Oil markets are best understood in layers: physical crude, refined products, and the financial instruments referencing both. Each layer responds to different pressures and on different timescales.
Physical crude trades against benchmark grades with quality and location differentials. Refined products — diesel, gasoline, jet fuel, fuel oil — depend additionally on refinery configuration, seasonal demand and regional specification.
Supply-side factors include production policy, field maintenance and geopolitical developments. Demand-side factors track industrial activity, transport and, increasingly, substitution toward alternative energy sources.
For a business buying petroleum products, the practical questions are narrower: specification, reliability of supply, delivery terms and the credibility of the counterparty offering them.