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反Q滤波算法中稳定性是关键。针对地下介质为层状Q模型结构,本文提出一种稳定的反Q滤波算法,基于波场延拓原理,对于每个常Q层反Q滤波算法分两步完成:(1)利用一种稳定的波场延拓算法,将地表波场记录直接延拓到当前层上;(2)在当前层内进行常Q反滤波。在步骤(1)中,利用稳定的波场延拓算法并结合稳定因子,将地表波场记录直接延拓到当前层上,避免了上覆层反Q滤波误差的累积。在步骤(2)中,对于当前层内的反Q滤波,通过对该层地震信号的Gabor谱分析,拾取时变的限幅频率,并确定相应于该频率值的限幅增益值来实现反Q滤波算法的稳定性。最后通过理论模型与实际数据验证了算法的优越性。
Anti-Q filtering algorithm stability is the key. Aiming at the layered Q model structure of underground medium, a stable inverse Q filtering algorithm is proposed in this paper. Based on the wave field continuation principle, an inverse Q filtering algorithm is implemented in two steps for each constant Q layer: (1) Of the wave field extension algorithm, the surface wave field records directly extended to the current layer; (2) in the current layer for the Q inverse filter. In step (1), using the stable wavefield continuation algorithm combined with the stability factor, the surface wavefield recording is directly extended to the current layer, avoiding the accumulation of the inverse Q filtering error of the overlay. In step (2), for the inverse Q filtering in the current layer, the Gabor spectrum analysis of the layer of seismic signals is performed to pick up the time-varying clipping frequency and determine the clipping gain value corresponding to the clipping value The stability of Q filtering algorithm. Finally, the superiority of the algorithm is verified by the theoretical model and the actual data.