Patent Application
20190262961
Embodiments of this disclosure relate generally to systems and methods for polishing polycrystalline diamond compacts (“PDCs”). More specifically, disclosed embodiments relate to systems and methods for polishing PDCs using a flowing, pressurized working fluid within an enclosed chamber.
Wellbores are formed in subterranean formations for various purposes including, for example, extraction of oil and gas from subterranean formations and extraction of geothermal heat from subterranean formations. A wellbore may be formed in a subterranean formation using an earth-boring rotary earth-boring tool. The earth-boring tool is rotated under an applied axial force and advanced into the subterranean formation. As the earth-boring tool rotates, the cutters or abrasive structures of the earth-boring tool cut, crush, shear, and/or abrade away the formation material to form the wellbore.
One common type of earth-boring tool used to drill well bores is known as a “fixed cutter” or “drag” bit. This type of earth-boring tool has a bit body formed from a high strength material, such as tungsten carbide or steel, or a composite/matrix bit body, having a plurality of cutters (also referred to as cutter elements, cutting elements, or inserts) attached at selected locations about the bit body. The cutters may include a substrate made of a hard material (e.g., cemented tungsten carbide), and a mass of superhard cutting material (e.g., a polycrystalline diamond table) secured to the substrate. Such cutting elements are commonly referred to as polycrystalline diamond compact (“PDC”) cutters.
With conventional substantially planar PDC cutting elements, a cutting face or leading face of the non-polished PDC might have a surface finish of about 20 μin. (about 0.508 μm) to about 40 μin. (about 1.02 μm) root mean square RMS (all surface finishes referenced herein being RMS), which is relatively smooth to the touch and visually planar (if the cutting face is itself flat), but which includes a number of surface anomalies and exhibits a degree of roughness which is readily visible to one even under very low power magnification, such as a 10× jeweler's loupe. However, an exterior surface of the diamond table may be treated to have a greatly reduced surface roughness. For example, an exterior surface of the diamond table may be polished to a surface roughness of about 0.5 μin. (about 0.0127 μm) RMS, as is disclosed in U.S. Pat. No. 8,919,462.
Additionally, portions of conventional PDC cutting elements may be polished by other methods, such as ion beams or chemicals, although the inherently inert chemical nature of diamond may make the latter approach somewhat difficult for diamond. Further, an exterior surface of the diamond table may be polished by a laser polishing process, as disclosed in United States Patent Publication No. 2009/0114628 A1, published May 7, 2009, to DiGiovanni.
However, PDC cutting elements having more complex geometries, such as those described in U.S. Pat. Nos. 9,617,792 and 9,650,837, may not be effectively polished by conventional polishing methods.
In some embodiments, the present disclosure includes a system for polishing a polycrystalline diamond compact, which may comprise a housing, at least one fluid inlet, at least one fluid outlet, a fluid reservoir, a pump, and fluid conduits. The housing may include internal surfaces defining an enclosed chamber therein. The housing may include a fixture, which may be configured to hold at least one polycrystalline diamond compact therein such that at least a portion of a surface of the polycrystalline diamond compact may be exposed within the chamber. The at least one fluid inlet may lead into the chamber from outside the housing. The fluid outlet may lead out from the chamber from inside the housing. The fluid reservoir may hold a working fluid therein. The pump may produce a flow of pressurized working fluid through the enclosed chamber within the housing and across the at least a portion of a surface of the polycrystalline diamond compact exposed within the chamber. The fluid conduits may define a circular fluid pathway extending from the fluid reservoir to the pump, from the pump to the fluid inlet, and from the fluid outlet to the fluid reservoir.
In other embodiments, the present disclosure includes a method of polishing a polycrystalline diamond compact, which may comprise securing the polycrystalline diamond compact in a fixture, enclosing a least a portion of the polycrystalline diamond compact within a chamber, flowing a pressurized working fluid through the chamber between a chamber inlet and a chamber outlet, and polishing at least a portion of a surface of the polycrystalline diamond compact. The pressurized working fluid may comprise abrasive particles suspended within a carrier fluid.
In still other embodiments, the present disclosure includes a method of polishing a polycrystalline diamond compact portion of a plurality of cutting elements for an earth-boring tool. Each of the plurality of cutting elements may comprise a polycrystalline diamond compact disposed on a substrate. The method may comprise securing each cutting element of the plurality of cutting elements in a fixture, enclosing at least a portion of the polycrystalline diamond compact of each cutting element of the plurality of cutting elements within a chamber, flowing a pressurized working fluid through the chamber between a chamber inlet and a chamber outlet, and polishing at least a portion of a surface of the polycrystalline diamond compact of each cutting element of the plurality of cutting elements within a chamber. The pressurized working fluid may comprise abrasive particles suspended within a carrier fluid.
