Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B10/00—Drill bits
  • E21B10/46—Drill bits characterised by wear resisting parts, e.g. diamond inserts
  • E21B10/56—Button-type inserts
  • E21B10/567—Button-type inserts with preformed cutting elements mounted on a distinct support, e.g. polycrystalline inserts
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B10/00—Drill bits
  • E21B10/46—Drill bits characterised by wear resisting parts, e.g. diamond inserts
  • E21B10/56—Button-type inserts
  • E21B10/567—Button-type inserts with preformed cutting elements mounted on a distinct support, e.g. polycrystalline inserts
  • E21B10/5673—Button-type inserts with preformed cutting elements mounted on a distinct support, e.g. polycrystalline inserts having a non planar or non circular cutting face

Definitions

• This invention is in the field of tools used downhole, in oil or gas wells, to mill or otherwise cut metal objects in the borehole.
• Background Art In the drilling, completion, or re-work of an oil or gas well, it often becomes necessary to cut into or through a metal object which is located downhole in the well bore. This can be required, for instance, in cutting through the wall of a well casing, removing a packer, or milling away some other metal obstruction which may be present in the borehole. This type of cutting or milling operation is very different from the type of metal cutting operations typically found in a machine shop environment.
• the downhole metal cutting operation involves the rotation of a very large tool by a very heavy workstring, by comparison with the typical machine shop operation.
• the downhole cutting operation itself involves a great deal of vibration and even severe impact, between the cutting tool and the metal object being cut. In fact, much of the force of any such impact or vibration is typically brought to bear directly on the cutting insert or inserts which are mounted on the cutting face of the downhole cutting tool.
• These cutting inserts are essentially the "teeth" of the cutting tool. They are typically made of a very hard material, such as tungsten carbide. The operator can not closely observe the downhole cutting operation and monitor the condition of the cutting insert or inserts.
• the machine shop operator can closely observe the cutting operation as it progresses, and he can change the cutting insert regularly as its cutting surfaces degrade. Stopping the operation in the machine shop is typically significantly cheaper than pulling a downhole tool from the well bore and checking or changing the tool out. This means that the typical machine shop operation is always done with a basically fresh cutting insert in good condition.
• the downhole operator on the other hand, must simply rotate the workstring and rely upon fairly remote indicators of the performance of the tool, such as vibration and rate of penetration, to judge the progress of the cutting operation. As a result, as the cutting operation continues, the cutting insert on the face of the cutting tool usually wears away and disintegrates.
• the insert can not cut effectively after having its original cutting edge worn away, the insert will not be an effective part of the tool, and it can even impede the action of nearby cutting inserts, by acting as a bearing surface, rather than as a cutting surface. It is also known to provide a chip breaking feature on the forward face of a cutting insert for use in the downhole environment, which causes the insert to break off metal chips from the work piece at short lengths, allowing the chips to be more easily removed from the well bore by the flow of drilling fluid. So, as wear progresses across the insert face, through the chip breaking feature, the insert might cease to break off short chips and begin to produce long, thin metal turnings.
• the present invention in summary, is a downhole cutting insert which has one or more lands on its cutting face, interspersed with one or more beveled surfaces, creating a robust cutting face on the insert.
• the juxtaposition of bevels with lands causes the insert to break off metal chips from the work piece at short lengths, allowing the chips to be more easily removed from the well bore by the flow of drilling fluid.
• Use of alternating multiple bevels and lands allows the insert to continue to effectively form short metal chips, even as the forward face and the edge of the insert gradually degrade.
• Figure 1 is an elevation view of a downhole cutting tool which can incorporate a cutting insert according to the present invention
• Figure 2 is a top or front elevation view of a first embodiment of a cutting insert according to the present invention
• Figure 3 is a top or front elevation view of a second embodiment of a cutting insert according to the present invention
• Figure 4 is a partial axial section view of a third embodiment of a cutting insert according to the present invention
• Figure 5 is a partial axial section view of a.
• a cutting insert according to the present invention can be mounted on a cutting tool 10 designed for use in cutting metal objects downhole, in an oil or gas well.
• the cutting tool 10 can be a pilot mill, junk mill, casing cutter, window mill, or any other type of downhole cutting tool.
• the cutting tool 10 has a tool body 12, which is adapted to mount to a work string WS.
• the tool body 12 has at least one cutting feature, such as the blades 14, attached thereto or formed thereon.
• Each cutting feature or blade 14 has at least one cutting insert 20 mounted on a cutting face 16 thereof, and oriented to face in the direction 18 in which the blades 14 and the cutting inserts 20 will advance when the cutting tool 10 is rotated. Advancement in the direction 18 will cause the cutting inserts 20 to advance toward and into the downhole metal object or work piece (not shown).
• the cutting inserts 20 can take various shapes, some of which will be designated as 20, 20A and 20B in the Figures discussed below. Other shapes can also be used without departing from the spirit of the present invention, as long as they exhibit the features described below.
