Cretaceous oil shale potential of the prairie provinces, Canada

Abstract
Four hundred forty-seven samples, obtained from cores and potash shafts penetrating the oil shale beds of the Upper Cretaceous Boyne and Favel Formations (1st and 2nd White Speckled shale zones respectively) at 29 locations across the Prairie Provinces, were analyzed for total organic carbon (TOC) and subjected to Rock-Eval pyrolysis. Of these, 382 samples from Saskatchewan and Manitoba were analyzed mineralogically by X-ray diffraction. Both oil shale are thermally immatuer, and ahve not been petroleum source rocks across the Prairie Provinces, except for an area of low maturity in western Alberta. Samples over most of the area contain up to 4% organic carbon which is derived from Type III humic kerogenL above that, total organic carbon values ranging to 10% are provided by the addition proportionately from 3.0 kg/t/1% TOC in the humic areas to 6.5kg/t/1% TOC were sapropel predominates. Two areas of optimum hydrocarbon yield can be mapped, in the Pasquia Hills of eastern Saskatchewan, and, from limited data, along the outcrop edge of both units in western Saskatchewan. In both areas, average TOC values may range up to 10% with average hydrocarbon recoveries anticipated in excess of 40 to 50 kg/t (10 to 12.5 US g/t) from both the Boyne and Favel Formations, Lithologically almost identical, both oil shale zones contain inversely related proportions of a quartz-clay-feldspar mode and a second mode dominated by calcite. Kerogen content increases to a maximum where the modes are essentially equal, or where calcite dominates slightly, but then decreases as pure limestone is approached. Numerous secondary minerals are present, including zeolites, non-hydrous silicates, sulfates, iron minerals and oxidesm and include many mineral forms differentiated only by varying degrees of hydration. Oxidation minerals are common and are enigmatic to the preservation of the kerogen: whether such minetals were formed by alteration during deposition and lithoification or are weathering products is not readily evident.

This publication has 0 references indexed in Scilit: