Russia’s state-owned oil giant Rosneft will supply $270 billion worth of crude oil to China, the company said on Friday, June 21 after clinching a deal likely to make Moscow China’s biggest energy supplier, RIA Novosti reported.

Rosneft’s head Igor Sechin said the contract envisages the export of 365 million tons of oil to China over the next 25 years.

The deal will reshape the geography of oil exports from Russia, currently the world’s largest producer of crude. Most Russian oil currently goes to Europe via a network of pipelines from West Siberia, while only a fifth of it is exported to Asia.

Sechin, a key ally of President Vladimir Putin, said Rosneft and China National Petroleum Corporation (CNPC) will jointly develop three offshore fields in the Barents Sea and eight oil deposits in East Siberia.