基于阻尼耗散能功率的微震P波到时拾取新方法研究

The research about new method of picking onset of microseismic P-wave based on power of damping energy

现有微震P波到时拾取算法在实际应用中往往需要根据具体实际情况选择阈值和计算时窗,阈值与计算时窗设置不合理将导致拾取误差变大,基于此提出一种基于追踪阻尼耗散能量功率的方法,以克服传统方法的不足。该方法是将信号转化为具有黏性阻尼的线弹性固定基单自由度振子的响应并提出通过直方图法与AIC法联合追踪阻尼耗散能量功率来拾取P波到时。该方法具有能够识别噪声信号、无需检测阈值、检测时窗设置的优点。利用加噪后的信号测试方法的抗噪性能,结果表明,在不同的信噪比下该方法较传统方法相比具有较优的抗噪性能。应用该方法对实际中监测的40个不同信噪比波形进行P波到时拾取,以局部放大后人工拾取为标准,并将结果与长短时均值比法(STA/LTA)对比分析得到该方法误差均值为1.17 ms,误差2 ms以内占比87.5%,4 ms以内占比100%;STA/LTA法误差均值为3.46 ms,误差2 ms以内占比55%,误差4 ms以内占比82.5%,综合可见所提出该方法更好。柿竹园微震监测应用结果表明:该方法能够显著提高微震事件的定位精度,具有重要的理论与实际意义。

In practical applications,unreasonable setting of the threshold value and the calculation time window will lead to a larger error in the algorithm of picking onset of P-wave.Based on this,a method based on tracking the power of damping energy to overcome the shortcomings of the traditional method.The method is that transform the signal into a response domain of a single-degree-of-freedom(SDOF)oscillator with viscous damping and then tracks the variation of the power of damping energy to pick P-wave phases by combining the histogram method and AIC method.This method has the advantages of recognizing noise signal,no detection threshold setting,and no detection window selection.The results show that the proposed method has better anti-noise performance than the traditional method under different SNR.Using this method,40 different Signal-to-noise ratio waveforms monitored in practice were picked up at the onset of P wave,and manual picking after local amplification was taken as the standard.By comparing and analyzing the results with the STA/LTA method,the mean error of the method in this paper was 1.17 ms.The errors within 2 ms account for 87.5%and the errors within 4ms account for 100%.While,the mean error of STA/LTA method is 3.46 ms,and the errors within 2 ms account for 55%,and the errors within 4ms account for 82.5%.It can be concluded that the method proposed in this paper is better.The results of microseismic monitoring in Shizhuyuan mine show that this method can significantly improve the accuracy of source location in microseismic and has important theoretical and practical significance.