NGWA Cable Tool Drilling Certification Exam A & B Practice Bank (2026/2027) — Verified Questions, Answers & Rationales

NGWA CABLE TOOL DRILLING EXAM (A/B) – COMPLETE
PRACTICE QUESTION BANK (1–200)



1. What is the fundamental mechanism by which a cable tool rig removes rock
while drilling?

 A) High-speed rotation grinding the rock into fine particles
 B) Chemical injection that dissolves the rock formation
 C) Repeated percussion and lifting that crushes and removes cuttings
 D) High-pressure water jets that erode the formation

Correct Answer: C) Repeated percussion and lifting that crushes and removes
cuttings

Rationale: Cable tool drilling is a percussive method. It operates by repeatedly lifting and
dropping a heavy steel bit to fracture and crush the rock. The cuttings are then removed
from the hole using a bailer, distinguishing it from rotary or hydraulic methods.




2. Which structural component on a cable tool rig is responsible for supporting the
drilling line, tools, and hoisting system?

 A) The walking beam
 B) The swivel
 C) The bull reel
 D) The derrick

Correct Answer: D) The derrick

Rationale: The derrick is the tall, framework-like tower on the rig. Its primary function is to
provide the necessary structural height and support for the drilling line, pulleys, and
suspended drilling tools, allowing them to be lifted and dropped effectively.

, 3. What is the specific purpose of the "swivel" in the cable tool drilling assembly?

 A) To rotate the entire drill string continuously
 B) To serve as the connection point that suspends and releases the drilling tools
 C) To pump drilling fluid down the hole
 D) To measure the electrical resistivity of the formation

Correct Answer: B) To serve as the connection point that suspends and releases the
drilling tools

Rationale: The swivel acts as the pivotal connector between the drilling line (coming from
the bull reel) and the drill stem. It allows the tools to be safely suspended, raised, and
dropped, and it facilitates the attachment and detachment of tools during tripping
operations.




4. The "walking beam" is a critical component that provides which specific action
to the drill string?

 A) A rotating motion to the drill bit
 B) A reciprocating up-and-down motion
 C) A hydraulic lifting force
 D) A vibrating motion to settle casing

Correct Answer: B) A reciprocating up-and-down motion

Rationale: The walking beam is a horizontal beam that pivots on a central fulcrum. As it
moves up and down via the pitman arm and crank, it translates the rotary motion of the
engine into the steady, vertical, reciprocating lifting and dropping action required for
percussion drilling.




5. What is the function of the "bull reel" on a cable tool drilling rig?

 A) To control the speed of the bailer line
 B) To wind and unwind the primary drilling wire line
 C) To store excess drilling mud
 D) To provide counterbalance to the walking beam

, Correct Answer: B) To wind and unwind the primary drilling wire line

Rationale: The bull reel is the large spool that holds the main drilling line. It is powered by
the rig's engine and is responsible for paying out line to lower the tools and reeling it in to
raise them, managing the depth and hoisting operations during drilling.




6. Why is a "sinker bar" incorporated into the cable tool drill string?

 A) To protect the drill bit from breaking on hard rock
 B) To act as a centralizer for the casing
 C) To add significant weight to the string, thereby increasing the percussion force
 D) To filter cuttings out of the drilling slurry

Correct Answer: C) To add significant weight to the string, thereby increasing the
percussion force

Rationale: The sinker bar is a heavy, solid steel bar placed directly above the drill bit. Its
weight provides the necessary mass and momentum to the dropping bit, ensuring it strikes
the formation with enough force to effectively crush and fracture the rock.




7. In the event that drilling tools become stuck in the borehole, what is the
primary purpose of the "drilling jars"?

 A) To increase the rotational speed of the stuck tools
 B) To deliver a sharp, upward jarring impact to help free the tools
 C) To inflate a packer to grip the casing
 D) To dissolve the surrounding rock with acid

Correct Answer: B) To deliver a sharp, upward jarring impact to help free the tools

Rationale: Drilling jars are telescoping tools placed in the drill stem. When the operator
pulls up on the line, the jars snap shut, delivering a powerful upward blow. This jarring
action helps to break the friction or mechanical lock that is holding the drill string or bit in
the hole.

, 8. Which material is most commonly and effectively used to manufacture cable
tool drilling bits?

 A) High-carbon steel
 B) Aluminum alloy
 C) Polycrystalline diamond compact (PDC)
 D) Tungsten carbide inserts

Correct Answer: A) High-carbon steel

Rationale: Cable tool bits have historically been, and continue to be, made from high-
quality, hardened steel. While modern bits may have other alloys, steel is the standard
because it provides the necessary toughness and impact resistance to withstand the
repeated heavy percussion without shattering.




9. When drilling through a formation characterized by large, loose boulders, which
specific bit shape is most appropriate?

 A) A straight, flat-bottom bit
 B) A center-bit with a pilot point
 C) A "Mother Hubbard" bit
 D) A "Star" bit

Correct Answer: D) A "Star" bit

Rationale: The star bit features a distinct cross-shaped cutting face with sharp, protruding
points. This design is specifically intended to "walk" or center itself on uneven surfaces and
is highly effective at catching, splitting, and breaking up large, hard boulders that would
cause other bits to glance off or bind.




10. In cable tool terminology, what does the process of "bailing" refer to?

 A) Securing the drill tools to the wire line