Collapse column identification method based on seismic waveform indication inversion and its application

During the CBM exploration and development, the collapse column is one of the important factors restricting the exploration effectiveness of coalbed methane. Therefore, the effective identification of collapse column is of great significance for the improvement of CBM exploration. The previous identification methods are based on the discontinuity of the in-phase axis of seismic reflection caused by collapse column. In this paper, the collapse column is innovatively regarded as a kind of geological anomaly, and the identification and prediction of the collapse column are attempted by means of waveform indication inversion. Firstly, through the analysis of logging data and geological modeling and forward modeling, various geophysical response characteristics of the collapse column development position in coal seam are identified:high p-wave impedance value, seismic waveform change and weakened amplitude. Secondly, starting from the basic principle of waveform indication inversion, it is clear that the inversion method can effectively identify the collapse column with the above three response characteristics. Finally, this paper took the Fanzhuang block of Qinshui basin as an example, this method was used to test the identification of collapse column. The identification results are consistent with the gas-bearing property and the hydrogeological background of boreholes, indicating that the inversion technology can effectively identify the collapse column and is an effective means to identify the collapse column.