Canadian Natural Resources Limited is a Canadian independent energy company engaged in the acquisition, exploration, development, production, marketing and sale of crude oil, natural gas liquids (NGLs), and natural gas production. The Company�s principal core regions of operations are western Canada, the United Kingdom sector of the North Sea and Offshore Africa. The Horizon Oil Sands Mining and Upgrading segment produces synthetic crude oil through bitumen mining and upgrading operations. Within Western Canada, the Company maintains certain midstream activities that include pipeline operations and an electricity co-generation system. The Company�s exploration and production activities are conducted in three geographic segments: North America, North Sea and Offshore Africa. As of December 31, 2011, the Company�s gross proved crude oil and NGLs reserves totaled 4,090 one million barrels, and gross proved plus probable crude oil and NGLs reserves totaled 6,521 one million barrels.