ABSTRACT

Within the Provost area of east-central Alberta, a major east-west trending sub-Cretaceous paleovalley occurs. This valley and its clastic lower Mannville fill form the eastern limb of the Edmonton Channel complex.

Erosion during pre-Cretaceous and lower Mannville time formed this valley, which is bounded to the north and south by Devonian and Mississippian carbonates and minor clastics. During lower Mannville time, clastics prograded from east to west in a dominantly fluvial environment. These clastics are preserved as the Ellerslie Formation and its equivalent, the Dina Member. This axis of fluvial deposition persisted into middle Mannville time and, in some areas, channel facies sandstone occur juxtaposed to the dominantly marine strata of the middle Mannville.

Hydrocarbon entrapment within the fluvial sediments of the Ellerslie Formation and Dina Member is largely stratigraphic in nature yet diverse in character, resulting in more than 50 known pools. These stratigraphic traps may be classified in four broad categories as:

1. traps due to sand/carbonate differential compaction
2. traps due to sand/shale differential compaction
3. late stage channelling and refill with sandstone
4. late stage channelling and refill with nonreservoir strata

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A comparison of the geometry of these trap types is enhanced by the use of seismic data.

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