Extra-heavy oil is one of several sources of syncrude, a type of synthetic fuel that closely resembles crude oil. Extra-heavy oil occurs naturally, and forms when oil that was once buried deep in the Earth is exposed to bacteria that breaks down the hydrocarbons and changes the oil's physical properties. The oil can be recovered through open pit mining or "in situ" (on site) collection. In situ collection involves piping hot steam or gas into a well to break up the heavy oil and collecting the fluid through a second well. Both methods have their limits. Open pit mining can only be used to collect extra-heavy oil near the surface. It also damages the environment by destroying forests and animal habitats, and the large amounts of water required has to be disposed of as waste after being used [source: Clark]. In situ methods need further research to gather large amounts of heavy oil.
The production process for many synthetic fuels creates products that are more or less ready to be used in engines and vehicles. Syncrude production, on the other hand, results in a synthesized crude oil that has to be further refined to be commercially sold, just like conventional crude oil. In its natural state, extra-heavy oil is basically a more viscous form of crude. If crude flows like water, then extra-heavy oil flows like honey. To get the extra-heavy oil into a useful form, it is typically exposed to heat and gases that break down the hydrocarbons into those that can be burned as fuel and those that can't. This is similar to the process of refining crude oil into fuels, but more expensive and complicated.