ELF-Band Noise Cancel System for Underground Transmission of Electromagnetic-Measurement While Drilling (EM-MWD)
Satoru Inoue, Akio Jitsumori, Kageo Akizuki, Takashi Shimada, Takaaki Maekawa, Teruo Usami, Takafumi Sakai · IEEJ Transactions on Electronics Information and Systems · 2000
In the field of oil or natural gas well drilling, Measurement While Drilling (MWD) is desired for the sake of safe and economical drilling operation. Among them, Electromagnetic-MWD (EM-MWD) has the advantage of higher data transfer rates. However, electromagnetic waves attenuate during propagation in the soil and are received as the weak signals that have been corrupted by environmental noises. The properties of the drilling field noise have been investigated. In order to increase transmission reliability, a new communication method has been established and a real-time adaptive noise canceller (ANC) has been developed. It has been verified by experiments in the drilling fields that the ANC reduces the noise by up to 20 dB and an underground transmission from a depth of 3, 300m has been successfully achieved.