Fastening apparatus, system, and method

A downhole tool includes a body having a rounded or cylindrical surface, at least one relieved space in the rounded or cylindrical surface, and a protuberance within the relieved space. The downhole tool also has a generally cylindrical retaining ring that surrounds a portion of the body. One or more crimple detents are formed in the retaining ring, each crimple detent comprising a portion of the retaining ring that has been deformed radially inward into an underlying portion of the relieved space such that the deformed material of the retaining ring contacts and deforms an underlying portion of the protuberance in the relieved space, thereby joining the retaining ring to the body.

BACKGROUND

The present disclosure generally relates to apparatuses, systems, and methods for fastening a first body to a second body, and more particularly to improved apparatuses, systems, and methods for fastening a first body to a second body by deforming an outer surface of the second body into a relieved space of the first body and deforming a protuberance on the first body that is located within the relieved space.

DETAILED DESCRIPTION

In one aspect, the present disclosure provides apparatuses, systems, and methods for fastening a first body to a second body by crimpling an outer surface of the second body into a relieved space of the first body and deforming a protuberance located on the first body within the relieved space. Exemplary embodiments of the present disclosure provide numerous benefits, including simpler manufacturing and potential reduction of manufacturing costs as compared to use of threaded components, and enhanced performance, durability, and reliability for downhole tools.

Exemplary embodiments of the present disclosure include a downhole tool, such as a bypass plunger, as disclosed herein. The tool may be a unibody dual pad bypass plunger that includes a hollow plunger body, a retaining ring, and pads. Other examples of downhole tools that may include embodiments of the present disclosure include packoffs and bumper springs.

One exemplary conventional bypass plunger is a device that is configured to freely descend and ascend within tubing of a well (e.g., an oil well or a gas well), typically to restore production to a well having insufficient pressure to lift the fluids in the well to the surface. A bypass plunger may include a self-contained valve—also called a “dart” or a “dart valve” in some instances—to control the descent and ascent of the plunger. Typically, the valve is opened to permit flow of fluids in the well through the valve and passages in the plunger body as the plunger descends through the well. Upon reaching the bottom of the well, the valve is closed, blocking the passages that allow fluids to flow through the plunger and converting the plunger into a piston. With the plunger converted to a piston, the upward flow of fluids or gas is blocked, and the residual pressures in the well increase to the point that the pressure is high enough to lift the plunger and the volume of fluid above it toward the surface. As the plunger rises, it pushes fluid upward into a conduit on the surface for recovery. When the plunger reaches the surface, a valve in the plunger is opened by a striker mechanism and the plunger thereafter descends to the bottom of the well to repeat the cycle.

While generally effective in lifting accumulated fluids and gas of unproductive wells, conventional bypass plungers tend to be complex and suffer from reliability problems in an environment (e.g., downhole) that subjects the bypass plungers to high impact forces, caustic fluids, and elevated temperatures. While attempts to simplify construction of bypass plungers and other downhole tools, to improve reliability and performance, and to reduce the cost of manufacture have been proposed, failures remain common and a need exists to eliminate the causes of these failures.

In at least one embodiment, a downhole tool is provided comprising a unitary body having a rounded or cylindrical surface, at least one relieved space in the rounded or cylindrical surface, and a protuberance within the relieved space. The downhole tool can also include one or more pads A retaining ring retains the tabs of the pads. One or more deformations or crimples formed in the retaining ring extend inward along corresponding radii of the retaining ring. This causes the material of the retaining ring to be pushed into a corresponding relieved space on the unitary body, and the inwardly extending material of the retaining ring in turn deforms a protuberance located within the relieved space to help join the retaining ring to the unitary body.

In the appended drawings, reference numbers that appear in more than one figure refer to the same structural feature. The drawings depict at least one example of each embodiment or aspect to illustrate the features of the present disclosure and are not to be construed as limiting the disclosure thereto. The term “plunger dart” or simply “dart” may also be named a poppet valve or a valve dart herein, all of which refer to the same component.

