郯庐断裂对青东凹陷古近纪沉积体系的控制

青东凹陷是新生代伴随郯庐断裂活动而形成的凹陷。郯庐断裂的构造活动, 特别是同沉积断裂及其组合样式控制了青东凹陷地层和沉积体系的发育分布。F 和F1 断裂带在古近纪的持续活动共同控制了北部深洼的沉积充填,F2 和F4 断裂分别控制了中部次洼和南部次洼的发育。长期活动的同沉积断裂形成的断裂坡折带构成了沉积体系的分界, 并控制了古近纪沉积相带的整体展布。东部盆缘断裂带形成的断裂坡折带控制着湖底扇、扇三角洲、辫状河三角洲等粗碎屑沉积体系的发育。F1、F2、F3、F4 同沉积断裂通常为沉积相的分界带。与生油洼陷相邻的主要同沉积断裂形成的断裂坡折带具备形成砂岩油气藏的各种有利条件, 其中东部盆缘断裂带和北部次凸F1 断裂缓坡带都是砂岩油气藏勘探的有利区带。

Controls of Tan-Lu Fault on Paleogene Depositional System in Qingdong Sag

Qingdong sag was shaped in Paleogene companied by Tan-Lu fault activity. So the structural activity, specially syndepositional faults and their combination patterns controlled the development and distribution of stratigraphic and depositional systems. Continuing activity of F and F1 fault zones in the Paleogene controlled depositional filling of the northern deep sub-sag, while F2 and F4 fault zones separately controlled development of middle and southern secondary sub-sags. The slope break zone of fault formed by long-term activity of syndepositional faults constituted the boundary of depositional systems and controlled the distribution of Paleogene sedimentary facies. The slope break zone of fault formed by the eastern basin marginal fault controlled development of coarse-clastic depositional systems, such as sublacustrine fan, fan delta and braided delta. The syndepositional faults of F1, F2, F3 and F4 are generally boundaries between sedimentary facies. The slope break zone of faults formed by main syndepositional fault adjacent to oil generating depression has favorable conditions for formation of sandstone reservoirs, and the eastern basin marginal fault zone and F1 fault gentle-slope zone of northern subswell are favorable sites of looking for potential sandstone reservoirs.