A China National Petroleum Corp. (CNPC) subsidiary has made a giant oil and natural gas discovery totalling an estimated 1 billion tons of reserves in the prolific Tarim Basin in northwestern China, according to reports.

“This has been the largest discovery of oil exploration in the Tarim Basin in the recent decade,” Tarim Oilfield Co.’s Yang Xuewen, general manager, reportedly told Chinese outlet CGTN. Tarim Oilfield is a subsidiary of CNPC.

The discovery was said to be at the Manshen No. 2 well in the Fuman oilfield. The massive resource was reported after six years of exploration work and drilling 56 100-ton wells, CGTN reported. 

The well was drilled to a depth of 8,470 meters and encountered a 550-meter oil test column, according to reports. CGTN said the well set records as the deepest oil production and the highest oil column in the desert area of the Tarim Basin.

Output from the basin was increasing before the latest discovery. Production from the region rose by 30,000 metric tons (mt) in 2020 to 1.52 million metric tons (mmt). Output is expected to grow to 2 mmt this year, Chinese media outlet Xinhua said.

The basin is in the heart of the Taklamakan Desert of the Xinjiang Uyghur Autonomous Region. The area is estimated to hold more than 16.1 billion mt of oil and gas resource, which could make it the largest oil and gas-bearing region in China, according to CGTN.

The area is considered one of the most difficult to drill in the world, since the hydrocarbons lie deep below the surface. The Fuman Oilfield’s major oil producing zone is about 8,000 meters deep, according to CGTN.

China became the world’s largest oil importer in 2017, and it imported an average 10.1 million b/d of crude in 2019, a 10% increase from the prior year, according to U.S. Energy Information Administration statistics. However, the Chinese government called on its national oil companies to start raising domestic output levels in 2018, according to an analysis by EIA.