青东凹陷东部边界走滑断层识别、特征分析及对构造圈闭的控制作用

Identification and characterization of the east boundary strike-slip fault in Qingdong sag and its control on structural traps

青东凹陷东部边界走滑断层属于郯庐断裂西南分支,控制着凹陷整体构造格局。通过分析地震波组特征、最大振幅属性及数据体切片,开展了青东凹陷东部边界走滑断层识别,对其平面分段特征进行了分析,结合凹陷构造演化史分析,认为东部边界走滑带断裂系统具有明显的走滑扭动成因,沿走向上呈"S型"或"反S型"弯曲展布,造成了不同弯曲部位的局部应力场与应变的不同,从而控制了构造圈闭的形成与古地貌及砂体的展布。在此基础上确定了凹陷边界走滑断裂带南北2个"S型"转弯下降盘的大型鼻状构造,并指出其为有利勘探目标区。

As the southwest branch of Tanlu fault zone,the east boundary strike-slip fault in Qingdong sag controlled the overall tectonic framework in the sag. This strike-slip fault was identified by analyzing wave group,maximum amplitude attributes and data volume slices,and it was considered that the east boundary fault was obviously in origin of strike-slip wrench movement,with some bends of ＂S type＂or ＂anti-S type＂along its strike,by analyzing its areal segmentation and the tectonic evolution history in the sag. The different local stress field and strain at different bends have controlled the formation of structural traps and the distribution of palaeogeomorphic elements and sand bodies. Furthermore,large nose structures were identified in the downthrown sides of two ＂S type＂bends in the northern and southern fault,and the favorable exploration targets were also indicated.