It was a wild week for oil markets. Iran shipped roughly 20 million barrels of crude into global markets after an interim agreement with the Trump administration loosened restrictions on Iranian exports and helped reopen the Strait of Hormuz — responsible for a fifth of the world’s oil flow during ordinary times. The sudden release of supply helped drive oil sharply lower from its spring highs and pushed the US average for gasoline prices below $4 a gallon. Crude prices clawed back some ground