Kerf-cutting apparatus and method for improved drilling rates
This patent describes a drill bit. It comprises: a bit body having an upper end and a lower end, the lower end forming an annular cutter for cutting an outer annular kerf on rotation of the drill bit; an inner drill member positioned concentrically within the bit body having an upper end connected to the bit body and a lower end forming an annular cutter for cutting an inner annular kerf positioned concentrically within the outer annular kerf on rotation of the drill bit; a first plurality of rotary drilling members attachedly arranged between the bit body and inner drill member for rotation relative to the bit body and inner drill member, having lowermost cutting edges positioned above lowermost cutting edges of the annular cutter of the bit body and inner drill member to remove material between the outer and inner annular kerfs; a second plurality of rotary drilling members attachedly arranged within the inner drill member for rotation relative to the inner drill member, having lowermost cutting edges positioned above lowermost cutting edges of the annular cutter of the inner drill member to remove material surrounded by the inner annular kerf; a drilling fluid conduit; and means for connecting the upper ends of the bit body and drilling fluid conduit to a string of drill pipe.
- Assignee:
- Exxon Production Research Co., Houston, TX
- Patent Number(s):
- US 4892159; A
- Application Number:
- PPN: US 7-277166A
- OSTI ID:
- 7181193
- Country of Publication:
- United States
- Language:
- English
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