基于横向约束的中心回线瞬变电磁一维反演

    One-dimensional inversion of central loop transient electromagnetic data based on transverse constraints

    • 摘要: 在中心回线瞬变电磁反演过程中,为保证反演结果横向连续性,可施加横向约束,将多个测点组合成一个整体进行反演,在相邻测点之间建立相关联系,从而保证反演结果的连续性。本文横向约束使用横向加权、垂向粗糙度约束来增强相邻测点之间联系,提高反演精度。在反演过程中引入自适应正则化因子,正则化因子通过计算每次迭代的数据目标函数和模型目标函数的范数自适应得到,可改善反演过程中对初始模型的依赖。最后使用该算法对基于非结构时间域有限元三维正演数据及实测数据进行反演,与实际结果相符,表明该算法可增强反演结果的连续性且具有很好的抗噪能力。

       

      Abstract:

      To ensure the transverse continuity of the inversion results of central loop transient electromagnetic (TEM) data, it is practical to combine multiple survey points into a whole by applying transverse constraints and to establish correlations between adjacent survey points. This study employed the constraints of weighted transverse and vertical roughness to improve the correlations between adjacent survey points and thus to improve the inversion accuracy. Furthermore, this study introduced the adaptive regularization factor, which was obtained adaptively by calculating the norms of the data and the model objective functions in each iteration. In this manner, the dependence on the initial model can be reduced. Finally, using the algorithm developed, this study conducted the inversion of the measured data and data from three-dimensional forward modeling based on the unstructured time-domain finite element method. The inversion results are consistent with the actual results, indicating that the proposed algorithm in this study can enhance the continuity of the inversion results and has a high anti-noise ability.

       

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