Annular barrier

Abstract

The present invention relates to an annular barrier for expansion in an annulus between a first metallic well tubular structure and an inner surface of a wellbore or of a second metallic well tubular structure for providing regional isolation between a first region and a second region of the annulus, the annular barrier having a first axial extent of extension, wherein the annular barrier comprises: a tubular metal member for mounting as part of a first metal well tubular structure, the tubular metal member having an outer surface; an expandable metal sleeve surrounding the tubular metal member, the expandable metal sleeve having an outer surface facing an inner surface of the wellbore or of the second metal well tubular structure and an inner surface facing an outer surface of the tubular metal member, a second axial extension along the first axial extension, each end part of the expandable metal sleeve is connected with the tubular metal part; an annular space between the expandable metal sleeve and the tubular metal member; an expansion opening on the tubular metal part through which a fluid can enter the annular space to expand the expandable metal sleeve, and wherein the annular barrier further comprises a eutectic material and / or a bentonite material, the eutectic material and / or the bentonite material is arranged on the outer surface of the tubular metal part in a first state at a first axial position different from a second axial extension of the expandable metal sleeve, and in a second state and a second axial position, the eutectic material and / or the bentonite material abuts the surface of the expandable metal sleeve, and in an intermediate state, the eutectic material and / or the bentonite material abuts the surface of the expandable metal sleeve. The eutectic material and / or the bentonite material is located between the first axial position and the second axial position. The invention also relates to a downhole system comprising an annular barrier and a downhole tool string comprising a heating unit for heating the eutectic material and / or bentonite material.

Description

Technical Field

[0001] The present invention relates to an annular barrier for expansion in an annulus between a first metallic wellbore structure and an inner surface of a wellbore or a second metallic wellbore structure to provide zonal isolation between a first region and a second region of the annulus. The present invention also relates to a downhole system comprising the annular barrier and a downhole tool string. Background Art

[0002] In salt formations, the wellbore of an oil or gas well may decrease over time, creating challenges for the completion components, casing, and liner deployed therein, as their dimensions correspond to the wellbore dimensions at the time of drilling. An annular barrier may be deployed along the casing or liner to provide zonal isolation; as the salt formation expands, the annular barrier is compressed against the wellbore wall. Some annular barriers are made of flexible materials, allowing them to flex with the expansion of the salt formation and still provide an adequate seal; however, if the salt formation continues to expand, the annular barrier may no longer provide an adequate seal, compromising zonal isolation. Summary of the Invention

[0003] An object of the present invention is to wholly or partly overcome the above-mentioned drawbacks and disadvantages of the prior art. More particularly, an object is to provide an improved annular barrier suitable for implementation into salt formations.

[0004] The above objects and numerous other objects, advantages and features that will become apparent from the following description are achieved according to the present invention by an annular barrier for expansion in an annulus between a first metallic well tubular structure and an inner surface of a wellbore or a second metallic well tubular structure for providing a zone separation between a first zone and a second zone of the annulus, the annular barrier having a first axial extension, wherein the annular barrier comprises:

[0005] - a tubular metal component for installation as part of a first metal shaft tubular structure, the tubular metal component having an outer surface;

[0006] an expandable metal sleeve surrounding the tubular metal part, the expandable metal sleeve having an outer surface facing the wellbore or the inner surface of the second metal well tubular structure and an inner surface facing the outer surface of the tubular metal part, a second axial extension along the first axial extension, and each end of the expandable metal sleeve being connected to the tubular metal part;

[0007] - an annular space between the expandable metal sleeve and the tubular metal part; and

[0008] an expansion opening in the tubular metal part, through which a fluid can enter the annular space in order to expand the expandable metal sleeve,

[0009] The annular barrier further comprises a eutectic material and / or a bentonite material, which in a first state is arranged on the outer surface of the tubular metal part at a first axial position different from the second axial extension range of the expandable metal sleeve, and in a second state and a second axial position, the eutectic material and / or the bentonite material abuts / rests against the surface of the expandable metal sleeve, and in an intermediate state, the eutectic material and / or the bentonite material is located between the first axial position and the second axial position.

