[usconservative]

I have no idea what api gravity means. I think I meant "thinner vs. thicker" ..... I see terms like "light/sweet crude" and "heavy" and "brent crude" in various oil related stories which I've always assumed to have something to do with the thickness of oil, which then has an impact on the ease or difficulty of refining that oil into other products.

This is one of those areas I have literally zero knowledge in which is why I'm asking what are likely very basic/rudimentary questions.

[thackney]

Light oil is thinner, has a higher API gravity (a measurement of viscosity). It contains more smaller molecules of hydrocarbons. Too light, like propane, and it cannot be used for gasoline, diesel etc.

Heavy oil is thicker. It is literally heavier. It weighs more per barrel than light oil. It has more larger hydrocarbon molecules. Ultra heavy oil is heavier than water. Refineries can break (crack) the larger molecules into smaller ones, but that cost energy (money).

All are a blend of many different sizes of hydrocarbon. API gravity and sulfur are the most common measurement of oil qualities.