Sequence Stratigraphic and Depositional Controls on Reservoir Continuity for the Cretaceous Doe Creek Member of the Kaskapau Formation, Valhalla Field, Alberta, Canada

L. E. Hunt and S. C. Atchley
Baylor University, Waco, TX

The Doe Creek Member of the Late Cretaceous (Cenomanian) Kaskapau Formation is located in northwestern Alberta on the Peace River Arch of the Western Canadian Sedimentary Basin. Valhalla Field was discovered in 1977 and is the major producer of hydrocarbons from the Doe Creek interval. Estimates of original in-place oil and gas at Valhalla are 279 million barrels and 44.7 billion cubic feet respectively. As of May 2008, 65 million barrels (82% of recoverable reserves) and 13.5 billion cubic feet (42% of recoverable reserves) have been recovered through primary and secondary depletion.

This study assesses the spatial and temporal distribution of reservoir facies within the Doe Creek Member by evaluating the sequence stratigraphic controls on reservoir quality and continuity across Valhalla Field. A total of ten retrogradationally stacking parasequences and/or associated bedsets were identified within the Doe Creek interval, of which, four include reservoir quality sandstone (I-1, I Sand, I+1 and I+2). For these sandstones, maps are provided which depict the spatial distribution of reservoir facies, average effective porosity, gross pore volume thickness and the average fraction of calcite cement. These maps are in turn compared to fieldwide trends of total fluid and oil production. A strong correlation exists between fluid production and trends of gross pore volume thickness, reservoir facies thickness and reservoir facies distribution. Based on this correlation a high resolution, sequence-keyed geologic model was constructed for use in enhanced oil recovery.

AAPG Search and Discover Article #90087 © 2008 AAPG/SEG Student Expo, Houston, Texas