Influence of coil structure on the distribution of transmitting magnetic field in downhole electromagnetic detection

The electromagnetic method is widely utilized for downhole detection, significantly enhancing the safety and efficiency of oil and gas production due to its sensitivity to resistivity and its capability for non-destructive testing. However, due to the narrow space within the downhole, the azimuthal resolution of downhole detection is not ideal. Based on the finite element method, this paper achieved the forward simulation of magnetic field distribution in three-dimensional wellbore electromagnetic detection. Various structures of the transmitting coil in electromagnetic detection tools were studied and compared, and the impact of the structure of the transmitting coils on their circumferential magnetic field distribution was analyzed. The simulation and analysis results offer valuable insights for accurately and effectively designing the transmitting coils to improve their azimuth resolution.