Bi-centered drill bit having enhanced casing drill-out capability and improved directional stability
AssigneeSmith International, Inc.
InventorsCarl Hoffmaster, Timothy P. Beaton
Life of this patent
Estimating the term…
Abstract
A bi-center drill bit is disclosed which includes a bit body having pilot blades and reaming blades distributed azimuthally around the body. The blades have cutting elements disposed thereon at selected positions. The body and blades define a longitudinal axis of the bit and a pass-through axis of the bit. In one aspect, selected ones of the pilot blades include thereon, longitudinally between the pilot blades and the reaming blades, a pilot hole conditioning section including gage faces. The gage faces define a diameter intermediate a pilot hole diameter and a pass-through diameter defined, respectively, by the pilot blades and the reaming blades.
Claims41
A bi-center drill bit, comprising:
- a bit body having pilot blades and reaming blades thereon distributed azimuthally around the bit body, selected ones of the blades having cutting elements thereon at selected locations, wherein selected azimuthally corresponding ones of the pilot blades and the reaming blades are formed into unitized spiral structures,
- the bit comprising, longitudinally between the pilot blades and the reaming blades, a pilot hole conditioning section comprising a plurality of gage faces, the gage faces defining a diameter intermediate a pilot hole diameter and a pass-through diameter defined respectively by the pilot blades and the reaming blades, the bit further comprising at least one tapered face intermediate the pilot blades and the gage faces.
A bi-center drill bit, comprising:
- a bit body having pilot blades and reaming blades thereon distributed azimuthally around the body, selected ones of the blades having cuffing elements thereon at selected locations, the body and blades defining a longitudinal axis of the bit and a pass-through axis of the bit;
- and
- at least one bidirectional cutting element attached proximate a line extending between the pass-through axis and the longitudinal axis, the bidirectional cutting element comprising a primary cutting surface oriented to cut earth formation when the bidirectional cutting element moves along the direction of rotation of the bit, the bidirectional cuffing element comprising a secondary cutting surface oriented to cut earth formation when the bidirectional cutting element moves opposite the direction of rotation of the bit.
A bi-center drill bit, comprising:
- a bit body having pilot blades and reaming blades thereon distributed azimuthally around the body, selected ones of the blades having cutting elements thereon at selected locations, the body and blades defining a longitudinal axis of the bit and a pass-through axis of the bit;
- and
- at least one reverse oriented cutting element attached proximate a line extending between the pass-through axis and the longitudinal axis, the at least one reverse oriented cutting element oriented to cut earth formation when the reverse oriented cutting element moves opposite a direction of rotation of the bit.
Dependencies are inferred from the claim text.