WO2021222496A1

WO2021222496A1 - Downhole seal assembly

Info

Publication number: WO2021222496A1
Application number: PCT/US2021/029785
Authority: WO
Inventors: Kevin Wayne HENRY
Original assignee: Schlumberger Technology Corporation; Schlumberger Canada Limited; Services Petroliers Schlumberger; Schlumberger Technology B.V.
Priority date: 2020-04-29
Filing date: 2021-04-29
Publication date: 2021-11-04

Abstract

A seal assembly includes a plurality of components arranged in a seal stack within a seal bore. The plurality of components include: a substantially T-shaped seal element; and two substantially V-shaped seal elements, one of the two substantially V-shaped seal elements positioned on each side of the substantially T-shaped seal element. In a first sealing position, the substantially T-shaped seal element contacts the seal bore, and the two substantially V-shaped seal elements do not contact the seal bore. In a second sealing position, the substantially T-shape seal element contacts the seal bore, and the two substantially V-shaped seal elements contact the seal bore.

Description

PATENT APPLICATION

DOWNHOLE SEAL ASSEMBLY CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present document is based on and claims priority to U.S. Provisional Patent Application Serial No. 63/017,494, filed April 29, 2020, which is incorporated herein by reference in its entirety.

BACKGROUND

[0002] Oil and gas wells utilize a borehole drilled into the earth and subsequently completed with equipment to facilitate production of desired fluids from a reservoir. Subterranean fluids, such as oil, gas, and water, are produced from the wellbore. Sometimes it is necessary to temporarily shut off the flow of fluids via an isolation valve. Further, it may be desirable to seal off an annular space with one or more seal assemblies. Such seal assembly can be a component of the isolation valve, or other wellbore devices. In some downhole applications, the seal assembly may need to be able to operate in high pressure environments without failure. Therefore, there is a need for a seal assembly configuration that performs reliably during high pressure downhole applications.

SUMMARY

[0003] According to one or more embodiments of the present disclosure, a seal assembly includes: a plurality of components arranged in a seal stack within a seal bore, the plurality of components including: a substantially T-shaped seal element; and two substantially V-shaped seal elements, one of the two substantially V-shaped seal elements positioned on each side of the substantially T-shaped seal element, wherein, in a first sealing position, the substantially T-shaped seal element contacts the seal bore, and the two substantially V-shaped seal elements do not contact the seal bore, and wherein, in a second sealing position, the substantially T-shaped seal element contacts the seal bore, and the two substantially V-shaped seal elements contact the seal bore.

[0004] According to one or more embodiments of the present disclosure, a seal assembly includes: a first seal element having a first size; and a second seal element having a second size, wherein the first size is larger than the second size under a first condition, and the first size and the second size are substantially the same under a second condition.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and:

[0006] FIG. 1 shows a seal assembly according to one or more embodiments of the present disclosure.

DETATEED DESCRIPTION

[0007] In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments are possible. This description is not to be taken in a limiting sense, but rather made merely for the purpose of describing general principles of the implementations. The scope of the described implementations should be ascertained with reference to the issued claims.

[0008] As used herein, the terms “connect”, “connection”, “connected”, “in connection with”, and “connecting” are used to mean “in direct connection with” or “in connection with via one or more elements”; and the term “set” is used to mean “one element” or “more than one element”. Further, the terms “couple”, “coupling”, “coupled”, “coupled together”, and “coupled with” are used to mean “directly coupled together” or “coupled together via one or more elements”. As used herein, the terms "up" and "down"; "upper" and "lower"; "top" and "bottom"; and other like terms indicating relative positions to a given point or element are utilized to more clearly describe some elements. Commonly, these terms relate to a reference point at the surface from which drilling operations are initiated as being the top point and the total depth being the lowest point, wherein the well (e.g., wellbore, borehole) is vertical, horizontal or slanted relative to the surface.

[0009] Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and/or within less than 0.01% of the stated amount. As another example, in certain embodiments, the terms “generally parallel” and “substantially parallel” or “generally perpendicular” and “substantially perpendicular” refer to a value, amount, or characteristic that departs from exactly parallel or perpendicular, respectively, by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degree.

