Tony Hayward, who stepped down as BP boss in the wake of the Gulf of Mexico oil spill, will imminently seal his return to the oil industry, by buying into Turkey's Genel Enerji, in a deal valuing the target at around $4 billion, a source close to the matter said on Tuesday.

Vallares, an acquisition vehicle established by Hayward and financier Nat Rothschild, has agreed in principle to a tie-up with Genel Enerji, which owns oil fields in the semi-autonomous Kurdish region of Iraq, and is expected to announce a deal in the coming days, the source said.

The exact terms of the deal are unclear but it is expected to net Hayward and his Vallares co-founders tens of millions of pounds.

In June, Vallares raised 1.35 billion pounds ($2.2 billion) from investors to target emerging-market oil assets.

The plan was to offer owners of oilfields a shortcut to a London Stock Exchange (LSE) listing, thus enabling them to raise finance to fund the development of their assets.

Hayward said he would be CEO of any acquired company and has assembled a team of big names around him, including former deputy CEO of BP and Chairman of Petrofac, Rodney Chase.

Hayward, Rothschild and the other Vallares founders, are entitled to a 6.67 percent stake in the enlarged group, following the completion of a deal, and this would be worth around $300 million if Vallares buys all of Genel Enerji.

The Turkish group, which is controlled by one of Turkey's richest men, Mehmet Emin Karamehmet, was valued at $3.3 billion to $3.6 billion in 2009, when it announced a planned merger with London-listed Heritage Oil , which subsequently collapsed.

Since then, political progress between the Kurdish regional government and Baghdad has led to a significant increase in the value of Kurdish oil assets, which would support a valuation above $4 billion.

Genel Enerji said in May it was considering selling a stake to an investment partner, seeking to capitalize on a surge in interest in Kurdistan in the past year, to raise capital to help fund developments.

A second source familiar with the matter said the Turkish group was close to announcing a deal. Genel Enerji and Vallares declined to comment.

Last month, Reuters reported the two sides were nearing a deal.

The tie-up will need to be blessed by the Kurdish Regional Government. The KRG oil minister, Ashti Hawrami, is due to attend an energy gathering in Istanbul on Thursday, according to the agenda for the event.

Cukurova Group, controlled by Karamehmet, owns around 56 percent of Genel Enerji, while the family of its CEO, Mehmet Sepil, owns around 44 percent.

(Reporting by Tom Bergin. Editing by Chris Wickham and Jane Merriman)

Iraq