China's crude oil imports from Russia are expected to double from next year with necessary infrastructure work on the second Sino-Russian crude oil transmission pipeline being completed on Sunday.

The pipeline, which will play a significant part in China's overall energy strategy, will help China increase annual crude imports from Russia to 30 million metric tons, and secure the country's energy security, said Zhang Xinjia, deputy head of the PetroChina Pipeline Co, a subsidiary under the China National Petroleum Corp, the country's largest oil and gas supplier and producer.

The 942-kilometer oil pipeline, from Mohe at the China-Russia border to the city of Daqing, is the China leg of the second East Siberia Pacific Ocean pipeline project pumping Russian crude oil to China.

The first 1,000-km East Siberia Pacific Ocean pipeline that originates in the Russian town of Skovorodino in the Amur region has been sending 15 million tons of crude oil from Russia each year to China since January 2011, delivering more than 104.92 million tons of crude oil by September this year, according to Heilongjiang Entry-Exit Inspection and Quarantine Bureau.

Analysts said the two countries, one being the world's second-largest energy consumer, and the other the world's top oil producer, have always complemented each other as producers and exporters.

Li Li, energy research director at ICIS China, a consulting company providing energy market analysis, said the step will further guarantee China's energy diversification.

"The pipeline transmission will ensure the convenience of crude imports in China's northeastern province and ease the tension of offshore and port transportation," she said.

"The pipeline ensures a more stable energy transmission to China, and security of pipeline transportation is better than that of shipments by sea."

Li said the China-Russia crude oil pipeline, together with the China-Myanmar oil pipeline and the China-Kazakhstan oil pipeline, will help diversify China's oil imports and ensure its energy security.