三维各向同性介质矢量波场保幅分离方法

发布时间：2019-03-10 18:24

【摘要】：三维各向同性介质中,基于常规散度和旋度算子分离得到的纵横波在物理意义和发生极性的反转位置上无法与原混合波场完全对应。现有的矢量波场分离方法是在波场求取散度和旋度基础上再做一次梯度和旋度运算,分离后的矢量纵横波与原波场极性反转位置一致,但不保幅。从一阶速度-应力方程出发,在波数域推导了矢量纵横波分离公式的表达形式,并结合有限差分过程给出了其在空间域的求解方法。该方法的本质是利用纵横波的传播速度对现有的矢量波场分离方法进行振幅校正,并将校正结果分别作为纵波与横波对于时间的二阶偏导。简单层状模型和SEG/EAEG盐丘模型的试算结果表明,该方法能够适应复杂波场的矢量纵横波分离,并保证分离后纵横波的波形与原混合波场保持一致,具有较好的保幅性。
[Abstract]:In three-dimensional isotropic media, the P-S wave based on the separation of conventional divergence and curl operators cannot completely correspond to the original mixed wave field in the physical meaning and the inversion position of the polarity. The existing vector wave field separation methods do gradient and curl operations on the basis of obtaining divergence and curl of the wave field. The separated vector P-S wave is consistent with the polarity inversion position of the original wave field, but does not preserve amplitude. Based on the first-order velocity-stress equation, the expression of vector P-S wave separation formula in wavenumber domain is derived, and the solution method in space domain is given in combination with the finite difference process. The essence of this method is to make use of the propagation velocity of P-S wave to calibrate the amplitude of the existing vector wave field separation method and take the correction result as the second order partial derivative of P-wave and S-wave to time respectively. The experimental results of the simple layered model and the SEG/EAEG salt mound model show that the proposed method can adapt to the separation of vector P-S wave in complex wave field, and ensure that the wave form of P-S wave after separation is consistent with the original mixed wave field and has good amplitude-preserving property.
【作者单位】：中国海洋大学海底科学与探测技术教育部重点实验室;青岛海洋科学与技术国家实验室海洋矿产资源评价与探测技术功能实验室;
【基金】：国家自然科学基金资助项目(41674118) 国家重大科技专项基金资助项目(2016ZX05027-002)
【分类号】：P631.4

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