Abstract:
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.