Improving the interference zone TFEM data quality by physical de-noising

In recent years, the time-frequency electromagnetic method (hereinafter shortly referred to as TFEM) has been widely used in oil and gas exploration. In practical application, the quality of data directly determines the effect of data inversion. If the external disturbance is significant, the TFEM data apparent resistivity curve may have sudden jump in the high frequency sectionunder the inference by the 50 Hz frequency band, and the traditional filtering means will remove the useful information in the high frequency range, so the simple mathematical de-noising method will increase the data error in high frequency section, thus affecting the shallow inversion accuracy. When the noise in the time frequency electromagnetic data is not statistically normal, the conventional de-noising method becomes less applicable. In this paper, the typical electromagnetic interference in the strong disturbance zone is investigated and analyzed, and the method of applying the physical de-noising method to improve the quality of the time-frequency electromagnetic data in the strong disturbance zone is proposed. The criterion is that the data after the de-noising is physically reasonable. The model test and the application of the measured data show that this method is a reasonable and effective de-noising method.