The BZ 25-1 Oilfield in north China's Bohai Sea opened for operation Tuesday.

The oilfield is the third largest in the Bohai sea and has recoverable oil reserve topping 200 million barrel. The BZ 25-1 Oilfield was co-developed by the China National Offshore Oil Corporation (CNOOC) and the American Chevron/Texaco Oil Company.

Located in the southern part of the Bohai Bay and about 150 kilometers southeast to Tanggu of Tianjin Municipality, the BZ 25-1 Oilfield has an oil-bearing area of 85 sq. km with recoverable oil reserves of 200 million barrels.

According to source of CNOOC, the oilfield is expected to produce for 20 years with daily output of 16,000 barrels.

Under the contract signed in October 2002, the CNOOC is the operator with a 83.8 percent of the project, and the Chevron/Texaco owns the remaining portion.