SIGNAL TEST OF WIRELESS ELECTROMAGNETIC METHOD(WEM)

The wireless electromagnetic method is a new geophysical method developed in recent years. It can be applied to resources, energy and deep engineering geological exploration. Its characteristic is that two directions long bipole near-south-north and near-east-west are established in high-resistance areas. With hundreds of kilometers of emission sources, high-power electromagnetic signals can cover the whole country. After the project of transmitter station being completed at the end of November 2015, the first signal test was carried out in the Renqiu Basin of the North China Oilfield, which is 960 kilometers away from the transmitter source. The signal was collected by high-precision acquisition system, and then the frequency spectrum was obtained by performing segmentation spectrum transformation. At last, the transmitted signal was evaluated through analyzing the signal-to-noise ratio and spectrum amplitude. Before the test, the optimal transmit duration was determined by a few uniformly distributed frequencies to save time. Other frequencies transmit duration can be obtained by interpolation. Through experiments, the electromagnetic field signal was successfully detected. When the frequency is greater than 0.353 78 Hz with east-west bipole source, and the frequency is higher than 1.4151 Hz with north-south bipole, source, the signal-noise-ratio is greater than 3 and considered being measurable. The test showed that the transmitter station can transmit effective signals, and other tests and joint test studies could be carry out in the whole country.