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New Previous HitHydrocarbonNext Hit Systems Data in the Paleozoic Oil-Prospective Hudson Bay Basin in the Canadian Arctic

Denis Lavoie

The Hudson Bay Basin covers ~820,000 km2 and is the largest intracratonic basin in North America. The succession of the Hudson Platform consists mainly of Paleozoic strata, with a maximum preserved thickness of about 2500 m. The Paleozoic succession includes Ordovician to Devonian shallow marine carbonates, reefs and shales with locally thick Devonian evaporites. Paleozoic strata are unconformably overlain by erosional remnants of Jurassic, Cretaceous and Tertiary non-marine and marine strata. In a first phase of exploration (1973-1985), over 46,000 line-km of seismic reflection data were acquired and 5 offshore exploration wells drilled. Most of the seismic profiles and all of the exploration wells are located in a relatively small area in the central part of Hudson Bay. Re-evaluation of the available seismic data indicate that syn-tectonic sedimentation occurred in Late Ordovician(?), Silurian and Early Devonian with significant depocentre migration with time. New biostratigraphic data, supported by the seismic evidence, indicate 3 major unconformities, with the most important one at the Silurian-Devonian boundary. Upper Ordovician oil shales with Type I and IIs organic matter are recognized, with TOC values up to 35% and thickness up to 10 metres. Lower Silurian shales have TOC values up to 2%. AFT data indicate maximum burial occurred in Middle to Late Devonian and, in agreement with organic matter reflectance data, imply that Ordovician strata entered the oil window. Previous HitHydrocarbonNext Hit generation models indicate hydrocarbons were generated in the most deeply buried parts of the basin, with peak oil generation in Late Devonian. Available Previous HithydrocarbonNext Hit system data are synthesized in 5 prospective petroleum plays, including recently recognized porous hydrothermal dolomites and Ordovician, Silurian and Devonian reefs. High-resolution bathymetric surveys in Hudson Bay indicate the presence of circular sea-floor depressions similar to fluid-escape pockmarks while interpretations of RADARSAT images suggest possible oil slicks at sea surface. Additionally, some Previous HitdirectNext Hit Previous HithydrocarbonNext Hit Previous HitindicatorsNext Hit are interpreted from the vintage seismic data. Altogether, these new Previous HithydrocarbonTop systems data suggest that large areas of the Hudson Platform are prospective for oil accumulations.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013