Patent Application
20240060384
A variety of tools are used in drilling, completion, stimulation, and production of oil and gas wells. Took are often tubular, to conform with the generally round profile of the drilled well and with other tubular tools. For example, a well may be drilled with a drill bit at the lower end of a string of tubular drill pipe that is progressively assembled to reach the desired well depth, and then removed. During drilling, fluid is circulated through the drill pipe to lubricate the drill bit and remove cuttings. After drilling, a string of relatively large diameter tubular casing may be lowered into the wellbore and secured by circulating cement downhole and through an annulus between the casing and formation. This casing string reinforces the wellbore and may be perforated at selected depths and intervals for extracting hydrocarbon fluids from a production zone(s) of the formation. The well may be stimulated by sealing off and delivering fluid to selected production zones. Then, a production tubing string may be run into the well to the production zone, protecting the casing and providing a flow path to a wellhead through which the oil and gas can be produced.
In each of the various wellbore operations, it is often necessary to seal between adjacent surfaces between tubular equipment and/or with the wellbore. For example, during fracturing or cementing operations various fluids are pumped into the well and hydraulically forced out into a surrounding subterranean formation. This typically requires sealing the wellbore to provide zonal isolation. Wellbore isolation devices, such as packers, bridge plugs, and fracturing plugs (i.e., “frac” plugs) are designed for these general purposes. Such wellbore isolation devices maybe used in direct contact with the formation face of the well or with a string of casing that lines the walls of the well. A universal challenge in downhole sealing systems is to design robust mechanisms that fit within the tight downhole confines.
This disclosure includes apparatus and methods for securing any of a variety of components to a tubular member of a downhole well tool. The disclosed examples are particularly well suited to securing a sealing element to a mandrel, for instance. Aspects of this disclosure are directed to retention of such a sealing element or other component in a way that reduces component stress during assembly and related sources of seal failure. The disclosed systems address certain challenges due, for example, to gas tight requirements, high pressure high temperature (HPHT) environments. The disclosed systems and methods are also well suited to dynamic sealing applications where space is limited, where reduced clearances between moving parts are required for seal functionality, and where materials systems are otherwise pushed to their limits.
In some examples, a retaining ring is secured on a mandrel by positioning pre-formed retention segments in a channel defined between the mandrel and retaining ring. The channel is cooperatively defined by a ring groove circumferentially extending along an inner surface of the retaining ring and a mandrel groove circumferentially extending along an outer surface of the retaining ring. The pre-formed segments may be individually inserted into the channel through an access opening on the outer surface of the retaining ring, and progressively sliding them into the channel. A closure, which may be embodied as a retention clip, is used to close the access opening, to optionally fill at least some of the remaining space within the channel not occupied by retention segments, and to secure the retention segments within the channel. Various example configurations are disclosed for the retention segments, the channel, the closure, and detailing other example features and benefits.
As further discussed below, a ring groove circumferentially extending along an inner surface of each retaining ring 40 and a mandrel groove circumferentially extending along an outer surface of the mandrel 12 cooperatively define an internal, circumferentially extending channel. A plurality of retention segments may be circumferentially disposed within the channel of the retaining ring 40 through an access opening 44. The retention segments prevent axial movement of the retaining rings 40 on the mandrel 12 to axially secure the retaining rings 40 to the mandrel 12. It should be recognized that the downhole seal assembly 10 of
The retention segments 50 can be inserted by hand, such as by dropping each one directly into the channel 42, using an insertion or positioning tool if necessary. After inserting a particular retention segment 50, the retaining ring 40 and/or mandrel 12 may be manipulated, such as by rotating one relative to the other, to facilitate the movement of the inserted retention segments 50 along the channel 42, so that additional retention segments 50 may be inserted. The retention segments 50 may be individually inserted, one-by-one, until the desired number of retention segments 50 have been inserted, such as to fill or partially fill the channel 42. A tool may be used as necessary (e.g., the tool 75 of
Each retention segment 50 shown in
The channel 42 need not be filled end-to-end with retention segments 50 to secure the retaining ring 40. For example, one or more embodiments may secure the retaining ring by collectively spanning a total of as few as 180 degrees of a 360-degree channel. However, each retention segment 50 added to the channel 42 will generally contribute an incremental amount of retention strength or stability. Thus, increasing the number of retention segments 50 to the channel 42 up to as much as the full 360-degrees of the channel 42 may also contribute to lateral or radial stability of the retaining ring 40 relative to the mandrel 12 by more completely filling up a volume of the channel 42. Thus, in some embodiments, enough retention segments 50 may be provided to substantially fill the channel 42, or leaving enough space for a closure at the access opening 44 and/or an optional spring or other element that occupies some portion of the channel 42 along with the retention segments 50.
