Back to results
US 4,733,735 AGranted
Rotary drill bits
AssigneeNL Petroleum Products Limited
InventorsJohn D. Barr, John M. Fuller, Malcolm R. Taylor
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeNL Petroleum Products Limited
InventorsJohn D. Barr, John M. Fuller, Malcolm R. Taylor
Estimating the term…
A rotary drill bit comprises a bit body having a leading face and a gauge region, a number of blades on the leading face of the bit body, and a number of cutting elements mounted along each blade. A passage in the bit body supplies drilling fluid to nozzles in the leading face of the bit body for cooling and cleaning the cutting elements. Each nozzle is so oriented, and the surface of the bit body in the region in front of each blade is so shaped, as to promote a vortex flow of drilling fluid around said region, with part of the periphery of the vortex extending across the cutting elements on the blade, so that fluid in the periphery of the vortex passes across the cutting elements mounted on each blade before escaping through an exit channel in the gauge region.
A rotary drill bit comprising a bit body providing a leading face, a gauge region, and an annulus on the side of the gauge region remote from the leading face, a number of blades on the leading face, each blade having an outer surface which, in use, faces the surface of the formation being drilled and a front surface facing in the direction of normal forward rotation of the bit, a number of cutting elements mounted along each blade, a delivery passage in the bit body for supplying drilling fluid to a number of openings in the leading face of the bit, and at least one exit passage for returning said drilling fluid past the gauge region to the annulus, at least one of the aforesaid openings being located in a region adjacent the front surface of a blade which region is bounded, when the bit is in use, partly by a surface portion of the bit body and partly by a surface portion of the formation being drilled, at least part of said surface portion of the bit body which defines the aforesaid region being smoothly and concavely curved and the cutting elements being so disposed that said surface portion of the formation being drilled is also concavely curved, whereby said region is enclosed by a continuous periphery without re-entrant portions, the opening being so oriented with respect to the said surface portions as to promote a vortex flow of drilling fluid around said region, with part of the periphery of the vortex extending across the cutting elements on the blade, said exit passage being so located that fluid may escape from the periphery of the vortex into said exit passage and thence to said annulus.
A rotary drill bit comprising a bit body providing a leading face, a gauge region, and an annulus on the side of the gauge region remote from the leading face, a number of blades on the leading face, each blade having an outer surface which, in use, faces the surface of the formation being drilled and a front surface facing in the direction of normal forward rotation of the bit, a number of cutting elements mounted along each blade, a delivery passage in the bit body for supplying drilling fluid to a number of openings in the leading face of the bit, and at least one exit channel formed in the outer surface of the gauge region for returning said drilling fluid past the gauge region to the annulus, at least one of the aforesaid openings being located in a region adjacent the front surface of a blade which region is bounded, when the bit is in use, partly by a surface portion of the bit body and partly by a surface portion of the formation being drilled, the opening being so orientated with respect to the said surface portions as to promote a vortex flow of drilling fluid around said region, with part of the periphery of the vortex extending across the cutting elements on the blade, at least a portion of the vortex flow over said surface portion of the formation being in a direction outwardly away from the central axis of rotation of the drill bit, whereby the fluid in the vortex reaches the outer periphery of the drill bit immediately after having passed outwardly across the cutting elements, there being provided an exit channel adjacent the front surface of the blade so that fluid may escape directly into said exit channel from the periphery of the vortex after having passed across the cutting elements, part of said surface portion of the bit body which is adjacent said exit channel being inclined inwardly so as to face partly towards the longitudinal axis of rotation of the drill bit.
Dependencies are inferred from the claim text.