Finnish refiner Neste Oil said the ship was bound for Western Europe from Primorsk, in Russia, when it ran aground.
Neste said in a statement there were some ruptures in the ballast tanks of the ship, the Propontis, but that its cargo hold was intact.
It said the authorities and Greek shipowner Tsakos were considering their next move, with the crew inspecting the damage to the double-hulled ship at sea, reports Reuters.