Depositional System of the Upper Sha4 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 upper Sha4 Formation(Paleogene) in Laizhouwan Sag,Bohai Bay has been verified.Laizhouwan Sag developed the fan delta and the saline lack deposit system.The fan delta developed in the eastern and northern of the fault basin boundary.Shallow carbonate developed in the northeast part that connected with Miaoxi Sag.Gypsum deposits and salt deposits developed to the central region.The fan delta distribution area,developed high quality reservoir of oil gas,is the oil-gas exploration key area belt.Salt deposits would be the formation of favorable conditions for lithologic trap reservoir.