Downhole Tools Maintenance Technician
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of a drilling jar in a bottom hole assembly?
a) To rotate the drill bit
b) To measure downhole pressure
c) To deliver an impact force to free stuck pipe
d) To centralize the drill string
Answer: c) To deliver an impact force to free stuck pipe
Rationale: Drilling jars are mechanical or hydraulic devices that store energy
and release it suddenly, generating an upward or downward blow to dislodge
stuck pipe.
2. Which type of jar fires when a preset tensile load is exceeded?
a) Hydraulic jar
b) Mechanical jar
c) Hydro-mechanical jar
d) Double-acting jar
Answer: b) Mechanical jar
Rationale: Mechanical jars rely on a detent or latch mechanism that releases
when the pull exceeds the preset load, providing a sudden impact.
3. During disassembly of a hydraulic drilling jar, what is the critical first step
after removing it from the string?
a) Sandblast the exterior
b) Drain the hydraulic oil completely
c) Apply heat to the connections
d) Immediately pressure test
, Answer: b) Drain the hydraulic oil completely
Rationale: Draining oil prevents contamination of the work area, allows
inspection of fluid condition, and avoids hydraulic lock during disassembly.
4. What torque value is most important to verify when redressing a mud motor
power section?
a) Rotor catch torque
b) Bit nozzle torque
c) Stator elastomer torque
d) Universal joint housing torque
Answer: a) Rotor catch torque
Rationale: Rotor catch torque verifies the interference fit between the rotor
and stator, indicating the condition of the elastomer and the motor’s power
output.
5. Which elastomer is commonly used in stator linings of positive displacement
mud motors for water-based mud?
a) Nitrile (NBR)
b) Fluoroelastomer (FKM)
c) Hydrogenated nitrile (HNBR)
d) Natural rubber
Answer: a) Nitrile (NBR)
Rationale: NBR offers good abrasion resistance and compatibility with water-
based drilling fluids at moderate temperatures.
6. A shock tool’s main function is to:
a) Increase weight on bit
b) Absorb axial vibrations and impact loads
c) Steer the bit directionally
d) Measure torque at the bit
Answer: b) Absorb axial vibrations and impact loads
Rationale: Shock tools use a spring, elastomer, or fluid-dampened mechanism
to dampen axial vibrations, protecting the bit and BHA components.
,7. When pressure testing a float valve, which standard specifies the low- and
high-pressure test criteria?
a) API 7-1
b) API 7-2
c) API 11D1
d) API 14A
Answer: a) API 7-1
Rationale: API 7-1 specifies performance properties for rotary drill stem
elements including float valves, defining test pressures and acceptance
criteria.
8. What is the typical drift gauge used to verify the minimum ID of a drill collar
after machining?
a) API ring gauge
b) Drift mandrel to API 7-2
c) Go/no-go plug gauge to API 7-1
d) Ultrasonic thickness gauge
Answer: c) Go/no-go plug gauge to API 7-1
Rationale: API 7-1 requires drill collars to pass a drift test with a specified
diameter go gauge over a defined length to ensure full bore access.
9. During inspection of a liner hanger slip assembly, the most critical wear point
to measure is:
a) Slip bowl taper angle
b) Slip surface wicker profile height
c) Setting sleeve OD
d) Cone ID
Answer: b) Slip surface wicker profile height
Rationale: Wicker teeth grip the casing; worn wickers reduce hanging
capacity. Measuring tooth height ensures adequate grip rating.
10.Which nondestructive testing method is preferred for detecting surface-
breaking cracks in threaded connections?
a) Ultrasonic testing
, b) Radiographic testing
c) Magnetic particle inspection (wet fluorescent)
d) Eddy current array
Answer: c) Magnetic particle inspection (wet fluorescent)
Rationale: Wet fluorescent MPI is highly sensitive to surface cracks and is the
standard method for thread root and shoulder inspection.
11.What is the primary reason for applying thread compound to rotary
shouldered connections?
a) To lock the connection permanently
b) To lubricate and provide a seal against downhole pressure
c) To prevent galling and control make-up friction
d) To increase break-out torque
Answer: c) To prevent galling and control make-up friction
Rationale: Thread compounds contain metallic or non-metallic solids that
reduce friction and prevent cold welding of thread surfaces under high
contact stress.
12.A technician measures the standoff of a rotary shouldered connection after
make-up. What does standoff verify?
a) Thread taper accuracy
b) Proper engagement and shoulder contact
c) Seal ring compression
d) Hydraulic locking
Answer: b) Proper engagement and shoulder contact
Rationale: Standoff (gap between shoulders or calculated position) confirms
that the connection has been made up to the design interference and
shoulder seal.
