Downhole sealing assembly

Abstract

The present invention relates to a downhole sealing assembly for providing a seal in a wellbore between a first face and a second face of a completion member having an axial extension direction along the wellbore, the downhole sealing assembly comprising: an annular sealing element for arrangement on the second face, the annular sealing element is provided with a base part, a first annular flange and a second annular flange, the first annular flange and the second annular flange extend from the base part in the axial extension direction, so that a cavity is formed between the first annular flange and the second annular flange, and the first annular flange is arranged to be closest to the first face and is provided with a protrusion used for abutting against the second face; a downhole seal assembly includes a base having a cavity, and a metal annular element disposed in the cavity, the metal annular element having a first annular end proximate the base and a second annular end opposite the first annular end, the metal annular element having a first annular surface formed with a first recess for receiving a first annular flange, a first spring element is arranged in the cavity between the first annular flange and the metal annular element so as to urge the first annular flange against the second face. The invention also relates to a downhole sealing unit comprising a first downhole sealing assembly and a second downhole sealing assembly. Further, the present invention relates to a completion member comprising a first member portion having a first face and a second member portion having a second face. Finally, the invention also relates to a downhole system comprising a completion member mounted as part of a metal well tubular structure and an annular barrier.

Description

Technical Field

[0001] The present invention relates to a downhole sealing assembly for providing a seal between a first face and a second face of a completion component in a wellbore, the completion component having an axial extension direction along the wellbore. The present invention also relates to a downhole sealing unit, which comprises a first downhole sealing assembly and a second downhole sealing assembly. In addition, the present invention relates to a completion component, which comprises a first component part having a first face and a second component part having a second face. Finally, the present invention also relates to a downhole system, comprising an annular barrier and a completion component installed as part of a metal well pipe structure. Background Art

[0002] Completion devices in oil or gas wells often require sealing mechanisms to control fluid flow in the well. One type of completion device is a sliding sleeve that can be operated to provide a flow path between the production tubing and the annulus. The sliding sleeve includes a port system that can be opened or closed by a sliding member that is usually controlled and operated by an intervention tool string. Known conventional sealing mechanisms are rated for a certain pressure differential and a certain temperature. However, for known sealing mechanisms to work in some wells, these wells experience greater pressure differentials and higher temperatures. Summary of the invention

[0003] An object of the present invention is to overcome in whole or in part the above-mentioned shortcomings and deficiencies in the prior art. More particularly, an object is to provide an improved sealing assembly capable of sealing between two end faces downhole at temperatures above 220°C and capable of withstanding pressure differentials above 1400 PSI.

[0004] The above objects and numerous other objects, advantages and features that will become apparent from the following description are achieved by the solution according to the present invention, namely by a downhole sealing assembly for providing a seal between a first face and a second face of a completion member in a wellbore, the completion member having an axial extension direction along the wellbore, the downhole sealing assembly comprising:

[0005] an annular sealing element for being arranged on the second face, the annular sealing element having a base and a first annular flange and a second annular flange, the first annular flange and the second annular flange extending from the base along the axial extension direction so that a cavity is formed between the first annular flange and the second annular flange, the first annular flange being arranged closest to the first face and having a protrusion for abutting the second face; and

[0006] a metal annular element arranged in the cavity, the metal annular element having a first annular end close to the base and a second annular end opposite to the first annular end, the metal annular element having a first annular surface formed with a first recess for receiving the first annular flange,

[0007] The downhole sealing assembly further comprises a first spring element, which is arranged in the cavity between the first annular flange and the metal annular element so as to push the first annular flange against the second surface.

[0008] Furthermore, the first recessed portion may be a curved portion extending from the first ring end to the second ring end, such that the first ring surface is concave, thereby forming the curved portion.

[0009] Furthermore, the first spring element may be plate-shaped or tubular.

[0010] Furthermore, the cavity may have an extension length extending from the base to an end of the first annular flange, the spring element having the same extension length as the cavity.

[0011] Furthermore, the first recess may have a first recess length along the axial extension direction.

[0012] Furthermore, the protrusion of the first annular flange may have a first protrusion length that is shorter than the first recess length.

[0013] Furthermore, the first spring element can have a first element length along the axial extension.

[0014] Furthermore, the metal ring element may have a second length along the axial extension direction, and the first element length may be substantially the same length as the second length.

[0015] Furthermore, the first spring element may be annular.

[0016] Furthermore, the first spring element can have a slit.

[0017] Furthermore, the metal ring element may have a slit so that the metal ring element may expand slightly when the metal ring element is installed.

[0018] Furthermore, the second annular flange may include a protrusion that protrudes away from the first annular flange.

[0019] Furthermore, the first annular flange may have a U-shaped cross section, formed with a lip flange for abutting the second face.

[0020] Furthermore, the protrusion of the first annular flange may be a part of the lip flange.

[0021] Furthermore, the metal ring element may be formed by two abutting ring elements, namely a first metal ring element and a second metal ring element.

[0022] Furthermore, the first annular surface formed as the first recess may be formed partly by the first metal annular element and partly by the second metal annular element for forming the cavity.

[0023] Furthermore, the lip flange may have a tip facing the base.

