Patent Application
20240271265
The invention relates to coatings applied to equipment and other substrates, and more particularly to thermally sprayed layers of alternating copper based and iron based layers for a wide range of substrates, including downhole equipment in oil and gas wells and marine devices.
Drilling wells for oil and gas recovery, as well as for other purposes, involve the use of drill pipes and other downhole equipment necessary for the exploration and production of oil and gas. Downhole equipment is exposed to severe abrasive wear conditions and corrosive environments. Thermal spray coatings have been used to help prevent (or mitigate) wear conditions for downhole components, but existing alloys are not particularly helpful for corrosive applications.
As is known in the art, the term “thermal spray” is a generic term for a group of processes in which metallic, ceramic, cermet, and some polymeric materials in the form of powder, wire, or rod are fed to a torch or gun with which they are heated to near or somewhat above their melting point. The resulting molten or nearly molten droplets of materials are projected against the surface to be coated. Upon impact, the droplets flow into thin lamellar particles adhering to the surface, overlapping and interlocking as they solidify. The total coating thickness is usually generated in multiple passes of the coating device; depending on the application, the layer may be applied in thick deposits exceeding 0.100,″ although ranges in the amount between 0.020″ up to 3.0″ are possible. Various thermal spray techniques may include flame spraying, flame spray and fuse, electric-arc (wire-arc) spray, and plasma spray. Thermal spray may be applied to a wide variety of tools, equipment, structures, and materials, and is not limited to merely downhole components. Thermal spray with special alloys is applied to drill pipe, casing, sucker rods and other components used in the drilling, completion and production of oil and natural gas. Among other benefits, this application is used to mitigate wear, reduce friction, and to create a standoff from the annulus of the hole.
The prior art discloses various methods for thermal spraying. For example, U.S. Pat. No. 7,487,840 (“the '840 patent”), incorporated herein by reference, discloses a protective wear coating on a downhole component for a well through a thermal spraying process in combination with an iron-based alloy. The thermal spraying process melts the material to be deposited while a pressurized air stream sprays the molten material onto the downhole component. The coating operation takes place at low temperatures without fusion or thermal deterioration to the base material. The wear resistance is increased while providing a lower coefficient of friction by the wear resistant layer relative to a coefficient of friction of the downhole equipment without the wear resistant layer. FIG. 3 of the '840 patent is reproduced in the present disclosure as
Likewise, U.S. Pat. No. 9,920,412 (“the '412 patent”), incorporated herein by reference, discloses a similar thermal spray technique with a chromium free composition of thermally sprayed material. The '412 patent discloses applying this composition onto tubulars to form centralizers. While conventional thermally sprayed layers (such as that disclosed in the '840 patent and the '412 patent) are useful in numerous instances, such compositions are not helpful for corrosive environments. There is a need in the oil industry for a highly corrosion resistant thermal spray product. Many oil wells contain highly corrosive compounds, including hydrogen sulfide, carbon dioxide, salt water, and microbes. Each of these induces destructive corrosion leading to leaks and failure of metal components that are used for flow control and pumping. Failure requires that a work over rig be contracted and the components pulled from the well and replaced, resulting in production down time and the expense of the work over rig as well as the replacement of the component. These oil production components stay in the well and remain in constant contact with the oil and corrosive agents.
Rather than manufacturing the components from solid corrosion resistant alloys, low alloy steels are often specified and then coated with a corrosion resistant alloy using the thermal spray process. For example, one current approach is to use twin wire arc spray (TWAS) where one wire is AWS A5.11 ERNiCu-7 (commonly known as Monel) and the second wire is stainless steel, such as AWS A5.9 ER316L. However, this combination, while better than other alloys, still corrodes at rates faster than desired.
Various alloys have utilized copper and nickel alloys for different purposes and different compositions than described herein. For example, U.S. Pat. No. 9,631,157, incorporated herein by reference, discloses a copper-nickel-tin alloy that is focused on friction and wear (not corrosion prevention), and the deposit is heat treated after deposition on a surface. U.S. Pat. No. 4,641,976, incorporated herein by reference, also discloses a copper-nickel-tin alloy that is used on a metal bearing and is focused on friction and wear protection as opposed to corrosion prevention. U.S. Patent Publication No. 2002/0197132, incorporated herein by reference, discloses a copper-nickel alloy that is used for sucker rod coupling. It is heat treated after deposition on a surface and has a different composition than that described herein.
