场地波速测量资料处理的小波变换方法

Wavelet analysis in wave-velocity logging

在场地波速测量中,由于噪声等因素的影响,很难准确识别P波、S波的初至时刻,致使波速结果存在很大的误差。本文给出了一种基于小波变换的波速测量的新方法。该方法利用波动信号的小波变换与弹性波群速度的关系准确识别弹性波初至时刻。弹性波小波变换的峰值时刻代表着以群速度传播的弹性波的初至时刻,使P波、S波的初至时刻的确定具有明确的物理意义,波速的结果准确、可靠、稳定。此外,利用波动信号的小波多尺度分析,还可以确定地层中传播的弹性波的频散特性。最后,该方法在场地波速测量的实测信号的应用表明,该方法可准确确定P波和S波速度。

It is difficult to identify the arrival time of P and S waves in wave velocity logging,which yields great error for P and S wave velocities.We present a new method for the cal-culation of wave velocities based on wavelet analysis.Peak values of wavelet-transformed signal represent the arrival of elastic waves with certain group velocities,which makes the calculation of wave velocities accurate and reliable.Furthermore,the dispersive character-istic of waves is also shown by wavelet method.An illustrated example shows that this method can determine the accurate P and S wave velocities.