[0010] By placing the eutectic material on the outer surface of the tubular metal component, the sealing ability of the annular barrier can be easily reestablished by heating the eutectic material, as the eutectic material then changes state to a flowable state and redistributes itself between the expandable metal sleeve and the wellbore. As the eutectic material changes state to a solid state, the volume of the eutectic material expands and provides a new adequate seal. Therefore, an annular barrier having such a eutectic material is suitable for implementation in salt formations, as the annular barrier can still provide an adequate seal even after a certain period of time when the salt formation has expanded.

[0011] The annular barrier may comprise a bentonite material which in a first state is arranged on the outer surface of the tubular metal part at a first axial position which is different from and does not overlap with the second axial extension of the expandable metal sleeve, and in a second state and a second axial position the bentonite material contacts the surface of the expandable metal sleeve.

[0012] In the intermediate state of the bentonite material, the material is positioned between the first axial position and the second axial position.

[0013] In the first state and the first axial position, the bentonite material may be in powder form in the chamber. When in the intermediate state, the bentonite material is released into the wellbore fluid and reacts with the wellbore fluid and expands and solidifies into the second state.

[0014] The bentonite material may be an absorbent swelling clay composed primarily of montmorillonite (smectite), which may be sodium montmorillonite or calcium montmorillonite. Sodium montmorillonite has a much greater swelling capacity than calcium montmorillonite.

[0015] Furthermore, the annular barrier may comprise only eutectic material in a first state and a first axial position, and in a second state and a second axial position, the eutectic material forms a solidified plug outside of the expandable metal sleeve and against the outer surface of the expandable metal sleeve.

[0016] Furthermore, the annular barrier may comprise only the bentonite material in the first state and first axial position, whereas in the second state and second axial position the bentonite material forms a solidified plug outside the expandable metal sleeve and abuts against the outer surface of the expandable metal sleeve.

[0017] Furthermore, the first axial position may not overlap with the second axial extension of the expandable metal sleeve.

[0018] In addition, the annular barrier may also include a fluid connecting channel having a first opening at a first axial channel position and extending toward a second opening at a second axial channel position, wherein the second axial channel position overlaps or abuts the axial position of the expandable metal sleeve, and the eutectic material is arranged upstream of the first opening in the first state, and in the second state the eutectic material and / or bentonite material abuts the surface of the expandable metal sleeve downstream of the second opening.

[0019] The axial position of the expandable metal sleeve may be the same as the second axial extension of the expandable metal sleeve.

[0020] Additionally, the first axial passage position may be closer to the first axial position than to the second axial position.

[0021] Furthermore, the fluid communication channel may be a tube.

[0022] Furthermore, the tube may be a metal tube that is metallically connected to the tubular metal part.

[0023] Furthermore, one of the ends of the expandable metal sleeve may be connected to the tubular metal member by a connecting member, and a fluid communication passage may extend through the connecting member, thereby providing fluid communication to the annular space.

[0024] Furthermore, in the second state the eutectic material and / or the bentonite material may overlap with the second axial extension.

[0025] Furthermore, the second opening may be arranged to overlap with the second axial extension of the expandable metal sleeve.

[0026] Furthermore, the fluid communication channel may be arranged to partially abut a portion of the outer surface of the expandable metal sleeve.

[0027] Furthermore, the annular barrier may further comprise a cavity arranged on the outer surface of the tubular metal component; in the first position, the eutectic material and / or the bentonite material may be in the form of a powder arranged in the cavity.

[0028] Additionally, the eutectic material may be a solid block composed of the eutectic material.

[0029] Additionally, the chamber may have a chamber opening in fluid communication with the first opening of the fluid communication passage.

[0030] Furthermore, the annular barrier may include a eutectic material and a bentonite material, the bentonite material being disposed in a cavity and the eutectic material being disposed in a cavity, and both cavities being disposed on the outer surface of the tubular metal component.

[0031] Additionally, the bentonite material may be in powder form in a first state and disposed within the chamber and then released into the annulus to react with the wellbore fluid and form an annular plug on top of and against the expandable metal sleeve.

[0032] Additionally, the eutectic material may be heated and then flowed into the annular space via the fluid communication passage to move to the second axial passage position.