[0024] Additionally, the downhole seal assembly may further include a second spring element disposed between the lip flange and the first annular flange.

[0025] Furthermore, the second spring element may overlap the base.

[0026] Likewise, the second spring element may be annular.

[0027] Furthermore, the second spring element can have a slot.

[0028] Furthermore, the metal annular element may have a second annular surface formed as a second recess for receiving the second annular flange.

[0029] Furthermore, the second annular surface may be recessed toward the second annular flange for receiving the second annular flange, so that the second annular surface is formed as a second recessed portion in the form of a curved portion extending from the first annular end to the second annular end.

[0030] Furthermore, the second recess may have a second recess length along the axial extension direction.

[0031] Furthermore, the protrusion of the second annular flange may have a second protrusion length that is shorter than the second recess length.

[0032] Additionally, the downhole seal assembly may further include a third spring element between the second annular surface and the second annular flange.

[0033] Furthermore, the second annular flange may be shorter than the first annular flange in the axial extension.

[0034] Furthermore, the second annular surface may face the second annular flange.

[0035] Furthermore, the second annulus may be straight.

[0036] Furthermore, the first annular surface may face the first annular flange.

[0037] Furthermore, one of the first and second toroidal surfaces may be substantially straight, and the other of the first and second toroidal surfaces may have a concave portion, such as a curved portion.

[0038] Furthermore, the downhole sealing assembly may further comprise a fourth spring element abutting against the second spring element so as to reinforce the second spring element.

[0039] Furthermore, the downhole seal assembly may further comprise a metal ring having a flange overlapping a base of the downhole seal assembly and a body portion abutting the base, thereby forming a backing / support member for the annular seal element.

[0040] Furthermore, the flange may have a flange length along the axial extension direction, and the flange length is greater than or equal to the first thickness of the base.

[0041] Furthermore, the annular sealing element may be made of polytetrafluoroethylene (PTFE).

[0042] Furthermore, the spring element can be made of spring metal or spring steel.

[0043] Furthermore, the metal ring element may be made of a metal which has been proven to be usable in oil or gas wells.

[0044] The present invention also relates to a downhole sealing unit, which includes a first downhole sealing assembly and a second downhole sealing assembly, wherein the base of the first downhole sealing assembly is arranged so that the distance between it and the base of the second downhole sealing assembly is smaller than the distance between the first annular flanges, so that the first annular flange of the first downhole sealing assembly extends from the base of the first downhole sealing assembly in a direction away from the first annular flange of the second downhole sealing assembly.

[0045] Furthermore, the first downhole seal assembly and the second downhole seal assembly may be arranged back-to-back, wherein the bases are located at a distance less than the first annular flanges are located at a distance from each other.

[0046] In addition, the downhole sealing unit may further include a metal ring having a T-shaped cross section, which is arranged between the first downhole sealing assembly and the second downhole sealing assembly and abuts against the bases of the first downhole sealing assembly and the second downhole sealing assembly.

[0047] Furthermore, the metal ring may include two flanges, each flange overlapping a base of the first downhole seal assembly and a base of the second downhole seal assembly, respectively, and the body portion is disposed between the first downhole seal assembly and the second downhole seal assembly.

[0048] Furthermore, a metal ring having a T-shaped cross section may be formed by the stem and the protruding flange.

[0049] Furthermore, the downhole sealing unit may further include a first element having a first inclined surface abutting against the second inclined surface of the metal ring.

[0050] Furthermore, the downhole sealing unit may further include a first element having a first inclined surface abutting against a second inclined surface on a first side of the metal ring and a second element having a first inclined surface abutting against a second inclined surface on a second side of the metal ring.

[0051] Furthermore, the metal ring may be formed by two abutting rings, namely a first metal ring and a second metal ring.

[0052] Furthermore, each abutting ring may have an L-shaped cross-section.

[0053] In addition, the downhole sealing unit may further include a first element and a second element, wherein the first element has a first inclined surface abutting against a second inclined surface on the first metal ring, and the second element has a first inclined surface abutting against a second inclined surface on the second metal ring.

[0054] In another embodiment, the downhole sealing unit may include a first downhole sealing assembly and a second downhole sealing assembly, wherein the first downhole sealing assembly abuts the second downhole sealing assembly such that a first annular flange of the first downhole sealing assembly extends toward and faces a first annular flange of the second downhole sealing assembly.

[0055] Furthermore, the downhole sealing unit may include a first metal ring and a second metal ring.

[0056] Furthermore, the first metal ring may be arranged to abut a base of the first downhole seal assembly, and the second metal ring may be arranged to abut a base of the second downhole seal assembly.

[0057] Furthermore, the first metal ring having an L-shaped cross section may be formed by the stem portion and one protruding flange.

[0058] Furthermore, a second metal ring having an L-shaped cross section may be formed by the stem and one protruding flange.

[0059] Furthermore, the metal ring element of the first downhole seal assembly may abut the metal ring element of the first downhole seal assembly.

[0060] Furthermore, the at least one through hole may intersect both metal ring elements such that a portion of the through hole is formed as a groove in one metal ring element and another portion of the through hole is formed as a groove in the other metal ring element, these grooves together forming the through hole.

