微地震监测数据时频域去噪方法

摘要

The microseismic monitoring data have low signal⁃to⁃noise ratio and contain lots of noise with different characteristics.The lo⁃cation accuracy of the microseismic event depends on the signal⁃to⁃noise ratio of microseismic monitoring data.In microseismic monito⁃ring data processing,it is very important to improve the signal⁃to⁃noise ratio.The improved S transform,which has high time⁃frequency solution,is useful for microseismic monitoring data.Microseismic events can be better processed in time⁃frequency spectrum than in con⁃ventional Fourier transform.Based on the fine focus in time⁃frequency domain and flexible window function choice of improved S trans⁃form,the authors designed a 2D time variable time⁃frequency filter,which was used to process micro⁃seismic monitoring data.The com⁃bined signal and field micro⁃seismic monitoring data demonstrate the feasibility and efficiency of the method.%原始微地震监测数据的信噪比相对较低，监测数据品质决定了微地震有效信号的定位精度，提高监测数据信噪比是微地震处理的关键环节。改进S变换对窗函数进行能量归一化处理，解决了常规S变换时频谱中频率定位不准的问题，具有更高的时频分辨率精度。利用改进S变换的良好二维时频域聚焦特性，设计时变的二维时频域滤波器，将时频域去噪方法引入到微地震监测数据的去噪处理中。利用改进S变换对微地震监测数据进行时频分析，能够更加准确地分析不同信号分量的振幅能量以及频率随时间的变化情况，实现微地震有效信号分量与噪声干扰分量的有效分离。通过合成模拟信号和实际井中微地震监测数据的试处理和对比分析，验证了该方法的可行性和有效性。