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本文基于逆散射理论利用正则化有限差分对比源反演算法对地震波传播速度进行反演,该方法是基于波动方程的频率域波形反演算法,利用非线性共轭梯度法,通过最小化目标优化函数不断迭代更新速度模型.由于地球物理反演问题的病态性和不稳定性,通过基于反演参数总变差的正则化处理,使反演问题变为良性问题且算法具有较强的抗噪声干扰能力.反演过程中使用了频率-空间域9点差分正演算子以及PML吸收边界条件.与其他反演算法相比,由于背景模型在反演迭代过程中保持不变,可以避免在每次迭代过程中重新构造正演算子及矩阵分解等相关计算过程,使得该算法非常适合于大规模三维反演计算.此外,本文采用基于MPI的并行计算,进一步提高了反演计算的效率.二维CSEG模型反演结果表明该方法可以反演得到高分辨率的地震波速度重建结果,为地震勘探数据处理及解释提供准确的速度信息.
In this paper, based on the backscattering theory, the regularized finite-difference contrast source inversion algorithm is used to invert the seismic wave velocity. The method is based on wave equation, and uses the nonlinear conjugate gradient method to minimize the target optimization The function iteratively updates the velocity model. Due to the ill-posed and unstable geophysical inversion problems, the inversion problem becomes benign by regularization based on the total variation of inversion parameters and the algorithm has strong anti-noise Interference ability.The inversion process uses the 9-point differential forward operator in the frequency-space domain and the PML absorption boundary conditions.Compared with other inversion algorithms, since the background model remains unchanged during the inversion iteration, In the iteration process, the correlative calculation processes such as forward operator and matrix factorization are reconstructed, which makes the algorithm suitable for large-scale three-dimensional inversion calculation. In addition, parallel computing based on MPI is used to further improve the efficiency of inversion calculation. The inversion results of the CSEG model show that the proposed method can be used to retrieve the high-resolution seismic velocity reconstruction results for seismic exploration data processing And explain to provide accurate speed information.