Abstract: A dynamometric measuring device for a drill pipe which includes, firmly attached to the rotating pipe, sensors disposed in a groove on the pipe and electronics for conditioning the signals supplied by the sensors. The measurement signals are transmitted by a commutator-fixed brush assembly to a fixed, non-rotating part. By providing follower-amplifiers of very low output impedance on the commutator, rotating, portion of the assembly and follower-amplifiers of very high input impedance on the fixed brush side of the assembly, the transmission of signals is carried out at zero current. To assure high quality signal analysis, a separation circuit on the fixed brush side of the assembly separates the DC and AC components of the signal prior to transmission to the surface.

Abstract: A method for transmitting data from the bottom of a well to the surface is disclosed. The method includes measuring data indicative of at least one drilling condition at the bottom of a well, transmitting into a stream of drilling mud injected into a well pipe string a series of encoded pressure pulses representative of the data measurement, and detecting the encoded pulses at the surface using a pressure sensor which is in communication with the stream of drilling mud as it is being injected into an inlet of the pipe string. The method also includes, as a way of improving data detection, using a surface sensor to measure vibrations in the pipe string which are generated as a result of the propogation of the encoded pulses through the drilling mud.