An inverse Q-filter algorithm based on stable wavefield continuation  

一种稳定的波场延拓反Q滤波算法(英文)

作　　者：张显文[1] 韩立国 张凤蛟[1] 单刚义[1] 

机构地区：[1]吉林大学地球探测科学与技术学院,长春130026

出　　处：《Applied Geophysics》2007年第4期263-270,共8页应用地球物理（英文版）

基　　金：This research is sponsored by the National"973"Project(No.2007CB209603);the"863"Project(No.2006AA06Z108)

摘　　要：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.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。

关 键 词：Inverse Q-filtering wavefield continuation DISPERSION DISSIPATION 

分 类 号：P631.4[天文地球—地质矿产勘探]