Wide-Azimuth Electric and Magnetic Field Detection Method Research

The controlled source electromagnetic method (CSEM) assesses electromagnetic field components across specific orientations within a field coordinate system to calculate apparent resistivity for electromagnetic detection. However, in complex terrains, capturing the x-, y-, or z-components accurately is often impracticable, leading to discrepancies in apparent resistivity calculations and impacting detection precision. To mitigate these challenges, this article proposes a method for observing electric and magnetic field components in any orientation, thereby enhancing wide-azimuth electromagnetic detection. First, this article analyzes the angular deviations and the limitations of zero-value bands in certain single-component observation methods. Second, it examines the geoelectric response of electric and magnetic fields in various orientations and the nonmonotonicity in apparent resistivity calculation. These analyses validate the feasibility of the wide-azimuth electric field observation method, substantially augmenting field observation flexibility. Moreover, the study identifies the challenges in accurately calculating apparent resistivity in wide-azimuth magnetic detection. This study provides innovative insights for advancing the CSEM detection method and improving detection accuracy.