Diagenesis and provenance of Marmora and Sable members of the Upper Logan Canyon Formation, in wells near Sable Island

Abstract

<p>Provenance and diagenesis are important processes to study in order to determine reservoir potential of sandstones within a sedimentary basin. The Scotian Basin is a large sedimentary basin located off the eastern part of Canada. Samples from the Upper Logan Canyon Formation of the Central Scotian Basin were studied in order to determine provenance and diagenesis. The studied wells are located near the West Sable oil and gas field and are targeted in the upward dome created by a large salt diapir.</p><p>Diagenetic minerals were studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). This allowed for identification of early seafloor diagenetic minerals, late diagenetic minerals, clay coats, and coated grains. The presence of clay coats is important because they prevent the formation of authigenic quartz, which helps to preserve porosity during prolonged burial.</p> <p>To understand provenance, detrital minerals were point counted from Back- Scattered Electron (BSE) Images, lithofacies were applied, and petrographic and chemical data was analyzed. The detrital mineralogy of these sandstones is similar to other analyzed wells in the Scotian Basin, and suggests that they were sourced by the Sable River, with minor detrital minerals coming from the Meguma Terrane, and Newfoundland. Whole rock geochemistry was also performed on selected mudstone intervals. It indicates that Cree Member mudstones were sourced by the Sable River or Newfoundland, and the Sable Member mudstones were sourced from the Meguma Terrane and the Sable River.</p>