Abstract: A method and a system for the transmission of information from a well (1; 20) drilled through geological formation layers (3) at least partly cased by metal tubes (4; 23; 24; 31). The method includes the placing in said well of an information transceiver (E) operating by electromagnetic waves created by the injection of an electric signal by a dipole (P1-P2) conductively connected to the metal tubes used for guiding the transmitted waves. In the method, identification takes place of the attenuation of the transmission by certain formation layers (3a, 3b; 25; 30) having a low resistivity and then there is an at least partial electrical insulation of the metal tubes located opposite the low resistivity layers.

Abstract: Seismic waves are recorded twice by a reference sensor (8) above ground and by a sensor (18) located in the drill hole (1). Measurements are synchronized by a clock system, the clock associated with sensor (18) being designed specifically for providing such synchronization in spite of operating conditions prevailing at the bottom of a drill hole (vibrations, shocks, temperature).

Abstract: This invention relates to a device for measuring the flow rate of spoil from a drilling brought to the surface by means of a drilling fluid. The device comprises means of collecting the spoil and means of continuously measuring the weight of spoil collected. The means of collecting the spoil comprise a receptacle in the shape of bucket articulated about a spindle and means of tilting the receptacle in such a way that the bucket is emptied. The measurement means comprise a measuring cell connected to the tilting means in order to measure a stress proportional to the weight of the spoil collected. The invention also relates to a method for the application of a measurement of the spoil flow rate from a drilling.