Various data exists that displays various corrosive effects of different materials and/or compositions with different corrosive media. For example, Oilfield Metallurgy and Corrosion (4th Edition), available from National Association of Corrosion Engineers (NACE) International, provides a table of different corrosive media that causes stress-corrosion cracking. See, e.g., Table 2-5 on page 83, incorporated herein by reference. As illustrated in Table 2-5, copper nickel is referenced as material no. 11 and Monel is referenced as material no. 13, and these alloys provide corrosion resistance to the vast majority of corrosive media tested, and particularly those likely to be found in downhole conditions. The following corrosive media are potentially problematic in downhole conditions: hydrogen sulfide, carbon dioxide, carbonic acid, and chloride salts (sodium chloride and potassium chloride), among others. Further, micro-biologicals downhole have been known to emit chemicals that corrode downhole components.
It is also known in the art that metallic coatings can be applied to marine structures to help control corrosion. For example, an April 1999 publication by the Copper Development Association entitled “Metallic Coatings for Corrosion Control of Marine Structures,” incorporated herein by reference, discusses copper nickel alloys that can be applied to marine structures for corrosion and biofouling resistance. These alloys are not thermally sprayed onto the marine devices, but are instead generally painted, welded onto or glued on, or otherwise attached by other mechanical methods such as screwing or clamping, or in some instances may form the entire material itself (such as solid copper based hulls). In many instances, an alloy sheathing requires electrical insulation to insulate the copper sheathing from the underlying steel, which then requires pumping cement or an epoxy into (or otherwise using an elastomer or rubber insulator) the annular space between the substrate and the copper sheath.
Applicant produces a product labeled CUNIA, which is a copper-based alloy that can be thermally sprayed on various items, including downhole pipe. Such a product and method of use is disclosed in U.S. Pat. No. 10,982,310 (“the '310 patent”), incorporated herein by reference. Another thermally sprayed composition in the prior art is found in U.S. Pat. No. 10,577,685, incorporated herein by reference. FIG. 2B of the '310 patent is reproduced in the present disclosure as
“The thickness of the coating varies based on the desired characteristics of the coating (wear resistance, impact resistance, corrosion resistance, etc.) and the intended application of the coated tool/substrate. In one embodiment, the total coating thickness may be generated in multiple passes. In one embodiment, the coating may be applied in thick deposits exceeding 0.100”, although ranges in the amount between 0.020″ up to 3.0″ are possible. The coating thickness (and/or each separate layer of the coating) may be relatively thin such as between 0.002″ to 0.020″, or bigger between 0.020″ to approximately 0.100″, or even greater thicknesses such as approximately 0.35″, 0.50″, or more. For example, U.S. Pat. No. 7,487,840 (the “840 patent”) discloses an iron based coating that is at least 0.100″ thick. An overall thickness of the disclosed coating may be less than 0.100″ thick (such as approximately 0.090″ or less), approximately 0.100″ thick, or greater than 0.100″ thick.”
A need exists for an improved method and system for thermally sprayed layers that are more resistant to corrosion. A need exists for an improved method and system for thermally sprayed layers on downhole components that is more corrosion resistant to conditions existing in downhole environments. A need exists for an improved thermal spray alloy system for marine environments to prevent biological growth. A need exists for an improved thermal spray alloy system that can be applied in thicknesses greater than 0.100″ for creating shapes such as centralizer blades or ribs on oilfield casing.
The present disclosure provides a thermal spray alloy system that is more resistant to corrosion than conventional alloy compositions. In one embodiment, the present disclosure utilizes layers of different alloys. In one embodiment, the present disclosure addresses issues of wear and corrosion by utilizing a coper-based alloy as one thermally sprayed layer and an iron based alloy as a second thermally sprayed layer via twin wire arc spray application processes, as is known in the art. Between 2-10 applications of each layer may be applied to a substrate.
Disclosed is a thermally sprayed coating on a substrate, comprising a first layer of thermally sprayed metallic material on a substrate, wherein the first layer is formed by a first metallic material that comprises about 50.0 wt % to about 95.0 wt % of copper, and a second layer of thermally sprayed metallic material on the substrate, wherein the second layer is formed by a second metallic material that comprises substantially iron. The coating may have a plurality of layers comprising at least two layers of the first metallic material and at least two layers of the second metallic material. The first layer provides corrosion resistance to the substrate and the second layer provides wear resistance to the substrate. The first metallic material may be formed of the aluminum bronze alloy. The first metallic material may be formed from a cored wire that utilizes a coper alloy strip encasing a powdered core. The metallic material forming the first layer comprises the following composition about 50.0 wt % to about 90.0 wt % of copper, about 4.0 wt % to about 30.0 wt % of aluminum, about 0.0 wt % to about 30.0 wt % of nickel, about 0.0 wt % to about 5.0 wt % of boron, about 0.0 wt % to about 6.0 wt % of silicon, and about 0.0 wt % to about 1.0 wt % of carbon. The coating may comprise an alternating plurality of layers formed of the first metallic material and the second metallic material, wherein each of the first and second layers is between 0.010″ and 0.10″ thick. The substrate may be a downhole component, a band on a tubular, a blade on a tubular, among other items.
