The world is drowning in oil. Saudi Arabia is pumping at almost full tilt. It is widely thought that the Saudis want to drive out higher-cost producers from the industry, including some of the fracking firms that have boosted oil output in the United States from 5m barrels a day (b/d) in 2008 to over 9m b/d now. Saudi Arabia will also be prepared to suffer a lot of pain to thwart Iran, its bitter rival, which this week was poised to rejoin oil markets as nuclear sanctions were lifted, with potential output of 3m-4m b/d.