| 摘要 |
A method for mitigating stick-slip oscillations in borehole equipment while drilling a borehole in an earth formation is described. The borehole equipment is modelled by a computational model for computer simulation. The model has elements representing a particular mechanical and physical behavior of the borehole equipment. In a simulated stick mode of the borehole equipment, physical quantities are loaded to the elements, which quantities represent an initial state of the borehole equipment prior to a transition from stick mode to slip mode. From a simulation of such transition, a time response of rotational speeds of a drive system and bottom hole assembly of the borehole equipment is recorded and a lower limit of the rotational speed of the drive system is determined for which the rotational driven speed of the bottom hole assembly is zero. |
