Downhole sealing arrangement with structural support

Abstract

A composite arrangement where a flexible member, typically a seal, is secured to a structural support. The interface, or region where the flexible member contacts the structural support is complex, providing resistance to detachment in the absence of damage that includes tearing, ripping, or shredding of the flexible material. The complex interface may include mechanically interlocking the flexible material to a feature of the structural support. The composite arrangements described may include sealing arrangements that are useful in downhole tools where seal failures are costly, potentially leading to closing wells or sections thereof. The described seal arrangements provide protection against seal failures during pressure related events, including pressure unloading following open of a valve assembly with a shifting sleeve.

Description

ENHANCED DOWNHOLE SEALING ARRANGEMENT TECHNICAL FIELD

[0001] The present technology relates to a seal arrangement between two materials. More specifically, the present technology relates, but is not limited to, seal arrangements formed between components of downhole tools.BACKGROUND

[0002] Sleeves and other downhole components commonly use seals to separate and isolate pressurized sections of wellbores used for resource extraction. Under certain conditions seals may be subjected to forces that promote detachment of the seal from its designed location. When detachment occurs, sealing ability may be compromised. For example, valve assemblies integrated as part of a wellbore string typically include a sliding sleeve within a housing, with firings strategically situated within grooves on the inner surface of the housing, or outer surface of the sleeve, to prevent fluid flow in the annulus between the sleeve and the housing. In some instances, there is a pressure differential across the seal, and when the sliding sleeve is shifted, pressure unloading, where fluid on the higher-pressure side rushes to the lower-pressure side, exerts force and pressure on the seal which has become exposed due to the shifting of the sliding sleeve. Depending on the differential, pressure unloading may force the seal out of position, rendering the valve assembly ineffective for continued use due to an inability to isolate pressure.

[0003] Conventional techniques for restraining a seal in a functional position include mechanical restraint or use of an adhesive to secure the seal in the desired position. For example, O-rings in valve assemblies may be mechanically restrained by a combination of the walls of the groove, backup rings, if present, and the sleeve. When the sleeve is opened by shifting the sleeve, the seal becomes exposed as it is no longer constrained on one side by the sleeve.Adhesives are typically used where the seal is secured to a component where mechanical restraint options are limited. Examples include bonding of packer elements to abutments or retaining elements (e.g. gauge ring) where the interface between the seal and the component it is attached to is relatively flat. Unfortunately, some adhesives, while extremely effective for restraining seals, are not compatible with all known sealing compositions or may be ineffective at higher temperatures.

[0004] For known sealing arrangements, whether adhesives or mechanical restraint are employed, the interface between the seal and the component is simple, comprising contact over only one or a small number of flat surfaces. Detachment of the seal in known sealing arrangements is typically due to interruption of the contact between the seal and the component at the interface, the seal being removed intact, and possibly deformed. What is needed is a sealing arrangement that resists detachment in response to applied forces without reliance on chemical bonding via adhesives.BRIEF SUMMARY

[0005] Embodiments of the present invention may encompass composite arrangements. The composite arrangements may include a structural support, and a flexible material, wherein the structural support and the flexible material contact one another at a complex interface. In some embodiments, the composite arrangements are seal arrangements.

[0006] In some embodiments, the complex interface may include shapes including at least one of a recess with a choke point, a tree structure, a recess with at least one support member, a lattice, a progressive lattice, and a lattice comprising non-uniform void sizes. In some embodiments, the complex interface may include a shape having greater than 5 distinct contours. In some embodiments, the complex interface may include mechanically interlocking the flexible material to the structural support. In some embodiments, the complex interface is defined by the shape of the structural support.

[0007] In some embodiments, the structural support may be formed from deformation-resistant material including metal, ceramic, polymers, and / or combinations thereof. In some embodiments, the structural support may be formed using additive manufacturing processes (e.g., 3D printing). In some embodiments, the complex interface may be formed after production of the structural support, via machining techniques that remove a portion of the material forming the structural support.

[0008] In some embodiments, the flexible member may be a seal. In some embodiments, the flexible material comprises a deformable material. The flexible material may include a thermoplastic material, an elastomeric material like rubber, or combinations thereof. The flexible material may include one or more of a fluoroelastomer (FKM, AFLAS ®), which may include a fluorocarbon-based fluoroelastomer that contains the monomer vinylidene fluoride),hydrogenated nitrile butadiene rubber (HNBR), ethylene propylene diene monomer rubber (EPDM), a perfluoroelastomer (FFKM), polytetrafluoroethylene (PTFE), and polyether ether ketone (PEEK).

[0009] The composite arrangement may also include an adhesive disposed between the structural support and flexible member at the complex interface. The composite arrangement may include a surface of the structural support, at the complex interface, having a roughened texture having a roughness average (Ra) of at least 5 microns.

[0010] In some embodiments, the composite arrangement is a seal arrangement on a downhole tool. The downhole tool can be a valve assembly, where the seal arrangement is disposed within a groove on the inner surface of the housing of the valve assembly, and the flexible material secured to flanking back-up rings at a complex interface. The downhole tool can also include a frac initiation assembly where the packing element is secured to a retaining ring at a complex interface.

