The heavy and extra heavy oils in Canada represent an amount of recovery oil resources of about 300 billion barrels. These vast quantities of heavy and extra heavy oil are trapped in shallow, accessible reservoirs, but are difficult to extract. Producers involved in heavy oil recovery face special challenges in producing these high-viscosity crudes.Conventional heavy oil recovery methods have showed to provide limited oil displacement efficiencies in Canada's heavy and extra heavy oil deposits. To overcome their inherent difficulties several variations of steam, air and solvent injection methods have been proposed. The most interesting ones appeared along with developments in horizontal well technology. These methods combine the concept of oil gravity drainage with the conventional air-steam and solvent-based heavy oil recovery processes and the horizontal well technology. Methods known as cyclic steam stimulation -CSS, steam-assisted gravity drainage -SAGD, solvent vapor extraction -VAPEX, and top-dow combustion, are examples of this class of methods.This article presents an overview of the recent production technologies for extra heavy oil reserves. Some of the properties of heavy oil are summarized and a review of the drilling/completion and production techniques that help to make heavy-oil reservoirs profitable assets is presented. Both, limitations and potential benefits of these techniques are described.
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