论文详情
背景速度是决定地震波传播的关键因素,是进一步反演速度场中高频成分的基础。针对反射波反射角孔径较小,通常只用于恢复速度场短波长分量的问题,重新推导了反射波场对背景速度的Fréchet导数,得到反射波路径,利用反偏移算子从背景速度场中获取反射波信息,以数据域反射波互相关函数作为目标泛函进行反演,实现了利用反射波信息来反演速度场的低波数成分的目的。该方法降低了波形反演对波动方程的依赖程度,从而能更好地克服局部极值问题。模型试算结果表明,该方法能够提高反演的稳定性。
The background velocity is the key factor for the propagation of seismic wave. It is also the basis of further inversion for higher frequency components of velocity field. Due to the narrow reflection angle aperture of reflections,it’s typically only used to recover short wavelength components of velocity field. The Fréchet derivative of reflections for the background velocity model is derived again,then the reflected wave path was obtained. We get reflections information from the background velocity field using demigration operators. Considering the optimum matching of reflections phase information,we construct objective function with reflections correlation function. Finally we achieve the low wavenumber components inversion of the velocity model using reflected wave information. The method reduces its dependency on wave equation,and can well avoid the local minima problem. Model tests demonstrate its better stability and application potentiality.
国家自然科学基金项目(41374122)资助。