[0061] In addition, the downhole sealing unit may further include a first element and a second element, wherein the first element has a first inclined surface abutting against the second inclined surface of the first metal ring, and the second element has a first inclined surface abutting against the second inclined surface of the second metal ring.

[0062] Furthermore, the metal ring may have at least one through hole extending radially in a direction perpendicular to the axial extension direction for providing fluid communication.

[0063] Furthermore, the at least one through hole may intersect both of the two abutting rings such that a portion of the through hole is formed as a groove in one of the two abutting rings and another portion of the through hole is formed as a groove in the other of the two abutting rings, and these grooves together form the through hole.

[0064] Furthermore, the metal ring may have a first protruding flange overlapping the base of the first downhole seal assembly in the axially extending direction, and a second protruding flange overlapping the base of the second downhole seal assembly in the axially extending direction.

[0065] Furthermore, the base may have a first thickness along the axial extension direction, the first annular flange may have a second thickness perpendicular to the axial extension direction, the second annular flange may have a third thickness perpendicular to the axial extension direction, and the first thickness may be greater than the second thickness and / or the third thickness.

[0066] Furthermore, the base may have a first height, and the annular sealing element may have a first length along the axial extension, which is longer than the first height.

[0067] Furthermore, the metal ring element may have a second length along the axial extension direction, the second length being shorter than the first length.

[0068] The present invention also relates to a completion component, which includes a first component part having a first face and a second component part having a second face facing the first face, the first component part and the second component part being slidable relative to each other, and the completion component also includes a downhole sealing assembly for being arranged between the first face and the second face.

[0069] Furthermore, the completion component may be a sliding sleeve or a telescoping joint.

[0070] Furthermore, the sliding sleeve may have a sliding sleeve part as the second component part, and the sliding sleeve part may be slidable relative to an opening in a tubular section as the first component part, the tubular section being installable as part of the metal well tubular structure.

[0071] Furthermore, the tubular section may comprise a groove in which the sliding sleeve is slidably arranged.

[0072] Additionally, the expansion joint may be installed as part of a metallic well structure, and the first component portion may include a first portion that overlaps a second portion of the second component portion.

[0073] Additionally, the expansion joint may include a plurality of downhole seal assemblies disposed between the first component portion and the second component portion for sealing against the first face and the second face.

[0074] Furthermore, the second member portion may include an outer protrusion protruding radially outward from the second face, the outer diameter of the outer protrusion being greater than the inner diameter of the first member portion, thereby preventing the first member portion from sliding through the outer protrusion.

[0075] Furthermore, the first component part may include an inner protrusion protruding radially inwardly from the first face so as to prevent the second component part from sliding past the inner protrusion.

[0076] The present invention also relates to a downhole system comprising an annular barrier and a completion component installed as part of a metallic well tubular structure.

[0077] Finally, the annular barrier may include a tubular metal part having a hole and an expandable metal sleeve surrounding the tubular metal part, each end of the expandable metal sleeve being connected to the tubular metal part, thereby forming an expandable space when fluid enters the hole to expand the expandable metal sleeve until the expandable metal sleeve is pressed against the wall of the wellbore. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] The invention and its many advantages will be described in more detail below with reference to the attached schematic diagrams which show only some non-limiting embodiments for illustrative purposes, in which:

[0079] Figure 1 shows a cross-sectional view of a downhole seal assembly for providing a seal between a first face and a second face of a completion member in a wellbore;

[0080] Figure 2 Shows Figure 1 A cross-sectional view of the downhole sealing assembly shown;

[0081] Figure 3 shows a cross-sectional view of another downhole seal assembly having first and second recesses opposite a spring element;

[0082] Figure 4 A cross-sectional view of another downhole sealing assembly is shown, wherein the first annular flange has a U-shaped cross-section, thereby forming a lip-shaped flange;

[0083] Figure 5 shows a cross-sectional view of yet another downhole seal assembly having a seal backing / support member;

[0084] Figure 6 shows a cross-sectional view of yet another downhole seal assembly, wherein the second annular flange includes a protrusion;

[0085] Figure 7 shows a cross-sectional view of a downhole sealing unit including two downhole sealing assemblies facing in opposite directions such that the lip flanges are opposite to each other;

[0086] Figure 8 shows a cross-sectional view of another downhole sealing unit having a plurality of through holes in a metal ring;

[0087] Fig. 9 shows a cross-sectional view of a downhole system including completion components as a sliding sleeve and an annular barrier;

[0088] Fig. 10A A cross-sectional view showing a completion member as a telescoping joint in an initial position;

[0089] Fig. 10B Shown in the "in stroke" position Fig. 10A completion components;

[0090] Fig. 10C Shown in the "out stroke" position Fig. 10A completion components;

[0091] Fig.11 A cross-sectional view showing yet another downhole sealing unit; and

[0092] Fig.12 A cross-sectional view of another downhole sealing unit is shown.

