crudes

Crudes, or crude oils, are naturally occurring liquids composed largely of hydrocarbons and other organic materials formed from ancient biological matter. They accumulate in porous rock formations and must be extracted and separated before refining.

Crude quality is commonly described by density and sulfur content. By density, crudes are categorized as light, medium, heavy, or extra heavy; by sulfur content, as sweet (low sulfur) or sour (high sulfur). Light, sweet crudes generally require less processing to produce transport fuels, while heavy or sour crudes may demand more upgrading in refineries.

Origin and production: They originate from decayed organisms transformed by heat and pressure over geological times. After extraction, crude oil is transported to refineries via pipelines, ships, or rail, then separated into fractions such as gases, gasoline, diesel, jet fuel, and residues.

Refining and economics: Refineries use various processes to convert crude into usable products, adjusting operations to crude quality and market demand. Global markets reference benchmark crudes, such as West Texas Intermediate (WTI) and Brent Crude, to price different crudes relative to quality and location. Additional regional varieties include Dubai Fateh, Mexican Maya, and Canadian heavy crudes.

Environmental and policy context: The extraction, transport, and refining of crudes contribute to greenhouse gas emissions and other environmental impacts. Efforts to reduce emissions and to shift toward lower-sulfur or lighter crudes influence industry investment and refining strategies.