Chinese main offshore oil firm, China National Offshore Oil Corporation, said it has started production from its Bozhong (BZ) 28-2S oil field, Reuters reported. The field has a capacity of 4,000 barrels of oil per day coming from four wells. BZ28-2S, located in the south of Bohai Bay at a depth of 21 meters, is the largest offshore oilfield among all the oil projects expected to come on stream this year, CNOOC said in a press statement. Production is expected to ramp up to an average 25,000 barrels of oil per day by 2011, it added. BZ28-2S was discovered in 2006.