The Nisku Format is defined by the gamma-ray and electric log markers which characterize the upper and lower boundaries of the Nisku Formation in Central Alberta. These markers are present over the Southern Alberta Shelf and throughout the Williston Basin where the Nisku Formation is no longer recognizable. In Saskatchewan the Nisku Format extends approximately as far north as Township 37. Gamma-ray logs are the best means of picking the Nisku contacts although lithologic markers can be used to supplement the gamma-ray log picks throughout most of the area.

Lithologic study has revealed the presence of three major textural-compositional facies: (1) The sucrosic dolomite facies of shoal regions, (2) the fossiliferous limestone facies of intershoal regions, (3) the dolomite-evaporite facies of restricted lagoon regions. Where one of these is dominant it can be recognized on lithofacies maps. Excellent porosity is found in the sucrosic dolomite facies. The fossiliferous limestone and dolomite-evaporite facies are relatively non-porous.

No commercial production of oil or gas has been obtained from the Nisku. Oil shows are common, but free oil has been recovered from only one test. In the eastern and northeastern parts of the area the formation water is highly saline although the intervening area has been flushed by an influx of fresh water and abnormally low salinities are found there.

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