[0093] All the figures are highly schematic and not necessarily to scale, and they show only those components which are necessary in order to elucidate the invention, other components being omitted or merely suggested. DETAILED DESCRIPTION

[0094] Figure 1 A downhole sealing assembly 1 is shown, which provides a seal between a first face 3 and a second face 4 of a completion component 50 in a wellbore 2, the completion component 50 having an axial extension direction L along the wellbore 2. The downhole sealing assembly 1 includes an annular sealing element 5 arranged on the second face 4, the annular sealing element 5 having a base 6, a first annular flange 7 and a second annular flange 8. The first annular flange 7 and the second annular flange 8 both extend from the base 6 in a first direction along the axial extension direction L, thereby forming a cavity 9 between the first and second annular flanges 7, 8. The first annular flange 7 is arranged closest to the first face 3 and has a protrusion 10 abutting the second face 4. The annular sealing element 5 is formed as a continuous ring. In another embodiment, the annular sealing element 5 may have a slit along the axial extension direction L, making it easier to install. The downhole sealing assembly 1 also includes a metal annular element 11 arranged in the cavity 9, which has a first ring end 12 closest to the base 6 and a second ring end 14 opposite to the first ring end 12. As shown Figure 2 As shown, the metal annular element 11 has a first annular surface 15 that is recessed toward the first annular flange 7, for receiving the first annular flange 7 when the downhole sealing assembly 1 is arranged between the first and second faces 3, 4. Therefore, the first annular surface 15 is formed as a first recess 16, such as a curved portion, from the first annular end 12 to the second annular end 14. The downhole sealing assembly 1 also includes a first spring element 17, which is arranged in the cavity 9 between the first annular flange 7 and the metal annular element 11 so as to push the first annular flange 7 to abut against the second face 4. When the downhole sealing assembly 1 is arranged between the first and second faces 3, 4, the annular sealing element 5 is squeezed, and the first annular flange 7 is pressed into the first recess 16, so that the first spring element 17 is stretched, and then the inherent spring force in the first spring element 17 will push the first annular flange 7 radially outward toward the second face 4, thereby providing enhanced sealing. Therefore, the downhole sealing assembly 1 is Figure 1 is shown in slight compression and tension in Figure 2 In FIG. 1 , the downhole sealing assembly 1 is shown in a relaxed state.

[0095] like Figure 1 and 2 As shown, the first spring element 17 is plate-shaped and tubular. Therefore, the first spring element 17 is annular. In one aspect, the first spring element 17 may have a slit (not shown) along the axial extension direction L, so that the first spring element 17 can expand slightly when installed in the cavity. The cavity 9 has an extension length extending from the base 6 to the end of the first annular flange 7, and the first spring element 17 has the same extension length as the cavity 9. The first recess 16 has a first recess length LI along the axial extension direction L. 1 , and the protrusion 10 of the first annular flange 7 has a length greater than that of the first recess LI 1 Short first protrusion length LP 1 (exist Figure 3 The first spring element 17 has a first element length LE along the axial extension direction L. 1 The metal ring element 11 has a second length L along the axial extension direction L. 2 , and the first element length LE 1 The metal ring element 11 may have a slit (not shown) along the axial extension direction L in one aspect, so that the metal ring element 11 can expand slightly when installed. The base 6 has a first thickness t along the axial extension direction L. 1 The first annular flange 7 has a second thickness t perpendicular to the axial extension direction L. 2 The second annular flange 8 has a third thickness t perpendicular to the axial extension direction L. 3 , the first thickness t1 Greater than the second thickness t 2 and the third thickness t 3 The base 6 has a first height h in the radial direction perpendicular to the axial extension direction L. 1 , and the annular sealing element 5 has a first length L along the axial extension direction L 1 , the first length L 1 Greater than the first height h 1 The metal ring element 11 has a second length L along the axial extension direction L. 2 , the second length is longer than the first length L 1 The first annular surface 15 faces the first annular flange 7, and the second annular surface 21 faces the second annular flange 8 and is straight. Figure 2 In the embodiment, one of the first annular surface 15 and the second annular surface 21 is substantially straight, and the other of the first annular surface 15 and the second annular surface 21 has a concave portion such as a curved portion, that is, the metal ring element 11 is concave on one side.

[0096] exist Figure 3 In the embodiment of the present invention, the metal annular element 11 has a second annular surface 21, which is formed with a second recess 22 for receiving the second annular flange 8. The second annular surface 21 is recessed toward the second annular flange 8 for receiving the second annular flange 8, so that the second annular surface 21 is formed as a second recess 22 in the form of a curved portion from the first annular end 12 to the second annular end 14. The second annular surface 21 faces the second annular flange 8, and the curved portion is configured to receive the second annular flange 8 when the downhole sealing assembly 1 is compressed between the first face 3 and the second face 4 of the completion member 50. The downhole sealing assembly 1 also includes a third spring element 23 between the second annular surface 21 and the second annular flange 8 so as to maintain the second annular flange 8 in sealing contact with the second face 4 of the completion member 50. During compression of the downhole sealing assembly 1, the second annular flange 8 is pressed into the second recess 22, so that the third spring element 23 is stretched, whereupon the inherent spring force in the third spring element 23 will push the second annular flange 8 radially outward toward the second face 4, thereby providing enhanced sealing. The second annular flange 8 is shorter than the first annular flange 7 along the axial extension direction L, and is also shorter than the metal annular element 11, so that the second recess 22 can more easily receive the second annular flange 8. By having the first recess 16 and the second recess 22, the downhole seal assembly 1 has double sealing flexibility, because during compression, both the first annular flange 7 and the second annular flange 8 can be received in the recesses, and due to the spring element, both annular flanges 7, 8 are pressed radially outward after compression, thereby providing enhanced sealing of the first face 3 and the second face 4.