Although not strictly required in every embodiment, filling the channel 42 with enough retention segments to collectively span a combined 360 degrees of the channel generally maximizes retention for a given channel and segment configuration. In some embodiments, it is sufficient to have the segments ride loosely in the channel and/or fill less than 360 degrees of the channel 42 because the tool would experience uniform loading (pressure) on all the segments simultaneously. Thus, in some embodiments, enough retention segments will be inserted to span at least half the circumference of the channel, i.e., nominally at least 180 degrees of the channel. This may have some advantages in certain applications, where less than 360 degrees of retention is sufficient to axially secure parts, such as to reduce part count and costs, weight, or rotational friction.
The retaining ring 40 may also be rotationally secured relative to the mandrel 12 with the use of a key or discontinuity 47 on or the mandrel or retaining ring in the channel 42 to limit movement of the retention segments around the mandrel 12. Just one example location of such a key or discontinuity 47 is indicated in the figure, which interferes with relative rotation between the mandrel 12 and retaining ring 40. Although one key or discontinuity 47 is shown by way of example, additional keys or discontinuities could be circumferentially spaced about the retaining ring 40. A key may be a piece of material added within the channel 42, for example. The key could be formed on the retaining ring by any suitable technique including but not limited to welding or press fitting the key into the mandrel groove. A discontinuity could alternatively be formed by simply not machining the mandrel groove completely around the OD of the mandrel 14 but leaving at least a small segment uncut. This may result in the channel 42 extending less than 360 degrees around the circumference of the mandrel 12.
Each retention segment 50 may be pre-formed during manufacturing to conform with the profile of the channel 42. The retention segments may be formed in any of a variety of ways. Various manufacturing processes can be used to produce the segments based on the material, cross section, and tolerance requirements of the retention segments 50. Such manufacturing processes include, for example, spring forming, water/plasma jet, computer numeric controlled (CNC) machining, additive manufacturing, casting, electrical discharge machining (EDM), as well as others. Additionally, the retention segments may be heat treated to obtain specific material properties such a yield strength and elongation.
The retention segments 50 and channel 42 may also be formed with any of a variety of sizes and cross-sectional shapes. Certain cross-sectional shapes can have certain benefits or features, such as strength, rigidity, or ease of assembly. Certain cross-sectional shapes (e.g. an I-beam) may include one or more flanges slidably captured within a portion of the ring groove and/or mandrel groove, enabling the retention segments 50 to take on radial loading in addition to shear loading. Examples of circular, stepped, and I-beam cross-sectional shapes are illustrated in
Those of skill in the art having benefit of this disclosure will appreciate, without further illustration, that a myriad of other cross-sectional shapes are possible beyond these specific examples. Having discussed the different retention segment and channel geometry possible, discussion returns to assembly using of the retaining ring 40 and retention segment 50 of
The end segments 90, which may be referring to as interlocking end segments, include features that interlock with the closure 60 and remain interlocked while in compressive engagement from the compression provided by the spring 170. In this embodiment, an end segment 90 is provided on each side of the closure 160, which may function like other retention segments 50 in terms of the interference to axial movement of the retaining ring. The end segments 90 also include an end feature 91 that overlaps with an end feature 161 of the closure 160. During assembly, after the retention segments 50 and end segments 90 have been inserted into the channel, the interlocking end segments may be urged outwardly against the compressive force provided by the spring 170 to provide enough space at the access opening 44 to insert the closure 160. In particular, the end segments 90 may be spread apart far enough to create clearance between the overlapping end features 91, 161 to insert the closure 160 into the channel 42. Then, the spring 170 may urges the interlocking end segments circumferentially within the channel 42 back into abutment with the closure 160 and with the end features 91, 161 overlapping. The overlapping end features 91, 161 on either side prevent or resist inadvertent removal of the closure 160 and loss of retention segments 50.
Any suitable closure for closing an access opening is also within the scope of this disclosure.
Accordingly, the present disclosure provides various apparatus, methods, and tools for securing a component such as a sealing element to a tubular mandrel of a downhole tool. These may include any of the various features disclosed herein, including one or more of the following statements.
Statement 1. An apparatus, comprising: a mandrel defining a mandrel groove circumferentially extending along an outer surface of the mandrel; a retaining ring defining a ring groove circumferentially extending along an inner surface of the retaining ring and an access opening to the ring groove from an outer surface of the retaining ring, the retaining ring positionable around the mandrel to cooperatively define a channel with the ring groove and the mandrel groove; and a plurality of retention segments insertable through the access opening into the channel for axil0ecuringcuring the retaining ring to the mandrel.
