BACKGROUND

Cross Reference Paragraph

[0001] This application claims the benefit of U.S. Provisional Application No. 63/379,937, entitled " ELASTOMER SEAL," filed October 18, 2022, the disclosure of which is hereby incorporated herein by reference.

Field

[0002] The present disclosure generally relates to elastomer seals, for example for use in oil and gas well completions, and more particularly to diamond elastomer seals for use with chevron stacks.

Description of the Related Art

[0003] Various seals and sealing systems are used in downhole oil and gas completions. For example, chevron seal assemblies or seal stacks can be used to seal between, e.g., radially between, concentric, generally cylindrical walls, such as concentric sliding sleeves. Such chevron seal assemblies include a plurality of stacked chevron-shaped seal elements.

SUMMARY

[0004] In some configurations, a downhole sealing system includes two seal stacks and an elastomer ring. Each seal stack includes a plurality of sealing elements. The elastomeric ring is disposed axially between the two seal stacks and has a diamond cross-sectional shape. The elastomeric ring is configured to provide a gas seal to the downhole sealing system.

[0005] In some configurations, a downhole tool includes a first sleeve, a second sleeve configured to move axially relative to the first sleeve, and a downhole sealing system disposed between the first sealing sleeve and the second sealing sleeve and including two seal stacks and an elastomer ring. Each seal stack includes a plurality of sealing elements. The elastomeric ring is disposed axially between the two seal stacks and has a diamond cross-sectional shape. The elastomeric ring is configured to provide a gas seal to the downhole sealing system. [0006] In some configurations, a method of sealing a downhole tool includes positioning a first sleave of the downhole tool proximate a second sleeve of the downhole tool, wherein the second sleeve is axially movable relative to the first sleeve. The method further includes positioning a downhole sealing system comprising two seal stacks and an elastomeric ring disposed axially between the two seal stacks and ring having a diamond cross-sectional shape between the first sleeve and the second sleeve to provide a gas seal to the downhole tool.

[0007] However, 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.

BRIEF DESCRIPTION OF THE FIGURES

[0008] Certain embodiments, features, aspects, and advantages of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein.

[0009] Figure 1 illustrates a cross-section of an example chevron seal stack.

[0010] Figure 2 illustrates an example sliding sleeve assembly including chevron seal stacks.

[0011] Figure 3 illustrates a cross-sectional view of an example seal according to the present disclosure.

[0012] Figure 4A shows a seal according to the present disclosure undergoing deformation as in use.

[0013] Figure 4B shows a prior art seal undergoing deformation as in use.

[0014] Figure 5 illustrates a cross-sectional view of another example seal according to the present disclosure.

[0015] Figure 6A illustrates a cross-sectional view of an example elastomer ring according to the present disclosure.

[0016] Figure 6B shows the elastomer ring of Figure 6A installed in a seal.

DETAILED DESCRIPTION [0017] 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.

[0018] 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.

[0019] Chevron seal stacks 100 include a plurality of stacked, chevron-shaped or V-shaped seal elements, for example as shown in Figure 1. In some configurations, the seal elements are made of or include a polymer, such as a plastic. Such seals are often used to seal between sliding sleeves 102, 104 in downhole components in oil and gas wells, for example as shown in Figure 2.

[0020] The present disclosure provides a diamond shaped elastomer element or ring that can be used with chevron seal stacks, and chevron seal stacks including such diamond shaped elastomer rings. The elastomer ring advantageously improves the sealing of gas of the chevron seal stack and provides sealing of gas in dynamic applications. As shown in Figure 3, a chevron seal stack 200 according to the present disclosure can include two traditional chevron stacks 204, each including a plurality of chevron-shaped seal elements or V-rings 202, and a diamond-shaped elastomer ring 210 positioned between, e.g., axially between, the two stacks 204. An elastomer ring 210 according to the present disclosure can have an elongated diamond shaped cross-section, for example as shown in Figure 6A, which may acquire a pseudo-hexagonal cross-section when installed, for example as shown in Figure 6B.

