Free Exam G: Reverse Circulation Drilling Practice Questions

Sample Practice Questions

Try these 10 sample questions from the Exam G: Reverse Circulation Drilling practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1A reverse-circulation crew is spotting its rig beside a 13,800-volt overhead distribution line. Under the OSHA rule that NIOSH summarizes for water well drillers, what minimum clearance must the equipment keep from that line?

   1. A. At least 15 feet away
   2. B. At least 10 feet away
   3. C. At least 20 feet away
   4. D. At least 35 feet away

   Answer: B

   Explanation: NIOSH summarizes 29 CFR 1910.333(c)(3)(iii)(A) for water well drillers: "Power lines up to 50,000 volts – keep equipment at least 10 feet away, plus an additional 4 inches for every 10,000 volts above 50,000." A 13,800-volt line is below 50,000 volts, so the required minimum is 10 feet. The 35-foot figure is NIOSH's more conservative recommendation, not the regulatory minimum asked for here.

   Reference: Electrocution is the leading cause of on-the-job death for water well drillers (NIOSH IC 9485, DHHS (NIOSH) Publication No. 2006-113) — Page 1, box "OSHA Regulations - 29 CFR 1910.333 (c)(3)(iii)(A) (summarized)"

2. 2Before raising the mast of a reverse-circulation rig, the driller learns that a nearby transmission line carries 115,000 volts. Applying the OSHA clearance rule as NIOSH summarizes it, what minimum distance must the equipment keep from this line?

   1. A. About 13 feet 10 inches
   2. B. About 10 feet 0 inches
   3. C. About 12 feet 2 inches
   4. D. About 31 feet 8 inches

   Answer: C

   Explanation: The summarized rule is "Power lines up to 50,000 volts – keep equipment at least 10 feet away, plus an additional 4 inches for every 10,000 volts above 50,000." The line is 65,000 volts above 50,000 (6.5 increments of 10,000 volts), so 6.5 x 4 inches = 26 inches is added to 10 feet, giving about 12 feet 2 inches. Applying the adder to the full 115,000 volts gives 13 feet 10 inches, ignoring the adder gives 10 feet, and adding 4 inches per 1,000 volts gives 31 feet 8 inches.

   Reference: Electrocution is the leading cause of on-the-job death for water well drillers (NIOSH IC 9485, DHHS (NIOSH) Publication No. 2006-113) — Page 1, box "OSHA Regulations - 29 CFR 1910.333 (c)(3)(iii)(A) (summarized)"

3. 3NIOSH notes the 10-foot OSHA minimum but gives water well drillers a more conservative working distance for overhead lines. How far does NIOSH advise keeping all parts of a reverse-circulation rig from power lines?

   1. A. At least 20 feet away
   2. B. At least 50 feet away
   3. C. At least 10 feet away
   4. D. At least 35 feet away

   Answer: D

   Explanation: NIOSH tells drillers: "Play it safe – keep all parts of your equipment at least 35 feet away from power lines." The 10-foot figure is the OSHA minimum for lines up to 50,000 volts, which NIOSH treats as a floor rather than its recommended working distance.

   Reference: Electrocution is the leading cause of on-the-job death for water well drillers (NIOSH IC 9485, DHHS (NIOSH) Publication No. 2006-113) — Page 2, "Overhead power line safety job site tips"

4. 4While the driller raises the mast of a reverse-circulation rig on a site crossed by an overhead line, where does NIOSH recommend the driller stand, and what should the helper be doing?

   1. A. Driller on the operator's platform, helper posted as a lookout
   2. B. Driller on the ground by the controls, helper posted as a lookout
   3. C. Driller on the operator's platform, helper holding a tag line
   4. D. Driller on the ground by the controls, helper holding a tag line

   Answer: A

   Explanation: NIOSH advises: "When raising or lowering the mast, stand on the operator’s platform. Use your helper as a lookout to make sure the mast is always at least 10 feet from any power lines." Standing on the ground while touching the controls would put the driller in the path between an energized rig and the ground, and a helper holding a line attached to the mast would also be in contact with the equipment.

   Reference: Electrocution is the leading cause of on-the-job death for water well drillers (NIOSH IC 9485, DHHS (NIOSH) Publication No. 2006-113) — Page 2, "Overhead power line safety job site tips"

5. 5The mast of a reverse-circulation rig touches an energized overhead line while the driller is at the controls on the rig, and nothing is on fire. According to NIOSH, what should the driller do?

   1. A. Step down onto the ground and walk away from the rig
   2. B. Stay in place on the rig and try to move the mast away
   3. C. Jump clear of the rig and hop away with feet together
   4. D. Climb down holding the rail and call the power utility

   Answer: B

   Explanation: NIOSH's steps state: "If you are on board the drill rig or hoist truck, stay in place unless it is on fire and you must get off." and "If you are on board a drill rig or hoist truck that is energized due to contact with an overhead power line, try to move the mast or boom at least 10 ft away from the lines." Jumping clear is reserved for a rig that is on fire; stepping or climbing down would make the driller a path to ground.

