flow
reduce drill string contact
maintain proper mud weight.
What common fishing tool are used in rotary drilling? - ANSOvershot
spear
fishing magnets
junk baskets
Regular maintenance of the rotary swivel consists of what? - ANSLubrication, 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? - ANSAirflow, foam injection, and polymer use.
How does air pressure change as the hole deepens? - ANSmust increase as the hole
deepens to maintain effective cuttings removal.
EXAM WITH COMPLETE SOLUTIONS
What precautions must be used when sand seams are encountered in air rotary drilling
in unconsolidated formation? - ANS1. 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? -
ANSContinuous 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? - ANSAir 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? - ANSPermeability of the Formation
Stability of the Formation
Formation Pressure
Groundwater Flow
Formation Composition.
When would you gravel pack a well? - ANSWhen 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? - ANSclay, sand, or shale.
What functions must a drill pipe perform to drill unconsolidated formations? -
ANSTransmit torque
circulate drilling fluid/air
support drill string weight
maintain borehole integrity
, When would you use heavy drill collars? - ANSto 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? - ANShelp collect cuttings for
accurate formation logging by preventing loss of samples during drilling, ensuring
representative data.
How does bit design vary with geology? - ANSvaries 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? - ANSbest used in the
air rotary process for stabilizing unconsolidated or collapsing formations.
What air compressor checks must be made daily? - ANSOil level
filters
belts
air pressure
leaks
What type of drill bit maintenance can be done in the field? - ANSCleaning
inspecting for wear
sharpening teeth
replacing damaged parts
Differential sticking of drill pipe can be prevented by what methods? - ANSUse higher
mud flow
reduce drill string contact
maintain proper mud weight.
What common fishing tool are used in rotary drilling? - ANSOvershot
spear
fishing magnets
junk baskets
Regular maintenance of the rotary swivel consists of what? - ANSLubrication, 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? - ANSAirflow, foam injection, and polymer use.
How does air pressure change as the hole deepens? - ANSmust increase as the hole
deepens to maintain effective cuttings removal.
