先存构造对断层后期生长及形态的影响:以海拉尔盆地红旗凹陷为例

Influences of Pre-Existing Structures on Future Growth and Geometry of Faults:A Case Study of Hongqi Sag,Hailar Basin

红西断层作为红旗凹陷的边界断裂长期控制着凹陷的形成演化与油气成藏,目前对断层的识别刻画及生长模式的认识还存在诸多不足.以地震剖面精细解释为基础,确定红旗凹陷几何学特征及边界条件,结合控制变量法进行多组构造物理模拟实验;将实验结果与红旗凹陷基底顶面构造图各项参数进行对比,最终确立红西断层先存构造的规模及断层的演化模式.实验结果显示,红旗凹陷先存构造总体规模至少占整个边界断层现今长度的50%,即34 km以上.红西断层的构造演化具有孤立断层(先存构造)分段发育→“软连接”→“硬连接”的生长模式,并且在断层转换部位发育典型的中继构造.

As the boundary fault of the Hongqi Sag,the Hongxi fault has long controlled the formation and evolution of the depression and hydrocarbon accumulation.At present,there are still many shortcomings in the recognition and description of faults and the understanding of growth patterns.Therefore,based on the defined interpretation of the seismic profile,the geometric characteristics and boundary conditions of the Hongqi Sag are determined,and multiple sets of structural physical simulation experiments were carried out in combination with the controlled variable method.Then,comparing the experimental results with the parameters of the tectonic map of the top surface of the Hongqi Sag basement,the evolution pattern of Hongxi fault controlled by the scale of the pre-existing structures can be established finally.Experimental results show that the total length of the pre-existing structures in the Hongqi Sag is 34 kilometers,which accounts for 50% of the current length about the entire boundary fault at least.The structural evolution of the Hongxi Fault has a growth pattern characterized by isolated fault segmentation(pre-existing structures) →“soft connection”→“hard connection”,meanwhile,there are typical relay structures at the transition site of Hongxi fault.