Hydrocarbon Systems in the Intracratonic Hudson Bay Basin: A New Prospective Frontier in the Canadian North
Denis Lavoie1, Nicolas Pinet1, Mathieu Duchesne1, Shunxin Zhang3, Virginia Brake1, Kezhen Hu2, Esther Asselin1, Rudolf Bertrand4, Barry P. Kohn5, Jim Dietrich2, Keith Dewing2, Derek Armstrong7, and Michelle
1Geological Survey of Canada, Natural Resources Canada, Quebec City, QC, Canada.
2Geological Survey of Canada, Natural Resources Canada, Calgary, AB, Canada.
3Canada-Nunavut Geoscience Office, Iqaluit, NU, Canada.
4Water, Earth, Environment Center, Institut national de la Recherche Scientifique, Quebec City, QC, Canada.
5Earth Sciences, University of Melbourne, Melbourne, VIC, Australia.
6Manitoba Geological Survey, Winnipeg, MB, Canada.
7Ontario Geological Survey, Sudbury, ON, Canada.
The Hudson Platform covers 600,000 km2 and is one of the largest Paleozoic sedimentary basins in Canada. The Hudson Platform encompasses parts of Manitoba, Ontario and Nunavut, with two thirds of the area covered by waters of Hudson Bay. The Platform contains the large Hudson Bay Basin and the smaller satellite Moose River and Foxe basins.
The Hudson Platform is the least studied intracratonic basin in North America; its surface area rivals that of other intracratonic basins although it is characterized by a thinner preserved sedimentary succession. The succession of the Hudson Platform consists of Ordovician to Cretaceous strata, with a maximum preserved thickness of about 2500 m. The Paleozoic succession includes Ordovician to Devonian shallow marine carbonates, reefs and thin mudstones with thick Devonian evaporites. Paleozoic strata are unconformably overlain by thin, erosional remnants of Jurassic and Cretaceous non-marine and marine sandstones, mudstones and lignite seams.
The hydrocarbon potential of the Hudson Platform is poorly constrained and the area is viewed as a frontier prospect. In a first phase of exploration (1970-1980), over 46 000 line-km of seismic reflection data were acquired and 5 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. A limited number of onshore wells have also been drilled. Although bitumen was been reported in wells, all were dry and exploration companies abandoned the area in the 1980s.
The Geological Survey of Canada and its partners are carrying out a re-evaluation of the petroleum systems and energy resource potential of the Hudson Platform. Results indicate that many prospective petroleum reservoir and trap types, including porous hydrothermal dolomites and reefs. Upper Ordovician oil shales are widespread with TOC values up to 35% (average of 15%); the thickness of these Type I/II source rocks range between 5 to 15 metres. Thermal maturation data on well cuttings suggest that oil window conditions (Rovit of 1%) have been reached in the intervals that host the Ordovician source rocks. New high resolution bathymetric surveys in Hudson Bay have led to the recognition of circular sea-floor depressions similar to fluid or gas-escape pockmarks, possible evidence of hydrocarbon migration. New hydrocarbon systems data suggest that large areas of the Hudson Platform are prospective for oil accumulations.
AAPG Search and Discovery Article #90130©2011 3P Arctic, The Polar Petroleum Potential Conference & Exhibition, Halifax, Nova Scotia, Canada, 30 August-2 September, 2011.������������������������������������������������