南堡凹陷高柳及四号构造带沙一段-东营组扇体的精细刻画及其成因机制

准层序组格架下扇体的精细刻画对于揭示陆相断陷湖盆内部沉积充填演化历史、沉积与构造活动等的耦合关系等具有重要意义，同时，也可为老油区的深入挖潜、细化勘探提供重要参考.利用岩心、测录井及三维地震资料，对南堡凹陷高柳及四号构造带沙一段-东营组的扇体演化特征、扇体形态、结构和成因机制进行研究.结果表明，从时空演化上，沙一段沉积期高柳地区扇体发育程度高，多位于中西部，到东营组沉积期4号构造带扇体发育规模逐渐增大.以外部形态和内部结构为依据，可将发育扇体划分为4个类型，分别为:（1）"外宽内窄"，平原河道稳定多分支，前缘河口坝靠近平原，在边界断裂断陷强度高于湖盆中沉降速率的背景下形成；（2）"外窄内宽"，平原河道少分支，河口坝数量多，单个规模小，在有逆牵引背斜区发育；（3）长条状，平原河道少分支，前缘河道不稳定，河口坝数量多，铺开面积大，在湖盆沉降速率高于边界断裂断陷速率背景下形成；（4）"鸟足状"，平原河道稳定，前缘河道多分支，河口坝数量少，单个规模大，在边界断陷速率与湖盆沉降速率相当的背景下形成.构造古地貌的差异性对扇体形态、内部结构的变化起到了重要的控制作用. 

Identification and Formation Mechanism of Fans Developed in 1st Member of Shahejie and Dongying Formations,Gaoliu and No.4 Tectonic Belt,Nanpu Sag

The identification of fans under the para-sequence framework helps to reveal the sedimentary filling history of continental rift basins, the relationship between sediment and tectonic activities, and to guide the further exploration for oil field. Cores, logging data, and seismic data are used to study the evolution process, shapes, internal architecture, and formation mechanism of fans. Fans are mainly developed in midwestern Gaoliu tectonic belt in 1st member of Shahejie Formation, and expand to No. 4 tectonic belt in Dongying Formation. The fans can be classified into 4 types based on shapes and internal architectures:(1) the fans are wide in delta plain, and gradually narrow down in delta front, channels are well developed with multi-branches in delta plain, mouth bars are deposited close to delta plain, and this type of fans is developed when the faulting rate of boundary faults is higher than subsidence rate in the lake; (2) the fans are narrow in delta plain, and gradually widen in delta front, the channels show limited branches in delta plain, the amount of mouth bars are large, but each mouth bar shows a small coverage area, and this type of fans is developed when the reverse drag anticlines appear; (3) the fans are elongated, the channels show limited branches in delta plain, the subaqueous channels are unstable, the mouth bars are large in quantity and total coverage area, and this type of fans is developed when the faulting rate of boundary faults is lower than the subsidence rate in the lake; (4) the fans are bird-foot shaped, channels are stable in delta plain, subaqueous channels show large amount of branches, the amount of mouth bars are small, but each mouth bar shows a large coverage area, and this type of fans is developed when the faulting rate of boundary faults is approximately equal with the subsidence rate in lake.