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初至的拾取是折射波资料分析、VSP处理和井间地震资料处理的基础工作。常规的初至拾取方法存在着较大的误差。Stockwell提出的S变换,可有效解决低信噪比地震记录初至拾取困难的问题。S变换后的单道地震记录,因其地震信号在初至起跳前后存在明显的频率差异,致使时频图上有明显的能量聚集。为检测该方法识别初至的容噪能力,设计了三种信噪比的理论记录,检测结果显示,不论地震信号波形的信噪比有多低,地震信号的时频谱都有明显的能量聚集存在,都可有效拾取地震信号的初至。实例表明,基于S变换的地震信号初至识别方法能够比较准确地拾取地震信号的初至。
The first arrival picking is the basic work of refraction data analysis, VSP processing and crosswell seismic data processing. The conventional first arrival pick-up method has a large error. Stockwell proposed S transform, which can effectively solve the problem of low signal to noise ratio seismic acquisition first arrival pick-up. S transform single-channel seismograms, because of its seismic signal before and after the start of the jump there is a significant frequency difference, resulting in significant time-frequency energy maps. Three kinds of theoretical records of signal-to-noise ratio (SNR) were designed to test the capacity of the method to recognize the initial noise. The results show that there is a significant energy accumulation in the time-frequency spectrum of the seismic signal no matter how low the SNR of the seismic signal Exist, can effectively pick up the first arrival of the seismic signal. The example shows that the first arrival of seismic signal based on S transform can pick up the first arrival of seismic signal more accurately.