Bi-center bit adapted to drill casing shoe
AssigneeDiamond Products International, Inc.
InventorsCoy M. Fielder, Rogerio H. Silva
Life of this patent
Estimating the term…
Abstract
The invention is directed to a bi-center drilling tool adapted to fit within and drill through a casing shoe without damage to the surrounding casing. In one embodiment, the tool comprises a bit body having a proximal and a distal end where the distal end defines a pilot bit and an intermediate reamer section, where each the pilot and reamer sections define a bit face including primary and secondary cutting blades and cutting elements disposed on said blades. In this embodiment, the cutting or wear elements disposed on the one or more cutting blades which extend to or are proximate to the pass-through gauge define a selected angle between the line of contact on the cutting or wear elements and the material to be drilled.
Claims14
A method to fabricate a bi-center bit adapted to rotate about a pass-through axis “B” or a rotational axis “A” where the bi-center bit comprises a bit body having a proximal end and a distal end where the distal end defines a pilot bit section and an intermediate reamer section, where the pilot and reamer sections define a bit face including primary and secondary cutting blades and cutting elements disposed on said blades where each cutting element defines a cutting face, the method comprising the steps of:
- fabricating a cutter profile for the bit about the rotational axis “A”;
- identifying the pass-through axis “B” of the bit;
- fabricating a cutter profile for the bit about the pass-through axis “B”;
- and
- situating selected ones of said cutting elements on the bit face of the pilot and reamer sections such that at least a portion of each cutting element is disposed about substantially all portions of said profiles when the bit is rotated about the rotational and pass-through axes.
A method to fabricate a bit which defines at least two axes of rotation, where the bit includes a bit body defining a proximal end adapted to be coupled to a drill string, a distal end, a pilot section and a reamer section, where both said pilot and reamer sections include one or more cutting blades, the method comprising:
- defining a rotational axis and a pass-through axis of the bit;
- and
- positioning cutting elements on the cutting blades of the pilot and reamer sections such as to create substantially complete cutter overlap when the bit is rotated about either the rotational or pass-through axis.
Dependencies are inferred from the claim text.