[0011] A method of securing a flexible member to a structural support is also described, and may include the steps of forming a structural support with a complex interface, flowing the flexible material, in flowable form, onto a surface of the structural support, allowing the flexible material to spread out across the complex interface, including within voids and recesses; and curing the flexible material into a solid form. The structural support may be formed, with a complex interface, using 3D printing.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] A further understanding of the nature and advantages of the disclosed technology may be realized by reference to the remaining portions of the specification and the drawings.

[0013] FIG. la is a cross-sectional view of a prior art valve assembly with a sleeve in the closed position.

[0014] FIG. lb is a cross-sectional view of the prior art valve assembly with a sleeve of FIG. la in the open position.

[0015] FIG. 1c is an axial cross-section view of a prior art seal arrangement from the valve assembly of FIG.la-b.

[0016] FIG. 2a is an axial cross-section of a prior art frac initiation assembly with focus on the packer element in a retracted position.

[0017] FIG. 2b is axial cross-section of the prior art frac initiation assembly of FIG. 2a with the packer element in sealed position.

[0018] FIG. 3 illustrates various cross-sectional schematic views of different complex interfaces between a structural support and a flexible material.

[0019] FIG. 4A illustrates an axial cross-sectional view of seal arrangement in a groove of a valve assembly, with two backup rings having complex interfaces according to embodiments of the present disclosure.

[0020] FIG. 4B illustrates a partial perspective view of a backup ring from the seal arrangement in FIG. 4A, showing the circumferential spacing of support members.

[0021] FIG. 5 illustrates operations of a method of attaching a structural support to a flexible material according to embodiments of the present disclosure.

[0022] Several of the figures are included as schematics. It is to be understood that the figures are for illustrative purposes and are not to be considered of scale unless specifically stated to be of scale. Additionally, as schematics, the figures are provided to aid comprehension and may not include all aspects or information compared to realistic representations and may include exaggerated material for illustrative purposes.DETAILED DESCRIPTION

[0023] The subject matter of embodiments of the present disclosure is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described.

[0024] Embodiments of the present disclosure are directed to systems and methods of securing a flexible material (rubber or plastic) to a structural support made from metal or plastic. In someembodiments, the structural support comprises part of a downhole tool, and the flexible material comprises a sealing element, or seal. By securing, it is meant to include attaching the flexible material to one or more structural supports, with or without an adhesive. A seal arrangement refers to the secured attachment of a flexible material to one or more structural supports, including the combination of the nature of the interface between the flexible material and the one or more structural supports, and the presence or absence of an adhesive or adhesives. By interface it is meant the points or surfaces of contact between the flexible material and the structural support. In some embodiments, the flexible material is secured to the structural support at a complex interface.

[0025] The composite arrangements described herein focus on the example of sealing arrangements relevant to downhole tools used in wellbores, including valve assemblies that control fluid communication between the wellbore and the underground formation, and packers used to isolate sections within a wellbore as part of a retrievable tool such as a fraction initiation assembly. Use of these examples to illustrate the concept of a composite arrangement with a complex interface is not intended to limit use to the downhole tools used for illustration, as the sealing arrangements described herein are one example of a composite arrangement. Other embodiments for use in any application requiring securement of a flexible member to a structural support, which may or may not involve a sealing component, may be considered as falling within the scope of concepts described herein.

[0026] A cross-section of a simple valve assembly showing the main elements is shown in FIG. 1A and FIG. IB. A typical valve assembly 10 includes a tubular casing or housing 12 having a central passage 14 for allowing fluid flow therethrough. The housing 12 has an uphole end 15 and a downhole end 16 configured to be connected between lengths of casing to facilitate integration as part of a wellbore string. A sleeve 17 disposed within central passage 14 can be shifted between hard stops 18 and 19. Shifting of the sleeve allows for control of fluid communication between central passage 14 and a reservoir adjacent the valve assembly via one or more ports 22.

[0027] In a closed position, as shown in FIG. 1A, sleeve 17 is axially aligned with ports 22. In an open position, as shown in FIG. IB, sleeve 17 is axially misaligned with ports 22, allowing fluid communication between central passage 14 and the adjacent reservoir via ports 22. For avalve assembly in the closed position to completely prevent fluid communication through ports 22, one more seals 24 are provided within the annulus between housing 12 and sleeve 17. For simplicity, only the seals 24 downhole from ports 22 are labeled. Sliding sleeve 17 from the closed position to the open position, may result in pressure unloading that exerts force upon and results in detachment of now exposed seal 24.

[0028] FIG. 1C illustrates an axial cross section of a seal arrangement commonly found in valve assemblies. An O-ring seal 24 is held within a groove 25, or other recess, on the inner surface of the housing 12, and supported by backup rings 26 to prevent movement of the seal through an extrusion gap. The points of contact, or interfaces 30, between the seal 24, groove 25, and backup rings 26 are simple, consisting of 5 surfaces that are primarily flat, when viewed in cross-section, and extend circumferentially around the tubular housing 12, acting to restrain the seal within groove 25. In some embodiments, an adhesive may be employed at one or more of the interfaces.