Also disclosed is a method for applying a coating to a substrate, comprising thermally spraying a plurality of different layers on an external surface of a substrate by twin wire arc spray, wherein a first layer of the plurality of different layers comprises a copper based alloy from a first metallic material, wherein a second layer of the plurality of different layers comprises an iron based alloy from a second metallic material. The first metallic material may comprise the following composition: about 50.0 wt % to about 90.0 wt % of copper, about 4.0 wt % to about 30.0 wt % of aluminum, about 0.0 wt % to about 30.0 wt % of nickel, about 0.0 wt % to about 5.0 wt % of boron, about 0.0 wt % to about 6.0 wt % of silicon, and about 0.0 wt % to about 1.0 wt % of carbon. The first metallic material may be a cored wire, wherein the copper is located substantially within an outer sheath of the cored wire. Each of the plurality of layers may comprise a thickness of between about 0.010 inches and 0.10 inches. Each of the plurality of layers may comprise at least two layers of the first metallic material and at least two layers of the second metallic material.
The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.
Various features and advantageous details are explained more fully with reference to the nonlimiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well known starting materials, processing techniques, components, and equipment are omitted so as not to unnecessarily obscure the invention in detail. It should be understood, however, that the detailed description and the specific examples, while indicating embodiments of the invention, are given by way of illustration only, and not by way of limitation. Various substitutions, modifications, additions, and/or rearrangements within the spirit and/or scope of the underlying inventive concept will become apparent to those skilled in the art from this disclosure. The following detailed description does not limit the invention.
Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
The present disclosure provides a thermal spray alloy system that is more resistant to corrosion than conventional alloy compositions. In one embodiment, the present disclosure utilizes layers of different alloys. In one embodiment, the present disclosure addresses issues of wear and corrosion by utilizing a copper-based alloy as one thermally sprayed layer and an iron-based alloy as a second thermally sprayed layer, both sprayed via twin wire arc spray application processes, as is known in the art. In one embodiment, the iron-based alloy may be the same or similar as that produced by Applicant under the ROTOGLIDE name, and the copper-based alloy may be the same or similar as that produced by Applicant under the CUNIA name. The first copper-based layer may be about 50.0 wt % to about 95.0 wt % of copper. Between 2-10 applications of each layer may be applied to a substrate.
In one embodiment, the copper-based alloy is the same alloy described in U.S. Pat. No. 10,982,310 (“the '310 patent”), incorporated herein by reference, and also referenced as CUNIA. Such a copper-based alloy may be found in a cored wire, as disclosed in the '310 patent. The copper alloy may also comprise nickel, tin, boron, and/or carbon, and may also comprise iron, titanium, aluminum, and/or magnesium. In one embodiment, the alloy comprises a majority weight percentage of copper and nickel and aluminum, with the remaining elements being optional and/or existing in trace amounts (e.g., less than 0.02 wt %). In one embodiment, a cored wire (which is typically used in thermal spray applications) is used which comprises an outer sheath that may comprise substantially copper and/or unalloyed copper.
The disclosed layered coating provides numerous advantages and benefits over conventional techniques. For example, the disclosed alternating layers of a copper-based alloy and an iron-based alloy is more corrosion resistant and wear resistant than existing thermally sprayed coatings.
The disclosed layered coating also allows application of thick deposits or layers of the layers on a substrate. In other words, in addition to the superior wear and corrosion resistant properties, the disclosed coating can be sprayed to achieve thick deposits (e.g., greater than 0.100″), deposits which may be formed up to 3.0″. The thick depositions can be used on existing tools or substrates to form centralizers or other shapes as desired.
