Calculation and Application of Apparent Resistivity in the Frequency Domain by TFEM

The time-frequency electromagnetic method (TFEM) is a controllable source electromagnetic method applied to oil and gas exploration. In traditional TFEM, the amplitude and phase of the electric field are used to correct the data in the frequency domain. It also contains information about the parameters of the observation system; therefore, it is challenging to directly correct the data, which affects the efficiency and precision of data processing. This study introduces the generalized apparent resistivity defined by the horizontal current field source and obtains the apparent resistivity in the frequency domain of a TFEM by combining the characteristics of the TFEM emitter and an observation system. The feasibility of the proposed method was verified by analyzing the characteristics of the electric field amplitude and apparent resistivity of the primary observation parameters, such as the offset and launch distance. The calculation of apparent resistivity in the frequency domain of TFEM and research based on the model provide scientific references for the design of TFEM exploration and data processing.