24-Pet-B4 Well Testing · Undated paper
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
EGBC National Exam — Petroleum Engineering, 17-Pet-B4 (May 2019, per its page footers). 3 hours duration; closed book. This paper's own cover page reads “17-Pet-B4, Petroleum Geology” and all five sections are descriptive/interpretive petroleum geology (terminology, source rocks, thermal maturation, stratigraphic traps, structural traps), no well-test pressure-transient content anywhere. The section marks are Section 1 = 30, Section 2 = 18, Section 3 = 22, Section 4 = 15, Section 5 = 15 (sum 100), used throughout below. The exam is entirely qualitative (explain/define/sketch).
Reference texts: Tissot, B.P. & Welte, D.H., Petroleum Formation and Occurrence, 2nd ed., Springer (kerogen typing, maceral groups, maturation stages, geothermometers); Selley, R.C. & Sonnenberg, S., Elements of Petroleum Geology, 3rd ed., Academic Press (petroleum terminology, source rocks, traps); Boggs, S. Jr., Petrology of Sedimentary Rocks, 2nd ed., Cambridge (source-rock petrology); Allen, P.A. & Allen, J.R., Basin Analysis: Principles and Applications to Petroleum Play Assessment, 3rd ed., Wiley-Blackwell (structural trap styles); Biddle, K.T. & Wielchowsky, C.C., “Trap Types in Petroleum Basins,” AAPG Memoir 60, ch.12 (stratigraphic and structural trap classification); Mossop, G.D. & Shetsen, I. (eds.), Geological Atlas of the Western Canada Sedimentary Basin, CSPG/Alberta Research Council, 1994 (Canadian trap examples).
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.
Four kerogen types are recognized, distinguished by their organic precursor, dominant maceral group, and generative potential:
Type I – precursor: lipid-rich lacustrine algae (e.g. Botryococcus-type) and amorphous algal/bacterial material accumulated in anoxic lacustrine (or restricted marine) settings; maceral: alginite (tela-/lamalginite, an amorphous form sometimes termed “bituminite”). Highest H/C, lowest O/C of any kerogen type. Generates abundant, high-quality, waxy PARAFFINIC OIL with the highest oil yield per unit TOC of any type (e.g. Green River Shale, Eocene, Utah/Colorado).
Type II – precursor: marine planktonic algae and zooplankton, plus bacterially reworked organic matter, deposited under anoxic/reducing marine conditions; maceral: liptinite/exinite group, dominated by amorphous marine liptinite with some sporinite/cutinite/resinite. Moderately high H/C. Generates a MIX of oil and gas (still oil-prone); this is the most common source-rock kerogen type worldwide (e.g. North Sea Kimmeridge Clay; many WCSB shales such as the Duvernay and Muskwa).
Type III – precursor: terrestrial higher-plant (woody, ligno-cellulosic) tissue deposited in deltaic, fluvial, or coastal-swamp/coal settings; maceral: vitrinite (huminite at lower rank), with subordinate liptinite (sporinite, cutinite, resinite). Low H/C, moderate–high O/C. Generates predominantly GAS, with only minor waxy oil (e.g. Cretaceous coals and coaly shales of the WCSB).
Type IV – precursor: highly oxidized, recycled, or charred/burned plant debris and reworked older kerogen; maceral: inertinite (fusinite, semifusinite, macrinite). Essentially INERT – no meaningful remaining hydrocarbon-generating potential; contributes to TOC without contributing generated hydrocarbons (“dead carbon”).
