| 摘要 |
In one aspect of the present invention, a drill bit has a jack element that is substantially coaxial with an axis of rotation of the drill bit and the jack element has an asymmetrical distal end that extends beyond a working face of the drill bit. A turbine is located within a bore formed in the drill bit and a flow valve is actuated by the turbine. The flow valve is adapted to route a drilling fluid in the bore into a porting mechanism adapted to extend the jack element farther beyond the working surface of the drill bit. The turbine is also adapted to rotate the jack element at variable speeds. |