[0029] An axial cross-section of a general packer assembly 38 and used for pressure isolation within a wellbore is shown in FIG. 3A. Packer 40 is disposed around a mandrel 42 and flanked by retaining rings 44 and 46. One of rings 44 and 46 is axially fixed to mandrel 42, while the other ring may become axially fixed, via slips or other means, to the casing or wellbore in which the tool is situated. Ring 44, in this configuration, is axially fixed relative to mandrel 42, allowing for compression of packer 40 in response to movement of ring 44 (and mandrel 42), towards ring 46, which has become axially fixed relative to casing 48 due to activation of slips 50. Compression of packer 40, which is retained between retaining rings 44 and 46, results in radial expansion, resulting in engagement with casing 48 and formation of a hydraulic seal (FIG.3B). While not necessarily required, the packer 40 may be secured using adhesives to fixed ring 44 to provide extrusion resistance. In the absence of means for mechanical restraint, securing packer 40 to fixed ring 44 solely with adhesives limits the number of adhesives and packer material available due to incompatibility issues, and limits the applications to temperatures below for which adhesives are still functional.

[0030] The interface between packer 40 and ring 44 is simple, comprising a single flat surface that extends circumferentially around mandrel 42. Alternative structures, including a groove within ring 44 and intended to increase surface area to promote adhesive bonding, have beendescribed but are still limited to a simple interface between the flexible material (packer) and the support structure (ring), comprising no more than 5 flat surfaces. Furthermore, inability to use an adhesive due to incompatibility issues would negate efforts to secure the packer 40 to ring 44 despite inclusion of a groove on the interface side of ring 44.

[0031] Provided herein is a composite arrangement comprising a flexible material and a structural support, wherein the flexible material is secured to and contacts the structural support at a complex interface. By complex interface, it is meant to include, but is not limited to, interfaces of embodiments described herein that are stated to include a complex interface. In some embodiments, the complex interfaces may include shapes that increase the number of planar, substantially planar, and / or non-planar surfaces that contact the flexible member. For example, the structural member may be shaped to have a complex-shaped groove or recess that receives the seal member, with greater than five distinct surfaces of the structural member (or reinforcement components, such as backup rings) contacting the seal member at various locations. The complex shape may help increase the bond strength and better retain the seal member within the recess. In some embodiments, the composite arrangement is a sealing arrangement.

[0032] For complex interfaces not specifically described, it is meant to include interfaces where assembly requires flowing the material over the structural support. That is, assembly cannot be accomplished simply by pressing the two components together. Furthermore, seal arrangements with a complex interface provide a higher bond strength such that detachment of the flexible material from the structural support requires damage, beyond simple deformation, of the flexible material, where damage includes, but is not limited to, tearing, ripping, and disintegration. In essence, detachment includes ripping the flexible material from its position, as opposed to it being sucked out with minimal damage. In some embodiments, detachment of the flexible material from the structural support requires tearing flexible material that is linked, or interconnected, with the structural support. In some embodiments, a complex interface is intended to include interfaces between the flexible material and the support structure where only a fraction of the interface is complex in that the interface in the complex interface fraction is consistent with embodiments described herein or with the requirements described for a complex interface.

[0033] In some embodiments, flexible members, including seals, may be bonded to structural supports, including sections of downhole tool components, using seal arrangements that provide greater bond strengths than conventional material joining techniques. The bond strengths may be increased, for example, by increasing the complexity of the interface between the seal and the downhole component and / or by creating mechanical locking features that lock, or link, the two together. The improved bond strengths provided by embodiments of seal arrangements described herein may enable the components to be utilized in high force and / or pressure applications without a high risk of the seal members detaching from the components. For example, the high bond strengths may enable the bonded materials to withstand high forces, including during pressure unloading experienced in downhole oil and gas operations. In some embodiments, the present technology may encompass seal arrangements formed between structural components and flexible members that facilitate such high bond strengths, as well as methods of bonding a flexible member to a structural component, which may include mechanical and / or chemical bonding in various embodiments.

[0034] While primarily described in conjunction with components for the oil and gas industry, it will be appreciated that the present disclosure is not limited to such components. Rather, the techniques for bonding flexible members to structural supports described herein may be utilized in applications across any number of industries, such as those in which conventional sealing techniques exhibit a high risk of failure due to high pressure and / or high force loads on the flexible member itself.

[0035] FIG. 3 illustrates schematic cross-sections of embodiments of seal arrangements between a structural support 200 and a flexible material 250, with particular focus on what may constitute a complex interface. A composite arrangement consistent with the present disclosure derives a complex interface based on the form of the structural support 200. The structural support may comprise one or more complex interfaces selected from the one or more of the group comprising a recess with a choke point, a tree structure, a recess with a support member, a lattice, and a progressive lattice. In some embodiments, a complex interface comprises greater than 5 distinct contours, or greater than 10 distinct contours, where contours can include primarily flat, concave, and convex. For structural supports which cover cylindrical shapes, suchas those common in downhole tools, the complex interface may extend circumferentially and include more than one shape described herein.