Statement 2. The apparatus of Statement 1, further comprising a spring insertable through the access opening into the channel to place the plurality of retention segments in circumferential compression within the channel.
Statement 3. The apparatus of Statement 1 or 2, further comprising: a closure removably securable to the retaining ring to close the access opening and secure the plurality of retention segments in the channel.
Statement 4. The apparatus of any of Statements 1 to 3, wherein the plurality of retention segments comprise two end segments disposed in the channel on opposing sides of the access opening, and the closure extends radially into the channel between the two end segments.
Statement 5. The apparatus of Statement 4, wherein at least one of the end segments has an interlocking end that interlocks with the closure extending radially into the channel.
Statement 6. The apparatus of Statement 5, wherein the end of the at least one of the end segments circumferentially overlaps with a portion of the closure.
Statement 7. The apparatus of any of Statements 1 to 6, further comprising a key formed along one or both of the ring groove and the mandrel groove to limit circumferential movement of the retention segments along the channel.
Statement 8. The apparatus of any of Statements 1 to 7, wherein the plurality of retention segments span at least 180 degrees of the channel.
Statement 9. The apparatus of any of Statements 1 to 8, wherein one or more of the retention segments comprise a stepped cross section including a radially-inner portion and a radially-outer portion, the radially-outer portion having a width greater than a width of the radially-inner portion.
Statement 10. The apparatus of any of Statements 1 to 9, wherein one or more of the retention segments has a beam-shape cross section including one or both of a flanged end slidably captured within the ring groove and a flanged end slidably captured within the mandrel groove when inserted in the channel.
Statement 11. The apparatus of any of Statements 1 to 10, further comprising: a sealing member secured to the mandrel by the retaining ring and configured for deploying outwardly from the mandrel.
Statement 12. A downhole tool, comprising: a mandrel defining a mandrel groove circumferentially extending along an outer surface of the mandrel; a retaining ring defining a ring groove circumferentially extending along an inner surface of the retaining ring and an access opening to the ring groove from an outer surface of the retaining ring, the retaining ring positionable around the mandrel to cooperatively define a channel with the ring groove and the mandrel groove; a plurality of retention segments insertable through the access opening into the channel for axially securing the retaining ring to the mandrel; a spring insertable through the access opening into the channel to place the plurality of retention segments in circumferential compression within the channel; and a sealing member secured to the mandrel by the retaining ring and configured for deploying outwardly from the mandrel.
Statement 13. The downhole tool of Statement 12, further comprising: a closure removably securable to the retaining ring to close the access opening and secure the plurality of retention segments in the channel; wherein the plurality of retention segments comprise two end segments disposed in the channel on opposing sides of the access opening, and the closure extends radially into the channel between the two end segments; and wherein each end segment has an interlocking end that interlocks with the closure by circumferentially overlapping with a portion of the closure when in compressive engagement from the compression spring.
Statement 14. A method of securing a component to a well tool, comprising: positioning a retainer ring on a mandrel of the well tool; and inserting a plurality of retention segments through an access opening on a retainer ring and into a channel defined between a ring groove on the retainer ring and a mandrel groove on the mandrel.
Statement 15. The method of Statement 14, further comprising: securing a closure to the retaining ring to close the access opening after inserting the plurality of retention segments into the channel.
Statement 16. The method of Statement 14 or 15, further comprising inserting a compression spring through the access opening into the channel to place the plurality of retention segments in circumferential compression within the channel.
Statement 17. The method of any of Statements 14 to 16, further comprising filling at least 180 degrees of the channel with the plurality of retention segments.
Statement 18. The method of any of Statements 14 to 17, further comprising securing a sealing member to the mandrel with the retaining ring.
Statement 19. The method of Statement 18, further comprising: further securing the sealing member to the mandrel by positioning a second retainer ring about the mandrel and inserting a second plurality of retention segments through an access opening on the second retainer ring and into a channel defined between a ring groove on the second retainer ring and another mandrel groove on the mandrel.
Statement 20. The method of any of Statements 14 to 19, wherein each retention segment comprises a circular cross-section, a stepped cross section, or a beam-shaped cross section.
For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values even if not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.
Therefore, the present embodiments are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present embodiments may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Although individual embodiments are discussed, all combinations of each embodiment are contemplated and covered by the disclosure. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. It is therefore evident that the particular illustrative embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present disclosure.
This is a divisional of U.S. application Ser. No. 17/179,79, filed Feb. 19, 2021, which is a nonprovisional application claiming priority to U.S. Provisional Patent Application No. 63/051,666, filed Jul. 14, 2020, the entire disclosures of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63051666 | Jul 2020 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17179973 | Feb 2021 | US |
| Child | 18370925 | US |
