苏北高邮凹陷下第三系地层厚度达3000～7000米,下部阜宁组沉积期为广湖相或间有海浸的影响,形成了大套的暗色泥岩,夹有碳酸盐薄层。阜宁组二、四段是本区主要的生油岩系,油气资源丰富。生油岩系的下部,在高邮凹陷的不少地区都直接与古生界的碳酸盐岩相接触。上部戴南组为河流泛滥平原到浅湖相沉积,沉积一套砂泥互层岩系。最上部为三垛组,为河流泛滥平原或河流相,沉积一套以块状砂岩体为主的岩 The thickness of the Lower Tertiary strata in the Gaoyou depression in northern Jiangsu Province is about 3000-7000 meters. The sedimentary period of the Lower Funing Formation is influenced by the Guanghu facies or between the seafloor. A large set of dark mudstone is formed with thin carbonate layers. The second and fourth sections of the Funing Formation are the major oil source rocks in this area with rich oil and gas resources. The lower part of the source rocks is directly contacted with Paleozoic carbonate rocks in many areas of the Gaoyou sag. The upper Dainan Formation is a sediment-sandstone interbedded strata deposited as a river floodplain to a shallow lake facies. The top of the three groups for the flood plain or river fluvial facies, deposition of a block of sandstone-based rock