[0097] exist Figure 4, the second annular flange 8 includes a protrusion 18 protruding away from the first annular flange 7. In a cross-sectional view, the first annular flange 7 has a U-shaped shape, formed with a lip flange 19 for abutting the second face 4. The lip flange 19 has a tip 32 facing the base 6. The downhole sealing assembly 1 also includes a second spring element 20, which is arranged between the lip flange 19 and the first annular flange 7 to maintain the first annular flange 7 in its intended extended position, regardless of whether the lip flange 19 is compressed, so that the lip flange 19 can function optimally as expected without being affected by any abnormal position of the first annular flange 7. The second spring element 20 overlaps the base 6 and abuts the curved portion of the first annular flange 7, that is, the "bottom" of the U shape, so as to keep the first annular flange 7 fully extended. The second spring element 20 is annular. In an aspect not shown, the first spring element 17 may have a slit to be more suitable for installation. The downhole seal assembly 1 can be pressurized from both sides, and when the pressure is greater on the left side, the pressure forces the lip flange 19 radially outward, thereby better sealing to the second face 4, and when the pressure is greater on the right side, the entire first annular flange 7 including the lip flange 19 is squeezed radially outward, thereby enhancing the ability to seal to the second face 4. The pressure from the right side also forces the second annular flange 8 toward the second face 4. Figure 4 As shown, the projection 10 of the first annular flange 7 is part of the lip-shaped flange 19 .

[0098] Figure 5 The second recess 22 has a second recess length L1 along the axial extension direction L. 2 The second concave length LI 2 Equal to the first concave length LI 1 The second annular flange 8 is shorter than the first annular flange 7 along the axial extension direction L. The downhole sealing assembly 1 further comprises a metal ring 24 having a flange 33 overlapping the base 6 of the downhole sealing assembly 1 and a main body portion 34 abutting the base 6, thereby forming a support / backing for the annular sealing element 5. The flange has a flange length LF along the axial extension direction L, which is equal to or greater than the first thickness t of the base 6. 1 , so as to support the base 6 and thus maintain the base of the annular sealing element 5.

[0099] exist Figure 6 In the embodiment, the protrusion 18 of the second annular flange 8 has a second protrusion length LP 2 , the second protrusion length LP 2 Compare Figure 5 The second recess length LI shown 2 short. Figure 6 The second annular flange 8 is Figure 5 The second annular flange 8 in the well is short, so that during the compression of the downhole sealing assembly 1, there is Figure 6 The second annular flange 8 including the protrusion 18 in the first recess 22 can be received in the second recess 22. The first recess 16 is slightly larger than the second recess 22 because the second annular flange 8 includes less material than the first annular flange 7 including the lip-shaped flange 19.

[0100] like Figure 7 As shown, the downhole sealing assembly 1 also includes a fourth spring element 31 abutting the second spring element 20 so as to strengthen the second spring element 20, thereby maintaining the first annular flange 7 in its intended extended position regardless of the compression of the lip flange 19, so that the lip flange 19 can function optimally as expected without being affected by any abnormal position of the first annular flange 7.

[0101] By having Figure 1-12 In the design of the downhole sealing assembly 1 shown, the annular sealing element 5 can be made of polytetrafluoroethylene (PTFE), so that the downhole sealing assembly 1 can withstand high temperatures above 225°C while still functioning as expected. Known seals using elastomers or similar traditional sealing materials cannot still work properly under such high temperatures because the material strength of such materials is significantly weakened at such high temperatures. The spring elements 17, 20 are made of spring metal or spring steel, and the metal annular element 11 is made of a metal that has been proven to be used in oil wells or gas wells. The materials of the downhole sealing assembly 1 are suitable for geothermal wells because all materials in the downhole sealing assembly 1 can withstand the high temperatures in such geothermal wells without losing their sealing ability. Therefore, the downhole sealing assembly 1 can operate at temperatures above 220°C and can withstand pressure differences above 1400PSI.

[0102] Figure 7 A downhole sealing unit 30 is shown, which includes a first downhole sealing assembly 1, 1a and a second downhole sealing assembly 1, 1b corresponding to the aforementioned downhole sealing assembly 1, wherein the base 6 of the first downhole sealing assembly 1, 1a faces the base 6 of the second downhole sealing assembly 1, 1b, so that the first annular flange 7 of the first downhole sealing assembly 1 extends from the base 6 in a direction away from the first annular flange 7 of the second downhole sealing assembly 1, 1b. Therefore, the first downhole sealing assembly 1, 1a and the second downhole sealing assembly 1, 1b are arranged back to back, wherein the distance between the two bases 6 is closer to each other than the distance between the two first annular flanges 7. Because the downhole sealing assemblies 1, 1a, 1b are arranged back to back, the downhole sealing unit 30 can better withstand high pressure from one side, also when sliding through the opening in the first face 3 of the completion member 50, because when one of the first downhole sealing assembly 1, 1a and the second downhole sealing assembly 1, 1b passes through the opening and thus does not have an optimal seal, the other downhole sealing assembly is able to provide sufficient sealing.

