| 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 b it (2), identifying events (k1, k2) at the drill bit, determining a plurality o f relative positions of the drill bit, and determining, based at least partly on a starting position ( ) and a sum of the relative positions, an absolute position of the drill bit. The method further comprises determining a positi on of the drill bit at a second event (k2) in relation to a position of the dri ll bit at a first event (k1), and determining a second seismic wave propagation velocity ( ) 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).
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