A METHOD OF AND A DEVICE FOR ESTIMATING DOWN HOLE SPEED AND DOWN HOLE TORQUE OF BOREHOLE DRILLING EQUIPMENT WHILE DRILLING, BOREHOLE EQUIPMENT AND A COMPUTER PROGRAM PRODUCT.

摘要

A method of and a device, borehole drilling equipment and a computer program product for estimating at least one of down hole speed and down hole torque of borehole drilling equipment while drilling a borehole in an earth formation. The borehole equipment comprising a rotational drive system, a drill string, a bottom hole assembly comprising a drill bit, a top end coupled to the rotational drive system, and a speed controller arranged for controlling rotational top end drive speed by commanding a top end drive torque. The method being performed in a computer based on a two-port spectral domain transfer matrix computational model of the borehole drilling equipment (50). While drilling, rotational top end drive speed and top end drive torque are obtained (54) and down hole speed and down hole torque of the borehole drilling equipment are calculated (55) by reducing spectral bandwidth of and applying a time delay term to