Kettle Point formation

The Kettle Point Formation subcrops in southwestern Ontario. It is up to 60 m thick, with organic carbon values usually in the range 5%-16% and Fischer Assay oil yields up to 70 1/t (17 gal/ton). The organic matter is dominantly kerogen of marine origin and has attained only an immature thermal maturation stage. A particularly rich upper zone is present over much of the subcrop area and its thickness seems to be controlled by post-Kettle Point erosion. Although studies are still preliminary, especially for the Devonian shales, the Kettle Point Formation appears to have the most potential for shale oil production in southern Ontario. 

Most of the Kettle Point Formation exceeds 5% TOC. Two or three, thin (<2 m) intervals in the lower section contain more than 10% TOC and a rich interval at the top has more than 10% TOC for up to 3.5 m. This upper interval is not encountered in all boreholes and appears to have been removed by post-Devonian erosion except where the Kettle Point Formation is capped by outliers of Port Lampton Group. 

Significant variation in organic geochemistry has been observed within the Whitby Formation and between the Whitby and Kettle Point Formations. Research is in progress to define the geological controls and to relate the resource potential as measured by TOC analyses and FA oil yields to observed variations in organic matter type and maturation level. 

In 1981, the Ontario Geological Survey began a program to assess the resource potential of the Whitby Formation and the other black shales of Ontario. Prior to this study, information on Ontario s black shales has been very sparse due to poor or non-existent exposure and limited subsurface information. Existing data suggested three units were sufficiently organic-rich to warrant further study—the Ordovician Whitby and the Devonian Kettle Point and Marcellus Formation (JL). ... 

In the Whitby Formation, the available FA oil yields (59 samples) are less than 60 litres/tonne (14 U.S. gallons/ton). This oil has a specific gravity in the range 0.893 to 0.942. Twenty FA determinations on Kettle Point samples revealed oil yields up to 72 1/t (17 gal/ton) with specific gravity in the range 0.896 to 0.956. Few FA analyses of Marcellus shales are available the highest oil yield to date is 64 1/t (15.4 gal/ton). 

Figure 2. The relationship between Fischer Assay oil yield and total organic carbon (TOC) content for shale samples from the Whitby (left) and Kettle Point (right) Formations.

Table I summarizes the indicated maturation levels of organic matter from the Kettle Point, Marcellus and Whitby Formations and equivalents in various areas. Using Figure 4, these may be related to thermal maturation. Only a few samples have been ex-...

None of the indicators alone provide a definitive indication of thermal maturation, but, when considered together, they provide a reasonably consistent picture. It seems that the Billings equivalent of the Whitby Formation in the Ottawa area is mature to overmature, while the Whitby Formation along its subcrop is marginally mature to mature. The Marcellus is marginally mature and the Kettle Point is immature to perhaps marginally mature. 

Figure 7. The relative proportions of amorphous (am), exinous (ex), and vitrinous plus fusinous (vit. + fus.) kerogen macerals. Key to formations , Kettle Point a, Marcellus , Manitoulin, Whitby A, Collingwood, Whitby and o, Toronto, Whitby.

Infrared absorption (I.R.) spectra provide a qualitative indication of the organic structures present in the kerogen and their variation between samples. In general, the I.R. spectra of Whitby and Kettle Point kerogens are dominated by aromatic and aliphatic absorption bands with a minor OH band. Many samples from the Whitby Formation of the Toronto area show stronger OH absorption, and perhaps a more aromatic than aliphatic nature compared to samples from other locales. 

The Middle Devonian Marcellus Formation is much thinner and less extensive where it subcrops on the north shore of Lake Erie, although thicknesses of 50 m have been inferred beneath the lake. TOC values up to 11% and Fischer Assay oil yields of 64 1/t have been found. The organic matter is slightly more mature than that in the Kettle Point, and so some bitumen is present. The kerogen is dominantly of marine origin. 

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