歧口凹陷古近系构造对沉积层序和砂体分布的控制

受盆地构造演化阶段的控制,歧口凹陷在古近纪经历了初始裂陷期半干旱浅湖环境、强烈裂陷期深水湖盆环境和裂陷晚期开阔浅湖沉积演化序列。受整个盆地古构造格架的控制,研究区内可划分7个次级构造单元,其分布决定着特定沉积相带的展布;构造格局影响并形成3大物源体系,在西南断阶带、凹陷南缘中部、东北部盆缘断裂与F1断裂交汇处以及东北部盆缘断裂与低凸起南缘断裂交汇处分别控制着4个规模较大的砂体分布。

The Sedimentary Sequence and Sand Body Distribution Controlled by Palaeogene Structures in Qikou Sag, Bohai Bay

With control of the structural evolution stages,Qikou sag in Paleogene underwent such sedimentary evolution sequences as semi-arid saucer lake environment in chasmic stage,deep-water lacustrine environment in strongly chasmic environment and open saucer lake environment in late chasmic stage.With control of the basin's palaeotectonic framework,seven sub-structural units can be classified into in this study area for the special distribution of sedimentary facies.Three source systems exist in Qikou sag which controlled the distribution of four sand bodies located at the southwest slope-break zone,the center of southern margin of the sag,the joint of F1 fault and northeastern margin fault and the joint of low swell southern margin fault and northeastern margin fault.