| 摘要 |
<p>A system is disclosed for transmitting information during a borehole drilling operation wherein a section of the drill string near the drill bit is utilized as a transmitting element of an electromagnetic wave propagation system. A receiving system at the surface uses a section of the drill string as one electrode and a metallic ring or ring of probes which penetrate the earth's surface at a given radius from the drill string as another electrode between which signal voltages are detected. In another embodiment, the receiving system comprises metallic rods at the surface which extend radially from the drill string. Signal currents induced in these radially extending rods are detected by a receiver coupled between the rods and the drill string.</p> |
