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) Total Organic Carbon (TOC) – the weight percent of a rock sample's mass that is organic carbon (kerogen + any bitumen), measured by combustion after removing inorganic (carbonate) carbon; the primary screening measure of a rock's source-rock richness (e.g. >1–2 wt% is typically considered a good oil source rock).
(b) Bitumen – the fraction of a rock's organic matter that is soluble in common organic solvents (e.g. chloroform, dichloromethane); it represents hydrocarbon-like material already generated from kerogen (or migrated in) but not yet expelled from the rock, distinct from insoluble kerogen and from free, migrated petroleum.
(c) Type I Kerogen – kerogen derived predominantly from algal/lacustrine (and some marine) organic matter, characterized by a high initial hydrogen index (HI often >600 mg HC/g TOC) and low oxygen index, giving it the highest oil-generating potential of any kerogen type.
(d) Catagenesis – the diagenetic stage of organic-matter maturation occurring roughly between 50 and 150–200 °C (burial to a few kilometres), during which thermal cracking of kerogen generates the bulk of the oil and wet gas (the oil window and the start of the gas window); it follows shallow, low-temperature diagenesis and precedes deep, high-temperature metagenesis (dry gas only).
