New Delhi, Sep 4 (IANS): ONGC Videsh, the overseas arm of state-run Oil and Natural Gas Corp (ONGC), on Friday said it has signed agreements to acquire up to 15percent stake in CSJC Vankorneft, that runs the Vankor oil field in East Siberia, from Russia's Rosneft Oil Company.

Without specifying an amount for the deal, the Indian explorer said the acquisition by ONGC Videsh Ltd, reportedly for $1.25 billion, is subject to relevant regulatory approvals and is expected to close by middle 2016.

"The agreement was signed by ONGC Videsh and Rosneft during the Eastern Economic Forum held in Vladivostok today (Friday) in the presence of Vladimir Putin, President of the Russian Federation," an ONGC statement here said.

"Rosneft and Indian ONGC Videsh during the Eastern Economic Forum signed the agreement of sale and purchase of 15 percent in Vankorneft. The document was signed by the chairman of Rosneft management board Igor Sechin and managing director of ONGC Videsh Narendra Verma," Rosneft said in a statement earlier on Friday.

Vankor is Russia's second largest field and accounts for 4 percent of Russian production, it said.

The daily production from the field is around 442,000 barrels per day of crude oil, of which ONGC Videsh's share will be about 66,000 bpd, the statement added.

The initial recoverable reserves of the Vankor field are estimated at 476 million tonnes of oil and 173 billion cubic meters of gas.