Exports of premium-grade base oils from the Spanish port of Cartagena rebounded in September, balancing out signs of a drop in shipments from the Mideast Gulf.Base oils exports of more than 60,000t from Cartagena in September rose from around 35,000t the previous month, port data showed.The volume was the second highest in six months and boosted total shipments to around 460,000t in the first nine months of the year.The volume rose from around 410,000t during the same period last year even as plant-maintenance work cut supply in the second quarter of the year.Europe’s prices for Group III base oils for supplies with approvals fell this year, but much less than the steep slide in prices for supplies with limited or no approvals, ICIS data showed. .Spain’s July base oils supply rises.Europe’s July Group III supply falls