Overpressured Fluid Compartment and Hydrocarbon Accumulation of Deep Layer of Es4 in the North Zone of Minfeng Sag, Dongying Depression

Key words: 
• compartment

Abstract: Overpressure is widespread developed in the third member(Es3) and the forth member(Es4) of the Shahejie Formation of Dongying Depression. Es3 and Es4 are divided into two compartments(Es3Es4s compartment and Es4x compartment) by sealing of the Calcareous mudstone and dark mudstone transition zone at the bottom of the upper part and the middle part of Es3 and the salt gypsum formation at the top and bottom of the Lower part of Es4 (Es4x). Good Source Rock is developed respectively in the two compartments, so Es3 and Es4 can be divided into two mutually independent petroleum systems (Es3Es4s petroleum system and Es4x petroleum system). “Rootfan seeling, midfan accumulation, outerfan migration” is the characteristic of the hydrocarbon accumulation in deep layer of nearshore subaqueous fan of Es4 in the north zone of Minfeng Sag. Hydrocarbon from the contemporaneous source rocks accumulates in the middlefan and forms “selfgeneration and selfaccumulation” lithologic reservoir.