NGWA page 4
What are some advantages and/or disadvantages of the top head and table drive system?
- CORRECT ANSWER:
Top head drive:
Advantages: Direct torque, better control, less drill string wear.
Disadvantages: More expensive, complex maintenance.
Table Drive:
Advantages: Simpler, lower cost.
Disadvantages: Less control, higher drill string wear.
Why is it important to keep the bit in gauge?
- CORRECT ANSWER: Ensures proper hole diameter, prevents well collapse, and
maintains drilling efficiency.
How is the DHH drill bit sharpened?
- CORRECT ANSWER: By grinding the worn or rounded edges of the bit's cutting
surfaces, usually with specialized grinding tools.
How could a crooked hole be corrected using air rotary?
- CORRECT ANSWER: Using stabilizers, reducing weight on the bit, and adjusting the
drilling angle.
Explain various methods for setting casing using air rotary equipment.
- CORRECT ANSWER:
Driving: Use a hammer or rig to drive the casing down.
Rotating: Rotate the casing into place using the drill rig.
Pushing: Use the rig's hydraulic system to push the casing down.
What could cause lost circulation in air rotary drilling?
- CORRECT ANSWER: Fractured formations, porous zones, or high-pressure air forcing
fluids into surrounding formations.
How are air rotary rigs sized?
- CORRECT ANSWER:
Air compressor capacity (CFM/PSI)
Drilling depth capacity
Mast height
If up hole velocities decrease, what could be the probable cause?
- CORRECT ANSWER:
Reduced air pressure
What are some advantages and/or disadvantages of the top head and table drive system?
- CORRECT ANSWER:
Top head drive:
Advantages: Direct torque, better control, less drill string wear.
Disadvantages: More expensive, complex maintenance.
Table Drive:
Advantages: Simpler, lower cost.
Disadvantages: Less control, higher drill string wear.
Why is it important to keep the bit in gauge?
- CORRECT ANSWER: Ensures proper hole diameter, prevents well collapse, and
maintains drilling efficiency.
How is the DHH drill bit sharpened?
- CORRECT ANSWER: By grinding the worn or rounded edges of the bit's cutting
surfaces, usually with specialized grinding tools.
How could a crooked hole be corrected using air rotary?
- CORRECT ANSWER: Using stabilizers, reducing weight on the bit, and adjusting the
drilling angle.
Explain various methods for setting casing using air rotary equipment.
- CORRECT ANSWER:
Driving: Use a hammer or rig to drive the casing down.
Rotating: Rotate the casing into place using the drill rig.
Pushing: Use the rig's hydraulic system to push the casing down.
What could cause lost circulation in air rotary drilling?
- CORRECT ANSWER: Fractured formations, porous zones, or high-pressure air forcing
fluids into surrounding formations.
How are air rotary rigs sized?
- CORRECT ANSWER:
Air compressor capacity (CFM/PSI)
Drilling depth capacity
Mast height
If up hole velocities decrease, what could be the probable cause?
- CORRECT ANSWER:
Reduced air pressure