13.What is the correct procedure when a made-up connection shows zero
standoff before reaching final torque?
a) Continue tightening until torque is achieved
b) Break out, inspect for damage, and clean threads
c) Add extra thread compound
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of a drilling jar in a bottom hole assembly?
a) To rotate the drill bit
b) To measure downhole pressure
c) To deliver an impact force to free stuck pipe
d) To centralize the drill string
Answer: c) To deliver an impact force to free stuck pipe
Rationale: Drilling jars are mechanical or hydraulic devices that store energy
and release it suddenly, generating an upward or downward blow to dislodge
stuck pipe.
2. Which type of jar fires when a preset tensile load is exceeded?
a) Hydraulic jar
b) Mechanical jar
c) Hydro-mechanical jar
d) Double-acting jar
Answer: b) Mechanical jar
Rationale: Mechanical jars rely on a detent or latch mechanism that releases
when the pull exceeds the preset load, providing a sudden impact.
3. During disassembly of a hydraulic drilling jar, what is the critical first step
after removing it from the string?
a) Sandblast the exterior
b) Drain the hydraulic oil completely
c) Apply heat to the connections
d) Immediately pressure test
, Answer: b) Drain the hydraulic oil completely
Rationale: Draining oil prevents contamination of the work area, allows
inspection of fluid condition, and avoids hydraulic lock during disassembly.
4. What torque value is most important to verify when redressing a mud motor
power section?
a) Rotor catch torque
b) Bit nozzle torque
c) Stator elastomer torque
d) Universal joint housing torque
Answer: a) Rotor catch torque
Rationale: Rotor catch torque verifies the interference fit between the rotor
and stator, indicating the condition of the elastomer and the motor’s power
output.
5. Which elastomer is commonly used in stator linings of positive displacement
mud motors for water-based mud?
a) Nitrile (NBR)
b) Fluoroelastomer (FKM)
c) Hydrogenated nitrile (HNBR)
d) Natural rubber
Answer: a) Nitrile (NBR)
Rationale: NBR offers good abrasion resistance and compatibility with water-
based drilling fluids at moderate temperatures.
6. A shock tool’s main function is to:
a) Increase weight on bit
b) Absorb axial vibrations and impact loads
c) Steer the bit directionally
d) Measure torque at the bit
Answer: b) Absorb axial vibrations and impact loads
Rationale: Shock tools use a spring, elastomer, or fluid-dampened mechanism
to dampen axial vibrations, protecting the bit and BHA components.
,7. When pressure testing a float valve, which standard specifies the low- and
high-pressure test criteria?
a) API 7-1
b) API 7-2
c) API 11D1
d) API 14A
Answer: a) API 7-1
Rationale: API 7-1 specifies performance properties for rotary drill stem
elements including float valves, defining test pressures and acceptance
criteria.
8. What is the typical drift gauge used to verify the minimum ID of a drill collar
after machining?
a) API ring gauge
b) Drift mandrel to API 7-2
c) Go/no-go plug gauge to API 7-1
d) Ultrasonic thickness gauge
Answer: c) Go/no-go plug gauge to API 7-1
Rationale: API 7-1 requires drill collars to pass a drift test with a specified
diameter go gauge over a defined length to ensure full bore access.
9. During inspection of a liner hanger slip assembly, the most critical wear point
to measure is:
a) Slip bowl taper angle
b) Slip surface wicker profile height
c) Setting sleeve OD
d) Cone ID
Answer: b) Slip surface wicker profile height
Rationale: Wicker teeth grip the casing; worn wickers reduce hanging
capacity. Measuring tooth height ensures adequate grip rating.
10.Which nondestructive testing method is preferred for detecting surface-
breaking cracks in threaded connections?
a) Ultrasonic testing
, b) Radiographic testing
c) Magnetic particle inspection (wet fluorescent)
d) Eddy current array
Answer: c) Magnetic particle inspection (wet fluorescent)
Rationale: Wet fluorescent MPI is highly sensitive to surface cracks and is the
standard method for thread root and shoulder inspection.
11.What is the primary reason for applying thread compound to rotary
shouldered connections?
a) To lock the connection permanently
b) To lubricate and provide a seal against downhole pressure
c) To prevent galling and control make-up friction
d) To increase break-out torque
Answer: c) To prevent galling and control make-up friction
Rationale: Thread compounds contain metallic or non-metallic solids that
reduce friction and prevent cold welding of thread surfaces under high
contact stress.
12.A technician measures the standoff of a rotary shouldered connection after
make-up. What does standoff verify?
a) Thread taper accuracy
b) Proper engagement and shoulder contact
c) Seal ring compression
d) Hydraulic locking
Answer: b) Proper engagement and shoulder contact
Rationale: Standoff (gap between shoulders or calculated position) confirms
that the connection has been made up to the design interference and
shoulder seal.
13.What is the correct procedure when a made-up connection shows zero
standoff before reaching final torque?
a) Continue tightening until torque is achieved
b) Break out, inspect for damage, and clean threads
c) Add extra thread compound
