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.
Kerogen is the fraction of organic matter dispersed in a sedimentary (source) rock that is INSOLUBLE in common organic solvents (this insolubility is what distinguishes it from bitumen, the soluble organic fraction) and insoluble in aqueous alkaline solvents. It is the solid, high-molecular-weight precursor material from which, upon sufficient burial and thermal maturation (catagenesis), petroleum – both oil and gas – is generated by thermal cracking. In practice a geochemist establishes whether a candidate source rock carries meaningful kerogen by measuring its total organic carbon (TOC) content and then splitting that TOC, by solvent extraction, into the small soluble bitumen fraction and the much larger insoluble kerogen residue that remains after extraction. This distinction matters because it is the KEROGEN fraction – not the bitumen, and not TOC as a whole – whose elemental composition (H/C, O/C) and Rock-Eval response (HI, OI, Q2-3/Q2-4) determine both a rock's kerogen TYPE (Q2-2) and how much oil or gas it is still capable of generating as burial proceeds.
