Free Exam E/F: Mud Rotary Drilling Practice Questions

Sample Practice Questions

Try these 10 sample questions from the Exam E/F: Mud Rotary Drilling practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1A driller is about to raise the mast of a truck-mounted mud rotary rig near an unguarded overhead distribution line rated at 13.8 kV. Under the OSHA clearance rule summarized in NIOSH guidance for water well drillers, what minimum distance must the equipment keep from the line?

   1. A. 4 feet
   2. B. 10 feet
   3. C. 20 feet
   4. D. 35 feet

   Answer: B

   Explanation: NIOSH summarizes the OSHA rule 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 13.8 kV line is below 50,000 volts, so no adder applies and 10 feet is the minimum. Four feet is the reduced clearance allowed only for equipment in transit with its structure lowered, not for a raised mast; 20 and 35 feet are larger recommended distances, not the regulatory minimum.

   Reference: Electrocution Is the Leading Cause of On-the-Job Death for Water Well Drillers (NIOSH) — Page 1, sidebar summarizing the OSHA overhead power line clearance regulation

2. 2Starting in loose sand and clay overburden, a mud rotary hole will continue down into shale and sandstone bedrock. According to the EPA monitoring-well handbook, which bit pairing is typical for these two materials?

   1. A. Drag or fishtail bit in the overburden; tricone bit in the bedrock
   2. B. Tricone bit in the overburden; drag or fishtail bit in the bedrock
   3. C. Fishtail bit in the overburden; drag-type blade bit in the bedrock
   4. D. Tricone bit in the overburden; fishtail blade bit in the bedrock

   Answer: A

   Explanation: The handbook states: "Unconsolidated deposits are sometimes drilled with drag or fishtail-type bits, and consolidated formations such as sandstone and shale are drilled with tricone bits." The overburden is unconsolidated (drag or fishtail bit) and the sandstone and shale are consolidated (tricone bit). The tempting reversal puts a drag or fishtail bit in bedrock, which the handbook assigns only to unconsolidated deposits.

   Reference: Handbook of Suggested Practices for the Design and Installation of Ground-Water Monitoring Wells (EPA/600/4-89/034) — Direct Mud Rotary (drilling methods), pp. 40-41

3. 3A new helper on a mud rotary rig sees mud draining slowly from the Marsh funnel and concludes that the mud must also be very heavy. How should the driller correct this understanding?

   1. A. Funnel viscosity rises in step with mud weight, so a slow funnel time confirms heavy mud
   2. B. Viscosity and weight are separate properties; a viscous mud can weigh barely more than water
   3. C. A slow funnel time means high solids, so the mud must weigh at least 10 pounds per gallon
   4. D. Funnel viscosity reflects only sand content, so the funnel time also gives the mud weight

   Answer: B

   Explanation: USGS TWRI 2-F1 warns that many people treat viscosity as a weight property and states: "However, a viscous mud actually can be only slightly heavier than water; conversely, a heavy mud might be low in viscosity." A slow Marsh funnel time therefore says the mud is thick, not that it is heavy; weight must be checked separately with a mud balance. The tempting idea that funnel time rises in step with weight is exactly the confusion the manual corrects.

   Reference: Application of Drilling, Coring, and Sampling Techniques to Test Holes and Wells (USGS TWRI Book 2, Chapter F1) — Hydraulic-Rotary Drilling, Drilling Mud, p. 19

4. 4A homeowner asks why the driller is spending a day developing a newly completed mud-rotary well before the pump is set. According to the Bureau of Reclamation Ground Water Manual, what is the primary purpose of well development?

   1. A. To verify plumbness and alignment of the casing and screen string
   2. B. To obtain maximum production efficiency from the completed well
   3. C. To kill bacteria introduced into the well during construction work
   4. D. To measure aquifer transmissivity for the well's water-rights file

   Answer: B

   Explanation: The Ground Water Manual states: "The primary purpose of well development or stimulation is to obtain maximum production efficiency from the well." Plumbness and alignment checks are construction checks, killing bacteria is the separate sterilization step, and aquifer testing is not the purpose of development.

   Reference: Ground Water Manual, Second Edition (Bureau of Reclamation) — Chapter XII, sec. 12-8 Well Development

5. 5Under the EPA Region 4 procedure for managing investigation-derived waste, where is it recommended that non-hazardous drill cuttings and spent drilling mud be placed for disposal?

   1. A. Into the facility's dumpsters, with permission from the facility's operator
   2. B. Into the mud pit, then covered over in place with the excavated native soil
   3. C. Into a unit with an environmental permit, such as a landfill or sanitary sewer
   4. D. Into a municipal dumpster, with written permission from the dumpster's owner

   Answer: C

   Explanation: The procedure says of non-hazardous IDW such as drill cuttings and drilling mud: "It is recommended that these materials be placed into a unit with an environmental permit, such as a landfill or sanitary sewer. These materials must not be placed into dumpsters." A permitted unit is therefore the recommended destination. The dumpster options are tempting because the same procedure lets non-hazardous PPE and paper go into facility or municipal dumpsters with permission, but cuttings and mud are expressly barred from dumpsters, and burying them in the mud pit is not the recommended disposal.

