The sedimentary basin area of the Northwest Territories of Canada, which lies between the pre-Cambrian Shield and Cordilleran Mountain area, covers approximately 256,000 square miles. Sediments ranging in age from Cambrian to Tertiary are present and of these only the Upper Devonian has produced oil in commercial quantities. Shows of oil have also been encountered in Cretaceous sediments.

The Norman Wells pool is a lenticular coral reef, lying within the black bituminous Fort Creek shales of Upper Devonian age. The pool is an example of a stratigraphic trap on the flank of a monocline dipping about 5° to 7° southwest. Near the crest of this coral reef, and very close to the up-dip side, the shallowest hole reached the top of this limestone reservoir at a depth of 1,040 feet, and on the down-dip edge the top of the reef limestone is reached at a depth as great as 1,893 feet.

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