垂直地震剖面资料中的随机噪声衰减

针对常规滤波方法没有考虑背景噪声的问题，提出了一种利用背景噪声统计规律的小波域随机噪声衰减方法．在假设背景噪声是统计平稳的前提下，首先估计背景噪声与直达波到达之后的实际地震记录的相关系数，在这个系数比较小的情况下，利用每一道直达波到达前的背景噪声估计该道噪声的统计参数，然后给出噪声阈值估计，进而在小波域衰减垂直地震剖面（VSP）资料的随机噪声，获得高保真的VSP资料．对合成地震记录和实际资料的仿真实验表明，新方法比常规滤波方法的信噪比提高了约2dB，且更能体现地震信号的时变特点，处理后的剖面同相轴更清晰．

Stochastic Noise Attenuation in Vertical Seismic Profile

Focusing on the problem that filtering method used in vertical seismic profile(VSP) data processing is not referred to the ambient noise,a wavelet shrinkage scheme which utilizes the statistical law of ambient noise is proposed.Based on the hypothesis that the ambient noise is statistically stationary,firstly the correlation between ambient noise and real data after the first seismic arrivals is estimated,when the correlation is small,the statistics of stationary noise can be derived from the data before the first seismic arrivals;then stochastic noise can be attenuated in wavelet domain using a threshold estimated by the statistics of stationary noise;and finally high fidelity VSP data is obtained.The smulation results of the syntheticaly seismic records and real data demonstrate that the signal-noise-ratio of the proposed method is about 2 dB higher than that of filtering method.The algorithm proposed can exhibit time-variant characteristic of seismic signal more sufficiently,and the cophase axis of the profile is more distinct after processing.