To address the difficulty in identifying liquid-level reflection points arising from the susceptibility of dynamic liquid-level echoes to interference from downhole operating conditions during drilling, this study proposes a method for identifying and extracting dynamic liquid-level signals in the time–frequency (T–F) plane using the synchrosqueezing generalized phase-shifting S-transform (SS-GPST). The method introduces adjustable parameters to regulate T–F resolution and phase-shift correction to improve phase consistency between the S-transform and synchrosqueezing reassignment, thereby obtaining high-resolution T–F distributions of dynamic liquid-level signals. On this basis, two-dimensional Gaussian filtering is applied in the T–F plane to smooth and suppress background noise. The T–F region containing the liquid-level reflection signal is then extracted for inverse-transform reconstruction, and the liquid-level reflection point and its occurrence time are determined from the position at which a pronounced abrupt change first occurs in the reconstructed waveform. The results show that, compared with the T–F distributions obtained using the synchrosqueezing S-transform (SS-ST), synchrosqueezing phase-shifting S-transform (SS-PST), and synchrosqueezing generalized S-transform (SS-GST), the SS-GPST achieves higher T–F resolution and preserves more local details. The measurement error of the SS-GPST does not exceed 1.2 m, and its relative error remains within 0.083%, confirming its ability to identify and extract dynamic liquid-level signals more accurately under complex interference conditions.

Triaxial induction logging is particularly outstanding in identifying reservoir parameters including anisotropic strata, inclined boreholes and horizontal wells. However, the coplanar systems follow the traditional induction method of using a shielding coil to offset the direct coupling. This method results in severe horns in the coplanar coil response, which makes it more difficult to evaluate the water (oil) saturation of the reservoir. In this study, we used an analytic method to derive the magnetic field in a finite-thickness anisotropic medium by applying tangential continuity of the electric and magnetic field strengths, introducing the magnetic vector potential and Bessel functions. The response model influenced by different parameters was established. Under the same environmental parameters, the measurement range of the vertical and horizontal conductivities was larger than that of the traditional coplanar system. The apparent conductivity of the target layer was closer to the true value of the vertical conductivity in the layered strata, with an accuracy improvement of 78.9%. Furthermore, the improved coplanar system mechanism was revealed by analyzing the spatial distributions of eddy currents and the magnitudes of the magnetic fields generated. Finally, we designed an experimental device for a coplanar sensing system. Under the same parameters, the received signals of the improved coplanar system were greater than those of the traditional coplanar system in the air, which laid a foundation for the quantitative evaluation of stratigraphic anisotropy response characterization and inversion.