Basic Petrophysics · Module B3
Log Quality Control
Before any property is calculated the data have to be fit for purpose. This module covers what each log family measures, the caliper and density-correction checks that flag bad hole, sonic cycle skipping, and why saturation uses the deep resistivity rather than the shallow.
- Level
- Beginner
- Position
- Module 3 of 7
- Video
- About 18 minutes, narrated
- Format
- Narrated video lesson with chapters; with the certified option, a graded module quiz.
What the module covers
- Log families and what each one measures
- Caliper and density-correction checks for bad hole
- Recognising cycle skips on the sonic log
- Deep versus shallow resistivity and the invaded zone
- Silent QC errors that pass a visual check
Learning outcomes
After the module you should be able to:
- Flag bad-hole intervals with explicit caliper and density-correction rules
- Recognise the common artefacts on density, neutron, sonic and resistivity logs
- Explain which curves can be trusted for which calculation
A short preview
A density correction larger than about 0.05 g/cc is a warning that the pad was not sitting firmly against the borehole wall, usually because the hole is washed out or rugose. The bulk density over that interval is then partly reading mud, and every porosity computed from it is too high. The fix is not to smooth the curve but to flag the interval, decide what replaces the density there, and record the decision, because a bad-hole interval in a thin reservoir can move net pay more than any parameter choice.
Who it is for
Geoscientists, reservoir and production engineers, and graduates who need to read a standard log suite and build a first-pass interpretation they can defend.
Prerequisites: None beyond basic geology and algebra.
Take the module in the Learning Hub
Basic Petrophysics: Seven foundational modules with narrated lessons and chapter-based navigation. The lesson opens in the Learning Hub once the track is purchased; graded quizzes and the certificate come with the certified option.