摘要
Beach-bar sandstone is thin and interbedded sediment that was widely developed in the high-energy shallow-shore lake environment.No enough attention has been paid to it and the exploration degree is very low.Focused on the research difficulties of beach-bar sandstone causes and oil accumulation in the upper of Es4 of Dongying Sag,this paper studies sedimentary characteristics,oil-forming factors and enriched regular pattern of beach-bar sandstone.It was suggested that the beach-bar sandstone deposition was controlled by palaeo-geomorphology,palaeo-current and palaeo-base level(three palaeo-controlling sandstone mechanism),while oil accumulation was controlled by faults and fractures,effective reservoir and overpressure of source rocks(three factor-controlling oil accumulation mechanism).Long-term palaeo-base level rising and short-term frequent palaeo-base level concussion formed the widespread beach-bar sandstone deposition.The"pressuresuck filling"caused by overpressure of source rocks and the water consumption and pressure reduction during the diagenetic process resulted in the widely bearing oils in the beach-bar sandstones.