[0010] The present disclosure generally relates to a system that facilitates improved sealing with respect to downhole seal assemblies. A seal assembly according to one or more embodiments of the present disclosure is a redundant seal, such as a seal stack, for example. In one or more embodiments of the present disclosure, the seal assembly may be moved from a first sealing position to a second, more robust, sealing position within a seal bore. During high pressure downhole applications, increased friction in and around a conventional seal assembly may prevent movement of the seal assembly from the first sealing position to the second sealing position. Advantageously, due to the configuration of the seal assembly according to one or more embodiments of the present disclosure, a relatively low coefficient of friction has to be overcome to move the seal assembly from the first sealing position to the second sealing position, even in high pressure downhole applications.

[0011] Referring now to FIG. 1, a seal assembly 10 according to one more embodiments of the present disclosure is shown. As shown in FIG. 1, the seal assembly 10 may include a plurality of components arranged in a seal stack within a seal bore 11, according to one or more embodiments of the present disclosure. Specifically, the seal assembly 10 according to one or more embodiments of the present disclosure includes a substantially T-shaped seal element (hereinafter, “T-seal”) 12 and a pair of substantially V-shaped seal elements (hereinafter, “V- seals”) 14. In one or more embodiments of the present disclosure, the T-seal 12 and/or the V-seals 14 may be pressure-energized elastomeric seals, for example. In one or more embodiments of the present disclosure, the T-seal 12 may be positioned in a relatively centered position within the seal assembly 10 with the two V-seals 14 positioned on each side of the T-seal 12. As shown in FIG. 1, for example, the V-seals 14 have a smaller size compared to the T-seal 12 so that the V-seals do not contact the seal bore 11 when the seal assembly 10 is in a first sealing position. In contrast, due to its relatively larger size, the T-seal 12 is the primary seal of the seal assembly 10 that remains in contact with the seal bore 11 at all times. That is, the T-seal 12 of the seal assembly 10 contacts the seal bore 11 when the seal assembly 10 is in each of the first sealing position and the second sealing position, and when the seal assembly 10 is moving from the first sealing position to the second sealing position. Because only the T-seal 12 of the seal assembly 10 contacts the seal bore 11 in this way, a lower coefficient of friction of the seal assembly 10 may be realized, enabling the seal assembly 10 to move relatively easily in the seal bore 11 from the first sealing position to the second sealing position.

[0012] Still referring to FIG. 1, the seal assembly 10 according to one or more embodiments of the present disclosure may include a backup ring 16 engaging one side of each V- seal 14. The seal assembly 10 according to one or more embodiments of the present disclosure may also include a male adapter 18 disposed adjacent the V-seal 14, but on an opposite side of the V-seal 14 relative to the backup ring 16. As further shown in FIG. 1, the seal assembly 10 according to one or more embodiments of the present disclosure may include a spacer 20 disposed between the T-seal 12 and each male adapter 18.

[0013] Still referring to FIG. 1, the backup ring 16 of the seal assembly 10 includes an angle Q at which the backup ring 16 engages one side of a corresponding V-seal 14. According to one or more embodiments of the present disclosure, this angle Q may be between about 45 degrees and about 90 degrees, for example. Moreover, the V-seal 14 may include an angle Q minus about 5 degrees at which the male adapter 18 engages the other side of the corresponding V-seal 14, according to one or more embodiments of the present disclosure. The male adapter 18 may engage the corresponding V-seal 14 at a protrusion having an angle Q plus about 5 degrees. These differing angles of components of the seal assembly 10 may contribute to the robustness and reliability of the seal assembly 10 when the seal assembly 10 is in the second seal position, as previously described, in one or more embodiments of the present disclosure.

