Supertankers carrying oil face up to a 10-day wait to discharge their loads as China seeks to double its reserve capacity from sources other than Iran, Bloomberg reported. The tankers typically must wait two days. “These delays are a reflection of China’s huge demand for oil, and they are allowing owners to push up rates,” said Nikos Varvaropoulos, an official at Greece-based Optima Shipbrokers. Oil shipping costs from the Middle East to Asia have risen 29% since January 1, according to the Worldscale measure of freight rates, with shipping profits on the route increasing 90% to US$39,532 per day. China has doubled its purchases of Venezuelan oil since last year and increased its deliveries from Angola by 25%, while those from Iran have fallen. China plans to raise its oil reserves to 271.8 million barrels from 103.2 million barrels, and to that end is building eight additional oil-stockpiling centers.