Unconventional Reservoirs · Module U4
Independent methods and the fusion
No single TOC method survives every rock. This module adds the methods that do not depend on resistivity: the Schmoker density deficit against an organic-free density, a uranium regression, the NMR-density deficit and a measured TOC log where one exists. It then shows how the workspace combines them with base weights and validity flags for gas, bad hole, maturity, very high resistivity and tight rock, and how a confidence curve reports whether the methods agree.
- Level
- Advanced
- Position
- Module 4 of 8
- Video
- About 18 minutes, narrated
- Format
- Narrated video lesson with captions and slide reading view; with the certified option, a quiz whose pass unlocks the next module.
What the module covers
- Density deficit against the organic-free density
- Uranium regression, and why a default slope stays out
- NMR-density deficit and a measured TOC log
- Base weights by method
- Validity flags and the confidence curve
- A tight carbonate that fools the overlays
Learning outcomes
After the module you should be able to:
- Explain a fused TOC's weights, flags and confidence at any depth, and keep a tight carbonate out of the source rock.
- Explain why a fused TOC at any depth carries the weights it does
- Recognize a tight carbonate that a resistivity overlay books as source rock
A short preview
A tight limestone can look like the richest rock in the well. Its resistivity runs to hundreds or thousands of ohm-m because it holds almost no pore water, not because it holds organic matter, so a resistivity overlay shows a wide separation and a high TOC. The density and uranium logs disagree: the rock is heavy and its uranium low. A fusion that flags very high resistivity and very low neutron porosity, and cuts the overlays' weight there, follows the methods that still apply and reports low confidence where they disagree.
Who it is for
Petrophysicists, geoscientists and reservoir engineers who evaluate organic shales and source rocks from logs and core, and carry TOC, net pay and gas in place into appraisal and development decisions.
Prerequisites: The Intermediate track, or working experience with shale volume, porosity and water saturation; the Geomechanics course is recommended before U8. The hands-on steps use the Organic Matter workspace in Formation Evaluation, and the brittleness steps in U8 use the Geomechanics workspace, available from the Professional plan.
Take the module in the Learning Hub
Unconventional Reservoirs: Specialty course, sold separately: eight modules that evaluate an organic shale from logs and core, from TOC methods fused and calibrated to core, through kerogen-corrected porosity and net pay, to free and adsorbed gas in place and brittleness. The lesson opens in the Learning Hub once the track is purchased; graded quizzes and the certificate come with the certified option.