基于早至波的特征波波形反演建模方法

近地表速度建模问题是地球物理建模的重点及难点问题。传统基于射线类的反演方法受到高频假设的限制,存在理论上的建模“盲区”,而全波形反演方法的应用又受到资料品质等诸多因素的限制。介绍了一种基于全波形反演思想的特征波波形反演方法,引入早至波的概念联合初至走时层析反演,利用早至波这一特征波的运动学和动力学信息,实现对近地表及中浅层的高精度建模。模型验证结果表明,该方法即使在初始模型精度较低的情况下仍然可以达到较好的建模效果。

The velocity model building for shallow layers is a key issue in the geophysics modeling.The traditional methods based on ray path theory are restricted by high-frequency approximations,and therefore the blind area of modeling exists theoretically.The application of full wave inversion is also restricted by the quality of seismic data.A characteristics waveform inversion technology based on the ideas of full wave inversion is proposed.We introduce early arrival waves,combine with first arrival tomography and utilize the kinematic and dynamic information of early arrival waves to accurately reconstruct the velocity model in shallow layers.The synthetic data test result shows high precision shallow velocity model could be built even for a poorly initial model with this technologie.