上覆地层形态对目的层成像振幅的影响

当前的叠前时间偏移等方法可以得到较准确的地下构造成像,但是受上覆地层的影响,从偏移剖面中提取的振幅属性无法真实的反映出目的层的岩性变化。虽然人们已经认识到上覆地层确实会对目的层成像后的振幅产生影响,但对于上覆地层构造和目的层成像振幅之间的关系却没有得到系统性的认识。经过叠前时间偏移后得到的目的层成像振幅结果等价于震源波场正向传播时目的层的能量分布。基于这一结论,使用波动方程正演方法来替代叠前时间偏移方法,借助于GPU高性能计算,通过不断将三维模型复杂化,初步认识了上覆地层构造的复杂程度和上覆地层对目的层成像振幅的影响程度之间的关系,为进一步分析上覆地层形态对目的层成像振幅的影响奠定基础。

Influence of overlying stratum on amplitude imaging of target intervalDeng Shuai, Liu Xuewei, You JiaChun, Bai Peng

Currently pre-stack time migration can get the exact underground structure imaging, but the amplitude extracted from migration section, influenced by overlying stratum, cannot reflect lithology change of target interval. It is known that overlying stratum can influence amplitude imaging of target interval, but the relationship between the structure of the overlying stratum and the amplitude imaging of target interval is lack of systematic understanding. The energy distribution of target interval when the source wave field travel forward is the same thing with the amplitude image result of target interval from pre-stack time-migrated zero-offset reflections. In this article, based on this conclusion, the forward modeling method is taken place of the pre-stack time migration method, with the help of GPU, by making the 3D model more complicated, the relationship between the influence of the overlying strata on the target layer and the complexity of the structure of the overlying strata is preliminary built up, further more, the foundation for further analysis of the influence of structural complexity of overlying strata on image of target interval is laid.