Most crude tankers float for less than a week; half of fuel oil tankers are carrying bitumen mixture. More than 20 tankers carrying crude and fuel oil are anchored off the ports of China's eastern Shandong province, as onshore storage tanks are full, according to trade sources and shipping data on Thomson Reuters Eikon. Frenzied buying by independent refiners, most of whom are located in Shandong, and trading companies seeking to re-sell crude to these refineries have filled up tanks, they said. "Oil inventories at storage tanks are very high," a China-based trader said. Most of the tankers that are carrying crude have been floating off Shandong for less than a week although tanker Seaways Portland, which has Russian ESPO crude onboard, has been in the area for two months, the data showed.