| 摘要 |
A method and a system for determining the position of a drill bit (2) are presented. The method comprises determining positions of seismic wave detectors (1a-1e, 12a-12d), recording seismic waves generated at the drill bit (2), identifying events (k1, k2) at the drill bit, determining a plurality of relative positions of the drill bit, and determining, based at least partly on a starting positionand a sum of the relative positions, an absolute position of the drill bit. The method further comprises determining a position of the drill bit at a second event (k2) in relation to a position of the drill bit at a first event (k1), and determining a second seismic wave propagation velocity (&ngr;2) between the drill bit and at least one of the detectors (1a), based at least partly on the determined position of the drill bit at the second event (k2). |
