Ultra-deep oil, gas production hit milestone in Tarim oilfield

China's largest ultra-deep oil and gas production base, the Tarim oilfield, has extracted 150 million metric tons of oil and gas equivalent from formations deeper than 6,000 meters so far, as China's oil giants accelerate ultra-deep exploration and technological advances to bolster energy security in recent years.

This accounts for 37 percent of the country's total oil and gas output last year, said its operator China National Petroleum Corp on Thursday.

Globally, formations deeper than 4,500 meters are classified as deep, while those exceeding 6,000 meters are considered ultra-deep.