CPG Technology & Digital Tools 2 — Questions and Answers
Question 1: Which seismic attribute is most commonly used to identify direct hydrocarbon indicators (DHIs) such as bright spots?
- Coherence
- Amplitude (Correct answer)
- Frequency
- Phase
Correct answer: Amplitude
Amplitude anomalies (bright spots) are the most widely recognized DHI on seismic data, indicating gas-charged sands due to impedance contrast changes.
Question 2: In petrophysical software, what does the 'Archie equation' primarily calculate?
- Porosity from neutron logs
- Water saturation from resistivity logs (Correct answer)
- Permeability from core data
- Shale volume from gamma ray logs
Correct answer: Water saturation from resistivity logs
Archie's equation uses formation resistivity, water resistivity, and porosity to estimate water saturation in clean (non-shaly) reservoir rocks.
Question 3: What is the primary purpose of a velocity model in seismic processing?
- To filter noise from raw shot gathers
- To convert seismic travel times to depths (Correct answer)
- To enhance fault imaging on stacked sections
- To calculate acoustic impedance contrasts
Correct answer: To convert seismic travel times to depths
The velocity model is used to perform time-to-depth conversion and migration, transforming seismic travel times into accurate subsurface depth representations.
Question 4: Which GIS data format is most commonly used to store vector-based geological map data with associated attribute tables?
- GeoTIFF
- Shapefile (Correct answer)
- SEG-Y
- LAS
Correct answer: Shapefile
Shapefiles (ESRI format) store vector geometry (points, lines, polygons) plus attribute tables and are the standard for GIS-based geological mapping.
Question 5: In reservoir simulation, what does 'history matching' involve?
- Calibrating the model to reproduce observed production data (Correct answer)
- Predicting future production rates under different development scenarios
- Building the static geological model from well and seismic data
- Calculating original oil in place using volumetric methods
Correct answer: Calibrating the model to reproduce observed production data
History matching adjusts reservoir model parameters (permeability, transmissibility, contacts) until the simulation reproduces actual historical production and pressure data.
Question 6: What does 'LiDAR' technology measure when used in geological field mapping?
- Subsurface resistivity variations
- High-resolution surface topography via laser pulses (Correct answer)
- Airborne gravity anomalies
- Ground-penetrating radar reflections
Correct answer: High-resolution surface topography via laser pulses
LiDAR (Light Detection and Ranging) emits laser pulses and measures return times to create highly accurate digital elevation models of Earth's surface.
Question 7: In a well log suite, which tool measures the natural radioactivity of formations to estimate clay content?
- Spontaneous potential (SP) log
- Gamma ray (GR) log (Correct answer)
- Caliper log
- Density log
Correct answer: Gamma ray (GR) log
The gamma ray log measures natural radioactivity from potassium, uranium, and thorium, with high readings typically indicating clay-rich or shale intervals.
CPG Technology & Digital Tools 2
Which seismic attribute is most commonly used to identify direct hydrocarbon indicators (DHIs) such as bright spots?