Iran and France’s Total SA expect to sign a contract to develop part of the world’s biggest natural gas field in the next few weeks in what would be the Persian Gulf country’s first investment by an international energy company since sanctions were eased last year.

Total and China National Petroleum Corp. signed a “heads of agreement” with National Iranian Oil Co. in November to develop phase 11 of the South Pars gas field, a deal that was valued then at $4.8 billion. Total Chief Executive Patrick Pouyanne told Euronews television on Tuesday that the company will sign a contract for the offshore gas project in the next few weeks.

“The text of the contract on phase 11 of the South Pars has been finalized and we think the contract will be signed within a week or two,” NIOC Managing Director Ali Kardor told reporters Tuesday, without specifying which companies would be signing. Iran also plans to hold a bidding round for rights to develop the Azadegan oil field in southwestern Iran in the next three to four months, he said.

Iran has the world’s biggest gas reserves and is the third-biggest oil producer in the Organization of Petroleum Exporting Countries. The country aims to attract companies such as Total, Royal Dutch Shell Plc and Russia’s Lukoil PJSC and Gazprom Neft PJSC to its oil and gas fields with new technology to boost energy output. Its oil production climbed 33 percent last year after sanctions related to its nuclear program were eased in January 2016, according to data compiled by Bloomberg.

Total in November put the cost of the first part of the South Pars project at $2 billion, with Total’s share at $1 billion. “We will sign this contract in coming weeks,” Pouyanne said in the Euronews television interview. “It will be an important project, aimed at the Iranian domestic market.” Paris-based Total was working on South Pars until sanctions forced the company to pull out in 2009.

CNPC didn’t immediately respond to emails seeking comment on whether the Chinese company is still involved in South Pars. Iran’s Petropars was also part of the preliminary agreement in November.

Eni SpA of Italy also may return to an Iranian field where it once worked. It signed a memorandum of understanding in Tehran on Tuesday to study development of the Darquain oil field, in southwestern Iran near the Iraqi border, and the Kish gas field in the Persian Gulf. Eni was developing the Darquain field in 2009 and ended the project by 2010.