基于三维数值模拟的激电法差分装置响应特征分析

Analysis of response characteristics of IP differential device based on 3D numerical simulation

为了深入分析激电法差分装置的响应特征,提出一种高精度、高效率的三维数值模拟方法。该数值模拟方法通过二维傅里叶变换将三维激电数值模拟问题转化为波数域一维数值模拟问题,使用一维有限单元法求解,同时引入算子进行迭代,最终获得高精度数值解。该算法可避免进行大型稀疏线性方程组的直接求解,大幅度降低了计算量和存储需求,提高了计算效率。以提出的三维数值模拟方法为工具,分析激电法差分装置响应特征。基于高阻/低阻的高极化异常体模型测试结果表明,单孔井—井测量下差分装置对井旁盲矿的分辨效果优于其他装置,且低阻体较高阻体对电流具有更强的敏感度;基于不同背景介质下的低阻高极化异常体模型的测试结果表明,井—地测量下采用差分装置得到的视电阻率和极化率比采用二极装置得到的视电阻率和极化率能更准确地反映背景介质和异常体在垂向上的空间分布特征。因此,激电法差分装置勘探效果优于其他方法装置,研究结论可为野外勘探测量装置的选择提供参考。

To analyze the response properties of the induced polarization(IP)differential device,this paper proposes a high⁃precision and high⁃efficiency 3D numerical simulation method.The proposed method transforms the 3D IP numerical simulation problem into a 1D numerical simulation problem in the wavenumber domain using a 2D Fourier transform method and solves it using a 1D finite element method.Operators are introduced for iterative computations,which eventually lead to high⁃precision numerical solutions.This approach avoids directly solving large sparse linear equations,greatly reducing the computational complexity and storage requirements and improving computational efficiency.The paper uses the proposed 3D numerical simulation method as a tool to analyze the response properties of the IP differential device.The test results of a high⁃polarization anomalous bulk model with high/low resistance indicate that the differential device for single well⁃well azimuthal measurement has a better resolution effect on blind ore near the well than the other devices,and the low resistance body has a stronger sensitivity to current than the high resistance body.Tests of low⁃resistance and high⁃polarization anomalous bulk models using different background media have shown that the apparent resistivity and polarizability of the differential device under well⁃ground measurement conditions can more accurately reflect the vertical spatial distribution properties of the background media and the anomalous bulk than those of pole⁃pole device.Therefore,the IP differential device has an ad⁃vantage over the other devices,and the research conclusions can provide a reference for the selection of field explora⁃tion and measurement equipment.