Hayward said low prices had stimulated demand - expected this year to be 2 million barrels a day of incremental increases over 2014 - but Iran and Libya were wild cards that could affect global supply and demand dynamics.

"I think we do need to be prepared for a period of sustained low prices absent any form of intervention," he told an African oil and gas conference in Cape Town.

(Reporting by Wendell Roelf and Ed Stoddard; Editing by James Macharia)