地震记录的Q值正演模拟与反滤波

Forward modeling and inverse filtering for Q of seismograms

成都理工学院, 成都610059

Applied Geophysies Department, Chengdu College of Tcchnology, Chengdu City, Internal Postcode: 610059

地震记录的正演模拟与反演方法是地震勘探中重要的处理和解释手段之一。目前普遍采用的正演方法都是已知地层速度、密度或波阻抗正演一定观测系统条件下的合成记录, 并没有考虑地下介质非弹性吸收的影响。正演获得的合成记录具有较多的假设条件, 与实际地震记录差距较大。本文提出的模拟方法是利用波场成像原理, 在递推上行波时应用Futterman模型同时考虑介质的吸收作用, 推导出频波域类似于相移正演算法的Q值正演模拟合成地震记录计算方法。同样用与相移偏移相类似的方法, 还可导出实现Q值反滤波的相移算法, 用数值模型及实际资料处理表明了这两种方法的良好效果。

The forward modeling and inversion for seismie data are accepted to be important tools for data processing and interpretation in seismic surveys. The forward method currently used is commonly performed under the conditions of given interval ve locities,densities or wave impedances without taking the effect from non-clastic absorption of subsurfaces into account. This is often the cause of significant difference in between a synthetic record by modeling and its corresponding actual seismogram. This paper suggests making use of the imaging principle for wave fields in forward modeling. By using the Futterman model and taking the media's absorption effect into consideration while continuing up-going waves, we have derived an f-k algorithm for Q forword modeling which is similar to the phase-shift forward algorithm. Morcover, in much the same way as phase-shift migration, anothor phase-shift algorithm for Q inverse filtering is derived as well. Both numerical modeling and field data processing have comfirmed the effectiveness of these two methods.