Depositional System of the Middle Sha3 Formation(Paleogene) in Laizhouwan Sag,Bohai Bay

The utilization the oil and gas bearing basin sedimentology's theory and the method,based on the massive core,the logging,the well logging and the seismic data analysis,the deposition system's type,the characteristic and the distributed rule of the Middle Sha3 Formation(Paleogene) in Laizhouwan Sag,Bohai Bay has been verified.Laizhouwan Sag is one of the typical rift lacustrine basins in the Bohai Gulf Basin,the fault boundary on the east,and onlap in the west,the braided river delta,fan delta and the lacustrine deposit system developed in the sag.The braided river delta system developed in the western,fan delta developed in the eastern part.The braided river delta and the fan delta distribution area,developed high quality reservoir of oil gas,is the oil-gas exploration key area belt.