[0036] The structural support 200 may be formed from various deformation-resistant materials such as, but not limited to, metal, ceramic, polymers, and / or combinations thereof. The shape of the complex interface may be incorporated during formation of the structural support using any means available, including using additive manufacturing processes (e.g., 3D printing) and / or may be formed after production of the structural support, such as via machining techniques that remove a portion of the material forming the structural support. Additive manufacturing may be particularly useful for more complex shapes, including geometries that may be difficult and / or impossible to machine. This may include shapes with voids of various shapes and sizes, or the inclusion of interlocking support members.

[0037] Flexible material 250 may be formed and / or otherwise positioned in contact with structural support, making contact at the interface, to be held against the structural support using mechanical and / or chemical bonds. Flexible material may be formed from a deformable material, such as a thermoplastic material and / or an elastomeric material like rubber in some embodiments. In some embodiments, the elastomeric material may be formed from a chemically resistant elastomer, such as a fluoroelastomer (FKM, AFLAS®) (which may include a fluorocarbon-based fluoroelastomer that contains the monomer vinylidene fluoride), hydrogenated nitrile butadiene rubber (HNBR), ethylene propylene diene monomer rubber (EPDM), and / or a perfluoroelastomer (FFKM). In some embodiments, a thermoplastic material may include polytetrafluoroethylene (PTFE) and / or polyether ether ketone (PEEK). Other materials may also be utilized, such as engineering plastics that may include carbon, glass, bronze, and / or other materials. As noted above, in some embodiments an adhesive may be provided at the interface between the structural support and flexible material. As used herein, the term “interface” is used to refer to a region where two materials contact one another. The adhesive may be selected based on the structural support and the elastomeric material. Suitable adhesives may include, without limitation, Chemlok® adhesives, epoxy, cyanoacrylate, and / or other adhesives.

[0038] Flexible material 250 may be formed to provide contact with the structural support 200 at the interface 210. For example, flexible material 250 may be provided in flowable form duringmechanical bonding with the structural support 200. Flexible material 250 in flowable form may move into and fill recesses within the structural support 200. Recesses can include large and small voids intentionally created during formation of the structural support (FIG. 3), such as recesses with a choke point or support member, and voids within lattice structures. Flexible material 250 may also flow into microstructures (e.g., grooves, ridges, dimples, and / or other 3-dimensional relief features within surface during a surface roughening process to increase surface area. In final form, flexible material 250 may be solidified, or cured, such as by cooling the flexible material 250.As illustrated in FIG. 3, a complex interface may comprise a recess with a choke point. A recess 210a that extends into structural support 200 includes at least two regions having different cross-sectional shapes and / or sizes. A first region, in close proximity to the outermost surface of structural support 200 comprises a smaller lateral dimension than a second region that extends furthest into the structural support 200. The first region acts to serve as choke point 212, which may help ensure that flexible material 250 may resist being pulled out of engagement with recess 210a, even when subjected to high lateral and / or pulling forces. A relative size of the lateral dimension of a narrowest point of choke point 212 may be selected to be sufficiently small relative to a widest point of the second such that when flexible material 250 is subjected to large sliding and / or pulling forces, elongation of the elastomeric material will not result in flexible material 250 being stretched to a sufficient thinness to be pulled through choke point 212. Some elastomeric materials may be elongated by up to 200%, which may cause a corresponding reduction in thickness. Therefore, designing choke point 212 should consider a lateral dimension that is smaller than the smallest possible thickness of a portion of flexible material 250 that is disposed within recess 210a while flexible material 250 is under elongation. For a sealing arrangement having a recess and a choke point, detachment of flexible material 250 from structural support 200 may require damage, beyond simple deformation, that includes tearing or ripping of flexible material 250.

[0039] Choke point 212 may have any cross-sectional shape, such as circular, rectangular, triangular, and / or other shape. While shown with two different regions, it will be appreciated that recess 210a may include greater than two regions in some embodiments. For example, recess 210a may include three regions, four regions, five regions, or more. In embodiments with greaterthan two regions, each region may comprise a lateral dimension, or cross-sectional area, that is different from the other regions.

[0040] As illustrated in FIG. 3, a complex interface 210 may comprise at least one tree structure 214 extending outward from the structural support 200. Tree structure 214 may include one or more trunks 214a that extend away from structural support 200 at orthogonal angles relative to a relatively flat portion of the surface of structural support 200. It will be appreciated that one or more trunks 214a may extend at other angles. Each trunk 214a may include one or more arms 214b that extend from the trunk 214a at an angle. While shown with each arm 214b extending away from a respective trunk 214a at orthogonal angles, it will be appreciated that one or more arms 214b may extend from each trunk 214a at other angles. While two tree structures 214 are illustrated, surface of structural support 200 may include any number of tree structures 214, which may each have a same or different size, shape, and / or number of arms 214b.Additionally, while shown with linear trunks / arms, it will be appreciated that some or all of the trunks and / or arms may include arcuate and / or bent portions. In some embodiments, each tree structure 214 may be a solid component, while in other embodiments some or all tree structures 214 may include lattice structures (similar to lattice structure described below) formed within the trunks 241a and / or arms 214b. It should be clear that the inclusion of multiple trunks 214a and arms 214b provides a complex interface with much greater than 5 distinct contours, even greater than 10 distinct contours, some of which may extend circumferentially around a tubular shaped structural support, and some of which may extend shorter distances depending on the size and shape of the trunk 214a or arm 214b on which they are situated.

