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.
(1) Non-associated gas — gas occurring in a reservoir with no significant crude oil present; it is the sole hydrocarbon phase (a “dry” or “gas” reservoir).
(2) Associated (free / gas-cap) gas — free gas that overlies and is in direct contact with an oil column in the same reservoir, forming a gas cap above the oil-gas contact.
(3) Dissolved (solution) gas — gas held in solution within the crude oil itself at reservoir pressure/temperature, which comes out of solution as free gas once reservoir pressure drops below the oil's bubble point.
The distinction matters economically because gas-cap and solution gas are typically co-produced with, and their development schedule constrained by, the oil program (e.g., gas-cap blowdown timing affects oil recovery), whereas non-associated gas is developed and priced purely on its own merits.
