Bearing elements for drill bits, drill bits so equipped, and method of drilling
AssigneeBaker Hughes Incorporated
InventorMohammad Swadi
Life of this patent
Estimating the term…
Abstract
A rotary drag bit carrying PDC cutters and elongated bearing elements associated with at least some of the PDC cutters on the bit face thereof Lateral positioning and angular positioning of the elongated bearing elements are adjusted so that all portions of an elongated bearing element travel substantially completely within a tubular clearance volume defined by the path through the formation being drilled by a PDC cutter with which that elongated bearing element is associated, the associated PDC cutter being positioned at about the same radius from the bit centerline as the elongated bearing element. A method of drilling and a method of drill bit design are also disclosed.
Claims42
A drill bit for subterranean drilling, comprising:
- a bit body having a centerline and including a leading end for contacting a formation during drilling and a trailing end having structure associated therewith for connecting the drill bit to a drill string;
- at least one cutter secured to the bit body over the leading end at a radial distance from the centerline;
- and
- at least one elongated bearing element over the leading end positioned at about the same radial distance from the centerline as the at least one cutter, the at least one elongated bearing element being dimensioned, positioned and oriented so as any transverse cross-section thereof lies substantially completely within, but at most only partially coincident with an associated transverse cross-section of a path cut in a subterranean formation by the at least one cutter by rotation of the drill bit.
A method of drilling a subterranean formation, comprising:
- disposing a rotary drill bit having a plurality of cutters fixed over a leading end thereof adjacent a subterranean formation to be drilled;
- applying weight and rotating the rotary drill bit to cause the cutters of the plurality to engage the subterranean formation and cut substantially helical paths therein;
- and
- contacting the subterranean formation with elongated bearing elements fixed over the leading end of the rotary drill bit and rotationally trailing at least some of the cutters, the contacting being effected by partial coincidence between each elongated bearing element outer periphery and the surface of each associated substantially helical path cut by each cutter of the plurality in the subterranean formation, such partial coincident contact occurring substantially completely within each associated substantially helical path.
A drilling structure for subterranean drilling, comprising:
- a body having a centerline defining an axis of rotation and including a leading end for contacting a formation during drilling and a trailing end having structure associated therewith for connecting the drilling structure to a drill string;
- at least one cutter secured to the bit body over the leading end at a radial distance from the centerline;
- and
- at least one elongated bearing element over the leading end positioned at about the same radial distance from the centerline as the at least one cutter, the at least one elongated bearing element being dimensioned, positioned and oriented so as any transverse cross-section thereof lies substantially completely within, but at most only partially coincident with an associated transverse cross-section of a path cut in a subterranean formation by the at least one cutter by rotation of said drilling structure.
A method of drilling a subterranean formation, comprising:
- disposing a rotary drilling structure having a plurality of cutters fixed over at least a portion of a leading end thereof adjacent a subterranean formation to be drilled;
- applying weight and rotating the rotary drilling structure to cause the cutters of the plurality to engage the subterranean formation and cut substantially helical paths therein;
- and
- contacting the subterranean formation with elongated bearing elements fixed over the leading end of the rotary drill bit and rotationally trailing at least some of the cutters, the contacting being effected by partial coincidence between each elongated bearing element outer periphery and the surface of each associated substantially helical path cut by each cutter of the plurality in the subterranean formation, such partial coincident contact occurring substantially completely within each associated substantially helical path.
Dependencies are inferred from the claim text.