Abstract: An instant acoustic logging method for use in oil drilling is disclosed in which a drill bit arranged at one end of a drill string and rotated in a well is used as the acoustic source. The method comprises the steps of measuring, at the top of the string, the vibration generated therein by the rotating drill bit, sensing acoustic signals from the drill bit at least one point on the ground away from said drill bit, and processing the signals to provide data on the rock around the well. The method comprises an additional preliminary step of processing the vibration measured at the top of the string to determine the nature of the pilot signals from the drill bit, the data on the rock around the well being obtained by comparing the acoustic signals sensed on the ground with the pilot signals from the drill bit.

Abstract: A device for processing and interpreting drilling data is mounted at the lower end of a drill-pipe string located in a drilling well and provided with a drill bit and, measuring assembly. The device is arranged to transmit data from the bottom to the surface, but transmits only abbreviated messages to the surface after interpreting the measurements made by the measuring assembly. A method for implementing the device while transmitting data from the bottom of a drilling well to the surface in the form of abbreviated messages after interpreting the measurements made by the measuring assembly.

Abstract: A method for determining the rotation speed of the drill bit arranged at one end of a rotating drill string. According to the method, the axial acceleration at one point on the drill string is measured, this measurement is processed with a multiplying coefficient which depends upon the point on the drill string where the measurement is taken to determine the rotational speed of the drill bit.