CPG Cheat Sheet 2026

The 30 highest-yield CPG facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is the primary purpose of using a type well or type log in regional stratigraphic research? → To establish a standard reference section for correlation across the study area
2. What type of rock is most commonly associated with reservoir rocks? → Sandstone
3. What does the neutron-density crossplot primarily identify in formation evaluation? → Lithology and gas-bearing zones
4. Which professional body has primary jurisdiction over CPG certification and ethical enforcement in the United States? → American Association of Petroleum Geologists (AAPG)
5. In formation evaluation, what does 'nuclear magnetic resonance (NMR) logging' provide that conventional porosity logs cannot? → Pore size distribution and bound vs. free fluid volumes
6. Why is velocity analysis important in seismic data processing? → To ensure accurate depth imaging and interpretation
7. Which petrophysical parameter is most critical for assessing the economic viability of a tight gas or shale formation? → Total organic carbon (TOC) combined with effective porosity and gas saturation
8. A salt diapir can create hydrocarbon traps through which of the following mechanisms? → Flank anticlines, cap rock seals, and fault traps around the diapir
9. What is the primary purpose of a mud weight (density) window in well design? → To maintain wellbore pressure between pore pressure and fracture gradient
10. In a well log suite, which tool measures the natural radioactivity of formations to estimate clay content? → Gamma ray (GR) log
11. Which approach best demonstrates professional competency in CPG practice? → Integrating education, experience, and evidence-based decision making
12. In petroleum seismic data processing, what QC step helps detect systematic errors introduced by a faulty geophone group? → Shot gather QC
13. Which drilling parameter is monitored to detect a washout in the drill collar or bit? → Sudden decrease in standpipe pressure
14. What is the ethical obligation of a CPG who identifies a previously unrecognized geologic hazard during a routine reserve evaluation? → Document the hazard and inform the client and relevant authorities
15. In reservoir simulation, what does 'history matching' involve? → Calibrating the model to reproduce observed production data
16. Eustasy, as used in sequence stratigraphy, refers to: → Worldwide changes in absolute sea level independent of local tectonics
17. A well that is temporarily abandoned for more than one year without production typically requires the operator to: → Submit a Mechanical Integrity Test (MIT) and obtain approval to maintain inactive status
18. In NMR logging, what does the T2 distribution primarily represent? → Pore size distribution, with larger pores having longer T2 relaxation times
19. When testifying as an expert witness in a petroleum resource dispute, the CPG's primary obligation is to: → Present objective, technically defensible opinions regardless of which party benefits
20. A value stream map in petroleum project management is primarily used to: → Identify waste and non-value-adding steps across an entire workflow
21. Evaporite minerals such as halite and anhydrite most commonly form in which depositional setting? → Restricted marine basins or coastal sabkhas with evaporation exceeding water input
22. How do CPG professionals establish measurable quality objectives? → Defining specific, measurable, achievable, relevant, and time-bound targets
23. Which tectonic setting is MOST favorable for the formation of foreland basin petroleum systems? → Continental collision and thrust belt systems
24. In seismic stratigraphy, what is an 'onlap' configuration? → Reflectors terminate against an underlying surface in an up-dip direction
25. When integrating multiple independent datasets with conflicting results, the most defensible approach in evidence-based petroleum geoscience is to: → Weight datasets by their relative uncertainty and seek a reconciled interpretation
26. Subsidence analysis (backstripping) in basin analysis is primarily used to: → Separate tectonic subsidence from sediment loading effects
27. In seismic stratigraphy, reflections that terminate against an inclined surface in an updip direction (onlap) indicate: → Relative sea-level rise with sediment filling toward the basin margin
28. What does a structural trap rely on? → Folding or faulting of rock layers
29. In a mud logging QC program, which parameter most directly confirms that lag depth corrections are applied correctly? → Correlation of gas peaks with formation tops from offset wells
30. Which HSE-related risk is most directly assessed during well site selection for an onshore exploration well? → Subsurface pore pressure prediction and well control risk