[0033] By placing the bentonite material on the outer surface of the tubular metal component, the sealing ability of the annular barrier can be easily re-established simply by allowing the bentonite material to enter the wellbore fluid. In addition, by having a eutectic material, the annular space can be filled with the eutectic material, displacing the fluid within the annular space, and forming a suitable plug as the eutectic material solidifies. The bentonite material can then be used on the outside of the annular barrier, and the eutectic material can be used on the inside of the annular barrier. However, in another embodiment, it can be the other way around. Thus, the flowable bentonite material and the flowable eutectic material are able to enter smaller gaps than the eutectic material could enter in its solid state, and upon solidification, the volume of the eutectic material and the bentonite material increases, filling the gap even better. Therefore, an annular barrier having such a eutectic material and bentonite material is suitable for implementation in salt formations because the annular barrier can still provide an adequate seal even after a period of time when the salt formation has expanded.

[0034] Additionally, the eutectic material may include bismuth or a bismuth alloy.

[0035] Furthermore, the eutectic material may be a late transition metal material, such as bismuth or a bismuth alloy, which is in bulk or powder form.

[0036] Additionally, in the first state, the eutectic material and / or the bentonite material may have a first volume, and in the intermediate state, the eutectic material and / or the bentonite material may have a second volume that is smaller than the first volume.

[0037] Furthermore, in the second state, the eutectic material and / or the bentonite material may be at least partially disposed on the outer surface of the expandable metal sleeve.

[0038] Furthermore, in the second state, the eutectic material and / or the bentonite material may be at least partially arranged in the annular space.

[0039] In addition, the annular barrier may further include a balancing fluid channel / pressure equalizing fluid channel, which provides fluid communication between the annular space and the annulus, for allowing fluid in the annular space to flow out of the annular space when the eutectic material and / or bentonite material displaces the fluid.

[0040] Additionally, the pressure equalizing fluid passage may have a first aperture in fluid communication with the annular space and a second aperture in fluid communication with the second region.

[0041] Furthermore, the first opening and the second opening may be arranged in the connecting component.

[0042] Furthermore, the annular barrier may further include a valve unit for controlling fluid communication between the expansion opening and the annular space via a conduit.

[0043] Additionally, the conduit may be used as a fluid communication channel.

[0044] Furthermore, the valve unit may be fluidly connected to the pressure equalizing fluid channel.

[0045] Furthermore, the expandable metal sleeve may be provided with a sealing unit on an outer surface of the expandable metal sleeve.

[0046] Furthermore, the sealing unit may be arranged in a circumferential groove of the expandable metal sleeve.

[0047] Furthermore, the sealing unit may further include an annular sealing element and a retaining element.

[0048] Furthermore, the sealing unit may comprise an intermediate element.

[0049] Furthermore, at least the retaining element may comprise a late transition metal material, such as bismuth or a bismuth alloy.

[0050] Furthermore, the annular sealing element may be made of an elastomer, natural or synthetic rubber, a polymer or similar material.

[0051] Furthermore, in the first state, the first opening may abut the eutectic material.

[0052] Furthermore, the first opening may include a plug at least partially made of a eutectic compound or alloy.

[0053] Furthermore, in the first state, the eutectic material and / or the bentonite material may extend at least partially around the circumference of the tubular metal component.

[0054] Furthermore, in the second state, the eutectic material and / or bentonite material may extend completely around the circumference of the tubular metal component.

[0055] Additionally, the first metallic well structure may have a higher melting point than the eutectic material.

[0056] Furthermore, the eutectic material and / or the bentonite material may have a first outer diameter when in the first state, and the first outer diameter may be less than or equal to an outer diameter of the expandable metal sleeve in an unexpanded state of the expandable metal sleeve.

[0057] Furthermore, in the intermediate state, the eutectic material and / or the bentonite material may be at least partially in a liquid state.

[0058] Alternatively, the first region may be a production region, and the eutectic material may be disposed in the second region. When the eutectic material enters the annular space and displaces fluid in the annular space, the lower pressure in the first region, due to the lower pressure in the production region, will assist the fluid in exiting the annular space through the pressure-equalizing fluid channel.

[0059] Furthermore, the annular barrier may further include a heating unit for heating the eutectic material, and the heating unit may be arranged on the outer surface of the tubular metal part near the eutectic material.

[0060] Furthermore, the annular barrier may further include a thermal insulator arranged to surround the heating unit and the eutectic material.

[0061] Furthermore, the present invention relates to a downhole system comprising an annular barrier and a downhole tool string, the downhole tool string comprising a heating unit for heating a eutectic material.

[0062] Additionally, the downhole tool string may further include a fluid displacement section disposed adjacent to the heating unit.

[0063] Furthermore, the heating unit may include a chamber having the thermite material, a liquid, and a heater in the form of a heating channel extending into the chamber having the eutectic material.

