Duvernay Reserves and Resources Report

Alberta Energy Regulator
2 Geological Overview
2.1 Geology
The Duvernay is a geological formation found over most of central Alberta that was deposited during
the Upper Devonian Period, over 372 million years ago (Rokosh et al., 2012). The Duvernay sediments
were deposited on the slope, base-of-slope, and distal basinal areas surrounding the coexisting Leduc
Formation reefs.
In the Fox Creek play, the Duvernay overlies the green shales of the Majeau Lake Formation; in the
Innisfail play, the Duvernay Formation conformably overlies the Cooking Lake Formation. In the Innisfail
play, the Duvernay interfingers with the associated Leduc reefs, thickening depositionally upslope
towards the Leduc buildups, where its lithology more closely resembles the lower Ireton Formation
(Glass, 1990). The upper contact of the Duvernay Formation is conformable with the overlying Ireton
Formation, making it difficult to pick from wireline logs (Glass, 1990). In areas south and east of the
Peace River Arch, the Duvernay conformably overlies the Waterways Formation (Glass, 1990).
The Duvernay is the source rock for the conventional hydrocarbon reservoirs in the Leduc reefs, the Swan
Hills buildups, the Nisku and Grosmont platform carbonates, and for other clastic reservoirs, such as the
Gilwood and Granite Wash sands. The Duvernay-sourced oil migrated as far as the Keg River carbonates
on the edge of the Late Cretaceous sub-basin northeast of the Peace River Arch in the northeastern Alberta
subsurface (Creaney et al., 1994).
The Duvernay dips to the southwest, with structural elevations ranging from approximately 900 metres
(m) below sea level in the northeast to approximately 3600 m below sea level near the deformed belt
(Appendix 2). Depths to the top of the Duvernay range from 1700 to 5000 m below ground surface.
Figure 3. Schematic cross-section showing the informal Duvernay lithostratigraphic members
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