New Delhi: State-run explorer ONGC's overseas arm ONGC Videsh Ltd (ONGC) has raised $1 billion through a US dollar bonds issue to finance its acquisition of 15 per cent stake in Russia's Vankor oil field, the company said in a stock exchange filing on Thursday. The company raised $600 million through a 10-year bond at a coupon rate of 3.75 per cent and another $400 million through a 5.5-year maturity bond at an interest rate of 2.875 per cent, Director (Finance) S P Garg told reporters here. "We will draw down the bonds sometime next week," he said. ONGC Videsh expects to use the proceeds of the proposed issue to refinance existing bridge loans incurred to acquire a 15 per cent stake in CJSC Vankorneft for $1.26 billion. ONGC, Oil India, Indian Oil Corp and Bharat Petroleum will collectively own a 49.9 per cent stake in Rosneft's Vankor field, and a 29.9 per cent stake in Rosneft's Tass-Yuryakh field at a total cost of up to $5.4 billion.