[0014] According to one or more embodiments of the present disclosure, the seal assembly 10 is under a first condition when the components of the seal assembly 10 remain static, such as when there is no differential pressure applied to either side of the seal assembly 10, for example. In contrast, the seal assembly 10 is under a second condition when a significantly higher differential pressure is applied on one side of the seal assembly 10. In operation, when a significantly higher differential pressure is applied on one side of the seal assembly 10, the stack of seals of the seal assembly 10 is pushed to the other side of the seal bore 11. As a result, the V- seal(s) 14 encounter the corresponding male adapter 18, expand in size, make contact with the seal bore 11, and create a more robust seal when the seal assembly 10 is in the second sealing position. Advantageously, the V-seal(s) 14 do not engage with the seal bore 11 during movement of the seal assembly 10 from the first sealing position to the second sealing position. As such, friction of the seal assembly 10 is minimized during movement, making the transition from the first sealing position to the second sealing position relatively easier than conventional seal assemblies having more than a T-seal engaged with the seal bore, for example. In the second sealing position, because both of the V-seal(s) 14 and the T-seal 12 are in contact with the seal bore 11, the overall friction coefficient of the seal assembly 10 is much higher than before, so that the seal assembly 10 remains relatively static and can no longer be moved easily within the seal bore 11. As such, in the second sealing position, the seal assembly 10 is more robust and has improved reliability for downhole high pressure applications. According to one or more embodiments of the present disclosure, this process may be reversed when the direction of the pressure differential is reversed.

[0015] Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments described may be made and still fall within the scope of the disclosure. It should be understood that various features and aspects of the disclosed embodiments can be combined with, or substituted for, one another in order to form varying modes of the embodiments of the disclosure. Thus, it is intended that the scope of the disclosure herein should not be limited by the particular embodiments described above.

Claims

CLAIMS What is claimed is:

1. A seal assembly, comprising: a plurality of components arranged in a seal stack within a seal bore, the plurality of components comprising: a substantially T-shaped seal element; and two substantially V-shaped seal elements, one of the two substantially V- shaped seal elements positioned on each side of the substantially T- shaped seal element, wherein, in a first sealing position, the substantially T-shaped seal element contacts the seal bore, and the two substantially V-shaped seal elements do not contact the seal bore, and wherein, in a second sealing position, the substantially T-shaped seal element contacts the seal bore, and the two substantially V-shaped seal elements contact the seal bore.

2. The seal assembly of claim 1, wherein at least one of the substantially T-shaped seal element, and the two substantially V-shaped seal elements is a pressure- energized elastomeric seal.

3. The seal assembly of claim 1, wherein the substantially T-shaped seal element is positioned in a relatively centered position within the seal assembly.

4. The seal assembly of claim 1, wherein the two substantially V-shaped seal elements do not engage with the seal bore during movement of the seal assembly from the first sealing position to the second sealing position.

5. The seal assembly of claim 1, further comprising: a backup ring engaging one side of each of the two substantially V-shaped seal elements.

6. The seal assembly of claim 5, further comprising: a male adapter disposed adjacent to each of the two substantially V-shaped seal elements on an opposite side of the V-seal element relative to the backup ring.

7. A seal assembly, comprising: a first seal element having a first size; and a second seal element having a second size, wherein the first size is larger than the second size under a first condition, and the first size and the second size are substantially the same under a second condition.

8. The seal assembly of claim 7, wherein the first seal element is in a substantially T- shape.

9. The seal assembly of claim 8, wherein the second seal element is in a substantially V-shape.

10. The seal assembly of claim 7, wherein the second condition has a substantially high differential pressure applied on one side of the seal assembly.

11. The seal assembly of claim 7, wherein at least one of the first seal element and the second seal element is a pressure-energized elastomeric seal.

12. The seal assembly of claim 7, wherein the first seal element is positioned in a relatively centered position within the seal assembly.

13. The seal assembly of claim 12, wherein the second seal element is positioned on either side of the first seal element.

14. The seal assembly of claim 7, wherein the first seal element and the second seal element are arranged in a seal stack within a seal bore.

15. The seal assembly of claim 14, wherein the first seal element remains in contact with the seal bore when the seal assembly is in a first sealing position and when the seal assembly is in a second sealing position.

16. The seal assembly of claim 15, wherein the seal assembly is in the first sealing position when the seal assembly is under the first condition, wherein the seal assembly is in the second sealing position when the seal assembly is under the second condition, and wherein the second condition has a substantially high differential pressure applied on one side of the seal assembly.

17. The seal assembly of claim 15, wherein the second seal element does not engage with the seal bore during movement of the seal assembly from the first sealing position to the second sealing position.

18. The seal assembly of claim 9, further comprising: a backup ring engaging one side of the second seal element.

19. The seal assembly of claim 18, further comprising: a male adapter disposed adjacent to the second seal element on an opposite side of the second seal element relative to the backup ring.