Depositional Facies Control of Reservoir Heterogeneity and Performance, Cretaceous Sandstone Reservoirs, South-Central Alberta Basin

REINSON, G. E., Geological Survey of Canada, Calgary, Alberta, Canada

The profound influence of depositional factors on external geometry and internal heterogeneity of clastic reservoirs has not been fully appreciated in the field of development geology to date. Reservoir geometry is primarily a function of depositional environment, whereas reservoir heterogeneity will be controlled by both depositional and diagenetic factors. Depositionally controlled heterogeneities are usually manifested as porosity and directional permeability contrasts resulting from textural variations between facies. Therefore, thorough documentation of depositional facies variability and reservoir architecture is mandatory for understanding permeability heterogeneities and for implementing secondary recovery schemes in any given reservoir.

Cretaceous reservoirs in the Alberta basin provide outstanding examples of depositional control on reservoir continuity and performance. The variable geometries of reservoir sandstone bodies in the Albian Viking Formation can be explained in terms of depositional framework related to an overall sequence stratigraphic model. This depositional framework also governs the complexity of internal facies-controlled heterogeneities related to directional textural contrasts. Similarly, hydrocarbon-bearing sandstone bodies in both the Aptian-Albian Mannville Group and the Turonian Cardium Formation display highly fluctuating reservoir-performance trends that are related to degree of facies complexity caused by variations in depositional framework trends.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)