The Opec oil cartel sees only a gradual improvement in the global crude market, with prices recovering to above US$70 a barrel after four years, according to a report released on Wednesday.

With the global benchmark oil price touching an 11-year low of US$36.04 on Monday, the cartel which produces a third of the world's crude said that it foresees a "gradual improvement in market conditions as growing demand and slower than previously expected non-Opec supply growth eliminate the existing oversupply and lead to a more balanced market".

The Organisation of the Petroleum Exporting Countries, in its annual World Oil Outlook report, bases its reference scenario on US$70.70 for a barrel of crude in 2020 and US$95 in 2040.