Sinopec (600028.SS),  is advancing development of shale oil at its pilot project Jiyang in east China, pumping 1,600 metric tons per day now, up from 100 tons in 2021, the state oil and gas group said on Wednesday.

At this rate, Sinopec is on track to deliver a target set in 2022 to produce 500,000 tons a year in 2025 at Jiyang, which is situated mostly in Shandong province and covers 7,300 sq km (1.8 million acres).

Following a call from the central government to boost domestic energy security, China's national oil companies are making greater efforts to tap hard-to-extract shale deposits to help compensate for older, fast-depleting conventional oilfields.

Currently Jiyang has 36 wells that each pump more than 100 tons a day, with the Fengye 1-1HF well having the highest daily output of 262.8 tons, Sinopec said.

The Jiyang shale oil zone, part of the ageing conventional Shengli oilfield, has an estimated shale oil resource of 10.5 billion tons, of which 1.73 billion tons have been identified as prospective reserves, Sinopec said.

Despite the huge resource size, shale oil remains among the geologically most challenging and costly types of oil to explore and produce, with output making up only 1% of China's total crude oil production.