[0103] The downhole sealing unit 30 further comprises a metal ring 24 having a T-shaped cross section and arranged between the first downhole sealing assembly 1, 1a and the second downhole sealing assembly 1, 1b, and abutting against the base 6 of the first and second downhole sealing assemblies 1, 1a, 1b. The metal ring 24 comprises two flanges 33, 33A, 33B, each flange overlapping the base 6 of the first downhole sealing assembly 1, 1a and the second downhole sealing assembly 1, 1b, respectively, and the main body 34 is arranged between the first downhole sealing assembly 1, 1a and the second downhole sealing assembly 1, 1b. The metal ring 24 has two flanges, namely a first protruding flange 33A overlapping the base 6 of the first downhole sealing assembly 1, 1a along the axial extension direction L and a second protruding flange 33B overlapping the base 6 of the second downhole sealing assembly 1, 1b along the axial extension direction L. The metal ring 24 thus forms a backing / support member of the first downhole sealing assembly 1, 1a and the second downhole sealing assembly 1, 1b. The thickness of the flanges 33, 33A, 33B is significantly thicker than the thickness of the lip flange 19. The metal ring 24 has at least one through hole 25 extending radially in a direction perpendicular to the axial extension direction L for providing fluid communication. When one downhole sealing assembly 1, 1a, 1b slides through the opening in the second face 4 of the completion component 50, the through hole 25 is used to balance the pressure on the seal; the pressure is quickly balanced through the through hole 25 to optimize the sealing ability of the other downhole sealing assembly 1, 1a, 1b. This is because when the first downhole sealing assembly 1, 1a passes through the opening and therefore does not seal optimally, the second downhole sealing assembly 1, 1b is then able to provide sufficient sealing because the pressure is balanced so as to also affect the second annular flange 8 of the second downhole sealing assembly 1, 1b. The metal ring 24 may have a plurality of through holes 25, such as Figure 8 Although not shown, the annular sealing element 5 is made of PTFE and other metal parts, wherein the spring elements 17, 20 are made of spring steel. A ring or a tubular member may be arranged in the through hole 25.

[0104] Fig. 9 The completion component 50 shown in FIG. 1 is formed as part of a downhole system 100 and includes a first component part 51 having a first face 3 and a second component part 52 having a second face 4 facing the first face 3. The first component part 51 and the second component part 52 are slidable relative to each other. The completion component 50 also includes a downhole sealing assembly 1, 1a, 1b as described above, which is arranged between the first face 3 and the second face 4. Fig. 9 In the embodiment, the completion member 50 is a sliding sleeve 50A or a telescopic joint 50B, and in Fig. 10A -C, the completion component 50 is an expansion joint 50B. Fig. 9The sliding sleeve 50A has a sliding sleeve portion 55 as the second component portion 52, and the sliding sleeve portion 55 can slide relative to the opening 56 in the tubular section 58 as the first component portion 51, and the tubular section 58 can be installed as a part of the metal well pipe structure 90. The tubular section 58 includes a groove 57, and the sliding sleeve portion 55 is slidably arranged in the groove 57. On the other hand, the sliding sleeve portion 55 can slide along the inner surface of the tubular section 58 without being arranged in the groove 57.

[0105] Fig. 10A -C's expansion joint 50B can be installed as part of a metal well pipe structure 90, and the first component part 51 includes a first part 61, which overlaps with the second part 62 of the second component part 52, so that when the temperature in the well changes and the length of the metal well pipe structure 90 decreases or increases, such decrease or increase in length is accumulated / compensated by the first part 61 and the second part 62 because the first part 61 and the second part 62 can slide relative to each other, thereby accumulating / compensating for the change in length of the metal well pipe structure. Fig. 10A The expansion joint 50B is shown in its initial position, in which it is ready to increase the length of the metal well tubular structure 90 and thus stroke to its Fig. 10C The "out stroke" position shown, or ready to reduce the length of the metal well structure 90 and thus stroke it to its Fig. 10B The "in stroke" position is shown. Fig. 10A -C includes one downhole sealing assembly 1, but in another embodiment may include multiple downhole sealing assemblies 1, 1a, 1b arranged between the first part 61 and the second part 62 for sealing against the first face 3 and the second face 4. The second member part 52 includes an outer protrusion 63 protruding radially outward from the second face 4, and its outer diameter is larger than the inner diameter of the first member part 51, so as to prevent the first member part 51 from sliding through the outer protrusion 63. The first member part 51 includes an inner protrusion 64 protruding radially inward from the first face 3, and the inner diameter of the first part 61 is smaller than the outer diameter of the outer protrusion 63 of the second member part 52, so as to prevent the first member part 51 from sliding through the inner protrusion 64.

[0106] like Fig. 9As shown, the downhole system 100 includes a completion component 50 installed as a part of a metal well pipe structure 90 and two annular barriers 80. Each annular barrier 80 includes a tubular metal component 85 having a hole 86 and an expandable metal sleeve 81 surrounding the tubular metal component 85, and each end 83, 84 of the expandable metal sleeve 81 is connected to the tubular metal component 85, so that when a fluid enters the hole for expanding the expandable metal sleeve 81 until the expandable metal sleeve 81 is pressed against the wall of the wellbore 2, an expandable space 82 is formed.

