The price of oil could tumble even further to a low of $20 (17.73 euros) a barrel – that’s the warning from Goldman Sachs in a report published on Friday.<br /><br /> It blames the global oversupply which it says is even worse than had been expected.<br /><br /> The investment bankers say they expect the surplus to continue next year.<br /><br /> Over the past two months crude oil has plunged from around $60 (53.2 euros) a barrel to below $40 (35.4 euros) at one point.<br /><br /> Goldman analysts believe prices will need to stay lower for longer to force production cuts.<br /><br /> GOLDMAN SACHS: Huge supply and weak demand could send oil prices plunging to $20 per barrel http://t.co/mlkfTlG282— BI Markets (@themoneygame) September 11, 2015<br /><br /> Oil prices have more than halved since summer last year – the result of a global glut as well as the decision by OPEC countries, led by Saudi Arabia, not to cut output but to fight for market share.<br /><br /> That move which shocked markets has prompted the International Energy Agency to forecast that
