Abstract: In some blocks of the Ordovician carbonate reservoirs in the Tahe Oilfield, the development has entered the middle and late stages, and the oil-water relationship is extremely complex, with a high risk of drilling. To solve the problem of predicting the distribution of remaining oil, a research and development experiment on detecting remaining oil using time-frequency electromagnetic methods has been carried out in the TH10X well area of the Tahe Oilfield. Aiming at the characteristics of strong heterogeneity in fractured-vuggy carbonate reservoirs, high-quality three-dimensional electromagnetic data have been obtained through the excitation of dual-source electromagnetic fields that are perpendicular to each other and three-dimensional data collection with an array of 100 m×100 m. On this basis, the resistivity-constrained inversion, polarizability-constrained inversion, and differential anomaly extraction have been carried out, and resistivity, polarizability anomalies, and dual-frequency phase differential anomalies in the study area was obtained. Finally, the production data of the actual drilled wells was used for calibration, and the potential areas of remaining oil distribution have been delineated. Later drilling verification has shown that there is abundant remaining oil at the No. 2 potential point, confirming the effectiveness of the method.