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目前地震、测井等断层解释方法都存在难以解释断层成因机制等缺点,因此选用构造应力场数值模拟从动力学方面解释断层。通过分析河西务构造带断层分布特征及活动特征,发现孔店—沙四期,在构造带南部发育了一系列南东倾向的次级正断层,且断层在平面上呈雁列式展布。为了解释这些次级断层的成因机制,运用Ansys软件对河西务构造带孔店—沙四期的古应力场进行数值模拟,分析应力场的分布特征。结果表明:孔店—沙四期,最小主应力基本为张应力,最小主应力与最大主应力差值在构造带南部较高,控制形成次级断层;构造带南部平面剪应力为左旋,控制断层优势走向为NE向;剖面剪应力为左旋,控制断层优势倾向为SE向。
At present, fault interpretation methods such as seismic logging and logging are all difficult to explain the mechanism of fault formation. Therefore, numerical simulation of tectonic stress field is used to explain the fault from the aspect of dynamics. Based on the analysis of fault distribution and activity characteristics of Hexiwu tectonic belt, it is found that a series of secondary normal faults with south-easterly tendency are developed in the south of the structural belt in Kongdian-Sha 4, and the faults are in an echelon distribution in the plane. In order to explain the genesis mechanism of these secondary faults, the Ansys software was used to simulate the paleotropical stress field of Hexiwu structural foraminifer store-Sha 4, and the distribution characteristics of stress field were analyzed. The results show that the minimum principal stress is basically tensile stress, the difference between the minimum principal stress and the maximum principal stress is higher in the southern part of the tectonic belt and controls the formation of the secondary fault. In the south of the structural belt, the plane shear stress is left-handed and controlled The fault predominance direction is NE direction. The shear stress in the section is leftward, and the predominant trend of fault control is SE direction.