24-Pet-A1 Principles of Stratigraphy and Sedimentation · May 2018
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
EGBC National Exam — Petroleum Engineering, 17-Pet-A1 Principles of Stratigraphy & Sedimentation, 2018-May. 3 hours duration; closed book, no calculator permitted. The paper has two parts: Part A (Questions 1–10, Sedimentology and Sedimentary Processes) – Questions 1 and 2 are mandatory (10 marks each, 20 marks), plus any five of the remaining eight (3–10) at 6 marks each (30 marks), for a Part A total of 50 marks; and Part B (Questions 11–19, Stratigraphy and Sedimentary Basin Analysis) – answer any six of the nine at 5 marks each, for a Part B total of 30 marks – an 80-mark maximum (50 for Part A + 30 for Part B).
Reference texts: Boggs, S. Jr., Principles of Sedimentology and Stratigraphy, 5th ed., Pearson (grain texture, sediment transport, bedforms, carbonate/evaporite systems, sequence stratigraphy, unconformities, stratigraphic principles); Tucker, M.E., Sedimentary Petrology, 3rd ed., Blackwell (sandstone/carbonate classification, diagenesis, dolomitization); Nichols, G., Sedimentology and Stratigraphy, 2nd ed., Wiley-Blackwell (fluvial/deltaic systems, sequence stratigraphy, stratigraphic units); Reading, H.G. (ed.), Sedimentary Environments: Processes, Facies and Stratigraphy, 3rd ed., Blackwell (facies models, deep-marine and shelf systems); Selley, R.C. & Sonnenberg, S., Elements of Petroleum Geology, 3rd ed., Academic Press (source rocks, basin classification, reservoir quality); International Commission on Stratigraphy, International Chronostratigraphic Chart (geological time scale).
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
Coal. Coal is a combustible, organic sedimentary rock formed by the burial, compaction and progressive chemical alteration (coalification) of accumulated plant material (peat) under waterlogged, oxygen-restricted (anaerobic) conditions that suppress complete decay; it consists predominantly of altered plant-derived organic matter (macerals), with a variable, subordinate content of inorganic mineral matter (ash).
Coal rank series (low to high fixed carbon). Coalification is a progressive diagenetic-to-low-grade-metamorphic process driven by increasing burial temperature, pressure and time, which drives off volatile matter and moisture while progressively concentrating fixed carbon:
| Rank (low → high) | Character |
|---|---|
| Peat | Unconsolidated, partially decayed plant matter; lowest fixed carbon, highest moisture/volatile content |
| Lignite | "Brown coal"; still high moisture content, low-grade combustion fuel |
| Subbituminous | Intermediate rank; reduced moisture relative to lignite |
| Bituminous | Common industrial/thermal and coking coal rank; well-developed banding, moderate volatile content |
| Anthracite | Highest rank; hard, glossy, lowest moisture/volatile matter, highest fixed carbon |
