The Final North America Conventional Oil Frontier: The Intracratonic Hudson Bay Basin in the Canadian Arctic

Lavoie, Denis; Pinet, Nicolas; Dietrich, Jim; Kohn, Barry P.; Zhang, Shunxin; Hu, Kezhen; Armstrong, Derek; Nicolas, Michelle; Asselin, Esther; Bertrand, Rudolf; Duchesne, Mathieu J.; Decker, Vincent; Galloway, Jennifer; Reyes, Julito; Brake, Virginia

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 indicates 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, suggest 3 major unconformities, with the most important one at the Silurian-Devonian boundary. Preliminary interpretation of AFT data suggest that maximum burial occurred likely in Middle to Late Devonian and in agreement with organic matter reflectance data (Rovit of 0.60 to 0.91%), imply that the Ordovician - Silurian interval went through the oil window. Available hydrocarbon system data are synthesized in 5 prospective petroleum plays, including recently recognized porous hydrothermal dolomites and reefs. Type I/II Upper Ordovician oil shales are recognized at several locations in the basin with TOC values up to 35% and thickness up to 11 metres. Lower Silurian shales may also have local potential (TOC values up to 2%). New high-resolution bathymetric surveys in Hudson Bay led to the recognition of circular sea-floor depressions similar to fluid-escape pockmarks and preliminary interpretations of RADARSAT images suggest possible oil slicks at sea surface. Some direct hydrocarbon indicators are interpreted from the vintage seismic information. Taken together, these new hydrocarbon systems data suggest that large areas of the Hudson Platform are prospective for oil accumulations.

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013