| 摘要 |
<p>Directional drilling equipment comprises a drill string with a hollow bottom rod (13) connected to a boring tool (11) by means of an obtuse-angle connection piece or "bent sub" (12). In order to restore the verticality of the drilling a vertical borehole section (F) is formed and then a probe (14) equipped with an inclinometer is lowered inside the bottom rod (13). The string is rotated into four angular positions and the inclination values of the probe in each angular position are detected at the depth reached. The string is rotated so as to bring it into an angular position corresponding to the maximum inclination value detected. The string is moved so as to move the boring tool further downwards and the inclination of the probe is detected again in order to check that the verticality has been reached.</p> |
