Crude oil is rarely consumed directly. The barrel of light sweet WTI that settles on NYMEX is a raw input — what comes out of the well — and almost none of it is in a form anyone burns in a car, a truck, a furnace, or a jet engine. The transformation from crude to fuel happens at refineries: complex industrial facilities that distill crude into fractions, then crack, hydrotreat, reform, and blend those fractions into the fungible products we actually consume.

Roughly half of every U.S. barrel of crude becomes gasoline; another quarter becomes distillates (diesel, heating oil, jet fuel); the remaining quarter splits among naphtha, fuel oil, residual products, asphalt, lubricants, and petrochemical feedstocks per EIA's Weekly Petroleum Status Report yield breakdowns.

The economic value of a refinery is the difference between what it pays for crude and what it sells the products for, less the operating cost of running the plant.