The background -- oddly not mentioned in the bbc article -- is  the blowup of the Doha meeting and SA using oil prices as an economic weapon to punish Iran and Russia with Venezuela getting caught up as collateral damage.  Plus their interests in cutting US and Canadian investment in domestic oil production.<p>see eg <a href="http:&#x2F;&#x2F;foreignpolicy.com&#x2F;2016&#x2F;04&#x2F;18&#x2F;to-punish-iran-saudis-scuttle-oil-freeze-plan&#x2F;" rel="nofollow">http:&#x2F;&#x2F;foreignpolicy.com&#x2F;2016&#x2F;04&#x2F;18&#x2F;to-punish-iran-saudis-sc...</a>