东营凹陷深陷期构造坡折带与低位扇序列

以钻井剖面相分析资料为基础，结合岩性、测井、地震响应特征及层序类型分析，研究东营凹陷深陷期层序的构成，着重探讨其中低位扇的沉积相类型、发育的控制因素及沉积序列。认为低位扇与构造坡折带有密切的成生关系，坡折带类型、规模和发育部位控制了低位扇的类型、规模和分布，形成了典型的陡坡型和缓坡型低位扇沉积序列，陡坡型低位扇体在“有限后退或持续下陷型”边界断裂控制下，从盆缘到中心依次发育了冲积扇、扇三角洲、近岸水下扇和深水浊积扇序列；缓坡型低位扇体在断裂坡折带控制下，发育了盆缘陆上下切谷充填及低位辫状三角洲、扇三角洲及缓坡深水浊积扇序列。图5表1参26

Fault break-slope and low-stand fan sequence in Dongying Sag

Based on the bore section, combining with the study on lithology, well logging, seismic facies and sequence type, the structure of the sequence in the deeply down-faulted Dongying Sag is analyzed emphasizing on the low-stand fan depositional type, its controlling factors and depositional sequence. Results suggest that the low-stand fans have a relationship with the fault break-slope. The type, scale and location of the fault break-slope controls the low-stand fan distribution, which results in the forming of the typical abrupt slope-type and gentle slope-type low-stand fan depositional sequence. On the abrupt slope, under controlling of the boundary fault of limited back-off or continuously down, the low-stand fans of alluvial fan, fan delta, inshore under-water fan and turbidity fan are subsequently developed from border to center of the depression. On the gentle slope, low-stand fans of incised channel filling, braided delta, delta fan and turbidity are subsequently developed from border to center of the basin under controlling of the fault break-slope.