Differential sensor measurement method and apparatus to detect a drill bit failure and signal surface operator

摘要

An apparatus and accompanying method for monitoring and reporting downhole bit failure. Individual sensors are placed on a sub which is separate from the drill bit itself, and are powered by a vibration driven power system. The sensor readings are used to compute values which represent the ratios of sensor readings on one sensor in relation to the readings of one or more other sensors. This creates a self-calibrating sensor system that accounts for changes in downhole conditions which might cause sensor readings to fluctuate, but which do not indicate failure.