Chinese energy firms had earlier put on hold or slowed work on energy projects in Iran from late 2010. Iran and six world powers, including China and the United States, clinched a landmark deal on July 14 that limits the Islamic nation's nuclear activities in return for lifting sanctions that have more than halved its oil exports since 2012.
Sources at Sinopec Group, parent of Sinopec Corp and China National Petroleum Corp said companies have since late last year stepped up work at existing main contracts, after prodding from Iranian counterparts as negotiations were continuing over the eventual easing of sanctions.
Sinopec Group is expected to start producing at the Yadavaran oilfield at 85,000 barrels per day (bpd) under phase-one development, two company sources said, part of a $2 billion deal signed in 2007 to build a 200,000 bpd producer.
"Yadavaran project is progressing smoothly and is expected to start producing at 85,000 bpd by the end of the year," said company spokesman Lu Dapeng.
Top energy group CNPC is also slated to kick off phase one at North Azadegan around early October, said a CNPC source, without specifying an output amount.
CNPC said in its inhouse newspaper on Thursday that the North Azadegan project "reached its final stage before production starts". Iranian media in early 2014 put phase one of North Azadegan at 75,000 bpd.
A CNPC media official said he had not been informed yet on the latest status regarding North Azadegan.
These two projects, both in Khuzestan province in the southwest, would be part of Tehran's plan to boost production by 500,000 bpd within two months of Western sanctions being eased.
A quick increase in output and exports before sanctions are lifted would be similar to what happened in early 2014 when the temporary agreement leading to this month's longer-term deal saw Iran boost its exports to Asia to nearly 1.4 million bpd.
Iran's current output is about 3 million bpd, while its exports to Asia in June were running at about 1.2 million bpd.
Sources at Sinopec said company and NIOC are already in discussions to develop phase two of Yadavaran.
As Iran starts to invest in its industry, Chinese companies are worried about being outrun by Western companies such as France's Total and Italy's Eni, which have older, more established relationships with Tehran.
"Chinese firms may have squandered some of the best opportunities during the worst sanction days by not being a friend in need," said a CNPC source.
CNCP in 2011 scaled back its participation in the giant South Pars field, leading to Iran suspending the state company's contract. In late 2010, CNOOC withdrew completely from the North Pars project.
"Once out of sanctions, Iran will be looking for European or American standards in building oil and gas facilities as well as in services," said a Sinopec official.
On the first visit to Iran for 12 years by a French foreign minister, Laurent Fabius was in Tehran this week to improve diplomatic relations with the Islamic Republic and win business for French companies.