A method for determination of bit whirl

摘要

The present invention is directed to a method for determining the existence of bit 14 whirl, the location of a bottom hole assembly (BHA) 12 and the diameter of a borehole 10 at the location of the BHA 12 to prevent tool failure. The method includes steps of measuring the acceleration of a bottom hole assembly; measuring rotational speed of said bottom hole assembly and calculations based on the values received from the above measurements, the existence and identification of a whirl condition within the bottom hole assembly. Also disclosed is equations for the calculating of both forward and backward whirl. The method can also make use of orthogonally positioned accelerometers and magnetometers to determine the values required. Graphical representations can also be constructed for the values mentioned above and for the radii and diameters of the borehole 10 and tool bit 14 respectively.