Simmons & Simmons is advising India’s largest oil exploration and production company on its purchase of a $2.47 billion offshore natural gas block in Mozambique.

ONGC Videsh Ltd., a subsidiary of state-owned Oil and Natural Gas Corp., is buying the 2.6-million acre block together with another state-owned enterprise, Oil India Ltd., from the oil and gas arm of Indian conglomerate Videocon Group.

The acquisition will give the companies a 10-percent share in Mozambique’s Rovuma Area 1 Offshore Block, which is estimated to hold recoverable reserves of between 35 trillion and 65 trillion cubic feet of natural gas.

The deal, subject to regulatory approval, is expected to close in the fourth quarter.

Hong Kong partners Vivien Yang and Ian Wood are leading the Simmons & Simmons team advising ONGC. The firm said it also conducted due diligence for Oil India but did not advise it on the purchase agreement. It is unclear if Oil India has retained another firm.

ONGC was also advised by Lisbon partner Manuel Santos Vítor of Portuguese firm PLMJ and Mozambique’s GLM Lawyers.

Amarchand & Mangaldas & Suresh A. Shroff Co. co-managing partner Shardul Shroff and Delhi partners Vidyut Gulati, Nikhil Narayanan, and Puja Sondhi, are representing the seller on the transaction.