【摘要】 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。更多还原

【Abstract】 Stability is the key to inverse Q-filtering.In this paper we present a stable approach to inverse Q-filtering,based on the theory of wavefield downward continuation.It is implemented in a layered manner,assuming a layered-earth Q model.For each individual constant Q layer,the seismic wavefield recorded at the surface is first extrapolated down to the top of the current layer and a constant Q inverse filter is then applied to the current layer. When extrapolating within the overburden,a stable wavefield continuation algorithm in combination with a stabilization factor is applied.This avoids accumulating inverse Q-filter errors within the overburden.Within the current constant Q layer,we use Gabor spectral analysis on the signals to pick time-variant gain-constrained frequencies and then deduce the corresponding gain-constrained amplitudes to stabilize the inverse Q-filtering algorithm.The algorithm is tested and verified application to field data.更多还原