China's largest offshore crude oil and natural gas producer announced Sunday that the cumulative proven oil and gas reserves of its Bozhong 26-6 oilfield has exceeded 200 million cubic meters, making it the largest metamorphic rock oilfield worldwide.

The Bozhong 26-6 oilfield is located in the southern waters of the Bohai Sea, about 170 km from north China's Tianjin Municipality, with an average water depth of over 22 meters. Discovered last year, the oilfield has revealed newly confirmed reserves of oil and gas exceeding 40 million cubic meters, China National Offshore Oil Corporation (CNOOC) said in a statement.

The reservoir of the Bohai 26-6 oilfield is buried in metamorphic rocks beneath the seabed at a depth of several kilometers, according to CNOOC.

It is estimated that the oilfield can yield more than 30 million cubic meters of crude oil, which can meet the daily transportation needs of a million or more urban residents for more than 20 years. The oilfield is also capable of producing over 11 billion cubic meters of natural gas, meeting the household gas consumption of a million or more urban residents for more than 60 years, said Zhou Jiaxiong, deputy general manager of the Tianjin branch of CNOOC.