CPA Drilling & Production Techniques 2 — Questions and Answers
Question 1: What is the primary purpose of a blowout preventer (BOP) stack on a drilling rig?
- To increase drilling fluid circulation rate
- To seal the wellbore and prevent uncontrolled flow of formation fluids (Correct answer)
- To support the weight of the drill string
- To filter cuttings from the mud system
Correct answer: To seal the wellbore and prevent uncontrolled flow of formation fluids
A BOP stack is a series of valves installed at the wellhead to seal the wellbore and prevent blowouts caused by unexpected formation pressure.
Question 2: Which drilling method uses a continuous steel tube wound on a reel instead of individual drill pipe joints?
- Rotary drilling
- Coiled tubing drilling (Correct answer)
- Cable tool drilling
- Percussion drilling
Correct answer: Coiled tubing drilling
Coiled tubing drilling uses a continuous flexible steel tube that is unwound from a large reel and inserted into the wellbore without connections.
Question 3: What does 'WOB' stand for in drilling operations?
- Weight On Bit (Correct answer)
- Well Offset Benchmark
- Wellbore Orientation Bearing
- Water Oil Balance
Correct answer: Weight On Bit
WOB (Weight On Bit) is the downward force applied to the drill bit by the drill collars, which is critical for efficient penetration of formation rock.
Question 4: In directional drilling, what instrument measures the wellbore's inclination and azimuth?
- Gamma ray tool
- Measurement While Drilling (MWD) tool (Correct answer)
- Caliper log
- Density neutron tool
Correct answer: Measurement While Drilling (MWD) tool
MWD tools transmit real-time wellbore inclination and azimuth data to the surface while drilling, enabling directional control.
Question 5: What is a 'kick' in drilling terminology?
- Sudden increase in drill bit rotation speed
- Unplanned influx of formation fluid into the wellbore (Correct answer)
- Mechanical shock from hitting hard rock
- Rapid increase in surface pump pressure
Correct answer: Unplanned influx of formation fluid into the wellbore
A kick occurs when formation fluid (gas, oil, or water) enters the wellbore because formation pressure exceeds hydrostatic pressure of the drilling fluid.
Question 6: Which type of well completion allows reservoir fluids to flow through perforations in the casing?
- Open-hole completion
- Cased-hole perforated completion (Correct answer)
- Sand screen completion
- Gravel pack completion
Correct answer: Cased-hole perforated completion
In a cased-hole perforated completion, shaped charges create holes through the casing and cement to connect the reservoir to the wellbore.
Question 7: What is the function of drill collars in a bottom hole assembly (BHA)?
- To stabilize the wellbore walls
- To provide weight on bit and keep the drill string in tension (Correct answer)
- To circulate drilling fluid to the surface
- To measure formation pressures
Correct answer: To provide weight on bit and keep the drill string in tension
Drill collars are heavy-walled steel tubes that provide the necessary weight on bit while keeping the drill pipe above them in tension to prevent buckling.
CPA Drilling & Production Techniques 2
What is the primary purpose of a blowout preventer (BOP) stack on a drilling rig?