Intermediate Petrophysics · Module I6
Petrophysical Driver Ranking
Sensitivity analysis for petrophysical inputs: how cut-offs, porosity, saturation and contact uncertainty move in-place volumes, how to build and read a tornado chart, and how to turn a driver ranking into a data-acquisition recommendation.
- Level
- Intermediate
- Position
- Module 6 of 8
- Video
- About 20 minutes, narrated
- Format
- Narrated video lesson and slide reading view; with the certified option, a quiz whose pass unlocks the next module.
What the module covers
- What sensitivity analysis means in petrophysics
- Building and reading a tornado chart
- Cut-off, porosity, saturation and column-height sensitivities
- A simple STOIIP walkthrough with combined parameters
- Ranking drivers and linking them to data acquisition
- Updating the ranking as new data arrive
Learning outcomes
After the module you should be able to:
- Rank uncertainty drivers and connect them to decisions.
- Build a tornado chart for in-place volume
- Identify which parameter deserves the most scrutiny
- Explain a driver ranking to people outside the discipline
A short preview
A one-porosity-unit change sounds small. On a sand with 20 percent porosity it is a 5 percent change in pore volume, and because STOIIP is a product, a 5 percent change in the in-place volume. Set beside it a water saturation that could be anywhere from 0.25 to 0.40, which moves the hydrocarbon fraction (1 − Sw) from 0.75 to 0.60, a 20 percent swing, and the ranking is clear before any software is opened. A tornado chart makes that comparison for every input at once.
Who it is for
Petrophysicists and geoscientists with some interpretation experience, and engineers who review petrophysical inputs before they reach a volumetric or simulation model.
Prerequisites: The Basic Petrophysics track, or equivalent working experience.
Take the module in the Learning Hub
Intermediate Petrophysics: Eight applied modules with checkpoints; with the certified option, pass each quiz to unlock the next lesson. The lesson opens in the Learning Hub once the track is purchased; graded quizzes and the certificate come with the certified option.