While this disclosure concludes with claims particularly pointing out and distinctly claiming specific embodiments, various features and advantages of embodiments within the scope of this disclosure may be more readily ascertained from the following description when read in conjunction with the accompanying drawings, in which:
The illustrations presented in this disclosure are not meant to be actual views of any particular system or device, but are merely idealized representations that are employed to describe the disclosed embodiments. Thus, the drawings are not necessarily to scale and relative dimensions may have been exaggerated for the sake of clarity. Additionally, elements common between figures may retain the same or similar numerical designation.
The following description provides specific details in order to provide a thorough description of embodiments of this disclosure. However, a person of ordinary skill in the art will understand that the embodiments of this disclosure may be practiced without employing these specific details.
The illustrations presented in this disclosure are not meant to be actual views of any particular system for polishing a polycrystalline diamond compact or components thereof, but are merely idealized representations employed to describe illustrative embodiments.
As used in this specification, the term “substantially” in reference to a given parameter, property, or condition means and includes to a degree that one skilled in the art would understand that the given parameter, property, or condition is met with a small degree of variance, such as within acceptable manufacturing tolerances. For example, a parameter that is substantially met may be at least about 90% met, at least about 95% met, or even at least about 99% met.
The term “earth-boring tool,” as used herein, means and includes any type of bit or tool used for drilling during the formation or enlargement of a wellbore in a subterranean formation. For example, earth-boring tools include fixed-cutter bits, core bits, eccentric bits, bicenter bits, reamers, mills, hybrid bits including both fixed and rotatable cutting structures, and other drilling bits and tools known in the art.
As used herein, the term “superabrasive material” means and includes any material having a Knoop hardness value of about 3,000 Kgf/mm2 (29,420 MPa) or more. Superabrasive materials include, for example, diamond and cubic boron nitride. Superabrasive materials may also be characterized as “superhard” materials.
As used herein, the term “polycrystalline material” means and includes any structure comprising a plurality of grains (i.e., crystals) of material that are bonded directly together by inter-granular bonds. The crystal structures of the individual grains of the material may be randomly oriented in space within the polycrystalline material.
As used herein, the term “tungsten carbide” means any material composition that contains chemical compounds of tungsten and carbon, such as, for example, WC, W2C, and combinations of WC and W2C. Tungsten carbide includes, for example, cast tungsten carbide, sintered tungsten carbide, and macrocrystalline tungsten carbide.
As used in this disclosure, any relational term, such as “first,” “second,” “over,” “top,” “bottom,” “side,” etc., is used for clarity and convenience in understanding the disclosure and accompanying drawings and does not connote or depend on any specific preference, orientation, or order, except where the context clearly indicates otherwise.
Disclosed embodiments relate generally to systems and methods for polishing PDC cutting elements. The systems and methods may be particularly useful for polishing PDC cutting elements having complex geometries. More specifically, disclosed embodiments relate to systems and methods for polishing PDC cutting elements for earth-boring tools through the use of a pressurized vessel containing a working fluid flowing across various faces of PDC cutting elements.
The housing 102 may include internal surfaces defining an enclosed chamber 103 therein. The housing 102 may be sealed for holding a working fluid 122 within the enclosed chamber 103. The housing 102, may have any suitable shape, although the housing 102 has a circular shape in the illustrated embodiment. In other embodiments, the housing 102 may be rectangular in shape, for example. The housing 102 may be constructed of any suitable material. Suitable materials may include steel and other metals and metal alloys.
The housing 102 may include an upper portion 102a and a lower portion 102b. The upper portion 102a and the lower portion 102b may be attached to one another with a fluid-tight seal therebetween. In one embodiment, the upper portion 102a and the lower portion 102b may each be threaded so that they may be attached and sealed via a threaded coupling 107. An elastomeric seal, such as an O-ring, may be provided along the interface between the upper portion 102a and the lower portion 102b. The threaded coupling 107 may be located below the inlet 108 and the outlet 110, as illustrated in
The housing 102 may enclose a fixture 105 within the chamber 103. In some embodiments, the fixture 105 may be an element separate from the lower portion 102b of the housing 102, while in other embodiments, the fixture 105 may be an integral portion of the lower portion 102b of the housing 102. The fixture 105 may be configured for holding one or more cutting elements 118 therein. The fixture 105 may be further configured to hold the cutting elements 118 within the housing 102 such that at least a portion of the PDC portion 118a of each of the cutting elements 118 is exposed within the chamber 103. The fixture 105 may be further configured such that no portion of the substrate 118b of the at least one cutting element 118 is exposed within the chamber 103.
