| 摘要 |
<p>Communications along the interior of a drill string are effected, for example while the drillstring is drilling a borehole and is positioned within the borehole. Wireless signals are launched within the drill string in a manner to give rise to at least one electromagnetic propagation mode arising from the drill string functioning as a waveguide. Adaptive frequency hopping is also applied, in order to identify and utilise spectral regions which propagate most effectively along the interior of the drill string waveguide. This invention recognises that a wireless communications channel within the drillstring may thus be established, even despite propagation mode conversion between narrow and broad sections of the drillstring, multi-mode propagation within broad sections, and single or multi-mode reverberations in each section of the drill string.</p> |