[0107] Fig.11 A cross-sectional view of another downhole sealing unit 30 is shown, which includes a first downhole sealing assembly 1, 1a and a second downhole sealing assembly 1, 1b corresponding to the aforementioned downhole sealing assembly 1, wherein the base 6 of the first downhole sealing assembly 1, 1a faces the base 6 of the second downhole sealing assembly 1, 1b, so that the first annular flange 7 of the first downhole sealing assembly 1 extends from the base 6 in a direction away from the first annular flange 7 of the second downhole sealing assembly 1, 1b. Therefore, the first downhole sealing assembly 1, 1a and the second downhole sealing assembly 1, 1b are arranged back to back, wherein the distance between the two bases 6 is closer to each other than the distance between the two first annular flanges 7. The downhole sealing unit 30 also includes a metal annular element 11, which is formed by two abutting annular elements 11a, 11b, namely a first metal annular element 11a and a second metal annular element 11b. Furthermore, the first annular surface 15 forming the first recess 16 is formed partly by the first metal annular element 11 a and partly by the second metal annular element 11 b for forming the cavity 9 .

[0108] In addition, the metal ring 24 is formed by two abutting rings 24a, 24b, namely the first metal ring 24a and the second metal ring 24b, so that the abutting first metal ring 24a and the second metal ring 24b have a T-shaped cross section, which is formed by the rod 53 and the protruding flanges 33, 54a, 54b, wherein each protruding flange 33, 54a, 54b overlaps with the first downhole sealing assembly 1, 1a and the second downhole sealing assembly 1, 1b, respectively. Therefore, each abutting ring 24a, 24b has an L-shaped cross section, which is formed into a T-shaped cross section when the rings abut. The downhole sealing unit 30 also includes at least one through hole 25 that intersects both abutting rings 24a, 24b, so that a portion of the through hole 25 is formed as a groove 25a in one of the two abutting rings, and another portion of the through hole 25 is formed as a groove 25b in the other of the two abutting rings, and these grooves together form the through hole.

[0109] The downhole sealing unit 30 further comprises a first element 41 having a first inclined surface 42 abutting against a second inclined surface 43 of the metal ring 24. By configuring the first element 41 having the inclined surface 42 to be able to slide relative to the second inclined surface 43, when pressure acts on the downhole sealing assembly 1, the first element 41 can slide and move toward the second surface 4, thereby pressing the downhole sealing assembly 1 so that the base 6 is pressed against the first element 41. By being able to move toward the second surface 4, the first element 41 maintains sufficient support / backing for the downhole sealing assembly 1 and provides a pre-tensioning force on the downhole sealing assembly 1 so that when the pressure is released, the first element 41 can push the downhole sealing assembly 1 to return to its less pressurized state. The first element 41 having the first inclined surface 42 abuts against the second inclined surface 43 on the first side 44 of the metal ring 24, and the downhole sealing unit 30 further comprises a second element 45 having a first inclined surface 46 abutting against a second inclined surface 47 on the second side 48 of the metal ring 24. The first member 41 and the second member 45 may be made of PEEK (polyetheretherketone) or PAEK (polyaryletherketone) or the like, or metal.

[0110] Fig.12 A cross-sectional view of another downhole sealing unit 30 is shown, which includes a first downhole sealing assembly 1, 1a and a second downhole sealing assembly 1, 1b corresponding to the previously described downhole sealing assembly 1. The first downhole sealing assembly 1, 1a abuts against the second downhole sealing assembly 1, 1b, so that the first annular flange 7 of the first downhole sealing assembly 1a extends toward and faces the first annular flange 7 of the second downhole sealing assembly 1b. Therefore, the first downhole sealing assembly 1, 1a and the second downhole sealing assembly 1b are arranged to abut and face each other, without a separate element arranged therebetween. Therefore, the metal annular element 11 of the first downhole sealing assembly 1, 1a abuts against the metal annular element 11 of the first downhole sealing assembly 1a.

[0111] The downhole sealing unit 30 also includes at least one through hole 25 intersecting the two metal ring elements 11, so that a portion of the through hole 25 is formed as a groove 25a in one metal ring element 11, and another portion of the through hole 25 is formed as a groove 25b in the other metal ring element 11, and these grooves together form the through hole.

[0112] The downhole sealing unit 30 further includes a first metal ring 24a and a second metal ring 24b. The first metal ring 24a is arranged to abut against the base 6 of the first downhole sealing assembly 1a, and the second metal ring 24b is arranged to abut against the base 6 of the second downhole sealing assembly 1b. The first metal ring 24a has an L-shaped cross section and is formed by a rod 53 and a protruding flange 54a, wherein the one protruding flange 54a overlaps with the base 6 of the first downhole sealing assembly 1a. The second metal ring 24b has an L-shaped cross section and is formed by a rod 53 and a protruding flange 54b, wherein the one protruding flange 54b overlaps with the base 6 of the second downhole sealing assembly 1b.

