基于惠更斯原理的波动方程共炮点道集地震正演

Wave-field modeling of common shot gather records based on Huygens Principle

地震非零炮检距正演模拟技术在叠前地震资料处理和解释中有重要意义。作者利用下行波将震源场延拓到地质介质任意深度,实现单程波动方程模拟叠前正演记录。用单程波动方程法对一个盐丘地质模型生成129个共炮点地震记录,并对所有共炮记录进行叠前深度偏移。在共炮记录中,来自盐丘地质模型的反射波和绕射波十分清晰。叠前深度偏移剖面和盐丘地质模型完全吻合。该方法生成记录质量好且计算效率高,并且叠前正演记录没有多次波、直达波和其他干扰波。

Non-zero offset or pre-stacking seismic forward modeling （SFM） usually performed by ray tracing and full-wave equation techniques plays an important role in the pre-stacking seismic data processing and interpretation. The calculating efficiency of the ray tracing technique is high and its precision low. And the calculating efficiency of the full-wave equation techniques is low and its extraordinarily precision with serious noise. The paper extrapolates the source-field to an arbitrary depth of the geological model with the down-wave equation and implements the forward modeling of non-zero offset seismogram. The paper produces 129 common shot seismic gathers for SEG/EAGE salt model by using one-way wave equation technique, and then images them by the common shot gather migration. The results show that the reflections and diffractions in those seismic gathers are quite clear and imaging is completely consistent with SEG/EAGE salt model. It is also important that high S/N ratio SFM records without any multiple waves, direct waves and other false events can be obtained by the new methods.