Qatar's Energy Minister Abdullah al-Attiyah has said that the recent rise in oil prices has not been caused by a supply shortage, Reuters has reported. Crude prices hit an 18-month high of $87.09 a barrel on April 6, although they have since slipped to just under $83. 'Inventory is very comfortable and even the highest in history,' he was quoted as saying ahead of a meeting of gas powers in the Algerian city of Oran.