考虑激电效应和电磁效应的复电阻率法二维数值模拟研究

    Research on two-dimensional complex resistivity forward modeling considering IP and EM effects

    • 摘要: 复电祖率实测数据是包含激电效应和电磁效应的影响,而传统的复电祖率法二维数值模拟只考虑激电效应会影响后续资料处理结果的精度,因此本文开展同时考虑激电效应和电磁效应的复电祖率法二维正演研究。本文正演是基于二次场满足的麦克斯韦方程组,通过傅里叶变换将其变换到波数域,结合有限单元法,引入Cole-Cole模型,形成正演矩阵方程,采用超松弛迭代双共轭梯度法求解该方程组可得波数域结果,再由反傅里叶变换将其转换至空间域,完成了正演研究。然后通过几个模型算例的计算验证了该算法的正确性,也为复电阻率法二维反演奠定了基础。

       

      Abstract: Complex resistivity(CR) data are influenced by induced polarization(IP) and electromagnetic(EM) effects, traditional two-dimensional(2D) complex resistivity forward modeling only considers IP effects which influences the accuracy of the subsequent processing results.In this paper, the research of 2D complex resistivity forward modeling takes IP and EM effects into account simultaneously.The forward modeling in this paper is based on the Maxwell’s equations in frequency domain which employs secondary field algorithm.Differential equations in wavenumber domain can be obtained by use of Fourier transform.Combine with the finite element method and the introduction of Cole-Cole model, then forming the forward matrix equation.Symmetric successive over relaxation bi-conjugate gradient method is used to solve the equations, and get the results in wavenumber domain.By inverse Fourier transform, the results in spatial domain can be obtained, the forward modeling is accomplished.After calculating several model tests, the accuracy of the forward algorithm is reliable and robust, and it provides the foundation for the complex resistivity inversion research.

       

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