"The project will help stabilize domestic natural gas supply in western regions and boost exports to Iraq," Hassan Montazer-Torbati was quoted as saying by the Oil Ministry news portal.
The 600 kilometer pipeline was built by domestic contractors under a build-operate-transfer contract, the NIOGC said. IGAT-6 has raised gas supply by 50-60 mcm per day.
"Close to 36,000km of high-pressure gas pipes are now operating," he said, adding that the transmission and distribution pipelines stretch over 350,000 km, Financial Tribune reported.
Iran plans to expand gas pipeline network from 36,000km to 45,000km in eight years.
Turkey and Iraq are the main buyers of Iranian gas. The former signed a 25-year deal in 1996 to buy 10 billion cubic meters of the fuel annually through a pipeline and the latter is importing 12 mcm/d from June 2017.
According to a reports published by BP Statistical Review of World Energy, Iran's annual gas consumption in 2017 was 214 billion cubic meters.
It said Iran accounts for almost 40% of gas consumption in the Middle East. China, the world’s second-largest economy and the most populous nation, consumed 191 billion cubic meters in that year.
IGAT is a series of nine large diameter pipelines built to supply gas from refineries in the south (Khuzestan and Bushehr provinces).
IGAT-1, 42 inches in diameter, was constructed between Bid Boland Refinery in Khuzestan and the port of Astara in northern Gilan Province.
IGAT-2 connects Fajr Refinery in Bushehr Province and Qazvin Province in the north, extends from Asalouyeh to Markazi Province and ultimately reaches Gilan Province.
Stretching 1,145km, IGAT-4 with a capacity of 110 mcm/d, transfers gas produced in South Pars phases 1 to 5 in Assalouyeh to Fars and Isfahan provinces.
IGAT-5 transfers sour gas from South Pars phases 6, 7 and 8 to Khuzestan Province for injection into oil wells to boost extraction.
IGAT-6 transfers gas from South Pars to southern and western regions namely Hamedan and Kermanshah provinces.
IGAT-7 stretches 900 km between Asalouyeh and Iranshahr in Sistan-Baluchestan Province.
The 56-inch-diameter IGAT-8, stretching over 1,000 km, transfers 110 mcm of gas from South Pars to the central regions on a daily basis.
The 56-inch-diameter IGAT-9 with a length of 1,863 km starts from Asalouyeh, crosses Ahvaz, Dehgolan and stretches to Bazargan district in the northwestern province of West Azarbaijan through 17 compressor stations.