• FIG 2 shows the forward or front elevation of a round or cylindrical cutting insert 20A, oriented in the drawing the same as the orientation of the cutting inserts 20 on the right hand blade 14 in Figure 1.
• the cutting insert 20 A has at least one land 22 A and at least one bevel or beveled surface 24A, with a first land 22A being located immediately next to the original leading edge 28A of the cutting insert 20A. Where present, successive lands 22A and bevels 24A are alternatingly arranged from the leading edge 28A toward the axis A of the cutting insert 20A.
• the cutting insert 20A is shown with three lands 22A and three bevels 24A, but it can have any number of each.
• the cutting insert 20A can also have a surface 26A substantially orthogonal to the axis A, on the front face of the insert 20A.
• the cutting insert 20 can also have a rectilinear shaped body, such as the insert 20B.
• the cutting insert 20B is shown oriented in the drawing the same as the orientation of the cutting inserts 20 on the right hand blade 14 in Figure 1. Where a rectilinear insert is discussed herein, it should be understood that a square or otherwise rectangular insert can be intended.
• the cutting insert 20B has at least one land 22B and at least one bevel or beveled surface 24B, with a first land 22B being located immediately next to the original leading edge 28B of the cutting insert 20B. Where present, successive lands 22B and bevels 24B are alternatingly arranged from the leading edge 28B toward the axis of the cutting insert 20B.
• the cutting insert 20B is shown with three lands 22B and three bevels 24B, but it can have any number of each.
• the cutting insert 20B can also have a surface 26B substantially orthogonal to the axis, on the front face of the insert 20B.
• FIG 4 shows the most basic illustration of the features of the lands 22 and bevels 24 on the inserts 20 shown in Figures 2 and 3, or on any insert 20 according to the present invention.
• the insert 20 has a solid body.
• Each land 22 is a substantially flat surface which is substantially orthogonal to the axis of the cutting insert 20.
• Each land can be, more specifically, angled between approximately 75 degrees and approximately 90 degrees relative to the insert axis. It can be seen that, on the round insert 20A shown in Figure 2, the land 22A would be a substantially planar, annular, surface, substantially or nearly orthogonal to the axis of the cutting insert 20A.
• the land 22B would be a substantially planar, rectangular or otherwise rectilinear, surface, substantially or nearly orthogonal to the axis of the cutting insert 20B.
• Each bevel 24 is angled forward, or in the direction 18 of rotation, above or forward of the outwardly adjacent land 22 by a distance 32, at an angle 34 from a plane orthogonal to the axis of the cutting insert 20.
• the angle 34 can be between approximately 20 degrees and approximately 70 degrees, with a preferred angle of approximately 45 degrees.
• the bevel 24 is also angled relative to the axis of the cutting insert 20, by an angle between approximately 20 degrees and approximately 70 degrees, with a preferred angle of approximately 45 degrees.
• a representative raised distance 32 could be on the order of approximately 0.015 inch. It can be seen that, on the round insert 20A shown in Figure 2, the bevel 24A would be a substantially frusto-conical surface, angled relative to the axis of the cutting insert 20A. It can further be seen that, on the rectilinear insert 20B shown in Figure 3, the bevel 24B would be a substantially planar, rectangular or otherwise rectilinear, surface, angled relative to the axis of the cutting insert 20B.
• the cutting insert 20 can also have a relief angle 36 between approximately 3 degrees and approximately 9 degrees, which promotes the cutting action of the edge 28 into the work piece.
• a rear face 40 is provided for mounting the cutting insert 20 on the cutting feature or blade 14 of the cutting tool 10.
• each bevel 24 rises above its outwardly adjacent land 22 terminates the bevel 24 either in the surface 26 or in an inwardly adjacent land 22, as shown in Figure 5, in which the cutting insert 20 has two lands 22 and two bevels 24.
• This embodiment has been found to be somewhat more robust in resisting impact than the single land, single bevel embodiment shown in Figure 4.
• the cutting insert 20 can have three sets of lands 22 and bevels 24, or even more. Each land can be relatively narrow, for example, in the range of approximately 0.004 inch to approximately 0.060 inch.
• the cutting insert 20 can also have other features on its leading face 26, such as a depression 38.

Landscapes

• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Mining & Mineral Resources (AREA)
• Geology (AREA)
• Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• Crystallography & Structural Chemistry (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Milling Processes (AREA)
• Cutting Tools, Boring Holders, And Turrets (AREA)
• Earth Drilling (AREA)
• Drilling Tools (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Citations (3)

Family Cites Families (3)

• 2004
  • 2004-09-28 US US10/954,106 patent/US20050109546A1/en not_active Abandoned
  • 2004-11-18 WO PCT/US2004/038712 patent/WO2005054621A1/en active Application Filing
  • 2004-11-18 CN CNA2004800397078A patent/CN1946916A/zh active Pending
  • 2004-11-18 RU RU2006122639/03A patent/RU2006122639A/ru not_active Application Discontinuation
  • 2004-11-18 CA CA002546938A patent/CA2546938A1/en not_active Abandoned
  • 2004-11-18 AU AU2004295689A patent/AU2004295689A1/en not_active Abandoned
  • 2004-11-18 GB GB0611242A patent/GB2424019B/en not_active Expired - Fee Related
• 2006
  • 2006-06-02 NO NO20062558A patent/NO20062558L/no not_active Application Discontinuation

Patent Citations (3)

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