基于水库气枪震源数据的频域水准比例因子反褶积方法分析

Analysis of Frequency Domain Water-level Deconvolution Method Based on Reservoir Airgun Source Data

摘要:

基于2016年福建南一水库气枪实验资料，利用频率域水准因子反褶积方法和互相关时延检测技术，研究水准比例因子及台站的背景噪声水平对反褶积计算结果的影响，并对反褶积法消除不同枪压引起的震源影响效果进行分析。结果表明：①水准比例因子越小，反褶积计算后的波形信噪比越小，当水准比例因子取值过小时，走时识别误差较大；②台站气枪记录的信噪比越大，走时识别精度越高，参考台记录的信噪比对结果的影响远大于远场台，当远场台记录的信噪比大于10时，走时误差一般小于6ms，而当参考台记录的信噪比为30左右时，走时误差可能达到20ms；③气枪震源差异较大时，频域水准反褶积方法去除震源效应的效果较好，而在震源差异较小时，可能引入方法误差。

Abstract:

Based on the experimental data of 2016 Fujian Nanyi reservoir airgun,we adopted the frequency domain water-level deconvolution method and cross-correlation time delay detection technique,studied the influence of level scaling factor and the background noise level of the station on deconvolution calculation results,and analyzed the effect of deconvolution on eliminating the influence of the source caused by different airgun pressures. The results showed that:① When the level scaling factor is smaller,the signal to noise ratio of the waveform after the deconvolution is smaller,but the identification error of travel time is greater. ② When the SNR of station record is higher,the recognition accuracy of travel time is higher,and the influence of SNR on the reference station record is far greater than the far station. When the SNR of the far station record is more than 10,the error of travel time is within 6ms,but when the SNR of the reference station record is 30,the travel time error may reach to 20ms. ③ When the airgun source difference is big,the frequency domain leveling deconvolution method has a better effect on eliminating the source influence,but the method error may be introduced when the source difference is small.