【摘要】 为了满足精细化地震勘探的要求,实现高精度地震波正演模拟和偏移成像,推导了高阶交错网格有限差分法地震波动方程正向外推和逆时延拓的计算公式,并给出计算所需的叠后逆时成像条件、稳定性条件和吸收边界条件。以复杂含孔洞介质模型为例,制作了不同主频情况下地震波零偏移距剖面和叠后逆时深度偏移剖面。计算结果表明,正演和逆时偏移剖面精度高,边界吸收效果好,其中低频地震勘探只能反映宏观的地质构造特征,对地层细节的刻画能力较差,而通过提高地震勘探主频,可以提高地震资料的分辨率,并准确刻画地层的变化规律和细节特征,从而能够有效指导地震资料数字处理。更多还原

【Abstract】 In order to meet the requirement of finely seismic prospecting and achieve high-precision seismic wave forward modeling and migrated imaging,the paper derives the seismic wave motion equation of forward extrapolation and computing formula of inverse time extension with high-order staggered grid finite difference method.It also presents the post-stack inverse time image-forming condition,stability condition and absorbing boundary condition in calculation.The zero offset seismic wave profile and post-stack reverse time depth migration profile are made taking a complex model of cavity medium as an example.The result indicates that the forward and reverse-time migration profiles have high precision and fine boundary absorption.Low frequency seismic prospecting can only reflect macroscopic geological structure characteristics,and it is poor in depicting formation details.So increasing the dominant frequency of seismic prospecting can improve the resolution of seismic data and accuracy of depicting formation and then efficacy of seismic data processing.更多还原