The fixture 105 may further comprise one or more receptacles 104, each of which is configured to receive a portion of a respective cutting element 118 therein. An O-ring 120 may be provided along an inner wall of each receptacle, such that a fluid tight seal is formed by each O-ring 120 between a lateral side surface of each cutting element 118 and the inner wall of the receptacle 104 in which the cutting element 118 is disposed such that the working fluid 122 does not contact the substrate 118b. The O-ring 120 may also assist in securing the cutting element 118 within the receptacle 104 such that at least a portion of a surface of the PDC portion 118a of the cutting element 118 is exposed within the chamber 103.
The fluid inlet 108 leads into the chamber 103 from outside the housing 102. Further, a fluid conduit 126 extends from the pump 112 to the fluid inlet 108 such that fluid pumped out from the pump 112 flows into the chamber 103 via the fluid conduit 126 and the fluid inlet 108.
The fluid outlet 110 leads out from the chamber 103 from inside the housing 102. Further, the fluid conduit 126 extends from the fluid outlet 110 to the fluid reservoir 106.
In additional embodiments, it may be possible to eliminate the fluid reservoir 106, in which case the fluid conduit 126 might extend from the fluid outlet 110 to the pump 112 so as to return the working fluid 122 to the pump 112 and complete a closed circuit fluid pathway.
Further, the inlet 108 and/or the outlet 110 may be removably coupled (e.g., threaded to) to the upper portion 102a and/or the lower portion 102b of the housing 102. As a non-limiting example, the inlet 108 and the outlet 110 may each be removably coupled to the upper portion 102a via a quick release coupler 132, as shown in
The fluid reservoir 106 may hold the working fluid 122 therein, which is circulated through the housing 102 under pressure by the pump 112. The working fluid 122 may comprise a carrier fluid and abrasive particles. The carrier fluid may comprise, for example, water. Alternatively, the carrier fluid may comprise water-based, oil-based, and water/oil based compounds. Any other inorganic or organic fluid that is capable of carrying the abrasive particles in suspension and that will not degrade the cutting elements 118 or the various components of the system 100 may be employed as the carrier fluid.
The abrasive particles may be, for example, diamond particles or particles of an abrasive ceramic material, such as carbides (e.g., tungsten carbide, boron carbide, tantalum carbide, etc.), oxides (e.g., silicon oxide, aluminum oxide, etc.), and/or nitrides (e.g., boron nitride, silicon nitride, etc.). A dispersant may be added to the working fluid 122 so that the abrasive particles may be maintained in suspension in the working fluid 122.
The polishing system 100 may further comprise a motion mechanism 114 for providing relative movement between the cutting elements 118 and the fluid inlet 108 and the fluid outlet 110. For example, the motion mechanism 114 may comprise a motor configured to drive rotation of the fixture 105 during operation of the system 100. For example, a drive shaft 117 of the motor may extend through a bottom wall of the lower portion 102b of the housing 102 in a fluid tight manner, and the drive shaft may be coupled to the fixture 105.
The system 100 further comprises a controller 116 for controlling the active components of the system 100, such as the pump 112 and the motion mechanism 114. The controller 116 may comprise, for example, a computer, laptop, tablet, or smartphone running software dedicated to the operation of the active components of the system 100. In other embodiments, the controller may comprise a programmable logic controller, or a dedicated custom electronic control device for the system 100.
In one embodiment, in operation, the cutting elements 118 may be secured in the receptacles 104 in the fixture 105 and enclosed and sealed within the chamber 103. The pump 112, the inlet 108, the chamber 103, the outlet 110, the fluid reservoir 106, and the fluid conduits 126, which together may comprise a fluid system 124, may be filled with the working fluid 122.
The pump 112 may direct a pressurized flow 130 of the working fluid 122 through the enclosed pressurized chamber 103, from the inlet 108 to the outlet 110, and across at least a portion of a surface of the PDC portion 118a of the cutting element 118 exposed within the pressurized chamber 103, which results in polishing of the exposed surfaces of the PDC portions 118a of the cutting element 118. In particular, the abrasive particles within the working fluid 122 may collide with and polish the surfaces of the exposed surfaces of the PDC portions 118a of the cutting element 118.
During operation of the system 100, the motion mechanism 114 may provide relative movement between the cutting elements 118 and the fluid inlet 108 and outlet 110. More specifically, the motion mechanism 114 may rotate the fixture 105 horizontally, such that all cutting elements 118 are subjected to similar flows of the working fluid 122, which will improve the uniformity of the polishing process amongst the various cutting elements 118.
