CPG Research Methods & Evidence-Based Practice 2 — Questions and Answers
Question 1: Which statistical method is most appropriate for identifying the relationship between porosity and permeability in a large core dataset?
- Chi-square test
- Linear regression analysis (Correct answer)
- Analysis of variance (ANOVA)
- Mann-Whitney U test
Correct answer: Linear regression analysis
Linear regression analysis quantifies the relationship between two continuous variables such as porosity and permeability.
Question 2: When evaluating published subsurface maps, a petroleum geologist should first assess:
- The color scheme used in the map
- The vintage, data density, and control point distribution (Correct answer)
- The publisher's reputation only
- The map scale without considering data quality
Correct answer: The vintage, data density, and control point distribution
Map vintage, data density, and control point distribution are fundamental quality indicators that govern reliability of interpreted surfaces.
Question 3: A geologist wants to integrate well log data with seismic data to improve reservoir characterization. Which approach best exemplifies evidence-based practice?
- Use seismic data alone to avoid conflicting interpretations
- Rely exclusively on analogue fields for reservoir parameters
- Cross-validate well-derived rock properties with seismic attributes at well locations before extrapolating (Correct answer)
- Apply a single interpretation without uncertainty assessment
Correct answer: Cross-validate well-derived rock properties with seismic attributes at well locations before extrapolating
Cross-validating well-derived properties with seismic attributes at calibration points ensures the relationship holds before spatial extrapolation.
Question 4: In petroleum geology research, what does a 'sensitivity analysis' primarily help determine?
- The optimal drilling mud weight
- Which input parameters most strongly influence the output estimate (Correct answer)
- The economic threshold for development
- The seismic acquisition geometry
Correct answer: Which input parameters most strongly influence the output estimate
Sensitivity analysis identifies which uncertain input variables drive the most variability in the output, guiding where to focus data acquisition.
Question 5: A P90 estimate in probabilistic resource assessment means:
- There is a 90% chance the resource is exactly that value
- There is a 90% probability the actual resource will be at least that amount (Correct answer)
- The resource estimate has 90% confidence in the mean
- 90% of wells in the area have exceeded that production rate
Correct answer: There is a 90% probability the actual resource will be at least that amount
P90 is the 10th percentile of a cumulative distribution, meaning 90% probability the true value meets or exceeds it (conservative estimate).
Question 6: Which type of bias occurs when a geologist preferentially collects samples from easily accessible outcrops rather than systematically sampling across a study area?
- Confirmation bias
- Sampling bias (Correct answer)
- Anchoring bias
- Publication bias
Correct answer: Sampling bias
Sampling bias results from non-random sample collection that causes certain data to be over- or under-represented.
Question 7: Which research design is most suitable for establishing a time-sequence relationship between diagenetic events in a carbonate reservoir?
- Cross-sectional study
- Randomized controlled experiment
- Longitudinal paragenetic sequence analysis (Correct answer)
- Case-control study
Correct answer: Longitudinal paragenetic sequence analysis
Paragenetic sequence analysis documents the chronological order of diagenetic events using crosscutting relationships and geochemical data.
CPG Research Methods & Evidence-Based Practice 2
Which statistical method is most appropriate for identifying the relationship between porosity and permeability in a large core dataset?