东营凹陷八面河地区沙河街组第四段高分辨率层序地层

应用取心、录井和测井资料对东营凹陷八面河地区沙四段不同级别的基准面旋回层序进行分析,从中识别出6个中期旋回和数十个短期旋回,其中短期旋回可细分为向上变深的非对称型、向上变浅的非对称型和向上变深复变浅的对称型三种类型.讨论了每种短期旋回的结构类型、叠加样式及其沉积相序列和组合,并且指出了有利储集体在短期旋回中的发育部位.在识别湖泛面和短期旋回叠加样式的基础上,对中期基准面旋回层序进行等时对比,建立了高分辨率层序地层格架.最后,分析了层序格架内储层的发育规律,指出短期旋回和中期旋回层序界面相叠合的位置为最有利于储层发育的部位,这些砂体与断层互相配合可形成断层-岩性油藏;而处于中期旋回内部的储层为辅助储层,是形成岩性油藏的有利部位.

High-resolution stratigraphy for Member 4 of Paleogene Shahejie Formation in the Bamianhe area, Dongying depression, China

According to the data of rock cores and well loggings,two order baselevel cycles are recognized from the fourth member of the Paleogene Shahejie Formation in the Bamianhe area of Dongying depression.They consist of 6 middle-term base-cycles and dozens of short-term base-cycles.The short-term base-level cycles can be divided into three structural types,namely up-deepening non-symmetry,up-shallowing non-symmetry and symmetry from up-deepening to upshallowing.Their structural types,stacking patterns and sedimentary facies sequences are deeply discussed by using high-resolution sequence stratigraphic theory and methods and the development positions of the advantage reservoir sand body are pointed out in each structural type.On the basis of single well analysis,higher-accuracy stratigraphic correlation of middle-term base-level cycle is done and the stratigraphic framework is built.The distribution models of reservoirs in the stratigraphic framework are also discussed in this paper.They show that the best reservoir sands lie on the sequences surfaces of the middle-term base-level cycles. These sandbadies may match with faults to form structural oil pools,and the other reservoir sands in the middle-term cycles are secondary and may form lithological reservoirs.