Geostatistical Rendering of the Architecture of Hydrostratigraphic Units within the Paskapoo Formation, Central Alberta

The Paskapoo Formation is one of the largest and most intensely used bedrock aquifer systems in Alberta, yet little is known about the internal architecture of the major hydrostratigraphical units contained within. This study summarizes the results of a computer-based geostatistical analysis of more than 35,000 borehole logs from the petroleum and water-well industries to define the internal three-dimensional geometry of sandstone bodies that can be considered regional aquifers. Sandstone abundance was estimated using cutoffs on gamma-ray logs and from an expert-based, subjective classification of sandiness from drillers' lithologs, and averaged in a series of 25 m thick slices extending through 750 m of sedimentary rock within the Paskapoo Formation. Analysis of the three-dimensional sandiness estimates reveals information on the relative abundance and distribution of sandstone found in splay and channel depositional settings.

The analytical processes developed and applied in this study enabled us to map the major hydrostratigraphical units within the Paskapoo Formation. This, in turn, has enabled us to provide new insights into the lithostratigraphical architecture of this formation and to make inferences about its sedimentary history.