东营凹陷沙四下亚段超压环境与油气成藏

断陷盆地盐湖相地层发育超压系统,在东营凹陷超压对沙四下亚段盐湖相烃源岩生烃的抑制作用和延缓现象不明显,但对于沙四上亚段和沙三段湖相烃源岩有机质生烃具有明显的抑制作用;超压环境有利于烃类转化,使得凝析气成藏所需要的储层物性下限值降低;超压环境有利于砂岩储层保留原生孔隙,超压流体溶蚀作用产生溶蚀孔隙,富含硅质或钙质的砂泥岩和碳酸盐岩在超压环境形成裂缝,大大改善储层储集性;超压还控制了油气运移和聚集作用;东营凹陷北部陡坡带是沙四下亚段盐湖相地层油气成藏和分布的主要区带。

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.