Valley fills in the McMurray Formation contain the main reservoirs of the southern Athabasca Oil Sands Region (AOSR), which are typically exploited by steam-assisted gravity drainage (SAGD). Despite the importance of the bitumen resources they contain, a comprehensive regional assessment of valley-fill geometry, planform morphology, and reservoir quality is lacking. To remedy this, a data set of 214 logged cores, hundreds of core photographs, 14,000 wire-line logs, and three-dimensional seismic data is used to map four McMurray Formation parasequence sets in the southern AOSR and determine the geometry and reservoir quality of associated valley fills.

The valley fills represent a complex network of sediment-routing systems that ultimately moved sediment north, toward the Boreal Sea. They are mainly composed of fluvial or tidally influenced point-bar deposits laid by rivers of varying width and depth. Between valley fills, the reservoir parameters governed by depositional architecture (i.e., sandstone porosity, shale volume, and net-to-gross) vary by less than 3%, with few exceptions. At a high level, this suggests that for analogue-based SAGD production forecasting, all projects exploiting valley-fill deposits are potential analogues to one another, regardless of the valley fill’s stratigraphic age.

The regional maps produced by this study can be used to investigate upstream–downstream sedimentological, ichnological, and morphological trends that may reveal critical insights into depositional processes and environments. Additionally, the devised stratigraphic framework can be employed when mapping point-bar deposits to predict facies changes in a formation that is particularly heterolithic and laterally discontinuous.

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