In one embodiment, the form of the thermally sprayed material is a cored wire, in which the outer sheath may be at least 50% copper by weight, or at least 75% by weight of copper or at least 90% by weight of copper, or a mixture of copper and nickel, such as approximately 70% copper by weight and 30% nickel by weight. In another embodiment, the outer sheath of the cored wire may be substantially copper, such as an unalloyed copper (e.g., an alloy of substantially copper that may contain trace amounts of other elements). Of course, one of skill in the art will recognize based on this disclosure that other ranges of copper and/or nickel is possible. In other embodiments, the disclosed alloy can be produced as a solid wire. In still other embodiments, the disclosed alloy may be applied as a powder. In one embodiment, a cored wire comprises an outer sheath and an inner core, as is known in the art. The outer sheath may comprise substantively copper and nickel in one embodiment, or in another embodiment substantially all copper. In one embodiment, the inner core comprises the powdered ingredients of the alloy, and include powdered materials such as borides, carbides, tin, iron oxide, aluminum, etc. In one embodiment, the powdered ingredients comprise aluminum and iron oxide. The making of such outer sheaths and inner cores of a cored wire is known to those of skill in the art. Such a cored wire and composition is disclosed in the '310 patent, incorporated herein by reference.
In one embodiment, the wire composition for thermally spraying to a substrate, prior to melting, may be a majority percentage by weight of copper. For example, the composition may comprise about 50.0 wt % to about 90.0 wt % of copper; about 4.0 wt % to about 30.0 wt % of aluminum; about 0.0 wt % to about 30.0 wt % of nickel; about 0.0 wt % to about 5.0 wt % of boron; about 0.0 wt % to about 6.0 wt % of silicon; and about 0.0 wt % to about 1.0 wt % of carbon. In one embodiment, the copper and nickel elements are located substantially within an outer sheath of a cored wire and may not be present in the inner core.
In another embodiment, the composition of the alloy is principally copper based and may include other alloys except for nickel. This nickel-less system may be used for both its corrosion resistance and heat transfer properties. Other potential elements in the disclosed wire composition include aluminum, iron, chromium, zirconium, silicon, manganese, boron, carbon, and/or tin. Depending on the application, these alloys may be changed and substituted to achieve the desired level of corrosion, wear, and/or friction resistance. An exemplary example of a nickel-less alloy composition may comprise principally copper alloyed with aluminum, iron, boron, tin, manganese and carbon, which may be applied to a component of a fire tube system called a separator.
As described above, the present disclosure is generally directed to forming a durable coating on a substrate that includes one or more layers of thermally sprayed material that is resistant to corrosion. In general, the methods of thermal spray are well known in the relevant art and a variety of different thermal spray techniques may be utilized to apply the disclosed alloy as a coating on a substrate. In one embodiment, to apply a thermal spray coating for a tool the following steps may be generally taken as is known in the art: (i) provide the necessary consumables and equipment, (ii) prepare the tool to be coated, (iii) clean and/or degrease the tool, (iv) sand blast the tool, (v) thermally spray the tool, and (vi) store the tool.
The process of thermal spray is well known to those of skill in the art. Thermal spray is a flexible process and can be applied to a wide variety of substrates and/or surfaces, such as irregular, tubular, or flat surfaces and to virtually any metal or non-metal substrate. In general, the process involves cleaning the substrate and forming a rough surface profile on the substrate, which may be done by grit blasting, chemical etching, or mechanical means. Once profiled, the surface is coated with the disclosed alloy using any of a variety of thermal spray processes, such as High Velocity Oxy-Fuel (HVOF), Twin Wire Arc Spray (TWAS), Cold Spray, and Kinetic Metallization. Each of these different thermal spray processes is well known to those of skill in the art. In one embodiment, the utilized spray gun may be traversed along a cylindrical object where the object is rotating in a fixture such as a lathe or riding on pipe rollers. Traversing of the spray gun may be done manually by a human operator, automatically by robot, or by affixing the gun to a traversing mechanism.
The disclosed coating may be applied to a room temperature substrate or the substrate may be pre-heated to approximately 200-400 degrees Fahrenheit. While typically the coating may be approximately 0.015″ thick, the disclosed coating can be applied both thinner and thicker as required. For example, the coating may be as small as 0.006″ or as large (or greater) than 0.100″ thick and up to approximately 3.0″ thick. The tool being coated and the particular application of the tool will dictate the coating thickness.
As discussed above, prior art coatings develop micro-cracks in the coating, some of which may extend to the surface of the coating. To address these cracks, conventional techniques typically paint or treat the coating surface with a low surface tension liquid to penetrate and seal the cracks. In one embodiment, the disclosed thermal spraying process does not require this subsequent treatment of the coating because it has no micro-cracks that open to the surface, so there is no path to absorb the low viscosity sealing liquids. In other words, the disclosed embodiment does not require a subsequent sealing step of the resultant thermally sprayed coating as is typical in conventional techniques.
In general, the disclosed alternating layers of a copper-based layer/coating and an iron-based layer/coating may be used on any tool (and is not limited to downhole equipment). For example, it may be applied to marine equipment, downhole equipment, drill pipe, drill bands, stabilizer blades, etc.
