微震P波到时拾取的PAI-k-MFV算法改进及应用  

Modified PAI-k-MFV picker of picking microseismic P-wave arrival time and its application

作　　者：朱梦博 王李管[1,2] 彭平安[1,2] 刘晓明[1,2] 赵嘉轩 

机构地区：[1]中南大学资源与安全工程学院,湖南长沙410083 [2]中南大学数字矿山研究中心,湖南长沙410083

出　　处：《煤炭学报》2017年第10期2698-2705,共8页Journal of China Coal Society

基　　金：国家重点研发计划资助项目(2017YEC0602905);中南大学研究生自主探索创新资助项目(2017zzts568)

摘　　要：为了充分发挥PAI-k-MFV算法参数自适应的优势,同时提高P波到时正确拾取率和拾取精度,通过引入STA/LTA算法和改进MFV准则,对PAI-k-MFV算法进行改进。首先,根据预先设置的时窗长度和置信概率的取值范围及步长,采用PAI-k算法拾取得到一组P波到时集;然后,运用STA/LTA算法初步计算P波到时区间,并将到时集中不在该区间内的到时元素剔除,得到更新后的到时集;最后,在新到时集的基础上,根据改进的最大频遇值(MMFV)准则最终确定P波到时。改进算法继承了PAI-k-MFV算法的参数自适应优点,无需人为调整太多参数,同时能够有效克服原MFV准则容易失效和拾取点滞后真实到时点等问题。对比其他算法,改进算法在拾取背景噪声段有强噪声的微震信号和弱微震信号P波到时具有明显优势。利用改进算法和PAI-k-MFV算法拾取冬瓜山铜矿115个实测低信噪比微震信号的P波到时,以人工拾取结果为参考标准,误差在5ms以内(对应30个采样点)视为正确拾取,结果显示:改进算法正确拾取率为96.52%,正确拾取的到时误差绝对值均值为1.1 ms,标准差为1.0 ms;较PAI-k-MFV算法,正确拾取率和拾取精度都大幅度提高。To give full play to the PAI-k-MFV picker＇s advantage of parameter adaptive,and improve the correct picking rate and pick accuracy of P-wave arrival time,a modified PAI-k-MFV picker was proposed on the basis of STA/LTA picker and the modified most frequent value criterion. Firstly,a P-wave arrival time set was calculated with the PAI-k picker according to preset the value range and step of window length and confidence probability. Secondly,the interval of P-wave arrival time was searched by STA/LTA picker,and the arrival times that were not in this interval were screened out. Finally,the P-wave arrival time was determined based on the updated arrival time set according tothe modified most frequent value criterion. The modified picker preserves PAI-k-MFV picker＇s characteristic of adaptive parameter,without too much parameter tuning,and overcomes the problems of the failure of MFV criterion and the picking points lagging behind the true P-wave arrival time. Compared with other pickers,the modified picker has an obvious advantage in picking P-wave arrival time of microseismic signal with strong background noise and weak microseismic signal. The modified picker and PAI-k-MFV picker were applied to pick P-wave arrival time of 115 Dongguashan microseismic signals with low SNR. The result indicates that the correct picking rate of the modified picker is96. 52% considering the manual picking results as a benchmark and the time difference within 5 ms that correspond to30 sampling points as a correct pick,and the correct picks＇ mean absolute value is 1. 1 ms,and the standard deviation is 1. 0 ms. The correct picking rate and the picking precision of the modified picker significantly increase comparing to PAI-k-MFV picker.

关 键 词：微震 P波到时拾取 PAI-k STA/LTA 频遇值准则 

分 类 号：TD32[矿业工程—矿井建设]