The overpressure environment and hydrocarbon accumulation of the salt lake formation of down Es4 sub-section in fault basin of Dongying

The salt lake formation developed the overpressure system in fault basins,there is not obvious hydrocarbon generation inhibition and delay phenomenon in the overpressure system of Es4 down salt lake formation,but there is obvious hydrocarbon generation inhibition and delay phenomenon in the overpressure system of Es4 upper and Es3 lake formation.The overpressure environment is conducive to hydrocarbons into condensate gas reservoir which needs the lower reservoir petrophysical limit,the overpressure environment is conducive to sandstone reservoir reserves primary porosity,overpressure fluid dissolution produces dissolution pores,the rich silicon or calcium carbonate and mudstone in overpressure environment greatly improved cracks,reservoir permeability.The overpressure also controls the hydrocarbon migration and accumulation,the north steep of Dongying sag is the oil-gas accumulation and distribution main zone in salt lake sediment formation.