[0021] The interference between the elastomer ring 210 and the gland makes the Chevron stacks gas tight. The elastomer ring 210 is designed to match or fit into the chevron or V-ring cavity, which prevents or inhibits rotation of the elastomer ring 210 and effectively energizes the chevron stacks 204. The diamond shape of the elastomer ring 210 also advantageously allows for optimization of the contact patch with the gland to maximize sealability while minimizing friction.

[0022] Other existing chevron seals have attempted to achieve gas functionality using an O-ring shaped elastomer ring or a diamond-shaped polymer ring between chevron stacks 204 with an elastomeric V-ring 202 in each stack 204. However, an elastomeric V-ring 202 packs off fully with a little amount of pressure and prevents the relief of back pressure by the seal stack 204. This leads to a significant increase in friction because the rings seeing the back pressure are also energized from the back. This also increases the risk of extrusion. An O-ring shaped elastomer ring is prone to rolling when acting as a dynamic seal.

[0023] In contrast, the design of seals according to the present disclosure does not affect the pressure relief functionality of the traditional chevron stack 204. The design can be optimized to allow the sealing elements 202 to relieve back pressure, resulting in improved friction. The shape of the diamond-shaped elastomer ring 210 also prevents or inhibits rotation by engaging with the polymer chevron or v-ring cavity shape formed by the sealing elements 202. The design also allows for optimization of the contact patch by adjusting the angles and fdlets of the diamond shape, which allows for a better control of friction and sealability. Figure 4A shows a seal 200 including a diamond-shaped elastomer ring 210 according to the present disclosure undergoing deformation as in use, compared to a chevron stack 204 including an elastomeric V-ring 202b undergoing deformation as in use in Figure 4B. In the illustrated configurations, V-rings 202a are made of or include polytetrafluoroethylene (PTFE). The illustrated seals also include polyether ether ketone (PEEK) rings 203. The design of Figure 4B produces higher strains than that of Figure 4A per finite element analysis (FEA) calculations. The present design, for example as shown in Figure 4A, achieves higher initial contact pressures with lower strains on the elastomer (making the elastomer less likely to break) and with a smaller contact patch (leading to lower friction).

[0024] Chevron seals 200 including a diamond-shaped elastomer ring 210 according to the present disclosure can be particularly well suited for, for example, intelligent completions, such as full-bore downhole flow control valves in gas wells. Downhole flow control valves (FCVs) manipulate flow coming into or out of a reservoir to optimize injection or production. Some existing FCVs operate hydraulically. Ingress of gases into the hydraulic chamber and hydraulic lines attached to FCVs downhole can compromise operation of the FCV and other downhole equipment. Chevron seals 200 including elastomer rings 210 according to the present disclosure advantageously allow flow control valves to operate in gas wells, for example, for natural gas production or CO2 injection for carbon capture, with minimum gas leakage into their hydraulic chambers. Chevron seals 200 according to the present disclosure can also be used in formation isolation valves (FIVs), safety valves (SVs), hydraulically set packers that are sensitive to gas ingress to the chamber, and/or other hydraulically actuated or other downhole completions equipment that requires a gas seal.

[0025] In testing, a flow control valve including a chevron seal 200 with a diamond-shaped elastomer ring 210 according to the present disclosure successfully completed the equivalent of a lifecycle for the subject flow control valve with no observed damage and minimal leakage.

[0026] Figure 5 illustrates a simplified version of a seal according to the present disclosure. As shown, the seal includes the central diamond-shaped elastomer ring 210 and a sealing element 202 in the form of a chevron sealing element or V-ring on either side. The two sealing elements 202 act as supporting or backup rings to prevent or inhibit rotation of the central diamond-shaped elastomer ring 210. The diamond-shaped elastomer ring 210 can also or alternatively be used with various other types of supporting or back-up members, such as metal spacers or PEEK backup rings. For example, in one or more embodiments, one or more v-shaped backups ring or metal spacers may be used in place of or in addition to the sealing elements 202.

[0027] 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.

[0028] 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.