   Reference: Electrocution is the leading cause of on-the-job death for water well drillers (NIOSH IC 9485, DHHS (NIOSH) Publication No. 2006-113) — Page 3, "Follow these steps if your equipment contacts an overhead power line," step 1

6. 6A reverse-circulation rig that is in contact with a live power line catches fire, so the driller must leave the operator's platform. How does NIOSH say the driller should get off and move away?

   1. A. Jump clear, land upright with feet together, then shuffle or hop away
   2. B. Jump clear, land and roll to one side, then run quickly away from it
   3. C. Climb down keeping one hand on the rig rail, then shuffle or hop away
   4. D. Jump clear, land with feet spread wide apart, then walk briskly away

   Answer: A

   Explanation: NIOSH instructs: "Jump clear of the rig and land upright with your feet close together. Be sure not to fall backward and contact the rig. Move away with short shuffling steps or by hopping." Keeping a hand on the rig while stepping to the ground, landing with feet apart, or running all expose the driller to the voltage difference around an energized rig.

   Reference: Electrocution is the leading cause of on-the-job death for water well drillers (NIOSH IC 9485, DHHS (NIOSH) Publication No. 2006-113) — Page 1, "How to get off equipment in contact with an overhead power line"

7. 7A helper on the ground sees the driller collapse on a reverse-circulation rig whose mast is resting against a power line. According to NIOSH, at what point may the helper approach to give aid?

   1. A. Once the line appears to have deenergized automatically
   2. B. Once wearing dry leather gloves and rubber-soled boots
   3. C. Once the utility has deenergized the line and equipment
   4. D. Once the rig engine has been shut off at the ground panel

   Answer: C

   Explanation: NIOSH directs: "Call the utility company and wait for them to deenergize the lines." and "Never attempt to assist an injured worker until the equipment is deenergized. If power lines appear to deenergize automatically, stay away; the lines could automatically reenergize." Shutting off the rig engine does not remove line voltage from the rig, and work gloves or boots are not protection against a line operating at thousands of volts.

   Reference: Electrocution is the leading cause of on-the-job death for water well drillers (NIOSH IC 9485, DHHS (NIOSH) Publication No. 2006-113) — Page 3, "Follow these steps if your equipment contacts an overhead power line," step 5

8. 8A reverse-circulation crew is deciding where to stack drill pipe and park the water truck on a lot where a service drop crosses one corner. What does NIOSH advise about that corner of the site?

   1. A. Keep pipe and trucks out from under or near the service drop
   2. B. Stack pipe under the drop only if the stack stays under 10 feet
   3. C. Park trucks under the drop only while their booms are stowed
   4. D. Use the area under the drop if those service wires are insulated

   Answer: A

   Explanation: NIOSH advises: "Never store supplies or park equipment under or near power lines." and "Avoid working near any lines, including service drops." It also warns that "Most overhead power lines are not insulated.", so assuming a drop is insulated, limiting stack height, or stowing booms does not make storage beneath it acceptable.

   Reference: Electrocution is the leading cause of on-the-job death for water well drillers (NIOSH IC 9485, DHHS (NIOSH) Publication No. 2006-113) — Page 2, "Overhead power line safety job site tips"

9. 9A city is choosing a drilling method for a large production well in unconsolidated sediments. NGWA describes reverse circulation rigs as primarily associated with wells in which diameter range?

   1. A. 12 to 20 inches in diameter
   2. B. 6 to 12 inches in diameter
   3. C. 24 to 50 inches in diameter
   4. D. 2 to 4 inches in diameter

   Answer: C

   Explanation: NGWA states: "These rigs are primarily associated with drilling large diameter wells in unconsolidated material ranging from 24 inches to 50 inches in diameter and up to 1000 feet deep." Smaller diameters such as 6 to 12 inches are typical of other rotary methods used for domestic wells, not the large-diameter work that defines reverse circulation.

   Reference: Reverse Circulation Drilling Method (NGWA Wellowner.org) — Reverse Circulation page, video transcript, paragraph 2

10. 10On a reverse circulation job the crew keeps hauling makeup water because a significant amount of fluid is lost from the borehole into the formation. What cause does NGWA give for this loss?

    1. A. The large drag bit fractures the formation and opens new flow paths
    2. B. The high upward pipe velocity forces fluid out into the borehole wall
    3. C. The flanged drill pipe joints leak fluid into the formation as it turns
    4. D. The water-based fluid has no bentonite to seal the borehole wall

    Answer: D

    Explanation: NGWA explains that "a significant amount of fluid is displaced and lost to the original formation as this system does not typically use bentonite and therefore does not entirely seal the hole during drilling." Fluid inside the drill pipe is moving up toward the pump, so pipe velocity and pipe joints are not what drives fluid into the wall.

    Reference: Reverse Circulation Drilling Method (NGWA Wellowner.org) — Reverse Circulation page, video transcript, paragraph 6