In other embodiments, during operation, the motion mechanism 114 may drive movement of the inlet 108 and the outlet 110, rather than movement of the fixture 105, to provide the relative movement between the cutting elements 118 and the fluid inlet 108 and outlet 110.
In yet other embodiments, the motion mechanism 114 could drive independent rotation of cutting elements 118 in place within the chamber 103, with or without providing relative movement between the cutting elements 118 and the fluid inlet 108 and fluid outlet 110.
In other embodiments, in operation the controller 116 may control the material removal rate from the surface of the PDC portion 118a of the cutting element 118 in order to achieve a desired average surface roughness, as a non-limiting example, about 1 μin (about 0.0254 μm). More specifically, the controller 116 may control the rotation speed of the motion mechanism 114.
In further embodiments, the controller 116 may control the fluid pump 112. More specifically, the controller 116 may control the speed and direction of the pressurized flow 130.
Referring to
For example, referring to
The receptacle 104 may be configured to receive a portion of a respective holder 111 therein. A drive shaft 115 of the one or more motors 113 may extend through a bottom wall of the lower portion 102b of the housing 102 in a fluid tight manner, and the drive shaft 115 may be coupled to the holder 111.
In other embodiments, the motion mechanism 114 may simultaneously drive horizontal rotation of both the fixture 105 and each of the plurality of cutting elements 118 held within the fixture, thereby exposing more than one surface of the PDC portion 118a of the cutting element 118 to the pressurized flow 130 of the working fluid 122.
In some embodiments the controller 116 may control the material removal rate from the surface of the PDC portion 118a of the cutting element 118. More specifically, the controller 116 may control, independently and/or simultaneously, the rotational speed and rotational direction of each of the plurality of holders 111 and the fixture 105 via the motion mechanism 114. The controller 116 may also control the fluid pump 112. More specifically, the controller 116 may control the speed and direction of the pressurized flow 130.
Referring to
Unlike the system 100 shown in
Similar to the system 100 in
In one embodiment, in operation, each of the plurality of cutting elements 118 may be secured in each of the plurality of receptacles 104 in the fixture 305 and enclosed and sealed within the chamber 303 such that at least one surface of the PDC portion 118a of the cutting element 118 is exposed to the working fluid 122 within the chamber 103 and the substrate 118b (not shown in
The polishing system 300 may further comprise a motion mechanism 114 and a controller 116. Each of the plurality of receptacles 104 may be operably coupled to the motion mechanism 114. The motion mechanism 114 and the pump 112 may be operably coupled to the controller 116.
In operation, the motion mechanism 114 may drive independent rotation of each of the plurality of cutting elements 118 in place within the chamber 303, with or without providing relative movement between the cutting elements 118 and the fluid inlet 108 and fluid outlet 110. More specifically, the motion mechanism 114 may rotate horizontally simultaneously or independently of each of the plurality of receptacles 104 thereby exposing more than one surface of the PDC portion 118a of the cutting element 118 to the pressurized flow 130 of the working fluid 122.
The controller 116 may control the material removal rate from the surface of the PDC portion 118a of the cutting element 118 in order to achieve a desired average surface roughness, as a non-limiting example, about 1 μin (about 0.0254 μm). More specifically, the controller 116 may control simultaneously or independently the rotational speed of each of the plurality of receptacles 104 via the motion mechanism 114. The controller 116 may also control the pump 112. More specifically, the controller 116 may control the speed and direction of the pressurized flow 130.
Additional non-limiting example embodiments of the disclosure are set forth below.
A method of polishing a polycrystalline diamond compact, comprising: securing the polycrystalline diamond compact in a fixture; enclosing at least a portion of the polycrystalline diamond compact within a chamber; flowing a pressurized working fluid through the chamber between a chamber inlet and a chamber outlet and polishing at least a portion of a surface of the polycrystalline diamond compact, the pressurized working fluid comprising abrasive particles suspended within a carrier fluid.
The method of Embodiment 1, wherein the polycrystalline diamond compact is disposed on a substrate, and wherein securing the polycrystalline diamond compact in the fixture comprises sealing the substrate from the chamber such that the flowing pressurized working fluid does not contact the substrate.
The method of Embodiment 1 or Embodiment 2, further comprising varying a direction of flow of the working fluid across the at least a portion of a surface of the polycrystalline diamond compact within the chamber.
The method of Embodiment 3, wherein varying the direction of flow of the working fluid across the at least a portion of a surface of the polycrystalline diamond compact within the chamber comprises providing relative motion between the polycrystalline diamond compact and the fluid inlet.