[0041] As illustrated in FIG. 3, a complex interface 210 may comprise a recess 216 in combination with one or more support members 216a spanning between the walls of recess 216.The inclusion of support members 216a provides an opportunity to interlock flexible material 250 with structural support 200. During bonding, flexible material 250 in flowable form can flow around one or more support members, linking the materials together after curing, or solidifying, of the flexible material 250. It should be understood that detachment of flexible material 250 that is interlocked with a support structure 200 comprising a support member 216a would require tearing flexible material 250 into two or more pieces. Multiple support members 216a within recess 216 may have similar or different size, shape, and positioning. Multiple support members216a may be equally or differentially spaced around the circumference of a cylindrically shaped support member 200. A specific embodiment of a gauge ring having a complex interface with a recess and support members is provided in greater detail below.

[0042] As illustrated in FIG. 3, a complex interface 210 may comprise a matrix or lattice structure 218 formed as part of structural support 200. Lattice structure 218 may include a number of interconnected solid regions 218a that define a number of voids 218b. As illustrated, lattice structure 218 includes a number of orthogonal solid regions 218a that connect with one another to form rectangular voids 218b. While illustrated in cross-section, it will be appreciated that the size and shape of the solid regions 218a and voids 218b extends in 3 dimensions, and that other shapes of solid regions 218a and voids 218b are possible in various embodiments. In The size and shape of solid regions 218a, and corresponding voids 218b, may vary throughout lattice structure 218. For example, a progressive lattice structure, also shown inf FIG. 3, includes voids 218 that decrease in size from the outermost position of interface 210 relative to the point that penetrates the furthest into structural support 200. This can be accomplished by varying the size, cross-sectional shape, and or spacing of solid regions 231. The size and shape of solid regions 218a and corresponding voids 218 may also be randomized. In some embodiments, a complex interface comprises a structural support having a progressive lattice design, with void volume increasing from the outermost surface of support structure 200 to the point that the lattice structure extends into the structural support.

[0043] For a sealing arrangement having a structural support comprising a lattice structure, detachment of flexible material 250 from structural support 200 may require damage, beyond simple deformation, that includes tearing or ripping of flexible material 250. The lattice structure, progressive or otherwise, provides interlocking functionality, similar to the recess with a support member. In some embodiments, the lattice structure comprises uniform void size. In some embodiments, the lattice structure comprises non-uniform void size. In some embodiments, the sealing arrangement comprises a structural support comprising a progressive lattice.

[0044] It will be appreciated that the embodiments described in relation to FIG. 3 are merely provided as examples of a complex interface and that numerous variations exist. Moreover, features from each embodiment may be combined with one another to create mechanical seal arrangements between structural support 200 and flexible material 250 that have differentcombinations of complex interfaces, including with or without interlocking features, to tailor a geometry and mechanical bond strength of the mechanical seal arrangement to meet the needs of a particular application. The mechanical bonds between the structural support 200 and flexible material 250 described in relation to FIG. 3 may require one or both materials to fail or tear in order to detach flexible material 250 from structural support 200. Thus, the mechanical bonds may improve the overall bonding (e.g., just the mechanical bond or the mechanical bond in combination with an adhesive bond) and may create connections between components that are the same or similar to the materials forming the connection. Additionally, the mechanical bonds described herein may enable adhesive-resistant materials (e.g., FFKM, PEEK, Inconel, etc.) to be strongly joined to other materials. The mechanical bonds described herein may also enable strong connections to be formed between components in applications that expose the connections to temperatures that exceed the maximum temperatures of compatible adhesives.

[0045] FIGs. 4A-4B illustrates an embodiment of a seal arrangement between two structural supports 300a and 300b and a flexible material 350 in accordance with the present disclosure. The example is meant to illustrate the incorporation of a complex interface into structural components. In this example, the structural supports 300a and 300b comprises two back-up rings, similar to those shown in detail in FIG. IB, differing only by the inclusion of a complex interface. The seal arrangement in groove 325 may be present on the inner surface of the housing of a valve assembly and can function by sealing the annulus between a sleeve and the housing. The arrangement with two back-up rings having a complex interface with a support member within a recess, allowing for interlocking the flexible material with the back-up rings, provides greater resistance to detachment during a pressure unloading event.

[0046] The complex interface 310 may comprise recess 320, which includes a first region 320a, a restriction point 320b, second region 320c, and support members 320d. The first region 320a, in close proximity to the outermost surface of structural support 300 comprises a lateral dimension that tapers inwardly from the outermost surface 300a to the restriction point 320b. The second region 320c, which comprises a larger lateral dimension than restriction point 320b, comprises a circular cross-sectional shape, but may comprise other shapes, including, but not limited to, ovoid, rectangular, and triangular. In this embodiment, the restriction point 320b, while not required, may act as a choke point so that flexible material 350 may resist being pulledout of engagement with recess 320a, even when subjected to high lateral and / or pulling forces. First region 320a may have any cross-sectional shape, such as circular, rectangular, triangular, and / or other shape. The presence of a taper in first region 320a may enable the thinner regions of structural support 300 proximate the outermost surface 300a to flex outward to accommodate an expansion of flexible material 350 when compressed against structural support 300. The taper may be linear as shown here or may have a variable slope. Other configurations of first, second, and / or third regions are possible in various embodiments. Additionally, while shown with three different regions, it will be appreciated that recess 320 may include only two regions or greater than three regions in some embodiments. For example, recess 320 may include two regions, three regions, four regions, five regions, or more.