In one embodiment, the relevant components are downhole oil well production components such as electrically submersible pumps, mud motors, centralizers, stabilizers, sucker rods, and related components and other artificial lift equipment. However, the disclosed wire composition and technique is beneficial in other markets where severe corrosion is present is advantageous. While an embodiment of the disclosure is directed to drill pipe or other downhole components used in the oil and gas industry, a thermally sprayed layer of the disclosed novel alloy can be used in a variety of applications and industries. As one example, the disclosed copper-based alloy may be used to form relatively thick coatings (greater than 0.100″), which can be used to form shapes on tools, such as centralizers. For example, the disclosed corrosion resistant thermally sprayed layer may be used for many other downhole components in the oil and gas industry, such as but not limited to drill pipes, drill pipe tool joints, heavy weight pipes, stabilizers, cross-overs, jars, MWDs, LWDs, drill bit shanks, etc. In one embodiment, the relevant components are downhole oil well production components such as electrically submersible pumps, sucker rods, and related components and other artificial lift equipment. The disclosed corrosion resistant thermally sprayed layer may also be used on objects other than downhole components where an increased corrosion resistant layer is needed, such as dredge pups, cable sheaves, helicopter landing runners, etc., including the automotive, aviation, and marine industries. The corrosion layer may also be used on banding to rigidly attach separate components, such as around drill pipe tool joints. In general, the disclosed alloy is applied to components that are subject to corrosion and thermal damage and is beneficial in other markets where severe corrosion is present and/or heat dissipation is advantageous.
Various corrosive tests show that the disclosed coating formed of alternating layers of iron-based alloy and copper-based alloy provides superior benefits as compared to prior art alloys. Table I (below) illustrates results of wear testing results of a substrate (RS CuRg) sprayed with a coating formed of alternating layers of CUNIA and ROTOGLIDE.
Table I illustrates test results of various revolutions and wear rates based on a sample of the disclosed alloy embodiment. Based on wear testing of simulated 56,000 rotational feet, only 14.9% of coating loss resulted. As disclosed by the tests, the abrasive wear resistance is equivalent or superior to premium hard-banding. As compared to hard-banding, the disclosed coating results in more galling resistance, lower friction, and does not change the metallurgy of pipe (liked welded hard-banding). The disclosed coating does not burn out the IPC, reduces the chance for differential sticking, and reduces vibration.
All of the methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the apparatus and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the invention. In addition, modifications may be made to the disclosed apparatus and components may be eliminated or substituted for the components described herein where the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the invention.
Many other variations in the system are within the scope of the invention. For example, the alloy may or may not include tin, manganese, and/or titanium, and may include boron and/or carbon. The tool to be coated may be a downhole component or other tool used in the oil and gas industry, or may be applied to any object or tool that needs an increased corrosive protection layer and/or thermally dissipative layer, such as in the aviation, refining, chemical, processing, and marine industries, as well as dredge pups, cable sheaves, and helicopter landing runners, among others. The alloy may have other desirable properties besides corrosion resistance, such as being a conductor of heat (for heat dissipation purposes) or crack resistant or wear resistant or electrical conductivity. In still other embodiments, the thermal spray alloy composition may not contain nickel and may contain primarily or substantially copper along with other alloys. In one embodiment, the substrate may be a metallic or non-metallic material, such as drill pipe or fiberglass. It is emphasized that the foregoing embodiments are only examples of the very many different structural and material configurations that are possible within the scope of the present invention.
Although the invention(s) is/are described herein with reference to specific embodiments, various modifications and changes can be made without departing from the scope of the present invention(s), as presently set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention(s). Any benefits, advantages, or solutions to problems that are described herein with regard to specific embodiments are not intended to be construed as a critical, required, or essential feature or element of any or all the claims.
Unless stated otherwise, terms such as “first” and “second” are used to arbitrarily distinguish between the elements such terms describe. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements. The terms “coupled” or “operably coupled” are defined as connected, although not necessarily directly, and not necessarily mechanically. The terms “a” and “an” are defined as one or more unless stated otherwise. The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”) and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, a system, device, or apparatus that “comprises,” “has,” “includes” or “contains” one or more elements possesses those one or more elements but is not limited to possessing only those one or more elements. Similarly, a method or process that “comprises,” “has,” “includes” or “contains” one or more operations possesses those one or more operations but is not limited to possessing only those one or more operations.
This application claims priority to U.S. provisional patent application No. 63/485,153, filed on Feb. 15, 2023, the entire contents of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63485153 | Feb 2023 | US |