[0113] Fig.12 The downhole sealing unit 30 further includes a first element 41 and a second element 45. The first element 41 has a first inclined surface 42 abutting against the second inclined surface 43 of the first metal ring 24a, and the second element 45 has a first inclined surface 46 abutting against the second inclined surface 47 of the second metal ring 24b.

[0114] "Fluid" or "wellbore fluid" refers to any type of fluid present downhole in an oil or gas well, such as natural gas, petroleum, oil-based mud, crude oil, water, etc. "Gas" refers to any type of gas component present in a well, a completed well, or an open hole, and "oil" refers to any type of oil component, such as crude oil, oil-containing fluids, etc. Gas, oil, and water fluids may therefore each include other elements or substances in addition to gas, oil, and / or water, respectively.

[0115] "Annular barrier" refers to an annular barrier comprising a tubular metal component installed as a part of a metal well tubular structure and an expandable metal sleeve surrounding and connected to the tubular metal component to define an annular barrier space.

[0116] "Casing" or "metal well casing" means any type of pipe, tubing, tubular structure, liner, tubular string, etc. used downhole in connection with oil or natural gas production.

[0117] Although the invention has been described above in conjunction with preferred embodiments thereof, it will be apparent to a person skilled in the art that several modifications are conceivable without departing from the invention as defined in the following claims.

Claims

1. A downhole sealing assembly (1) for providing a seal in a wellbore (2) between a first face (3) and a second face (4) of a completion member, the completion member having an axial extension direction (L) along the wellbore, the downhole sealing assembly comprising: an annular sealing element (5) for being arranged on the second face, the annular sealing element comprising a base (6), a first annular flange (7) and a second annular flange (8), the first annular flange and the second annular flange extending from the base in the axial extension direction so that a cavity (9) is formed between the first annular flange and the second annular flange, the first annular flange being arranged closest to the first face and having a protrusion (10) for abutting the second face; as well as a metal annular element (11) arranged in the cavity, the metal annular element having a first annular end (12) close to the base and a second annular end (14) opposite the first annular end, the metal annular element having a first annular surface (15) formed with a first recess (16) for receiving the first annular flange, The downhole sealing assembly further comprises a first spring element (17), which is arranged in the cavity between the first annular flange and the metal annular element so as to push the first annular flange against the second surface.

2. The downhole sealing assembly according to claim 1, wherein: The first spring element is plate-shaped and tubular.

3. The downhole sealing assembly according to claim 1 or 2, wherein: The second annular flange includes a protrusion (18) that protrudes away from the first annular flange.

4. A downhole sealing assembly according to any one of the preceding claims, wherein: The first annular flange has a U-shaped cross section and is formed with a lip-shaped flange (19) for abutting against the second surface.

5. The downhole sealing assembly according to claim 4, further comprising a second spring element (20) arranged between the lip flange and the first annular flange.

6. A downhole sealing assembly according to any one of the preceding claims, wherein: The metal annular element has a second annular surface (21) formed with a second recess (22) for receiving the second annular flange.

7. The downhole sealing assembly according to claim 6, further comprising a third spring element (23) located between the second annular surface and the second annular flange.

8. A downhole sealing unit (30), comprising a first downhole sealing assembly (1, 1a) and a second downhole sealing assembly (1, 1b) according to any one of the preceding claims, wherein the base of the first downhole sealing assembly is arranged so that the distance between it and the base of the second downhole sealing assembly is smaller than the distance between their annular flanges, so that the first annular flange of the first downhole sealing assembly extends from the base of the first downhole sealing assembly in a direction away from the first annular flange of the second downhole sealing assembly.

9. The downhole sealing unit according to claim 8 further comprises a metal ring (24) having a T-shaped cross-section, wherein the metal ring is arranged between the first downhole sealing assembly and the second downhole sealing assembly and abuts against the base of the first downhole sealing assembly and the base of the second downhole sealing assembly.

10. The downhole sealing unit according to claim 9, wherein: The metal ring has at least one through hole (25) extending radially in a direction perpendicular to the axial extension direction for providing fluid communication.

11. The downhole sealing unit according to claim 9 or 10, wherein: The metal ring has a first protruding flange overlapping with the base of the first downhole sealing assembly along the axial extension direction, and a second protruding flange overlapping with the base of the second downhole sealing assembly along the axial extension direction.

12. A downhole sealing assembly according to any one of the preceding claims, wherein: The base has a first thickness (t1) along the axial extension direction, the first annular flange has a second thickness (t2) perpendicular to the axial extension direction, and the second annular flange has a third thickness (t3) perpendicular to the axial extension direction, and the first thickness is greater than the second thickness and / or the third thickness.

13. A completion component (50), comprising a first component part (51) having a first surface (3) and a second component part (52) having a second surface (4) facing the first surface, the first component part and the second component part being slidable relative to each other, the completion component also comprising a downhole sealing assembly according to any one of claims 1 to 7 for being arranged between the first surface and the second surface.

14. The well completion component (50) according to claim 13, wherein: The completion component is a sliding sleeve (50A) or a telescopic joint (50B).

15. A downhole system (100) comprising an annular barrier (80) and a completion component according to claim 13 or 14 installed as part of a metallic well tubular structure (90).

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