ONGC Videsh Ltd,subsidiary of ONGC,and Oil India have signed an agreement to buy a 10 per cent stake in a Mozambique gas field from Videocon Group for $2.48 billion,the state companies said on Tuesday. ONGC,which faces diminishing supplies from its ageing oil and gas fields in India and has been buying interests in overseas assets,announced the deal earlier this month but later withdrew the statement. This acquisition is a significant step towards the energy security of our country, ONGC chairman Sudhir Vasudeva said in a statement on Tuesday. Demand for gas in Asias third-largest economy far outstrips production,as Indias need to keep prices cheap for strategic industries deters investment in costly producing areas and in pipelines and terminals for more expensive LNG. India,the worlds fourth-largest energy consumer,uses coal for nearly 56 per cent of its energy needs,while oil accounts for another 26 per cent. It aims to double the portion of gas in its energy mix to 20 per cent by 2020. Recent discoveries have turned Mozambiques Rovuma offshore field into a major draw for global energy producers and boosted Mozambiques gas reserves to around 150 trillion cubic feet,enough to supply world number-one LNG importer Japan for 35 years. The Rovuma field has the potential to become one of the worlds largest liquefied natural gas producing hubs by 2018 and is located close to the India market.