Unconventional Reservoirs · Module U1
Unconventional reservoirs and the source-rock step
The opening module explains why a source rock has to be read differently from a sandstone. It sets out what kerogen does to the gamma ray, density, neutron, sonic and resistivity logs, the ways a shale misleads a conventional interpretation, and the order the course follows: shale volume first, the organic-matter step next, and only after that porosity, water saturation and net pay. It also introduces the course well and the Organic Matter workspace.
- Level
- Advanced
- Position
- Module 1 of 8
- Video
- About 16 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
- Source, reservoir and seal in one rock
- What kerogen does to each log
- How the overlay, porosity, clay and net pay can each mislead
- The order of operations from shale volume to net pay
- Source-rock mode and the Organic Matter workspace
- Zone fluid types and the curves the step writes
Learning outcomes
After the module you should be able to:
- Name what organic matter does to each log, and where the organic-matter step sits, before reading a TOC.
- Predict which way kerogen moves each log before reading a TOC
- Explain why the organic-matter step runs after shale volume and before porosity
A short preview
Kerogen is light, slow and rich in hydrogen, so it imitates pore space on every porosity log. A shale holding 5 percent organic carbon by weight carries about 12 percent kerogen by volume. Swapping that much matrix for kerogen of 1.25 g/cc lowers the bulk density by close to 0.18 g/cc, which a standard matrix reads as about ten porosity units that are not there. The uranium that organic matter fixes raises the gamma ray too, so the same rock reads as more clay. The two errors push net pay in opposite directions, which is why the organic step comes first.
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.