24-Pet-B3 Petroleum Geology · December 2015
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams, December 2015 — 98-Pet-B3, Oil and Gas Evaluation and Economics (3 hours, closed book, approved non-programmable calculator only). The exam's own cover page is titled "Oil and Gas Evaluation and Economics" and every question is property valuation / reserves & production economics / DCF-NPV screening content — no geology anywhere.
Reference texts: Thompson & Wright, Oil Property Evaluation; Canadian Oil and Gas Evaluation Handbook (COGEH), Vol. 1 (Society of Petroleum Evaluation Engineers, Calgary Chapter); National Instrument 51-101, Standards of Disclosure for Oil and Gas Activities (Canadian Securities Administrators); SPE/WPC/AAPG/SPEE Petroleum Resources Management System (PRMS); Ahmed, Reservoir Engineering Handbook.
The exam's own instructions ask for only 7 of the 10 short-answer questions and note the Cash-Flow/Future-Value tables are graded by column; for "choose N of M" exams, every item below is answered in full as a study resource. Questions 1–10 correspond to the exam's printed Short-Answer items 1–10; Questions 11–20 correspond to the printed Multiple-Choice items 1–10; Question 21 is the Future Value table; Question 22 is the Cash Flow table.
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.
Answer: (a). “Associated gas” is most commonly used as a synonym for solution (dissolved) gas — gas held in solution in the crude oil and released as the pressure drops. Strictly, the PRMS definition of associated gas also includes gas-cap (free) gas (option c) as a second subset, so (c) is not wrong in a broader sense; but as a single best match for common usage on this exam's own short-answer Q10 (which lists dissolved gas and gas-cap gas as two SEPARATE classifications), (a) is the intended answer — (b) describes coalbed/shale-adsorbed gas, an unconventional category, and (d) describes hydrate-bound gas, neither of which is “associated” with an oil column at all.
