Abstract: BZ28-2S Oilfield is located at central structural ridge of Huanghekou Sag south of Bohai Sea. It is a high quality and middle size scale oilfield with reserves of 4500×104m3 that was found by CNOOC in 2006. Oilfield was produced in 2009 and had an annual production of 180 × 104m3. The main produced oil layer is lower Minghuazhen Formation. The burial depth of oil layers is about 900~1600m. The sourcereservoir- seal assemblage of lower Minghuazhen Formation is good and belongs to shallow water delta. The discovery of BZ28-2S was devious. Exploration about this structure was terminated because the shallow targets of adjacent structure failed in 1980s. BZ28-2S Oilfield was found after 24 years later till the recognitions about the model of migration and accumulation was got during the evaluating of BZ34-1 Oilfield in 2005. These recognitions of fault of migration, transfer station model and high-amplitude in oil which were analyzed before drilling were verified during evaluating of BZ28-2S Oilfield. BZ28-2S Oilfield's discovery process inspired explorers again that new discovery could be got in old exploration field only the new thinking was taken.

Key words: BZ28-2S Oilfield, transfer station, failed well, reverse verdict, amplitude