[0047] In some embodiments, complex interface 310 may define at least one support member 320d that extends through at least a portion of recess 320. Each support member 320d may be spaced apart from a distal end (e.g., deepest point) of recess 320 such that there is a void formed between the support member 320d and the distal end of recess 320. As illustrated, each support member 320d extends through second region 320c, however first region 320a, and / or additional regions, if present, may include one or more support members 320d in various embodiments. In embodiments in which multiple support members 360 are included, adjacent support members 320d (FIG. 4B) may be spaced apart from one another such that gaps 320e are formed between the adjacent support members 320d. In some embodiments, support members 320d may be evenly spaced around the circumference of a tubular shaped structural support. In some embodiments, support members 320d may be distributed at irregular intervals around the circumference of a tubular shaped support structure.

[0048] Each gap may be connected to at least one void formed between a support member 320d and the distal end of recess 320, which may provide a path for flexible material 350 to flow into the voids as will be discussed in greater detail below. In the illustrated embodiment, each support member 320d extends from a first side (as illustrated, top side) of recess 320 to a second side (as illustrated, bottom side) of recess 320, however other configurations are possible. Each support member 320d may have a same or different shape. As illustrated, each support member 320d is arcuate, however support member 320d may be linear and / or bent in various embodiments. Additionally, while shown with a concave portion of each support member 320facing the distal end of recess 320, arcuate portions of one or more support members 320 may face an opening of recess 320 in some embodiments. In some embodiments, rather than (or in addition to) discrete support members 320d, structural support 300 may include one or more support members within recess 320 that each form a matrix or other lattice structure (similar to lattice structure 218) that include a number of solid regions that define interior voids and / or a support structure (similar to tree structures 214). While a complex interface comprising a recess with a support member is used for illustration in FIGs. 4A-4B, it should be understood that the complex interface can comprise any of those shown in FIG. 3. Furthermore, the retaining ring 44 in FIG. 2 can incorporate any of the complex interfaces of FIG. 3 in a similar manner to inclusion of the recess with a support member for the backup rings of the valve assembly in FIG. 1

[0049] The seal arrangements described herein may create complex interfaces between two materials, such as between a seal member and a structural component, that may increase the bond strength between the two materials. The complex interfaces may create additional surface area between the materials, additional contact points between the two materials, and / or mechanical interlocks between the two materials that improve the bond strength, with or without the use of adhesives. A roughened surface texture, in contrast to smoothly machined, may provide further increases to bond strengths between the structural support and the flexible material.

[0050] For example, one or more manufacturing techniques may be utilized to impart a roughened surface texture on the structural support at the complex interface, which may result in a number of voids (e.g., valleys formed between high points) being formed. Such manufacturing techniques may include, for example, additive manufacturing processes (e.g., 3D printing) and / or surface treatments such as abrading (e.g., filing, grinding, etc.), sand blasting, laser etching, acid etching, and / or other techniques for roughening a surface. Additive manufacturing techniques may involve the deposition of a number of layers of material to form a given component, which may naturally result in an imperfect, roughened outer surface. Surface treatments may be used to impart a roughened surface on an already formed component by removing portions of material on an outer surface of the component. The roughened surface may be formed by creating microstructures (e.g., grooves, ridges, dimples, and / or other 3-dimensional relief features withinthe surface, which may increase the surface area of the roughened area. Each relief feature (or a majority of the relief features) may have lateral and / or depth dimensions that are in the range of between 0.5 microns and 1000 microns, between 1 micron and 500 microns, or between 5 microns and 100 microns. Similarly, a lateral distance between adjacent microstructures may be between 0.5 microns and 1000 microns, between 1 micron and 500 microns, or between 5 microns and 250 microns. The roughened surface texture may have a root mean square (RMS) surface roughness of at least 100, such as between 100 RMS to 1000 RMS, or any other range therebetween. In some embodiments, the roughened surface texture may have a roughness average (Ra) of at least 5 microns, at least 7.5 microns, at least 10 microns, at least 12.5 microns, at least 15 microns, or greater. This roughened surface texture may increase the contact area between structural support 200 and flexible material 250 and may therefore promote an increased mechanical bonding strength over conventional smooth finished surfaces. For example, the contact area for a substantially planar surface having a roughened texture (e.g., via inclusion of micro-relief features) may be increased by at least 25% at least 50%, at least 75%, or more relative to a smooth, machined surface, depending on a size, shape, and quantity of micro-relief structures within the contact area.

