Russia has been looking for new markets for its energy exports because of shrinking demand in Europe, its traditional market, said Liao Na, the vice-president of energy consultancy ICIS C1 Energy.

"The seller and the buyer both have strong willingness to reach the deal provided the price was comfortable for each of them.

"It is a good timing, considering current international oil prices," she said, adding that most institutions and commodity consultancies do not expect any dramatic oil price fluctuations.

She said after the deal was finalized, Rosneft is scheduled to open a refinery in Tianjin in cooperation with a Chinese company, in the second half of the year.

In 2009, the two countries reached a framework agreement in which Russia would deliver about 70 billion cubic meters of natural gas to China annually for 30 years starting from 2014.

China, the world's largest energy consumer, used 145 billion cu m of natural gas last year and will import 78.5 billion cu m of natural gas in 2014, according to data from ICIS C1 Energy.

Liao said the two countries also have huge potential for cooperation in non-traditional energy sectors, and Russia may become the next major supplier of coal to China.