| 摘要 |
<p>Apparatus for transmitting measurement made at the bottom of a borehole to the surface, in the form of pressure pulss applied to the flow of drilling mud, which can be detected at the surface, ois fitted to the lower part of the drill string. It comprises a measuring instrument or depth gauge a device for converting the measurements to corresponding electrical signals, by connection to a source of electrical current by a valve placed in the stream of drilling, mud and serving for the production of pressure pulses.</p> |