The method of Embodiment 4, wherein providing relative motion between the polycrystalline diamond compact and the fluid inlet comprises moving the fluid inlet relative to the fixture.
The method of any one of Embodiments 1 through 5, wherein the at least a portion of a surface of the polycrystalline diamond compact is non-planar.
The method of any one of Embodiments 1 through 6, wherein the at least a portion of a surface of the polycrystalline diamond compact comprises at least a portion of each of at least two non-coplanar surfaces of the polycrystalline diamond compact.
The method of any one of Embodiments 1 through 7, wherein the carrier fluid comprises water.
The method of any one of Embodiments 1 through 8, wherein the abrasive particles are selected from the group consisting of diamond, carbides, oxides and nitrides.
The method of any one of Embodiments 1 through 9, further comprising adding a dispersant to the working fluid.
The method of Embodiment 10, wherein the dispersant is selected from the group consisting of water-based, oil-based, and water-and-oil-based compounds.
A method of polishing a polycrystalline diamond compact portion of a plurality of cutting elements for an earth-boring tool, each of the plurality of cutting elements comprising a polycrystalline diamond compact disposed on a substrate, the method comprising: securing each cutting element of the plurality of cutting elements in a fixture; enclosing at least a portion of the polycrystalline diamond compact of each cutting element of the plurality of cutting elements within a chamber; flowing a pressurized working fluid through the chamber between a chamber inlet and a chamber outlet and polishing at least a portion of a surface of the polycrystalline diamond compact of each cutting element of the plurality of cutting elements within a chamber, the pressurized working fluid comprising abrasive particles suspended within a carrier fluid.
The method of Embodiment 12, wherein securing each cutting element of the plurality of cutting elements in the fixture comprises sealing the substrate of each cutting element of the plurality of cutting elements from the chamber such that the flowing pressurized working fluid does not contact the substrate.
The method of Embodiment 12 or Embodiment 13, further comprising varying a direction of flow of the working fluid across the at least a portion of the surface of the polycrystalline diamond compact of each cutting element of the plurality of cutting elements within the chamber.
The method of any one of Embodiments 12 through 15, wherein the at least a portion of the surface of the polycrystalline diamond compact of each cutting element of the plurality of cutting elements is non-planar.
The method of any one of Embodiments 12 through 15, wherein the at least a portion of the surface of the polycrystalline diamond compact of each cutting element of the plurality of cutting elements comprises at least a portion of each of at least two non-coplanar surfaces of the polycrystalline diamond compact.
The method of any one of Embodiments 12 through 16, wherein the carrier fluid comprises water, and the abrasive particles are selected from the group consisting of diamond, carbides, oxides and nitrides.
A system for polishing a polycrystalline diamond compact, comprising: a housing including internal surfaces defining an enclosed chamber therein, the housing including a fixture configured to hold at least one polycrystalline diamond compact therein such that at least a portion of a surface of the at least one polycrystalline diamond compact is exposed within the chamber; at least one fluid inlet leading into the chamber from outside the housing; at least one fluid outlet leading out from the chamber from inside the housing; a fluid reservoir for holding a working fluid therein; a pump for producing flow of pressurized working fluid through the enclosed chamber within the housing and across the at least a portion of a surface of the at least one polycrystalline diamond compact exposed within the chamber; and fluid conduits defining a circular fluid pathway extending from the fluid reservoir to the pump, from the pump to the at least one fluid inlet, and from the at least one fluid outlet to the fluid reservoir.
The system of Embodiment 18, further comprising a mechanism for varying a direction of flow of the working fluid across the at least a portion of a surface of a polycrystalline diamond compact within the chamber.
The system of Embodiment 19, wherein the fixture is configured to hold a plurality of cutting elements for an earth-boring tool, each including a polycrystalline diamond compact disposed on a substrate, therein such that at least a portion of a surface of the at least one polycrystalline diamond compact of each cutting element of the plurality is exposed within the chamber and such that the substrate of each cutting element of the plurality is sealed from the chamber.
While certain illustrative embodiments have been described in connection with the figures, those of ordinary skill in the art will recognize and appreciate that the scope of this disclosure is not limited to those embodiments explicitly shown and described in this disclosure. Rather, many additions, deletions, and modifications to the embodiments described in this disclosure may be made to produce embodiments within the scope of this disclosure, such as those specifically claimed, including legal equivalents. In addition, features from one disclosed embodiment may be combined with features of another disclosed embodiment while still being within the scope of this disclosure, as contemplated by the inventor.
