Geochemistry of crude oil from Bent Horn field (Canadian Arctic Archipelago) and its possible Paleozoic origin

Geochemical analysis shows that oil from Devonian reservoirs at Bent Horn field in the Canadian Arctic Archipelago is non-biodegraded and has a maturity corresponding to the mid-late part of the oil window. It is characterized by a smooth n-alkane profile, low concentration of acyclic isoprenoids and saturated hydrocarbon biomarkers, with some variability in sterane composition. Compared with oil from Mesozoic strata of the Canadian Arctic Islands, the Bent Horn oil shows higher paraffin indices and aromatic hydrocarbon maturity indicators (MPI, MDR), dominant tricyclic terpanes and different distribution of regular steranes. Geological evidence suggests a Paleozoic source rock for the oil. Rock-Eval pyrolysis and total organic carbon (TOC) data indicate good source rock potential for the Silurian basinal facies and Upper Silurian-Lower Devonian clastics of the Boothia Uplift. These intervals are enriched in Type II oil-prone organic matter (commonly 2.0-5.0% TOC, maximum 13.6%) and are mature with respect to petroleum generation. Based on preliminary biomarker analysis, maturity, and stratigraphic and geographic proximity to the Bent Horn oil field, the Cape Phillips Formation appears to be the most likely source rock for the hydrocarbon accumulation at Bent Horn.