China’s state-owned CNPC has started developing a new offshore shale oil field near the Bohai Rim Basin, the company said via its official newspaper on Feb. 28.

CNPC aims to produce 50,000 tonnes of shale oil from the Bohai Rim Basin in 2019 and to achieve production capacity of 1 million tonnes by 2028.

The new drilling venture is in response to president Xi Jinping’s call to step up national energy security, CNPC said.

Shale oil production from China’s continental crust created huge technological difficulties because of the unique geological formations, according to CNPC.

At the Bohai Rim Basin, shale oil was formed and stored unevenly across sedimentary shale rock layers. About 100 kilograms of shale rocks yield about 1 kilogram of oil output from the new field, the company said.

In comparison, shale oil drilling in offshore North American basin is easier because the basin is floored by oceanic crust where shale oil is deposited often in one place.

CNPC also said it will prioritize shale oil-related exploration at the Songliao Basin, Ordos Basin, and Jungar Basin.