US 5,145,017 AGranted

Kerf-cutting apparatus for increased drilling rates

AssigneeExxon Production Research Company

InventorsJesse L. Holster, Roy D. Estes, Jack Castle, Paul G. Parys

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Abstract

An improved earth drilling bit and method that cuts at least one annular kerf ahead of at least one rolling cutter and provides for rock chip removal and bit cooling thereby increasing drilling rate and bit performance. One embodiment of the invention includes a bit body having a lower end forming an annular kerf cutter for cutting an outer annular kerf, an inner drill member positioned concentrically within the bit body having a lower end forming an annular kerf cutter for cutting an inner annular kerf, and at least one rolling cutter mounted to the bit body and extending from the interior of the outer kerf cutter to the longitudinal axis of the drill bit. Other embodiments include a chipway port defined by the drill bit for channeling rock chips away from beneath the bit; baffles for directing and accelerating drilling fluid flow; cutting edges having connecting webbs providing egress for rock chip and drilling fluid; and slots extending along the bit body for reducing surge and swab pressure.

Claims14

Dependent claims

A drill bit comprising:

(a) a bit body having an upper end and a lower end, said lower end having an outer kerf cutter with cutting edges for cutting an outer annular kerf on rotation of the drill bit;
(b) an inner drill member positioned concentrically within said bit body having an upper end connected to said bit body and a lower end having an inner kerf cutter with cutting edges for cutting an inner annular kerf positioned within the outer annular kerf on rotation of the drill bit;
(c) at least one rolling cutter attached by mounting means to said bit body in a manner to permit rotation relative to the mounting means and extending from the interior of the outer kerf cutter to the longitudinal axis of the drill bit, said rolling cutter having cutting edges wherein lowermost cutting edges are positioned above cutting edges of said inner and outer kerf cutters to remove material between said inner kerf cutter and said outer kerf cutter and material within said inner kerf cutter;
(d) a drilling fluid conduit disposed within said drill bit for delivering drilling fluid to said inner and outer kerf cutters and said rolling cutter, said conduit separately discharging fluid to regions bounded between and within said inner and outer kerf cutters;
and
(e) means for connecting the upper ends of said bit body and drilling fluid conduit to a string of drill pipe.

3 more elements

A drill bit comprising:

(a) a bit body having an upper end and a lower end, said lower end having an outer kerf cutter with cutting edges for cutting an outer annular kerf on rotation of the drill bit;
(b) an inner drill member positioned concentrically within said bit body having an upper end connected to said bit body and a lower end having an inner kerf cutter with cutting edges for cutting an inner annular kerf positioned within the outer annular kerf on rotation of the drill bit;
(c) at least one rolling cutter attached by mounting means to said bit body in a manner to permit rotation relative to the mounting means, said rolling cutter having cutting edges wherein lowermost cutting edges are positioned above cutting edges of said inner and outer kerf cutters to remove material between said inner kerf cutter and said outer kerf cutter and material within said inner kerf cutter;
(d) at least one chipway port formed by said bit body and inner drill member extending from within said inner drill member through said inner drill member and bit body to an outer surface of the bit body for channeling rock chips away from beneath the bit;
(e) a drilling fluid conduit disposed within said drill bit for delivering drilling fluid to said inner and outer kerf cutters and said rolling cutter, said conduit separately discharging fluid to regions bounded between and within said inner and outer kerf cutters;
and
(f) means for connecting the upper ends of said bit body and drilling fluid conduit to a string of drill pipe.

4 more elements

Dependencies are inferred from the claim text.