摘要 |
In one aspect of the present invention a drill bit has a jack element with a distal end extending beyond a working face. A porting mechanism within the bore comprises first and second discs contacting along a flat interface. The first disc is attached to a turbine which is adapted to rotate the first disc with respect to the second disc. The discs comprise a first set of ports adapted to align and misalign with each other as the first disc rotates. The first set of ports is adapted to route a drilling fluid to extend the jack element.
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