Iran has managed to increase its oil exports to pre-sanctions level, a report said.
Iran's total crude oil and condensate sales likely reached around 2.8 million barrels per day (bpd) in September.
The figure nearly matches a 2011 peak in shipments before sanctions were imposed on Iran.
According to the report, Iran sold 600,000 bpd of condensate for September - up from about 350,000 bpd in August and including about 100,000 bpd shipped from storage - to meet robust demand in Asia.
September crude exports increased slightly from the previous month to about 2.2 million bpd.
Iran, along with Libya and Nigeria, is allowed to produce "at maximum levels that make sense" as part of any output limits in a surprise deal reached last week by the Organization of the Petroleum Exporting Countries (OPEC).