[0051] It will be appreciated that the complex interfaces between the two materials may include any combination of the above features. For example, the complex interfaces may include roughened surface textures, micro or macro relief structures, shapes that increase the number of general contours (including planar, substantially planar, and / or non-planar surfaces) that contact the seal member, and / or interlocking structures. Additionally, in some embodiments, one or more adhesives may be provided at the complex interfaces to further increase the bond strength between the two materials.

[0052] FIG. 5 illustrates operations of a method 500 of forming a seal arrangement between a support structure and a flexible material. Method 500 may be used to form any of the seal arrangements described herein, including the complex interfaces for seal arrangements described in relation to FIG. 3 and / or a component of a downhole tool, such as a valve assembly or fracturing initiation assembly, or other device. Method 500 may include a number of optional operations, which may or may not be specifically associated with some embodiments of methods according to the present technology. Method 500 may include optional operations prior toinitiation of method 500, or the method may include additional operations. For example, method 500 may include operations performed in different orders than illustrated. In some embodiments, the structural support may be prefabricated. In other embodiments, method 500 may include forming the structural support at operation 505. Forming the structural support may include forming a final shape of the structural support by machining and / or by using additive manufacturing techniques. For example, the structural support may be 3D printed, such as using selective laser sintering 3D printing, binder jetting 3D printing, powder bed fusion, directed energy deposition, fused deposition modeling, and / or other 3D printing techniques. Forming the structural support may include forming one or more voids (e.g., grooves, recesses, lattice voids, and / or other voids) in a surface of the structural support. Such voids may be formed using machining techniques, additive manufacturing processes (e.g., 3D printing), and / or surface treatments such as abrading (e.g., filing, grinding, etc.), sand blasting, laser etching, acid etching, and / or other techniques for roughening a surface.

[0053] At operation 510, method 500 may include flowing the flexible material onto the complex surface of the structural support, while the flexible material is in a flowable state. A portion of the flexible material may flow into one or more voids formed between portions of the structural support to create contact along the entirety, to the extent possible, of the complex interface. In some embodiments, flowing the flexible material into one or more voids may include injecting an elastomeric material into a recess and / or other void formed in a surface of a structural support. In some embodiments, a portion of the flexible material may flow about, encapsulate, and / or surround a portion of the structural support, such as a support member, lattice structure, and / or support structure. This may mechanically interlock a portion of the structural support with the flexible material and further increase the bond between the structural support and the flexible material. In some embodiments, a sealing end of the seal member that extends away from the surface of the component body may be formed, such as by flowing the flexible material such that a portion of the flexible material extends beyond the surface of the structural support. In some embodiments, the application of flexible material may be performed using 3D printing or other additive manufacturing techniques, while in other embodiments injection molding and / or other manufacturing techniques may be utilized. Once formed, the flexible material may be cured into a solid, non-flowable form at operation 515. This may involve, for example, reducing a temperature of the flexible material, such as by circulating airover and / or exposing the flexible material to a cooler environment. In some embodiments, prior to flowing the flexible material onto the structural support, method 500 may include applying an adhesive to at least a portion of the surface of the structural support that is to receive the flexible material.

[0054] It should be noted that the methods, systems, and devices discussed above are intended merely to be examples. It must be stressed that various embodiments may omit, substitute, or add various procedures or components as appropriate. Also, features described with respect to certain embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. Also, it should be emphasized that technology evolves and, thus, many of the elements are examples and should not be interpreted to limit the scope of the disclosure. Some embodiments were described as processes depicted as flow diagrams or block diagrams. Although each may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process may have additional steps not included in the figure.

[0055] Specific details are given in the description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, well-known structures and techniques have been shown without unnecessary detail in order to avoid obscuring the embodiments. This description provides example embodiments only, and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the preceding description of the embodiments will provide those skilled in the art with an enabling description for implementing embodiments of the disclosure. Various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the disclosure.

[0056] Also, the words “comprise”, “comprising”, “contains”, “containing”, “include”, “including”, and “includes”, when used in this specification and in the following claims, are intended to specify the presence of stated features, integers, components, or steps, but they do not preclude the presence or addition of one or more other features, integers, components, steps, acts, or groups.

[0057] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly or conventionally understood. As used herein, the articles “a” and “an” refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, “an element” means one element or more than one element. “About” and / or “approximately” as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, encompasses variations of ±20% or ±10%, ±5%, or ±0.1% from the specified value, as such variations are appropriate to in the context of the systems, devices, circuits, methods, and other implementations described herein. “Substantially” as used herein when referring to a measurable value such as an amount, a temporal duration, a physical attribute (such as frequency), and the like, also encompasses variations of ±20% or ±10%, ±5%, or ±0.1% from the specified value, as such variations are appropriate to in the context of the systems, devices, circuits, methods, and other implementations described herein. As used herein in the context of shapes, the terms “generally” and “substantially” are understood to mean that a large percentage of the shape of a component (e.g., greater than 70%, greater than 80%, greater than 90%, or more) has the described shape, however some smaller percentage of the component may stray from the shape described. For example, the component may include a number of protrusions, cutouts, and / or small components that prevent the component from perfectly matching the described shape.

