Downhole measurements transmitted to surface - by converting transducer signals into digital drilling fluid pressure pulses

摘要

Appts. transmits information from down a bore-hole to the surface by producing pressure fluctuations in the drilling fluid. The appts. includes a transducer producing a voltage signal as a measure of some physical variable, e.g. temp., a system within a cavity to convert the signal into digital signal which is amplified and used to effect switching of a valve which allows drilling fluid to discharge from the conduit into the bore-hole annulus. This will produce a pressure drop at the outlet of the pump, and this digital variation is detected and converted back to analog.