UPDATE 1-India's Petronet to buy 1.5 mln T/year Gorgon LNG

(Adds details, background)

NEW DELHI/PERTH, May 8 (Reuters) - India's Petronet LNG (PLNG.BO) said on Friday it had signed an agreement to buy 1.5 million tonnes a year of liquefied natural gas (LNG) for its terminal in Kochi in southern India.

It said a formal sale agreement would by signed by June by a unit of of Petronet and Exxon Mobil's (XOM.N) subsidiaries Australia Resources Co Pty Ltd and Mobil Exploration & Producing Australia Pty Ltd.

It said there was potential for additional supplies for the 20-year deal but did give commercial details.

The deal comes just a week after Chevron Corp (CVX.N), operator of the Gorgon project, secured a conditional approval from the Australian state environmental regulator for the expansion of the project by a third to 15 million tonnes per year. [nSYD355497]

Chevron has a 50 percent stake in the project, while Exxon and Royal Dutch Shell (RDSa.L) own 25 percent each. The three companies are marketing their share of gas separately. (Reporting by Himangshu Watts in NEW DELHI and Fayen Wong in PERTH; Editing by Michael Urquhart)