东营凹陷沙三段、沙四段普遍发育超压,在沙三上亚段底部与沙三中亚段顶部钙质泥岩与暗色泥岩过渡带、沙四下亚段顶部和底部稳定盐膏岩层的封隔作用下,形成了两个超压封存箱,即沙三段—沙四上亚段超压封存箱和沙四下亚段超压封存箱。由于每个超压封存箱内均发育优质烃源岩,因此,沙三段、沙四段又可划分为两个相互独立的含油气系统,即沙三段—沙四上亚段含油气系统和沙四下亚段含油气系统。东营凹陷民丰洼陷北带沙四段深层近岸水下扇具有"扇根封堵、扇中富集、扇缘输导"的油气成藏特征,油气来自同期发育的、与近岸水下扇侧向接触的烃源岩,主要形成"自生自储"型岩性油气藏。
Overpressure is widespread developed in the third member(Es3) and the forth member(Es4) of the Shahejie Formation of Dongying Depression.Es3 and Es4 are divided into two compartments(Es3-Es4s compartment and Es4x compartment) by sealing of the Calcareous mudstone and dark mudstone transition zone at the bottom of the upper part and the middle part of Es3 and the salt gypsum formation at the top and bottom of the Lower part of Es4(Es4x).Good Source Rock is developed respectively in the two compartments,so Es3 and Es4 can be divided into two mutually independent petroleum systems(Es3-Es4s petroleum system and Es4x 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 Es4 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.