Qatar has started drilling new natural gas wells in its shared gas field with Iran in the Persian Gulf, while Tehran’s plans to expand production remain dormant.

Qatar Petroleum, the national oil and gas company announced April 16 that it has started development in the north field, which Iran calls the South Pars. One-third of this underwater gas reserve is in the Iranian territorial waters and the rest belongs to Qatar.

Qatar started the development of the gas field in 1990 and has extracted 2.5 times more natural gas than Iran since then.

Qatar Petroleum announced that by drilling 80 new wells it will expand daily production to 120 million cubic meters and in the next phase will add another 60 million to its capacity.

Iran is handicapped in its efforts to expand production as large international companies stay away from deals that can violate U.S. sanctions, reimposed in 2018.

Iran’s production last year marginally declines but extraction of the natural gas will decrease by 10 billion cubic meters each year due to fall in the natural pressure pushing the gas out. Iran needs to use much heavier platforms equipped with powerful pumping equipment to maintain production, but that needs cooperation with large international oil and gas companies.

After international sanctions against Iran were lifted in 2016, the French giant Total and China’s CNPC signed a $4.8 billion contract with Iran to help in the project, but both later pulled out as President Donald Trump imposed U.S. sanctions.