Saint-Petersburg (AFP) June 21, 2013Russian oil giant Rosneft and Chinese state firm CNPC signed Friday a $270 billion deal to supply China with oil over 25 years as Russian President Vladimir Putin pushes to diversify the country's energy customer base away from Europe. The agreement between Russia, the world's largest energy producer and China, the world's largest energy consumer - one of the biggest deals in the history of Reported by Energy Daily 1 hour ago.