U.S. Gulf Coast heavy grades continued to surge on Friday as the Iran conflict spurred several Middle Eastern producers of heavy crude to curtail production and drove buyers to scoop up U.S. barrels. Prices of Mars sour crude, the flagship crude produced in the U.S. Gulf of Mexico and favored by refiners globally, traded at a $11 premium to U.S. benchmark West Texas Intermediate (WTI) crude on Friday, brokers said. That was the highest since April 2020, and up $4 from Thursday.