A METHOD OF AND A DEVICE FOR DETERMINING OPERATIONAL PARAMETERS OF A COMPUTATIONAL MODEL OF BOREHOLE EQUIPMENT, AN ELECTRONIC CONTROLLER AND BOREHOLE EQUIPMENT.

摘要

A method of and a device for computer controlled determination of operational parameters of a computational model of borehole equipment for drilling a borehole in an earth formation. The borehole equipment comprising a rotational drive system, a drill string having a bottom hole assembly and a top end coupled to the rotational drive system, and a speed controller for controlling rotational drive speed of the drive system. The drive system is controlled such that a torque provided by the drive system while driving the drill string is varied over a time period. From the varying torque and rotational top end drive speed of the drill string an estimated torque-speed transfer function is obtained and matched with a torque-speed transfer function computed from the computational model of the borehole equipment. The operational parameters are determined from the matched estimated torque-speed transfer function and the computed torque-speed transfer function.