Origin of overpressure and booster mode of upper Es4 formation of western Dongying depression

Beach bar sandstones are important sedimentary reservoirs in upper Es4 formation of western Dongying depression and overpressure has significant controlling effect on hydrocarbon accumulation of beach bar sandstones.By using response characteristics of logging parameters on overpressure,a discrimination method of overpressure causes has been established.Through overpressure causes analysis,it believed that rapid sedimentary burial of sand in Dongying depression is one of the important factors of overpressure.The extensive development and the thermal evolution of the four sub-segment sand source rocks makes hydrocarbonbooster become another important reason for the formation of overpressure.The booster mode of western Dongying depression has been established and the overpressure evolution can be divided into three stages,namely normal compaction stage,early under-compaction hydrocarbon booster stage,and a lot of hydrocarbon generation and expulsion supercharged stage.At different stages in the overpressure development,under-compaction and hydrocarbon booster have become the most important factors.