South Korea\'s Iranian crude oil imports increased more than double in September from August, official data said. South Korea imported 571,909 tons of Iranian crude last month, or 139,736 barrels per day (bpd), more than doubles the August barrels, preliminary customs data shows. That puts the Asian country\'s imports from Iran for June-September at 133,676 bpd, Reuters\' calculations said. The total means South Korea remains close to the 125,814 bpd it aims to achieve in its imports from Iran in the six months through November. South Korea\'s Iranian crude oil imports vary from month to month as one of the two Korean refiners that import Iranian oil receives the oil only every two months, according to industry sources. South Korea, the world\'s fifth-largest crude buyer, imported a total of 10 million tons of crude last month against 11.1 million tons in September 2012, data from the Korea Customs Service also showed on Tuesday.