Russian crude oil (ESPO) is commanding a 20+ USD premium over Brent due to constrained global supply. China's independent refineries are forced to buy Russian oil at elevated prices because US sanctions on Iran have cut off their preferred Iranian supply and disrupted Strait of Hormuz shipping. This supply crunch is driving Chinese buyers to source from alternative suppliers (Canada, Brazil, West Africa) at even higher premiums (up to 30 USD/barrel above Brent), indicating a tightening energy market for Asian refiners.