US 4,892,159 AGranted

Kerf-cutting apparatus and method for improved drilling rates

AssigneeExxon Production Research Company

InventorJesse L. Holster

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Abstract

An earth drilling bit that cuts concentric annular kerfs ahead of primary drilling means and thereby increases drilling rate. The bit includes a bit body having a lower end forming an annular cutter for cutting an outer annular kerf, an inner drill member positioned concentrically within the bit body having a lower end forming an annular cutter for cutting an inner annular kerf, a plurality of rotary drilling members attachedly arranged between the bit body and inner drill member positioned so lowermost cutting edges are above lowermost edges of the annular cutters of the bit body and inner drill member for removing material between the outer and inner annular kerfs, and plurality of drilling members attachedly arranged within the inner drill member positioned so lowermost cutting edges are above lowermost edges of the annular cutter of the inner drill member for removing material within the inner annular kerf.

Claims35

Dependent claims

A drill bit comprising:

(a) a bit body having an upper end and a lower end, said lower end forming an annular cutter 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 forming an annular cutter for cutting an inner annular kerf positioned concentrically within the outer annular kerf on rotation of the drill bit;
(c) a first plurality of rotary drilling members attachedly arranged between said bit body and inner drill member for rotation relative to said bit body and inner drill member, having lowermost cutting edges positioned above lowermost cutting edges of the annular cutter of said bit body and inner drill member to remove material between the outer and inner annular kerfs;
(d) a second plurality of rotary drilling members attachedly arranged within said inner drill member for rotation relative to said inner drill member, having lowermost cutting edges positioned above lowermost cutting edges of the annular cutter of said inner drill member to remove material surrounded by the inner annular kerf;
(e) a drilling fluid conduit disposed within said drill bit for delivering drilling fluid to said annular cutters and said first and second plurality of rotary drilling members, said conduit separately discharging fluid to said first and second plurality of rotary drilling members;
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

A drill bit comprising:

(a) a bit body having an upper end and a lower end, said lower end forming an annular kerf-cutting skirt for cutting an outer annular kerf on rotation of the drill bit, said skirt having a generally saw-tooth configuration, a plurality of face plates comprising diamonds attached to cutting faces of the skirt, and defining outlet passages between adjacent skirt teeth for removal of cuttings from below the bit, said bit body defining spaced apart grooves extending longitudinally from the annular kerf-cutting skirt toward the upper end of said bit body for removal of cuttings and drilling fluid from below 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 forming an annular kerf-cutting skirt for cutting an inner annular kerf positioned concentrically within the outer annular kerf on rotation of the drill bit, said skirt having a generally saw-tooth configuration, a plurality of face plates comprising diamonds attached to cutting faces of the skirt and defining outlet passages between adjacent skirt teeth for removal of cuttings from below the bit;
(c) three spaced apart cutting wheels attachedly arranged between said bit body and inner drill member for rotation relative to said bit body and inner drill member to remove material between the outer and inner annular kerfs, said cutting wheels having cutting teeth comprising tungsten carbide with lowermost cutting teeth positioned above lowermost cutting edges of the skirt teeth and below uppermost edges of the outlet passages of said bit body;
(d) three spaced apart roller cone cutters attachedly arranged within said inner drill member for rotation relative to said inner drill member to remove material surrounded by the inner annular kerf, said roller cone cutters having a plurality of cutting carbide teeth protruding from the surface of said roller cone cutters with lowermost cutting teeth positioned above lowermost cutting edges of the skirt teeth of said inner drill member and below the uppermost edges of the outlet passages of said inner drill member;
(e) a drilling fluid conduit disposed within said drill bit for delivering drilling fluid to said cutting wheels, roller cone cutters, and annular kerf-cutting skirts, said conduit comprising separate passageways discharging separately above and between each of said spaced apart cutting wheels and roller cone cutters;
(f) means for connecting said drilling fluid conduit and the upper end of said bit body to a string of drill pipe.

3 more elements

Dependencies are inferred from the claim text.