DEPOSITIONAL ENVIRONMENTS AND RESERVOIR QUALITY OF THE DINA FORMATION, EAST-CENTRAL ALBERTA

The Dina formation is the basal unit of the Lower Mannville Group in east-central Alberta and is early to mid-Cretaceous (late Barremian to late Aptian). Overlying a 2nd-order regional unconformity, the Dina formation serves as reservoir rock for large accumulations of oil within the Provost oil field and has a total thickness of approximately forty metres in the study area. It was deposited during transgression from the north (late Barremian to early Albian), which inundated the Western Sedimentary Basin to create the epeiric Western Interior Seaway. Three cores from two wells (section 23, township 37-6W4) are analysed in this thesis using core descriptions, well-log correlations, and thin sections to determine depositional environments and reservoir quality (i.e. porosity) of the Dina formation. Lithofacies gradually coarsen upwards, from fine-grained, low-angle sandstones and bioturbated mudstones near the bottom (of the cored interval) to coarse-grained, steeply-dipping sandstones near the top. Depositional environments change from brackish, low-diversity marine embayment deposits near the bottom (of the cored interval) to marine-influenced fluvial channel deposits near the top. Hydrocarbon saturation of the beds is lithofacies-dependent, and appears to be highest within sandstones near the bottom of the cored interval.