CWD Technology & Digital Tools 2 — Questions and Answers
Question 1: Which type of downhole camera system is best suited for inspecting casing integrity in a turbid, water-filled well?
- Standard optical camera with LED lights
- Sonar/acoustic imaging camera (Correct answer)
- Thermal infrared camera
- Ultraviolet fluorescence camera
Correct answer: Sonar/acoustic imaging camera
Sonar/acoustic imaging cameras use sound waves to image well interiors in murky or turbid water where optical cameras cannot see clearly.
Question 2: A driller uses a data logger during a pump test. What primary advantage does electronic data logging provide over manual reading?
- It eliminates the need for a submersible pump
- It captures continuous high-frequency water level measurements (Correct answer)
- It automatically calculates aquifer transmissivity
- It replaces the need for a wellhead seal
Correct answer: It captures continuous high-frequency water level measurements
Electronic data loggers record water levels at programmable intervals (e.g., every second), capturing transient data that manual readings would miss.
Question 3: What does the term 'mud weight' refer to when using electronic drilling instrumentation?
- The dry weight of drill cuttings per foot
- The density of drilling fluid measured in pounds per gallon (Correct answer)
- The total weight of the drill string
- The viscosity of the drilling fluid
Correct answer: The density of drilling fluid measured in pounds per gallon
Mud weight refers to the density of drilling fluid, typically measured in pounds per gallon (ppg), which is monitored to maintain proper borehole pressure.
Question 4: A GPS/GNSS survey unit on a drill rig is most commonly used to:
- Detect underground utilities before drilling
- Record precise borehole location coordinates for regulatory submittals (Correct answer)
- Measure formation dip angle during drilling
- Calibrate the rotary speed sensor
Correct answer: Record precise borehole location coordinates for regulatory submittals
GPS/GNSS units are used to record accurate latitude/longitude coordinates of the well location, which are required on most state well completion reports.
Question 5: Which software feature in modern well-design programs helps drillers ensure casing strings do not exceed tensile yield limits?
- Color-coded formation logs
- Load case analysis and casing stress modeling (Correct answer)
- Automated billing and invoice generation
- GPS mapping of nearby wells
Correct answer: Load case analysis and casing stress modeling
Casing stress modeling within well-design software calculates axial, burst, and collapse loads to ensure casing selection meets safety factors.
Question 6: When a magnetic multishot survey tool is run in a borehole, what does it measure?
- Formation resistivity at multiple depths
- Borehole inclination and azimuth at multiple stations (Correct answer)
- Acoustic velocity of the formation rock
- Groundwater temperature gradient
Correct answer: Borehole inclination and azimuth at multiple stations
A magnetic multishot tool records inclination (deviation from vertical) and azimuth (compass direction) at multiple depth stations to create a borehole trajectory survey.
Question 7: A driller reviews a digital formation evaluation log showing a spontaneous potential (SP) curve. A strong negative SP deflection typically indicates:
- A highly resistive, tight formation
- A permeable, porous sand or gravel formation (Correct answer)
- A zone of lost circulation
- The top of the water table
Correct answer: A permeable, porous sand or gravel formation
A negative SP deflection (deflecting left on a standard log) indicates a permeable, porous zone such as a sand or gravel aquifer relative to shale baseline.
CWD Technology & Digital Tools 2
Which type of downhole camera system is best suited for inspecting casing integrity in a turbid, water-filled well?