层状半空间叠前地震记录的波动方程正演模拟

振幅随偏移距变化 (AVO)分析是一项利用振幅随偏移距变化特征来分析岩性和油气藏的地震勘探技术 ,它极大地改善了地震勘探的烃类检测能力。并不是所有气层的反射振幅都随偏移距增加 ,特殊岩性体也会产生AVO效应。利用弹性动力学方程变换和递归算法 ,计算了反射矩阵 ,从理论上推导了球面波在层状弹性半空间传播时产生的地面反射记录的计算公式。在实例模拟中 ,对计算速度和精度、空间假频、截断效应等给出了相应的解决方案。计算实例说明 ,波场模拟有助于AVO分析和叠前反演。

Wave equation forward modeling of prestack seismogram in a stratified half space

The amplitude variation characteristics with offset (AVO) technique was used to analyze lothology and hydrocarbon reservoir. AVO analysis has greatly improved hydrocarbon detection. However, not all the reflection amplitudes of gas reservoir increase with offset, and special lothosome can also generate AVO effects. Reflection matrix was computed by the transformation and recursive algorithm of elastodynamic equations. Furthermore, the equation of surface reflection seismogram generated by spherical wave propagation in a stratified elastic half space was derived theoretically. In real data simulation, the programs for solving computing speed and precision, space aliasing and truncation effect were also given. Wave field simulation may be a powerful tool for AVO analysis and prestack inversion.