为揭示断陷盆地缓坡区的控砂控藏机制,以高品质的800km~2三维地震和91口钻井资料为基础,层序地层和沉积演化分析表明,受控于断块掀斜和差异沉降作用,歧口凹陷歧北斜坡南侧在古近纪表现为具挠曲坡折的缓坡带。该带层序界面标志清晰,包括削截、顶超和上超等反射终止类型,由此将古近系划分为3个二级层序和11个三级层序。三级层序的结构样式类似于具陆架坡折的被动大陆边缘,其低位体系域和湖扩体系域普遍发育不同类型的岩性圈闭。其中,沙河街组三段—沙河街组二段沉积期,研究区断陷作用强烈,挠曲坡折带的坡度较大,层序的低位体系域主要发育大型低位扇;随后,拗陷作用增强,挠曲坡折带的坡度逐渐减小,至东营组沉积期转变为以低位三角洲沉积为主。湖扩体系域的岩性圈闭发育在沙河街组二段—沙河街组一段和东营组,发育湖相碳酸盐岩滩坝和碎屑岩滩坝。研究区挠曲坡折带明显控制了地层-岩性圈闭的发育和分布,成为缓坡带油气勘探的有利场所。通过勘探实践,新增三级储量近4×10~8t,探井成功率达80%,展示了挠曲缓坡带地层-岩性油气藏良好的勘探前景。 Based on the high quality 800km ~ 2 3D seismic data and 91 drilling data, the sequence stratigraphy and sedimentary evolution analysis show that controlled by the fault block tilting and differential settlement On the south side of the northern slope of Qikou depression in Qikou, it appears as a gentle slope with flexural slope in ancient times. The belt sequence interface mark is clear, including cut-off, top-over and over-supersession termination types, which divide Paleogene into three second-order and eleven third-order sequences. The structural sequence of the third-order sequence is similar to that of the passive continental margin with continental shelf slope collapse, and different types of lithologic traps generally develop in the lower system tract and the lake expanding system tract. Among them, the sedimentary period of the second member of Shahejie Formation, the second member of Shahejie Formation, has a strong role in fault depression in the study area, and the slope of the flexural slope break zone is relatively large. Large low-level fans mainly develop in the lowstand system tract of the sequence. Subsequently, The gradient of flexural slope break decreases gradually, and the sedimentary period of Dongying Formation is changed to the sedimentation of low delta mainly. The lithologic traps in the extended system tract of the lake developed in the first section of Shahejie Formation and the Dongying Formation in the second section of Shahejie Formation, and developed lacustrine carbonate rock beach and clastic rock beach dam. The flexural slope-break zone in the study area obviously controls the development and distribution of stratigraphic-lithologic traps, and is a favorable site for oil and gas exploration in the gentle slope zone. Through the exploration practice, the newly added tertiary reserves of nearly 4 × 10 ~ 8t, exploration success rate of 80%, showing the flexure gentle slope strata - lithologic reservoirs a good prospect.