NEW YORK (The Deal) -- OAO Rosneft CEO Igor Sechin may have had his travel options crimped by U.S. sanctions linked to the Ukraine crisis, but the restrictions have had little effect on his globe-trotting dealmaking.

The head of Russia's biggest oil company signed off on more than 12 agreements over the last two days of the annual St Petersburg International Economic Forum, an ostensibly energy-focused get-together that closed on Saturday, May 24.

Amongst the flurry of signatures was that of BP's Russia President David Campbell, who signed off on a $300 million-plus investment in 49% of a new Russian shale gas joint venture with Rosneft.

Russia's biggest oil producer also secured a deal to buy an indirect 13% stake in Italian tire maker Pirelli for 553 million ($755 million); set out plans to buy a "significant stake" in North Atlantic Drilling Ltd., a unit of the world's largest offshore drilling company Seadrill; and tied up joint venture and supply deals with oil companies from Azerbaijan, Venezuela, Mongolia, India, Cuba and the United Arab Emirates.

The stream of deals is a blow to U.S. efforts to isolate Sechin and put pressure on Russia over its perceived support for pro-Russian separatists in eastern Ukraine. Sechin, a close political ally of President Vladimir Putin, was named on May 1 on a list of seven people and 17 entities to face U.S. sanctions following the unilateral referendum in Crimea about joining Russia.

U.S. hopes of pressuring Russia had already suffered a significant set back last week when Putin on May 21 secured a long-term agreement for OAO Gazprom to sell natural gas to China. Details of the deal were not released but it is thought to be worth about $400 billion over 30 years, significantly easing Russia's dependence on Western European gas markets.

Washington's sanctions led some banks, incuding Citigroup (C - Get Report) and Morgan Stanley (MS - Get Report) to stay away from the St Petersburg get-together. They were not, however, enough though to dissuade the heads of many oil companies. Amongst the attendees were BP CEO Bob Dudley, Royal Dutch Shell CEO Ben van Beurden, Neil Duffin, president of ExxonMobil (XOM - Get Report)'s upstream subsidiary Exxon Mobil Development Co., Total CEO Christophe de Margerie and Eni CEO Paolo Scaroni.

The oil executives' stays in Moscow were often short, and many chose to keep a low profile.

Not all of them had that option though. BP, which owns 19.75% of Rosneft, has little choice but to make its support for the Russian oil company clear. BP CEO Dudley has insisted that the sanctions against Sechin are unrelated to Rosneft's activities.

"I am able to meet with him [Sechin] to solve issues related to the Rosneft oil company," Dudley was quoted as saying by Russia's state-owned new service Interfax.

The British oil company deepened its ties with Rosneft on May 24 at a signing ceremony attended by Sechin, and overseen by Putin. BP, which was represented by its Russian head Campbell, committed to a minority stake in a JV that will prospect for shale gas in Russia's Volga-Urals region. BP will pay part of the historical costs relating to Rosneft's exploration in the region and will provide $300 million

That deal could be dwarfed by Rosneft's announcement that it will take a stake in North Atlantic Drilling, a unit of Norway's Seadrill. A Rosneft statement on the deal did not say how big the stake will be but described it as "significant" and said it will underpin a cooperation agreement that will give the Norwegian business access to the Russian exploration market.

It could also eventually lead to Rosneft owning as much as 50% of Seadrill, the world's largest offshore drilling company, according to Sechin. "We are becoming Seadrill shareholders," he was quoted saying by Russia's Interfax news agency. "In time we could increase our stake to 50%."

Seadrill, which has a market capitalization of 102 billion Norwegian kroner ($17.1 billion), is 28% owned by Norway's John Fredriksen. It is listed in Oslo and New York.

Rosneft's acquisition of a 13% stake in Pirelli was the other high profile deal from the weekend. The Russian oil company will acquire the stake by buying 50% of a holding company that owns 26.19% of the tire making company. A consortium, including Unicredit, Intesa Sanpaolo and Italian PE shop Clessidra, is selling the stake.

The shareholding will underpin a new commercial agreement through which Pirelli will sell tires at Rosneft gas stations in Russia. The acquisition values Pirelli at 12 per share, in line with Pirelli's Fridayclosing price.