FIG.1illustrates an exploded view of a first embodiment of a downhole tool100according to the disclosure. The downhole tool100includes a body120, a central body126, a retaining ring110, first pads130, second tabs140, a retaining nut128and an end nut129. The central body126, the retaining nut128, the end nut129, the retaining ring110, and the first and second pads130/140may be machined from a suitable material, such as stainless steel alloy. The central body126may include a relieved area122having a protuberance124therewithin. The protuberance may form a single concentric ring around the central body within the relieved space122. The retaining ring110may have a concentric groove112formed in an outer surface114of the retaining ring110. The first pads130may have tabs132and134at each end. Likewise, the second pads140may have tabs142and144at each end.

In at least one exemplary method, the downhole tool100may be assembled by first affixing the end nut129to the central body126. Next, the second pads140may be placed next to the central body126, with the tabs144of the second pads140placed under a portion of the end nut129(shown in cross-section inFIG.3B). The retaining ring110may be slipped over the end of the central body126opposite the end nut129. The pads140may be placed next to the central body126, with tabs142of the second pads being located under a first inner end of the retaining ring110(seeFIG.3B).

The retaining ring110may now be crimped at one or more places along the groove112to deform portions of the retaining ring110and corresponding portions of the protuberance124underlying the deformed portions of the retaining ring110. Deforming a portion of the retaining ring110and an underlying portion of the protuberance124is hereinafter referred to as forming a “crimple.” Forming such a crimple helps to firmly join the retaining ring110to the central body126.

The first pads130may then be placed next to the central body126, with tabs134of the first pads130being located under a second inner end of the retaining ring110(seeFIG.3B). The retaining nut128may then be affixed to the central body126, with tabs132of the first pads130being located under an inner end of the retaining nut128.

One or more crimples410a,410b,410c, and410d(described in detail hereinbelow with reference toFIGS.4A,4B, and4C) may be formed in the groove112around the circumference of the retaining ring110. The crimple(s)410a,410b,410c, and410dprovide a mechanism to lock the retaining ring110on to the central body126, thereby preventing the retaining ring110from rotating or wiggling on the central body126. Affixing the retaining ring110to the central body126with the crimple(s)410a,410b,410c, and410d, and preventing the retaining ring110from moving with respect to the central body126helps to reduce wear on the retaining ring110that is associated with the retaining ring110moving (e.g., rotating or wiggling) with respect to the central body126.

FIG.2Ais a view of the central body126indicated at A inFIG.1. The diameter of the thinner portion of the central body126may, for example, be in the range of 0.5 to 2 inches. The diameter of the larger portion of the central body126containing the relived area122and the protuberance124may, for example, be in the range 1 to 2.25 inches.

FIG.2Bis an enhanced view of a portion of the larger diameter portion of the central body126that includes the relived area122and the protuberance124, as indicated at B inFIG.2A. The width256of the relieved space122may be between 0.1 and 0.2 inches. The protuberance124may, for example, be a sharp point, a small radius (e.g., 0.001 to 0.008 inches), or a small flat 0.001 to 0.01 inches wide. The angle250between the two sides of the protuberance124may, for example, be in a range of 40° to 135°. An angle that is too small may cause cracking to occur in the protuberance124when the crimple is formed. An angle that is too large may cause the protuberance124to spring back when the crimple is formed, which may result in the retaining ring110not being firmly affixed to the central body126, which would allow the retaining ring to move relative to the central body126. As noted above, this can cause wearing and ultimately failure of the downhole tool.

The transition from the sides of the protuberance may have a radius252in a range of 0.005 to 0.025 inches. The transition, from the radius252to the sides of the relieved space122, may have a radius254in a range of 0.010 inches to 0.1 inches. The sides of the relieved space122may be formed at an interior angle258having a range of 40° to 120°. Of course, all of these dimensions are only examples that would apply to a downhole tool as described. Alternate embodiments of a downhole tool that make use of the disclosed methods of forming crimples could have alternate dimensions.