[0058] Where a range of values is provided, it is understood that each intervening value, to the smallest fraction of the unit of the lower limit, unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Any narrower range between any stated values or unstated intervening values in a stated range and any other stated or intervening value in that stated range is encompassed. The upper and lower limits of those smaller ranges may independently be included or excluded in the range, and each range where either, neither, or both limits are included in the smaller ranges is also encompassed within the technology, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included.

[0059] As used herein, including in the claims, “and” as used in a list of items prefaced by “at least one of’ or “one or more of’ indicates that any combination of the listed items may be used.For example, a list of “at least one of A, B, and C” includes any of the combinations A or B or C or AB or AC or BC and / or ABC (i.e., A and B and C). Furthermore, to the extent more than one occurrence or use of the items A, B, or C is possible, multiple uses of A, B, and / or C may form part of the contemplated combinations. For example, a list of “at least one of A, B, and C” may also include AA, AAB, AAA, BB, etc.

Claims

WHAT IS CLAIMED IS:

1. A seal arrangement, comprising:a structural support; anda flexible material;wherein the structural support and the flexible material contact one another at a complex interface.

2. The seal arrangement of claim 1, wherein the complex interface comprises at least one of:a. a recess with a choke point;b. a tree structure;c. a recess with at least one support member;d. a lattice;e. a progressive lattice.; andf. a lattice comprising non-uniform void sizes.

3. The seal arrangement of claim 1, wherein the complex interface comprises greater than 5 distinct contours.

4. The seal arrangement of claim 1, wherein the complex interface comprises mechanically interlocking the flexible material to the structural support.

5. The seal arrangement of any of claims 1 to 4, wherein the structural support comprises a deformation-resistant material including metal, ceramic, polymers, and / or combinations thereof.

6. The seal arrangement of any of claims 1 to 5, wherein the complex interface is defined by the shape of the structural support.

7. The seal arrangement of any of claims 1 to 6, wherein the structural support is formed using additive manufacturing processes (e.g., 3D printing).

8. The seal arrangement of any of claims 1 to 6, wherein the complex interface is formed after production of the structural support, via machining techniques that remove a portion of the material forming the structural support.

9. The seal arrangement of any of claims 1 to 8, wherein the flexible member is a seal.

10. The seal arrangement of any of claims 1 to 9, wherein the flexible material comprises a deformable material.

11. The seal arrangement of claim 10, wherein the flexible material comprises a thermoplastic material, an elastomeric material like rubber, or combinations thereof.

12. The seal arrangement of claim 10, wherein the flexible material comprises at least one of:a. a fluoroelastomer (FKM, AFLAS ®), which may include a fluorocarbon-based fluoroelastomer that contains the monomer vinylidene fluoride);b. hydrogenated nitrile butadiene rubber (HNBR);c. ethylene propylene diene monomer rubber (EPDM)d. a perfluoroelastomer (FFKM);e. polytetrafluoroethylene (PTFE); andf. polyether ether ketone (PEEK);13. The seal arrangement of any of claims 1 to 12, further comprising an adhesive disposed between the structural support and flexible member at the complex interface.

14. The seal arrangement of any one of claims 1 to 13, wherein the surface of the structural support at the complex interface comprises a roughened texture having a roughness average (Ra) of at least 5 microns.

15. A downhole tool comprising the seal arrangement of any of claims 1 to 14.

16. The downhole tool of claim 15 wherein the downhole tool comprises a valve assembly comprising;a. a tubular housing, having inner and outer surfaces;b. one or more ports through a wall of the housing;c. a sleeve disposed within the housing and slidable between and open position and a closed position to control access through the one or more ports, and an inner surface and an outer surface; andd. a groove on one of the inner surface of the housing and the outer surface of the sleeve;wherein the seal arrangement is disposed within the groove, and comprises a flexible material secured to flanking back-up rings at a complex interface, the seal arrangement acting to seal an annulus between the outer surface of the sleeve and the inner surface of the housing.

17. The downhole tool of claim 15, wherein the downhole tool comprises a frac initiation assembly comprising:a. a mandrel;b. a packing element slidably disposed around the mandrel;c. an uphole retaining ring secured to the mandrel, positioned uphole from the packing element and secured to the packing element; andd. a downhole retaining ring slidably disposed around the mandrel and disposed down hole from the packing element;wherein the seal arrangement comprises the secure attachment of the uphole retaining ring to the packing element, and the complex interface is on a downhole end of the uphole retaining ring.

18. A method of securing a flexible member to a structural support, comprising:a. forming a structural support wherein at least a part of the surface of the structural component comprises a complex interface:b. flowing the flexible material, in flowable form, onto a surface of the structural support;c. allowing the flexible material to spread out across the complex interface, including within voids and recesses; andd. curing the flexible material into a solid form.

19. The method of securing a flexible member to a structural support of claim 18 wherein forming the structural support with a complex interface comprises 3D printing the structural support to provide a surface for the complex interface.

20. The method of securing a flexible member to a structural support of claim 18 wherein flowing the flexible material, in flowable form, onto the surface of the structural support comprises injecting the flexible material into one or more recesses of the complex interface.

21. A composite arrangement, comprising:a structural support; anda flexible material;wherein the structural support and the flexible material contact one another at a complex interface.

Images