| 摘要 |
An apparatus for shaping boreholes used in seismic operations. A drill body (20) is attached to a drill bit (14) and is movable in axial and rotational directions. Selective operation of the drill body (20) causes a moveable sleeve (30) to operate a reaming bit (26) to extend through a drill body port (32) and into contact with the borehole wall. A cover (34) seals the portion of the port not covered by the reaming bit (26) to prevent loss of a transport fluid within the drill (20) body and to prevent drill cuttings from entering the drill body interior. The cover can be integrated within the moveable sleeve (30) or can comprise a separate component. |
