método para manter uma linha de perfuração e conjunto de perfuração

摘要

A method for maintaining a drilling line including: imparting a feed force from a drill to an asymmetric drill bit; identifying deviation of the asymmetric drill bit from the drilling line; and controlling the feed force imparted to the asymmetric drill bit such that the feed force is not synchronised with rotation of the asymmetric drill bit or is synchronised with rotation of the asymmetric drill bit in response to the asymmetric drill bit following the drilling line or deviating from the drilling line respectively such that deviation from the drilling line is corrected.