陷落柱的地震响应特征分析及应用

Seismic response characteristics of the collapse column analysis and application

通过分析陷落柱的地质特征和物性特征,进行地震数值模拟,分析其地震响应特征,在实际资料中进行应用.结果表明:从单炮记录上观测陷落柱,主要是考虑陷落柱的下凹特征,需考虑凹界面的曲率与埋深之间的关系.从物性上看,陷落柱内部与外部的物性差异变化为地震资料区分陷落柱建立了基础.在陷落柱上方,地层裂隙发育,引起地震振幅能量弱,具有下凹趋势,在陷落柱的内部,地震波反射波到达时间延迟,能量弱,相位下凹,甚至反射波零乱.在水平切片上,能看到明显的圈状异常.

Base on the collapse column characteristics and physical properties of geological features, seismic response characteristics of the collapse column were analyzed by seismic numerical simulation, and proved according to a practice of collecting data. The results show that： the physical properties difference among the upward, internal and surrounding of the collapse column lead to changes in seismic waves. On the top of the Collapse columns, the layers show slightly or significantly subsidence with informing concave surface, ground fissures. The inner layer of the Collapse columns show obvious subsidence, and the lower P-wave velocity and density comparing with the surrounding. For a single shot record, we need to consider the relationship between concave curvature and the depth of the interface. If the source locates in the center of the Concave interface, there is rotation wave, if we set shot and receiver to locate at the center of the concave interface, we can clearly see the focus reflection in the single shot record. If the shot is below the concave center, we can see the ordinary reflected wave, while the reflected wave delays. For a stacked seismic data, if there is the collapse column, we can observe the different seismic response characteristics in different locations. On the top of the collapse Column, the wave＇s energy shows weak, the reflected wave looks Inferior. The inner layer of the collapse Column has a concave features, we can see ring-shaped anomaly in the horizontal slice.