Indian oil producer OGNC is readying a bid for a stake in a West African oilfield owned by Blackstone Group LP (NYSE:BX) portfolio company Kosmos Energy LLC, according to Reuters. OGNC has tapped Citigroup Inc. (NYSE:C) to advise it on a bid for Kosmos' stake in an oilfield in Ghana, Reuters said Monday. It pegged the deal at $3 billion to $5 billion, citing anonymous sources. A spokesman for Citigroup declined to comment. In a media call in May, Blackstone president Tony James cited the success of an oil and gas explorer in its portfolio, saying an exit could be on the horizon. The firm's E&P holdings included Kosmos Energy LLC, which it bought in 2004, as well as Osum Oil Sands Corp., which it purchased last summer. About a year ago, Warburg Pincus and Blackstone affiliate Blackstone Capital Partners committed $500 million to Kosmos Energy LLC to help the Dallas-based oil company accelerate exploration in offshore West Africa. Among the others said to be eying Kosmos' deep-water oil field in Ghana is Chinese oil and gas producer CNOOC Ltd. Goldman, Sachs & Co. (NYSE:GS) is reportedly advising CNOOC. Other possible bidders for the target, known as Jubilee, might also include BP plc (NYSE:BP), Shell Oil, Exxon Mobil Corp. (NYSE:XOM) and Italy's Eni SpA. The bidding deadline has been extended, with a new date to be set in the next 30 days, Reuters said. - Christine Idzelis Source: thedeal.com