24-Pet-B4 Well Testing · December 2015
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
EGBC National Exam — Petroleum Engineering, 2015-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, migration/unconventional reservoirs, carbonate traps, structural traps, Canadian basin geography) – 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. The paper is almost entirely qualitative (draw/describe/define/list), with one true numeric calculation (Q3-2, capillary seal-breach column height).
Reference texts: Selley, R.C. & Sonnenberg, S., Elements of Petroleum Geology, 3rd ed., Academic Press (source rocks, migration, traps, carbonate systems); 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 and carbonate lithofacies); Allen, P.A. & Allen, J.R., Basin Analysis: Principles and Applications to Petroleum Play Assessment, 3rd ed., Wiley-Blackwell (structural styles, unconventional systems); Biddle, K.T. & Wielchowsky, C.C., “Trap Types in Petroleum Basins,” AAPG Memoir 60, ch.12 (structural trap classification); James, N.P. & Jones, B., Origin of Carbonate Sedimentary Rocks, Wiley-Blackwell (carbonate platform/ramp/sabkha facies models); Law, B.E. & Curtis, J.B., “Introduction to unconventional petroleum systems,” AAPG Bulletin 86 (basin-centred gas); Mossop, G.D. & Shetsen, I. (eds.), Geological Atlas of the Western Canada Sedimentary Basin, CSPG/Alberta Research Council, 1994 (WCSB stratigraphy and Canadian basin geography).
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 growth fault is a normal fault that is active during deposition (syn-depositional), so its throw increases progressively with depth/age as more sediment accumulates on the downthrown side than the upthrown side over the same time interval – producing a markedly thicker stratigraphic section in the hanging wall than the footwall, and commonly a listric (concave-upward, flattening at depth) fault geometry that rolls the downthrown beds into a hanging-wall rollover anticline, which becomes the structural trap.
Growth faults are most commonly found in (1) deltaic depositional systems, where rapid progradation deposits a thick, unstable, over-pressured prodelta mud that fails gravitationally beneath the advancing, sand-rich delta front, generating listric growth faults (e.g. the classic Niger Delta and Gulf of Mexico deltaic growth-fault provinces); and (2) passive continental-margin slope systems, where rapid sediment loading over an unstable, often over-pressured or salt-cored substrate similarly triggers gravitational listric normal faulting basinward of the shelf edge.
Example region. The Gulf of Mexico Basin (onshore and offshore Louisiana/Texas) is a classic, prolific example of a growth-fault province, hosting enormous cumulative hydrocarbon volumes trapped in Cenozoic deltaic/slope rollover-anticline traps associated with regionally extensive listric growth faults.
