24-Pet-B4 Well Testing · December 2014
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
EGBC National Exam — Petroleum Engineering, 2014-Dec. 3 hours duration; closed book. This sitting's own cover page reads “98-Pet-B4, Petroleum Geology” and every question is descriptive/interpretive petroleum geology (source rocks, generation, migration, traps, Canadian basin geography) – no well-test pressure-transient content anywhere. Five (5) of the paper's six 20-mark sections are marked (NOTES item 5); all six are solved in full below so this set also serves as a complete study reference. The paper is almost entirely qualitative (draw/describe/define/list), with one true numeric calculation (Q3-2, capillary seal-breach column height).
Reference texts: Selley, R.C. & Sonnenberg, S., Elements of Petroleum Geology, 3rd ed., Academic Press (source rocks, migration, traps); Tissot, B.P. & Welte, D.H., Petroleum Formation and Occurrence, 2nd ed., Springer (kerogen typing, oil/gas windows, primary migration); Boggs, S. Jr., Petrology of Sedimentary Rocks, 2nd ed., Cambridge (source-rock lithofacies); Allen, P.A. & Allen, J.R., Basin Analysis: Principles and Applications to Petroleum Play Assessment, 3rd ed., Wiley-Blackwell (extensional basins, structural styles); Biddle, K.T. & Wielchowsky, C.C., “Trap Types in Petroleum Basins,” AAPG Memoir 60, ch.12 (stratigraphic/structural/salt trap classification); Mossop, G.D. & Shetsen, I. (eds.), Geological Atlas of the Western Canada Sedimentary Basin, CSPG/Alberta Research Council, 1994 (WCSB stratigraphy and play types).
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.
(a) Spill point – the structurally lowest point of a trap's closure at which hydrocarbons begin to leak out (spill) along the migration pathway once the trap is completely filled; it sets the maximum possible hydrocarbon column height for a given closure, independent of seal capillary limits.
(b) Evaporite – a sedimentary rock (e.g. halite, gypsum/anhydrite, potash salts) precipitated from the evaporative concentration of saline water in a restricted basin; evaporites are important both as regional top seals (very low permeability, ductile) and, where thick, as the mobile substrate for salt tectonics.
(c) Diagenesis – the physical, chemical and biological changes a sediment undergoes after deposition and before metamorphism (compaction, cementation, dissolution, replacement, recrystallization), which control the reservoir-quality (porosity/permeability) evolution of a rock through burial.
(d) Disconformity – an unconformity in which the bedding above and below the erosional/non-depositional surface is parallel (no angular discordance), typically representing a period of subaerial exposure, erosion, or non-deposition without associated tectonic tilting.
