时间域激电法组合源装置抗电磁耦合性能三维正演分析

    Three-dimensional forward modeling of the anti-electromagnetic coupling performance of a combined source array in the time-domain induced polarization method

    • 摘要: 针对时间域激发极化法大功率勘探中电磁耦合干扰严重的问题,采用基于Green函数的三维有限元法进行直流电阻率正演,结合改进Talbot逆Laplace变换实现Cole-Cole模型的时变电阻率计算,构建互补型电偶极组合源观测系统。数值模拟结果表明,组合源装置较传统中梯装置的电磁耦合抑制效果提高10~20倍,极性反转布局中心形成低噪声观测窗,有效信号时间范围显著扩大。双侧供电装置对典型理论模型的异常体分辨效果良好。该研究可为复杂地质条件下TDIP高效勘探提供理论支撑。

       

      Abstract: This study aims to overcome the severe electromagnetic coupling interference in high-power exploration conducted using the time-domain induced polarization (TDIP) method. Specifically, using a three-dimensional finite element method based on Green's function, the forward modeling of direct current resistivity was performed. In combination with an improved Talbot's inverse Laplace transform, the time-varying resistivity of the Cole-Cole model was calculated.Accordingly, a complementary acquisition geometry with a combined source array composed of electric dipoles was constructed. Numerical simulation results indicate that compared to a conventional central gradient array, the combined source array enhanced the electromagnetic coupling suppression effect by 10~20 times. Concurrently, a low-noise observation window was formed at the center of the polarity-reversal layout, significantly increasing the effective signal time range. Notably, the bilateral power supply configuration demonstrated a high resolution for anomalies in typical theoretical models. This study can provide theoretical support for the efficient exploration using the TDIP method under complex geological conditions.

       

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