庙西北洼陡坡带断裂对明下段油气成藏的控制

针对渤海湾盆地庙西北洼陡坡带新近系明下段浅水三角洲差异沉积及油气差异成藏问题，从分析边界断裂组合样式、断裂活动性及基准面升降变化对砂体叠置样式的控制等方面入手，开展油气差异成藏的研究，取得了以下几方面的认识：庙西北洼新近系油气成藏具备近源供烃、断裂输导、储层发育和晚期成藏的优越组合条件；洼陷边界断裂自南向北形成了“座椅式”、“马尾式”、“顺向断阶式”3种断裂组合样式；古地貌形态及断裂活动强度的差异决定了平面上北块储层更为发育，基准面升降变化决定了垂向上砂体叠置样式的差异；明下早期发育“孤立式”水下分流河道砂体，中期发育“拼合板状”展布砂体，晚期发育“席状化”展布砂体。综合油气成藏条件的差异，构造区北块油气最为富集、中块次之、南块最差。

Boundary Fault of the Steep Slope Zone and Its Control on Hydrocarbon Accumulation of the Lower Minghuazhen Formation of Neogene in the Miaoxibei Sag of Bohai Basin

Focusing on differential deposition and oil and gas accumulation in the shallow water delta of the Neogene Minghuazhen Formation in the steep slope zone of the Miaoxibei Sag, Bohai Bay Basin, this study analyzes the boundary fault combination style, fault activity, and influence of datum level change on sandstone stacking style and differences in oil and gas accumulation. The analysis showed that the formation is a favorable combination of hydrocarbon accumulation near source rocks, fault transporting, reservoir development, and late accumulation in the Neogene of the Miaoxibei Sag. The structures of the depression boundary faults, from the southern to the northern blocks, are seat, horsetail, and cascade types. Differences in paleogeomorphology and intensity of fault activity determine horizontal reservoir development in the northern blocks, and datum level change determines sandstone stacking style in the vertical direction. "Isolated" underwater distributary channel sand bodies developed in the early stage of the lower Minghuazhen Formation, sandstone reservoir with "laminations" developed widely in the middle stage, and in the late stage, the sand body is distributed with "similar sheets". The formation factors for integrated oil and gas accumulation are highest in the north blocks, good in the middle blocks, and poorest in the southern blocks.