Depositional and diagenetic controls on reservoir quality and their petrophysical predictors within the Upper Cretaceous (Cenomanian) Doe Creek Member of the Kaskapau Formation at Valhalla Field, Northwest Alberta.

Valhalla Field, discovered in 1979 and located in northwest Alberta, produces from the Upper Cretaceous Doe Creek Member of the Kaskapau Formation. Original reserves in place are 44 x 106m3 of oil, of which 10.3 x 106m3 of oil (82% of recoverable reserves) have been produced (ERCB, 2008). This study evaluates the depositional and diagenetic controls on reservoir quality within the Doe Creek at Valhalla Field in order to identify reservoir-prone facies and predict their distribution in wells lacking core. Analysis of core and well log data indicates that intervals of highest reservoir quality are preferentially associated with thin (meter-scale) sandstone bodies deposited in proximal lower and upper shoreface environments. Based upon the relationships of facies to deep resistivity, mud content as gamma-ray derived shale volume, and density-neutron porosity separation within cemented zones, a well log transform was created that successfully predicts the distribution of reservoir-prone facies and calcite cement.