Method and system for analysing the behaviour of a drill string

摘要

The analyser includes a sensor (4) placed above a drilling bit and monitoring its speed. A second sensor (10) is placed on a rod (11) which actuates the bit. Electrical cables make the connection to surface equipment via a rotating adaptor. Additional gauges are provided on the drilling bit to measure the weight on bit, torque, acceleration, temperature and pressure, and magnetic field components. The signal collected from the bit is then analysed to determine the characteristics of the drilling operation. The signal is split into time segments of determined length which are then converted to frequency signals by applying a wavelet transform. The characteristic coefficients of the wavelet are then estimated.