Sedimentology, diagenesis and reservoir characterization of the Montney Formation at Sturgeon Lake South 'F' Pool, west-central Alberta

The Triassic Montney Formation at the Sturgeon Lake South Pool, as indicated by 12,000 measured grains, is a shale that is dominated by siltstones that are of reservoir quality. Siltstones are well sorted and have a mineral framework rich in detrital feldspar and dolomite. Comparisons of this framework mineralogy with minerals from Pleistocene loess suggest that the Montney Formation material was sourced from loess and possibly transported to the site of accumulation by wind.; Seven depositional lithofacies and two post-depositional lithofacies were identified (LF1--9). The two most common lithofacies are: (1) structureless siltstone (LF1); and (2) an interbedded ripple-laminated siltstone with fine siltstone or shale (LF3a). Fine-grained lithofacies with similar characteristics are known from several modern muddy coastlines, Guianas, South America; Mississippi, Louisiana; and Jiangsu, China.; Diagenetic and authigenic mineralization occluded pores with grain-rimming dolomite, quartz, carbonate fluoroapatite and potassium feldspar. This mineralization reflects diagenesis under arid conditions and meteoric and saline ground water. The combination of complicated depositional and diagenetic patterns have resulted in a reservoir with complex architecture.