Iran increased gas imports from Turkmenistan by 104 percent to above 9 billion cubic meters (bcm) in 2015 year-to-year, said OPEC's Annual Statistical Bulletin.
Iran's gas import from Turkmenistan was 4.422 bcm in 2014.
Tehran produced 257.623 bcm of raw gas in 2015, about 5 percent more than the previous year, of which about 226.673 bcm was commercial gas and the rest of that was re-injected to oil fields to maintain crude oil production.
Iran's commercial gas production increased 6.5 percent, while re-injections decreased 2.5 percent in 2015, year-to-year.
The country's proven gas reserves also stood at 35.5 trillion cubic meters.
Iran's gas exports increased 2.2 percent to 8.541 bcm last year, the report said.
The country's natural (sweet) gas demands stood at 184.9 bcm last year, which indicates 5.9 percent growth year-to-year.