Crude oil is one form of raw, unrefined fossil fuel material that is extracted from the earth, the other main fuels being coal and natural gas.

Although bought and sold, crude oil is not usually considered a fuel nor does it really have a use by itself. More important is that crude oil is a mixture of many types of fossil fuels which can be refined into gasoline, diesel, fuel oils, kerosene, jet fuel, asphalt, road oil and a variety of other fuels. Even the “oil” that we purchase for our engines is just a part of crude oil that has been refined to form lubricants.

Differences in the conditions that led to the formation of crude oil can result in it being quite different from region to region. For instance the colour and thickness of oil can vary from thick and black to thin and golden, and contain different levels of impurities such as sulphur and water. These differences determine how much refining needs to be done before the fuel is ready for distribution and use.

Oil Sands accounted for 33% of Canada's crude oil production in 2003, and could provide more than 50% by 2010 if development continues at the current pace and conventional light oil availability continues to decline.