India's largest liquefied natural gas (LNG) importer, Petronet LNG has signed a deal worth $6 billion with US based gas firm, ExxonMobil, to get additional supply of 1.5 million tonne LNG.

The Gorgon field, being developed by ExxonMobil, Chevron and Royal Dutch Shell, has gas reserves of over 40 trillion cubic feet.

The gas, under less than 20 year gas supply agreement, would be used for upcoming Kochi terminal in Kerala. NTPC's large power plant at Kayamkulam in Kerala, facing acute shortage of gas, would also get gas from Exxon's Gorgon LNG terminal in Australia.

A joint statement by both companies said, "An agreement has been reached on intent to supply LNG. Both the two companies would continue working on binding agreements to conclude the purchase and sale in June."

The deal came at a time when LNG is available at around $4 per unit in the international market. However, traders said that LNG prices may increase in 2014 and both the buyer and seller were aware while they discussed the deal.

Petronet Managing Director, P Dasgupta said, "Price details cannot be disclosed. Petronet LNG looks forward to finalizing the agreements and moving forward with the LNG infrastructure needed to supply natural gas to consumers in the Kerala region."

Earlier, Petronet had also signed a similar deal with Rasgas of Qatar for its Dahej terminal.