Oil markets will remain awash with crude well into 2017, Opec warned on Monday, as the resilience of the US shale industry and new streams of oil production threaten to keep pressure on prices. The producer cartel revised higher for this year and next oil supply forecasts from non-member countries, implying that demand for its crude will remain far lower than current near record output of more than 33m barrels a day. The larger than expected surplus threatens to derail hopes that supply and demand will come into balance by next year, putting a damper on prices that remain less than half mid-2014 levels. Opec is due to meet other large producers later this month to discuss possible output curbs, with talks likely to receive a jolt of urgency following the latest forecasts. Brent, the international crude benchmark, fell 2 per cent to $47 a barrel shortly after the publication of the cartel’s monthly oil report. Opec kingpin Saudi Arabia and Russia, the largest exporter outside the group, agreed last week to work together to stabilise the market but there are still big doubts that a deal to reduce or freeze production is attainable.