| 摘要 |
<p>A method of installing a sensor in a borehole drilled through underground formations, wherein the borehole is drilled with a hollow drill string formed from a series of pipe sections connected end-to-end, a drill bit being positioned at one end of the drill string and having an closure that is operable to provide an opening between the borehole and the inside of the drill string, the method comprising: drilling the borehole to a predetermined depth using the drill string and bit; partially withdrawing the drill string from the borehole so that the drill bit is positioned above the predetermined depth; lowering a sensor inside the drill string by means of a cable; operating the closure so that the sensor can pass out of the drill string into the borehole; and progressively withdrawing the drill string and drill bit from the borehole over the cable so as to leave the sensor in the borehole.</p> |
