Work Exam Questions And Correct

CA D09 Drilling, Blasting & Oil Field Work Exam Questions And Correct Answers (Verified Answers) Plus Rationale2026 Q&A| Instant Download Pdf

• What is the primary purpose of drilling in oil field operations?
• Constructing pipelines
• Extracting minerals
• Accessing subsurface hydrocarbons
• Soil stabilization

Rationale: Drilling is conducted primarily to reach reservoirs

containing oil or gas to enable extraction.

• Which type of drilling fluid is most commonly used in oil wells?
• Water-based
• Air-based
• Mud-based (drilling mud)
• Oil-based only

Rationale: Drilling mud provides lubrication, cooling, and pressure

control during drilling operations.

• What is the function of a blowout preventer (BOP)?
• Increase drilling speed
• Prevent uncontrolled release of formation fluids
• Measure well depth
• Pump drilling fluid

Rationale: A BOP is a safety device installed to prevent blowouts,

which are uncontrolled flows of oil or gas. 1 / 3

• Which explosive is commonly used in controlled blasting in

construction and mining?

• TNT only
• Ammonium nitrate only
• ANFO (ammonium nitrate/fuel oil)
• Dynamite only

Rationale: ANFO is widely used due to cost-effectiveness, stability,

and ease of handling in blasting operations.

• What is the purpose of casing in drilling operations?
• Remove drill cuttings
• Increase drilling speed
• Prevent well collapse and isolate formations
• Measure drilling depth

Rationale: Casing lines the wellbore to maintain its integrity and

prevent contamination between subsurface layers.

• Which method is used to determine the direction of a drill bit

underground?

• Visual inspection
• Depth gauge
• Directional drilling surveying
• Gravity measurement

Rationale: Directional drilling techniques allow operators to steer the

well along a planned path.

• What does “spudding a well” mean?
• Closing the well
• Starting the drilling process
• Installing a casing
• Pumping oil

Rationale: Spudding refers to the initial penetration of the drill bit

into the ground to start a new well.

• What is the role of a detonator in blasting operations?
• Increase explosion speed
• Measure explosive energy
• Initiate the main explosive charge
• Stabilize rock formations

Rationale: A detonator triggers the explosive at a precise time to

achieve controlled blasting. 2 / 3

• In oil field drilling, what is “kick”?
• Pump malfunction
• Casing collapse
• Unexpected influx of formation fluids into the wellbore
• Drill bit breakage

Rationale: A kick indicates a sudden entry of oil, gas, or water into

the well, which can lead to a blowout if uncontrolled.

• Which of the following is a common safety measure during

blasting?

• Increasing explosive load
• Reducing drill speed
• Establishing a blast exclusion zone
• Ignoring weather conditions

Rationale: Safety protocols include evacuating personnel and

securing the area to prevent accidents.

• What is the main purpose of using a drill bit with tungsten

carbide inserts?

• Reduce drilling fluid viscosity
• Enhance cutting efficiency in hard rock
• Stabilize the wellbore
• Reduce borehole diameter

Rationale: Tungsten carbide is extremely hard and improves

penetration in tough rock formations.

• What is the typical role of a mud logger in drilling operations?
• Operate the drill rig
• Pump drilling fluid
• Monitor drilling parameters and analyze cuttings
• Set explosives

Rationale: Mud loggers track well conditions and geological

information for safety and decision-making.

13. In oil field terminology, “formation pressure” refers to:

• Atmospheric pressure
• Pump pressure
• Pressure of fluids in underground rock formations
• Casing pressure

Rationale: Formation pressure helps determine safe drilling practices

and prevents blowouts.

• / 3