Design and development of borehole three-component time-domain electromagnetic detection system

This paper proposes a three-component time-domain electromagnetic detection system for borehole applications to meet the requirements of long-range detection in underground wellbore spaces. Under the structural constraints of limited borehole spaces, the system integrates several key components: an electromagnetic pulse-transmission circuit based on adaptive passive constant voltage clamping, multi-channel reception and master control circuits, three-component transmitting coil, and low-noise three-component magnetic field sensors. The detection system, thus, designed and developed has undergone system integration and experimental testing. Test results demonstrate that the system achieves optimized control of high-power pulsed current excitation with fall-edge turn-off, three-component dynamic electromagnetic signal transmission, multi-channel high-precision acquisition/storage of received signals, and data communication. The overall structure and performance indicators meet the requirements of time-domain electromagnetic detection in borehole environments. Thus, this research holds significant exploratory and practical potential for promoting and applying time-domain electromagnetic detection technology in borehole applications.