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

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.