ANALYZING TOOLFACE VELOCITY TO DETECT DETRIMENTAL VIBRATION DURING DRILLING

摘要

A downhole drilling vibration analysis involves measuring orientation data in at least two orthogonal axes downhole while drilling with a drilling assembly. For example, two orthogonal magnetometers can be used. A toolface of the drilling assembly is determined using the measured sensor data, and velocity (RPM) values for the toolface for a plurality of revolutions of the drilling assembly are determined. From these determined values, a coefficient of variation for the toolface velocity (RPM) values for the revolutions of the drilling assembly is calculated. When a pattern in found in the toolface velocity (RPM) and/or the calculated coefficient of variations exceed one or more thresholds, the processing device determines that detrimental vibrations are occurring in the drilling assembly.