Heavy oil is a type of crude oil that is characterized by an asphaltic, dense, viscous nature and is also described as asphaltene content. This means there are very large molecules that incorporate a large number of sulfur and metals in the content of the oil. Heavy oil is similar to molasses and contains impurities such as waxes and carbon reside that have to be removed before the refining process takes place. Heavy oil is abundant but it also comes with technological and economical challenges, even though it is a very important energy resource.
