Slippery road ahead for Opec's extended oil cut

London

THE world's two biggest oil exporters seem to have finally figured out how to eliminate a global surplus that's kept crude prices in check for almost three years.

Saudi Arabia and Russia said in Beijing on Monday they favour prolonging this year's oil curbs to the first quarter of 2018.

If they convince fellow producers to adopt the strategy when the Organization of the Petroleum Exporting Countries (Opec) a…