(Bloomberg News) One of the biggest oil deals in history has made Viktor Vekselberg the richest man in Russia.

The founder of Moscow-based Renova Group, a closely held conglomerate that controls investments in energy, construction and mining, added $1.5 billion to his net worth yesterday after OAO Rosneft, Russia's state-controlled oil and gas operator, agreed to pay $54.8 billion to acquire TNK-BP in the third-biggest oil acquisition ever.

The 55-year-old Vekselberg is worth $18 billion, according to the Bloomberg Billionaires Index, more than $700 million ahead of metals and technology investor Alisher Usmanov, who had been the country's richest person since March 5, when the ranking debuted.

"This is a super deal which is the logical outcome of TNK's 15-year history," said Andrei Shtorkh, a spokesman for Vekselberg, who said the billionaire will focus on technology investments in the future.

Rosneft will buy BP Plc's 50 percent stake in TNK-BP for $26.8 billion in cash and shares, and has an initial agreement to acquire the half of the company that is owned by Alfa-Access- Renova -- a consortium of billionaires including Vekselberg, Mikhail Fridman, German Khan, Alexey Kuzmichev and Len Blavatnik -- for $28 billion in cash, according to a statement yesterday.

Fridman's net worth jumped $1.2 billion to $15.1 billion, moving him past Russian billionaires Roman Abramovich and Alexey Mordashov on the index. The 48-year-old is now the country's fifth-richest person.

Blavatnik, a Russian-born American industrialist who attended the Moscow Railway Transport Engineering Institute with Vekselberg, saw his fortune rise $1.5 billion. With a net worth of $15.4 billion, the 55-year-old is the 46th-richest person in the world, ahead of Microsoft Corp. co-founder Paul Allen, and Nike Inc. chairman Philip Knight.

Khan, 50, is worth $10.3 billion, and Kuzmichev, 50, has a $8 billion fortune, according to the index.

The acquisition of TNK-BP puts an end to a tumultuous eight-year relationship between BP and AAR. Last year, the five AAR billionaires scuttled BP's attempt to create an arctic exploration deal with Rosneft. The fracture simmered until May, when Fridman quit his post as CEO and BP began seeking buyers for its half of the operation.

After the deal, Rosneft will match the output of Exxon Mobil Corp., the world's largest publicly traded oil producer, and control more than 40 percent of Russia's crude output. President Vladimir Putin, who has sought to reassert government control over the oil and gas industry, said yesterday's accord was important for the Russian economy.

Vekselberg's rise was aided by a decline in wealth for Usmanov, 59, whose fortune has dropped more than $1 billion in the past week as market demand for MegaFon OAO, Russia's second-largest mobile-phone company, is falling. The company postponed a planned marketing campaign in advance of its anticipated initial public offering.

"The latest deals the company has made have shown that its risks have increased", said Evgeny Golosnoy, senior telecommunications analyst at IFC Metropol in a telephone interview on October 22. Included in those risks are MegaFon's plans to spend as much as $1.33 billion to acquire up to 50 percent of handset retailer Euroset Holding NV.