NIOC had promised the field to Sinopec under a 2004 agreement that required the Chinese company to develop the field and buy 10 million tonnes of liquefied natural gas (LNG) a year over 25 years.

However, progress has been slow in finalising a contract, after US opposition to other Chinese energy deals being agreed in Iran, including China National Offshore Oil Corporation’s deal on the North Pars gas field.

NIOC managing director Seyfollah Jashnsaz, told Iran’s official energy news agency Shana that a final deal will be reached next month but declined to comment on the structure of any deal.

The Yadavaran field has oil reserves of 18.3bn barrels, of which about 3.2bn barrels are recoverable, while its gas reserves amount to 12.5 trillion cubic feet, with 2.7 trillion recoverable.