   Reference: Management of Investigation Derived Waste (EPA Region 4 Operating Procedure) — Section 3, Management of Non-Hazardous IDW, page 4

6. 6Your crew must set up a rig with its mast raised near a transmission line operating at 150 kV. Using the OSHA clearance rule as summarized in NIOSH guidance for water well drillers, what minimum clearance must the raised mast keep from the line?

   1. A. 10 feet 0 inches
   2. B. 15 feet 0 inches
   3. C. 13 feet 4 inches
   4. D. 7 feet 4 inches

   Answer: C

   Explanation: NIOSH summarizes the OSHA rule: "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 100 kV (100,000 volts) above 50 kV, which is 10 steps of 10,000 volts, or 40 inches, so the clearance is 10 ft + 3 ft 4 in = 13 ft 4 in. Using 10 feet leaves out the adder. Using 15 feet applies the adder to all 150 kV instead of only the part above 50 kV. Using 7 feet 4 inches starts from the 4-foot transit value.

   Reference: Electrocution Is the Leading Cause of On-the-Job Death for Water Well Drillers (NIOSH) — Page 1, sidebar summarizing the OSHA overhead power line clearance regulation

7. 7On a top-head-drive mud rotary rig, the operator can apply bit weight with the rig's pull-down system or by adding drill collars. Which statement correctly describes how each method loads the bit?

   1. A. Collars transfer rig weight to the bit; pull-down adds weight directly to the stem
   2. B. Pull-down transfers pump pressure to the bit; collars add weight directly to the stem
   3. C. Pull-down transfers rig weight to the bit; collars add weight directly to the stem
   4. D. Pull-down transfers rig weight to the bit; collars add weight by raising pump pressure

   Answer: C

   Explanation: The handbook explains: "Pull-down devices transfer rig weight to the bit; drill collars add weight directly to the drill stem." Pull-down uses the rig's own weight pushing down on the string, while heavy collars hang just above the bit and add their weight to the drill stem. Swapping the two roles (collars transferring rig weight) is the most tempting error; neither method works through mud pump pressure.

   Reference: Handbook of Suggested Practices for the Design and Installation of Ground-Water Monitoring Wells (EPA/600/4-89/034) — Direct Mud Rotary (drilling methods), p. 40

8. 8Planning the mud program for a production well in a permeable sand aquifer, a driller must choose a target mud weight. Which approach does USGS TWRI 2-F1 recommend?

   1. A. Use the heaviest mud the pump can circulate, so the extra weight gives the most wall support
   2. B. Keep the mud at about 11 pounds per gallon so the column overbalances every water zone
   3. C. Let the clay content of the cuttings set the weight, so native solids build the final mud
   4. D. Use the lightest mud weight that still controls the formation pressures and caving in the hole

   Answer: D

   Explanation: The manual advises: "In general, use the lightest weight drilling mud possible considering the formation pressures and caving problems that may be encountered. The lighter weight muds will result in shallower invasion of permeable zones, thus permitting easier development of the aquifer upon completion of the well." Heavier mud does not simply add safety; it pushes mud deeper into permeable zones and makes later development harder, so the heaviest-possible or fixed high-weight options are wrong.

   Reference: Application of Drilling, Coring, and Sampling Techniques to Test Holes and Wells (USGS TWRI Book 2, Chapter F1) — Hydraulic-Rotary Drilling, Drilling Mud, p. 19

9. 9A driller is estimating how much development effort different drilling methods will leave behind in a sand aquifer. According to USGS TWRI Book 2, Chapter F1, which standard drilling method causes the most aquifer damage and the greatest need for development?

   1. A. Cable tool
   2. B. Air rotary
   3. C. Mud rotary
   4. D. Reverse rotary

   Answer: C

   Explanation: TWRI 2-F1 ranks the methods: "The standard drilling methods that cause the most damage to the aquifer and result in greater need for development are: (1) mud rotary, particularly when proper drilling-mud control is not practiced;" Cable tool (casing compaction), reverse rotary and air rotary are listed after mud rotary, with air rotary described as probably the cleanest.

   Reference: Application of Drilling, Coring, and Sampling Techniques to Test Holes and Wells (USGS TWRI Book 2, Chapter F1) — Well-Development Techniques

10. 10A crew has several drums of non-hazardous development water from a monitoring well it just finished. Under EPA Region 4's IDW procedure, where may this water be poured when site conditions permit?

    1. A. Onto the ground surface up gradient of the monitoring well
    2. B. Back down the casing of the same monitoring well it came from
    3. C. Onto the ground surface right around the monitoring wellhead
    4. D. Onto the ground surface down gradient of the monitoring well

    Answer: D

    Explanation: The procedure states: "Non-hazardous monitoring well purge or development water may also be poured onto the ground down gradient of the monitoring well when site conditions permit." It adds: "Under no circumstances, however, should monitoring well purge water be placed back into the well from which it came." Down gradient is the permitted location; up gradient or right at the wellhead would let the water drain back toward the well, and returning the water to the well it came from is prohibited.

    Reference: Management of Investigation Derived Waste (EPA Region 4 Operating Procedure) — Section 3, Management of Non-Hazardous IDW, pages 4-5