声波阻抗反演识别陷落柱研究

Identification of collapse columns using acoustic impedance inversion

岩溶陷落柱是煤田开采中一种常见的地质灾害体.为研究利用反演方法识别陷落柱,根据煤矿陷落柱的地质特征,设计了整体塌落型和垮落型两类陷落柱地质模型,并通过正演模拟获得了相应的地震剖面.通过对正演剖面进行声波阻抗反演,发现整体塌落型陷落柱的波阻抗值明显高于煤层,垮落型陷落柱柱体与煤层接触的部位的波阻抗值略高于煤层,并且柱内地层存在沉降现象.将这一结论应用到实际三维地震采区,发现与实际资料的吻合度较好,陷落柱的位置和规模在反演上有较清晰的显示,能够识别直径小于50 m的小型陷落柱异常.

Karst collapse column is a common geologic hazards in coal mining,in order to research and identify the collapse column by seismic inversion methods, according to the geology features of collapse column,overall collapsing collapse column model which has the integrity of the formation and caving collapse column model which is filled with gravel are designed. Seismic forward modeling of collapse column model with different macroaxis of two types and the inversion of the forward results are studied. The results show that the overall collapsing collapse column has higher impedance than coal seam,the caving collapse column has higher impedance when contact with the coal seam and its inner formation displays subsidence. The conclusions above are applied to study on 3D seismic data of a real mining district and the results are highly consistent with actual data. The location and scale of collapse column are displayed clearly on inversion results. Moreover,the small collapse column whose macroaxis are less than 50 m are identified.