52% of all economically viable oil available to private investors resides in Alberta, Canada

Alberta is home to nearly 170 billion barrels of proven and probable oil reserves (much of it amongst easily processed oil sand) exceeded only by Saudi Arabia and Venezuela (AP:China eyes Canada oil, US's energy nest egg) In Alberta alone, more than 1.6 trillion barrels of oil in inferred resource isn't even included because extraction methods SAGD and THAI/CAPRI aren't able to bring it to the surface by economically viable means. However, considering conventional sources only, Canada has major sources outside Alberta (Saskatchewan and Newfoundland combined have about 1.4 times as much oil reserves as Alberta). (NEB - Energy Reports Canadian Energy Ovewview) Approximately 20% of Alberta's oil sands are close enough to the surface to be recovered by open pit mining, the rest requires vairous in-situ technologies; the government of Alberta requires that oil companies bring the land back to 'equivalent land capability' that is, restore it to a level that makes it useful to the community either as boreal forest (which was initially destroyed) or pasture for bison (though many companies have only restored a fraction of that, for example Syncrude Oil restored 22%). Oil sands operations have been approved to use about 360 million m3 of water from the Athabasca River (runs through the mining district, water source is a glacier over 1,200 km away), that's twice as much water used by the entire city of Calgary though less than 1% of the water from the river is used by the province and oil operations; 24 m3 of water is used to produce 1 m3 of synthetic oil.
By 2045 oil sands will produce close to 11M bbls/d and that will continue for a century. Between 2012 and 2020 oil output from the tar sands will double (1.7 mbpd --> 3.4 mbpd) and triple in the next 25 years to 5.1 million barrels per day.

With crude oil fetching higher prices in Asia, Canadian producers are looking to expand into new markets (nearly all Canadian oil (2M bbls/d) currently heads south, 2010). (Reuters:Foes fight Canada pipeline to rich Asia market) The supply chain has, more recently been overwhelmed in the United States due to the release of 30M barrels of reserve oil onto the market Parkersburg News and already filled up pipelines and storage tanks. With China's interest in Canada growing, the 728 mile Northern Gateway pipeline from Edmonton to Kitimat, BC is gaining the attention of politicians and oil companies eager to broaden their customer base.

Ironically, environmentalists are both helping and hampering efforts to provide access for Asia; The oil pipelines face fierce opposition from environmentalists and Native Indian groups concerned over wildlife and possible oil spills (like what happened with Enbridge in Michigan in 2010); at the same time American environmental groups have opposed the oil sands on the grounds that it makes excessive use of water and increases greenhouse gas emissions.

Keystone XL, another oil pipeline struggling through the approval phase, aims to bring more of Canada's oil to the United States in an effort to reduce their dependency on Middle East oil 'potentially to nil'. Among other top sources, Mexico is an unsustainable source due to dwindling reserves there and Saudi Arabia (number 2) is viewed as unstable due to its situation within the Middle East. TransCanada's $7 billion pipeline project would double Alberta's oil exports to the United States. Though Obama rejected the permit in January 2012 he didn't completely shut the door on the project, saying that the company is free to re-apply. Whether or not the project goes ahead one thing is for sure, Alberta will continue to produce oil. As of last summer there were 22 active exploration projects in Athabasca alone.

The reason that it's 52% even though all of Canada doesn't have half of the world's oil is that, much of the new oil being discovered/produced is heavy-extra heavy oil and a lot of it is in countries like Venezuela which don't allow foreign investment/ownership of their state run oil companies. Even in Colombia where capitalism is as popular as it has ever been, big oil companies like Ecopetrol remain off limits to foreign investors (in August Ecopetrol (majority state owned) will have its biggest share sale since 2007 in which it will make available between 3 and 5% of Ecopetrol shares but only Colombian citizens are allowed to participate).