透射槽波相邻道质心频率的层析成像方法

Tomography method for adjacent channel frequency shift of transmitted in-Seam waves

槽波勘探是煤层工作面小构造探测的主要方法之一,该方法主要是利用槽波的能量衰减特征。当检波器的耦合差或工作面存在较大地质异常时,会显著影响槽波在不同频段上的能量分布,降低槽波探测结果的稳定性和准确性。利用槽波信号的质心频率变化特征进行反演成像是一种创新且有效的方法,但该方法存在震源质心频率准确估算及兼顾震源差异性的难题。为此,提出基于透射相邻道槽波信号,估算其质心频率相对变化量的层析成像方法。基于理论分析,推导出相邻道槽波质心频率相对变化量(M)的计算公式;采用二维数值模拟方法,验证槽波M值与传播距离的正向线性变化规律;通过槽波实测试验,对比分析了相邻道质心频率成像方法的效果。结果证明,槽波信号存在频移现象,槽波相邻道M值层析成像方法是有效,该方法克服了震源差异性和震源质心频率人为选择不当对成像结果造成的影响,为槽波勘探数据处理提供了一种新的思路。

In-Seam Seismic is one of the main detection methods for small geological structures in the coal mining working face.In this method,the energy attenuation feature of in-seam waves is mainly utilized.In case of any significant geological anomaly or receivers coupling difference in coal working face,the energy distribution of the in-seam wave at different frequency bands will be significantly affected,and the stability and accuracy of in-seam wave detection results will be decreased.Using the centroid frequency change features of the in-seam wave signals for inversion imaging is an innovative,effective method.However,for this method,there are difficulties in eliminating diversity influence of seismic source.Therefore,the tomography method base on the adjacent in-seam frequency shift of transmitted inseam waves,for the estimation of the relative variety of the centroid frequency,was proposed.On the basis of the theoretical analysis,the formula for calculating relative variation of the centroid frequency shift(M)based on the adjacent inSeam transmitted channel waves was derived;the positive linear correlation between Mand the propagation distance of in-seam wave was verified by two-dimensional numerical simulation;and the normal and new imaging results of field test signals were compared and analyzed.As demonstrated by the above experiment results,there is a frequency shift in in-seam wave signals,and the tomography method with the Mvalue is effective.The above method overcomes the effects that are caused by the source difference and the improper artificial selection of source centroid frequency on imaging results,providing a new approach for the processing of in-seam wave data.