FIG.3Ais a view of the downhole tool100in an assembled condition.FIG.3Ashows downhole tool100, retaining ring110, single body120, first pads130, second pads140, retaining nut128and end nut129. When assembled, tabs132of the first pads130are positioned under a portion of retaining nut128. Similarly, the tabs144of the second pads140are positioned under a portion of the end nut129. The tabs134of the first pads130and the tabs142of the second pads140are positioned under the retaining ring110.

FIG.3Bis a cross-sectional view of the downhole tool100taken along section line C-C inFIG.3A. As shown, the first pads130are shown in the cross-section with an upper portion130aand a lower portion130b. Similarly, the second pads140are shown in the cross-section with an upper portion140aand a lower portion140b.

FIG.3Cis a detail of the portion of the downhole tool100shown at D inFIG.3B. As shown, the groove112of the retaining ring110is above the relieved space122of the central body126, when the downhole tool is assembled. Also, tabs134of the first pads130are beneath a first inner end of the retaining ring110, and tabs142of the second pads140are beneath the second inner end of the retaining ring110. Thus, the first pads130and second pads140are retained by the retaining ring110, when the downhole tool is assembled.

FIG.4Ais a view of the downhole tool100with first pads130, second pads140, retaining nut128and end nut129removed to expose central body126. Retaining ring110has been deformed/crimped, with one crimple visible at410a.

FIG.4Bis a cross-sectional view through the central body126and retaining ring110taken along section line E-E inFIG.4A. As illustrated, the retaining ring110has been crimped at four locations, forming four crimples410a,410b,410c, and410dwith the central body126.

FIG.4Cis an enhanced view of a portion ofFIG.4Bindicated at F before the crimples are formed. As illustrated, the protuberance124extends upward from the central body126. The retaining ring110surrounds the central body and the protuberance, with a gap formed between the inner surface of the retaining ring110and the outer, upper edge of the protuberance.

FIG.4Dis an enhanced view of a portion ofFIG.4Bindicated at F after the crimple410bhas been formed. The protuberance124still extends upward from the main body126on both sides of the crimple410b. Because the crimping of the retaining ring110deforms the retaining ring110radially inward, the material of the retaining ring crushes into the protuberance124, locking the retaining ring110to the central body126. This prevents the retaining ring110from moving with respect to the central body126.

A crimple as disclosed herein eliminates the need for threads or separate parts, such as pins, screws, ball detents, lock nuts or washers, to lock a retaining ring or other part and onto a central body, to thereby prevent the retaining ring or other part from loosening or moving with respect to the central body. An advantage of the crimple technique and mechanism is to more reliably prevent the inadvertent disassembly of the components secured to the downhole tool, thereby ensuring a true unibody downhole tool (e.g., a bypass plunger) that remains a single unit throughout many cycles of use. In exemplary embodiments, the term crimple is a crimp and/or dimple that may approximate a crimp at a defined point as opposed to a complete circumferential crimp.

In the disclosed embodiment, a portion of the retaining ring110is deformed so that it engages and deforms an underlying portion of a circular protrusion124formed in the relieved area122on the main body, this structure comprising a crimple. This type of deformation can be superior to forming a crimp or deformation that presses a portion of the retaining ring110into underlying threads on the main body126. For example, the circular protrusion124could have physical characteristics that are undesirable for threads, but which help to better affix the retaining ring110to the main body126when the crimple is formed. This could include forming the circular protrusion124to have a higher height than a corresponding threaded portion, or forming the circular protrusion124so that it is easier to deform and/or will better affix the retaining ring110to the main body when the crimple is formed.

Also, it may be easier and less expensive to form a single circular protrusion124on the main body126, as opposed to forming threads on the main body126. For example, it may be possible to cast the main body so that it includes a single circular protrusion124, as opposed to performing a machining operation to form threads.

Also, while the disclosed embodiment includes only a single circular protrusion124, alternate embodiments could include additional circular protrusions124.

