By the untimely death of the "South Stream"

But while Iran says it intends to:
 - To double by 2018 oil production - up to 5 to 7 million. Barrels (up to 4, 1 million. This year),
 - Gas production to increase from 150 to 360 billion. Cubes (and 36 billion. Added this year),
 - Put into operation this year, the first export LNG terminal at 10m. Tons (13 billion. Cubes)
 - And demanded his share of the gas market in Europe
Incidentally know how China has forced Iran to discount the sale of oil to China - when it was introduced against Iran oil embargo?
China instead of what would increase the purchase, cut them in half, replacing oil from Saudi Arabia.

That is, Iran has lost not only export to Europe and half of exports to China.
But Iran to China at that time was very old oil supplier relations and the two countries were quite friendly.

China - a very tough negotiator