24-Pet-B4 Well Testing · December 2016
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
EGBC National Exam — Petroleum Engineering, 2016-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, hydrocarbon chemistry, oil sands and tight-oil development, shale gas and coalbed methane, carbonate traps, siliciclastic/deltaic traps) – 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. This sitting's Section 6 is a Siliciclastic Traps section (wave-dominated delta, grain-size–permeability–porosity relations, sandstone diagenesis). The paper is entirely qualitative (draw/describe/define/list), with no numeric given data anywhere.
Reference texts: Selley, R.C. & Sonnenberg, S., Elements of Petroleum Geology, 3rd ed., Academic Press (source rocks, migration, traps, carbonate systems, oil sands); Tissot, B.P. & Welte, D.H., Petroleum Formation and Occurrence, 2nd ed., Springer (kerogen typing, maceral groups, catagenesis); Boggs, S. Jr., Petrology of Sedimentary Rocks, 2nd ed., Cambridge (source-rock, deltaic and carbonate lithofacies; sandstone diagenesis); James, N.P. & Jones, B., Origin of Carbonate Sedimentary Rocks, Wiley-Blackwell (carbonate platform/ramp/sabkha facies models); Butler, R.M., Thermal Recovery of Oil and Gas, Prentice Hall, 1991 (SAGD, CSS, oil sands thermal recovery); Green, D.W. & Willhite, G.P., Enhanced Oil Recovery, SPE Textbook Series Vol. 6 (thermal EOR mechanisms); Law, B.E. & Curtis, J.B., “Introduction to Unconventional Petroleum Systems,” AAPG Bulletin 86, 2002 (shale gas, tight gas, coalbed methane); Lee, W.J. & Wattenbarger, R.A., Gas Reservoir Engineering, SPE Textbook Vol. 5 (unconventional gas reservoir characterization).
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) Rimmed platform. A shallow carbonate platform with a well-defined, elevated, high-energy margin (a barrier reef or ooid/skeletal shoal complex) at the shelf edge, which shelters a lower-energy, more restricted lagoon on its landward side and drops off relatively steeply into the adjacent basin.
(b) Ramp. A shallow, low-relief carbonate depositional profile with a gentle, continuous, unbroken dip from a high-energy shoreline down into progressively deeper, lower-energy water – there is no distinct shelf-edge break in slope or barrier rim as on a rimmed platform.
(c) Sabkha. An arid, supratidal coastal (or continental salt-flat) surface above normal high-tide level where evaporative pumping of shallow groundwater/seawater precipitates evaporite minerals (gypsum, anhydrite, halite), typically as nodular or displacive textures; sabkha evaporites commonly serve as excellent top seals for underlying carbonate reservoirs.
(d) Lagoon. A shallow, semi-enclosed body of water situated landward of a protective barrier (a reef, shoal, or barrier island), characterized by lower wave/current energy, restricted circulation, and often elevated or variable salinity, favouring deposition of fine carbonate mud and, in arid settings, evaporites.
