Measurement of sensor signal to detect noise reduction indicating a drilling event such as shutdown of mud pumps

摘要

A method for determining a drilling event includes measuring a signal 200 from a sensor over a first selected time interval 201, measuring the signal from the sensor over a second time interval 202 and determining if a noise is reduced in the second signal. The presence of noise may be indicative of whether mud pumps in the borehole are switched on or off. The advantage of determining when mud pumps are switched off is that more accurate surveys or measurements may be made during this quiet period. Alternatively, a signal from a sensor may be transformed into power versus frequency data and a determination made whether the mud pump is operating based on a power signal at an operating frequency of a mud pump. The sensor may be a pressure sensor, a magnetometer or an accelerometer.