NGWA Mud Rotary Drilling Certification Exam
(Exam E) – Practice Exam Questions And
Correct Answers (Verified Answers) Plus
Rationales
1. What is the primary purpose of drilling fluid in mud rotary drilling?
A. Increase drilling speed only
B. Cool the drill bit and stabilize the borehole
C. Reduce labor requirements
D. Eliminate the need for casing
Answer: B
Drilling fluid cools and lubricates the bit, carries cuFngs to the
surface, and helps stabilize the borehole.
2. Which component provides circulation of drilling mud?
A. Kelly
B. Swivel
C. Mud pump
D. Rotary table
Answer: C
The mud pump moves drilling fluid from the pit through the drill
string and back to the surface.
3. The main function of bentonite in drilling mud is to:
A. Increase hardness of formation
B. Provide viscosity and suspension
C. Improve fuel efficiency
, D. Prevent corrosion of tools
Answer: B
Bentonite increases viscosity, allowing cuFngs to be carried to
the surface.
4. What does mud viscosity primarily affect?
A. Bit rotation speed
B. Cuttings transport
C. Casing strength
D. Pump horsepower rating
Answer: B
Proper viscosity ensures efficient lifting of drill cuFngs.
5. Which drilling method uses circulating drilling fluid to remove
cuttings?
A. Cable tool drilling
B. Air rotary drilling
C. Mud rotary drilling
D. Driven well method
Answer: C
Mud rotary relies on drilling fluid circulation.
6. Excessive mud weight can cause:
A. Faster drilling
B. Formation fracturing
C. Reduced borehole pressure
D. Increased penetration rate
Answer: B
High mud weight can exceed formation pressure and fracture it.
, 7. What is the purpose of a shale shaker?
A. Mix drilling additives
B. Remove large cuttings from drilling mud
C. Increase mud density
D. Pump mud into the borehole
Answer: B
Shale shakers separate drilled cuFngs from returning mud.
8. Which property measures resistance of fluid to flow?
A. Density
B. pH
C. Viscosity
D. Filtration
Answer: C
Viscosity indicates how thick or thin the drilling fluid is.
9. What is the typical pH range for bentonite drilling mud?
A. 2–4
B. 4–6
C. 8–10
D. 12–14
Answer: C
A slightly alkaline pH supports bentonite performance.
10. The annulus is the space between:
A. Drill bit and formation only
B. Casing and ground surface
C. Drill string and borehole wall
D. Pump and mud pit
(Exam E) – Practice Exam Questions And
Correct Answers (Verified Answers) Plus
Rationales
1. What is the primary purpose of drilling fluid in mud rotary drilling?
A. Increase drilling speed only
B. Cool the drill bit and stabilize the borehole
C. Reduce labor requirements
D. Eliminate the need for casing
Answer: B
Drilling fluid cools and lubricates the bit, carries cuFngs to the
surface, and helps stabilize the borehole.
2. Which component provides circulation of drilling mud?
A. Kelly
B. Swivel
C. Mud pump
D. Rotary table
Answer: C
The mud pump moves drilling fluid from the pit through the drill
string and back to the surface.
3. The main function of bentonite in drilling mud is to:
A. Increase hardness of formation
B. Provide viscosity and suspension
C. Improve fuel efficiency
, D. Prevent corrosion of tools
Answer: B
Bentonite increases viscosity, allowing cuFngs to be carried to
the surface.
4. What does mud viscosity primarily affect?
A. Bit rotation speed
B. Cuttings transport
C. Casing strength
D. Pump horsepower rating
Answer: B
Proper viscosity ensures efficient lifting of drill cuFngs.
5. Which drilling method uses circulating drilling fluid to remove
cuttings?
A. Cable tool drilling
B. Air rotary drilling
C. Mud rotary drilling
D. Driven well method
Answer: C
Mud rotary relies on drilling fluid circulation.
6. Excessive mud weight can cause:
A. Faster drilling
B. Formation fracturing
C. Reduced borehole pressure
D. Increased penetration rate
Answer: B
High mud weight can exceed formation pressure and fracture it.
, 7. What is the purpose of a shale shaker?
A. Mix drilling additives
B. Remove large cuttings from drilling mud
C. Increase mud density
D. Pump mud into the borehole
Answer: B
Shale shakers separate drilled cuFngs from returning mud.
8. Which property measures resistance of fluid to flow?
A. Density
B. pH
C. Viscosity
D. Filtration
Answer: C
Viscosity indicates how thick or thin the drilling fluid is.
9. What is the typical pH range for bentonite drilling mud?
A. 2–4
B. 4–6
C. 8–10
D. 12–14
Answer: C
A slightly alkaline pH supports bentonite performance.
10. The annulus is the space between:
A. Drill bit and formation only
B. Casing and ground surface
C. Drill string and borehole wall
D. Pump and mud pit
