Diagenetic history of Ordovician and Devonian oil ... - Geology Ontario

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however the low relief of the Algonquin Arch was such that deposition occurred over it
without significant variation in thickness (Bailey, 1984). In fact, Bailey (1984) suggests
the Algonquin Arch was not a true lineament but was there simply because the adjacent
basins subsided.
RESERVOIR CHARACTERISTICS
Middle Ordovician oil pools form linear trends up to 6 km by l km. Sanford et al.
(1985) suggests the reservoirs are located along the flanks of the Findlay Arch and to a
lesser extent along the Algonquin Arch at intersecting fracture systems; specifically, on the
downdropped side of fault-blocks.
Middle Ordovician oil produced in southwestern Ontario is of exceptionally good
quality with oil gravity between 38.2 and 43.0 deg API and sulfur content of 0.11 to
G.25% (Bailey Geological Services Ltd. and Cochrane, 1983).
In 1983 an oil shale assessment project was carried out by the Ontario Geological
Survey, in conjunction with the University of Waterloo and Geological Survey of Canada
(Powell et al., 1984; Snowdon, 1984). The Ordovician Collingwood Member of the
Lindsay Formation, Middle Silurian Eramosa Formation and the Devonian Kettle Point
Formation were considered to be potential hydrocarbon source rocks. The Collingwood
Member appears to be the most suitable source of Middle Ordovician hydrocarbons based
on its geochemical characteristics and maturation level. Although the Kettle Point
Formation has a similar geochemical character, the Devonian strata did not reach suitable
maturation levels for hydrocarbon generation. Both Nunn et al. (1984) and Powell et al.
(1984) found the hydrocarbons of the Middle Ordovician and Devonian to be very similar
but those of the Silurian appear to have been derived from a different source. Devonian and