FIG.5shows exemplary downhole tools capable of utilizing embodiments of the affixing methods detailed herein. Downhole tool510is an example bypass-single pad plunger that may utilize one or more crimples as described above with reference toFIGS.1to4C. Downhole tool520is an example bypass-dual pad plunger that may utilize one or more crimples as described above with reference toFIGS.1to4C. Downhole tool530is an example bypass-shorty plunger that may utilize one or more crimples as described above with reference toFIGS.1to4C. Downhole tool540is an example bypass-sliding sleeve plunger that may utilize one or more crimples as described above with reference toFIGS.1to4C. Of course, there are many other downhole tools that could be assembled or partially assembled with crimples as disclosed herein where a portion of a first body overlying a relieved area on an underlying second body is crimped to form a crimple.

FIG.6illustrates an exemplary die for use in a press to form a crimple. The body600of the die includes a reduced diameter shank602that is shaped at its end to form the crimples410in the outer surface of the retaining ring110of the downhole tool100. The crimples410are shown in detail inFIGS.4A,4B, and4C. The crimples410, which are indentations into the outer surface of the retaining ring110, are produced by the shape of the crimple blade604. The crimple blade604includes a major radius606, a minor radius608, and a fillet radius610. The major radius606shapes the blade604to the radius of the retaining ring110at the groove112. In some embodiments, the major radius606is formed to a radial dimension slightly larger than the body of the retaining ring110or downhole tool on which the crimple is to be formed. Thus, when the blade604contacts the retaining ring110or downhole tool and begins to form the crimple410, the stresses produced in the metal retaining ring110or downhole tool tend to cause the material under the blade604to flow outward, forming a smooth crimple410. In alternate embodiments, the major radius606of the blade604may be substantially the same as or smaller than the radial dimension of the retaining ring110or downhole tool. Different retaining ring110or downhole tool diameters may require separate dies having different major radii606appropriate for each retaining ring110or downhole tool.

The minor radius608is provided for a similar reason—to allow the stresses of formation of a crimple to cause the material underlying the blade604flow outward along the work piece (e.g., the retaining ring or downhole tool). A small fillet radius610is provided on the outside edges of the blade604to reduce stress riser occurrence.

FIG.7is a flowchart of steps of a method of securing a first body to a second body. The first body may be, for example, the central body126(seeFIG.1) of the downhole tool100, and the second body may be, for example the retaining ring110.

At block702, operations700begin with inserting at least a portion of the first body into the second body, wherein the first body has a rounded or cylindrical surface, a relieved space in the rounded or cylindrical surface, and a protuberance within the relieved space.

At block704, operations700continue with forming a dent in a wall of the second body to cause a portion of the material of the second body to extend inwardly into the relieved space of the first body and to deform a portion of the protuberance.

Conditional language, such as, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain implementations could, but do not necessarily, include certain features and/or elements while other implementations may not. Thus, such conditional language generally is not intended to imply that features and/or elements are in any way required for one or more implementations or that one or more implementations necessarily include these features and/or elements. It is also intended that, unless expressly stated, the features and/or elements presented in certain implementations may be used in combination with other features and/or elements disclosed herein.

The specification and annexed drawings disclose example embodiments of the present disclosure. Detail features shown in the drawings may be enlarged herein to more clearly depict the feature. Thus, several of the drawings are not precisely to scale. Additionally, the examples illustrate various features of the disclosure, but those of ordinary skill in the art will recognize that many further combinations and permutations of the disclosed features are possible. Accordingly, various modifications may be made to the disclosure without departing from the scope or spirit thereof. Further, other embodiments may be apparent from the specification and annexed drawings, and practice of disclosed embodiments as presented herein. Examples disclosed in the specification and the annexed drawings should be considered, in all respects, as illustrative and not limiting. Although specific terms are employed herein, they are used in a generic and descriptive sense only, and not intended to the limit the present disclosure.