Rotary drill bit
AssigneeCamco International (UK) Limited
InventorsTerry R. Matthias, Nigel Dennis Griffin, Peter Raymond Hughes
Life of this patent
Estimating the term…
Abstract
A rotary drill bit includes cutters arranged in a series of concentric rings, the cutters of one of the rings having a different wear resistance to the cutters of another of the rings with the result that the stability of the drill bit improves with wear. Although the wear resistance is different, the cutters have substantially the same impact toughness.
Claims14
A rotary drill bit comprising a bit body having an axis of rotation, and a plurality of cutters arranged in concentric rings centered on the axis of rotation, the plurality of cutters comprising a first type of cutter of a relatively low abrasion resistance and a second type of cutter of a relatively high abrasion resistance, at least one of the rings consisting of cutters of the first type, at least another of the rings including at least one cutter of the second type, wherein the first type of cutter has substantially the same impact toughness as the second type of cutter, and wherein each cutter of the second type comprises a table of polycrystalline diamond which defines a matrix of interstices containing a catalyzing material, and wherein the interstices close to a working surface of the table contain less catalyzing material than the interstices spaced from the working surface.
A rotary drill bit comprising a bit body having an axis of rotation, and a plurality of blades angularly spaced around the axis of rotation, a plurality of cutters being mounted upon the blades, the plurality of cutters comprising a plurality of cutters of a first type having a relatively low abrasion resistance and a plurality of cutters of a second type having a relatively high abrasion resistance, at least one of the blades having mounted thereon at least one of the cutters of the first type and at least one of the cutters of the second type, wherein each cutter of the second type comprises a table of polycrystalline diamond which defines a matrix of interstices containing a catalyzing material, and wherein the interstices close to a working surface of the table contain less catalyzing material than the interstices spaced from the working surface, and wherein the first type of cutters has substantially the same impact toughness as the second type of cutters.
A rotary drill bit comprising a bit body having an axis of rotation, a plurality of cutters being mounted upon the bit body, the plurality of cutters comprising a first type of cutter and a second type of cutter having a higher abrasion resistance than the first type of cutter, said first type of cutter having substantially the same impact toughness as the second type cutter wherein each cutter of the second type comprises a table of polycrystalline diamond which defines a matrix of interstices containing a catalyzing material, and wherein the interstices close to a working surface of the table contain less catalyzing material than the interstices spaced from the working surface.
Dependencies are inferred from the claim text.