[0064] The heating unit may comprise a pump arranged to facilitate circulation of the heated liquid inside the heating channel.

[0065] Furthermore, the bentonite material can be arranged in a chamber having a piston which divides the chamber into a first chamber part and a second chamber part, the bentonite material being arranged in the first chamber part having an opening with a shear disc and the second chamber part having a pressurized charge 48, such as thermite, a gas cylinder or the like, the piston being held in the first piston position by a shear pin.

[0066] Finally, the present invention relates to a downhole system comprising an annular barrier and a downhole tool string comprising a fluid displacement section arranged inside a tubular metal component opposite the annular barrier. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] The invention and its many advantages will be described in more detail below with reference to the accompanying schematic diagrams, which show some non-limiting embodiments for illustrative purposes only, in which:

[0068] Figure 1 shows a cross-sectional view of an annular barrier having a block of eutectic material in a first state;

[0069] Figure 2A shows a cross-sectional view of another annular barrier having eutectic material in a first state;

[0070] Figure 2B shows a eutectic material in a second state Figure 2A A cross-sectional view of the annular barrier;

[0071] Figure 3 showing a cross-sectional view of a portion of another annular barrier having a block of eutectic material in a first state;

[0072] Figure 4 shows a cross-sectional view of a portion of yet another annular barrier having a chamber containing powdered eutectic material in a first state;

[0073] Figure 5 showing a cross-sectional view of a portion of yet another annular barrier having a block of eutectic material in a first state;

[0074] Figure 6 shows a cross-sectional view of another annular barrier having eutectic material in a first state;

[0075] FIG7 a shows a cross-sectional view of another annular barrier having eutectic material in a first state;

[0076] FIG7 b shows a cross-sectional view of the annular barrier of FIG7 a having the eutectic material in a second state;

[0077] Figure 8 showing a cross-sectional view of yet another annular barrier having eutectic material in a first state;

[0078] Figure 9 shows a cross-sectional view of another annular barrier having eutectic material in a first state;

[0079] Figure 10 showing a cross-sectional view of yet another annular barrier having eutectic material in a first state;

[0080] Figure 11A showing a cross-sectional view of another annular barrier having eutectic material in a first state at a first axial position;

[0081] Figure 11B Shown Figure 11A a cross-sectional view of an annular barrier having eutectic material in a second state located outside of and abutting the annular barrier at a second axial position;

[0082] FIG12 a shows a cross-sectional view of yet another annular barrier having eutectic material and bentonite material in a first state;

[0083] FIG12 b illustrates a cross-sectional view of the annular barrier of FIG12 a having the eutectic material and the bentonite material in a second state, wherein the eutectic material is disposed inside the expandable metal sleeve and the bentonite material is disposed outside of and abutting the expandable metal sleeve;

[0084] Figure 13 shows a cross-sectional view of a portion of yet another annular barrier having a heating unit with a heating channel inside a chamber having a eutectic material;

[0085] Figure 14a shows a cross-sectional view of a portion of yet another annular barrier having a chamber with bentonite material in a first state; and

[0086] 14b shows a cross-sectional view of a portion of the annular barrier of FIG. 14a having the bentonite material in a second state, wherein the bentonite material is disposed outside of and abuts the expandable metal sleeve.

[0087] All the figures are highly schematic and not necessarily to scale, and they show only those parts which are necessary in order to elucidate the invention, other parts being omitted or merely suggested. DETAILED DESCRIPTION

[0088] Figure 1An annular barrier 1 is shown in its expanded state in an annulus 103 between a first metal well tubular structure 3a and the inner surface 4 of a wellbore 5, for providing zonal isolation between a first region 101 and a second region 102 of the annulus. The annular barrier 1 has a first axial extension 2 along which it extends along the longitudinal extension of the metal well tubular structure 3a and the wellbore 5. The annular barrier 1 comprises a tubular metal component 6 for installation as part of the first metal well tubular structure 3a. The tubular metal component 6 has an outer surface 7 facing the inner surface 4 of the wellbore 5. The annular barrier 1 further comprises an expandable metal sleeve 8 surrounding the tubular metal component 6, the expandable metal sleeve 8 having an outer surface 9 facing the inner surface 4 of the wellbore 5 and an inner surface 10 facing the outer surface 7 of the tubular metal component. The expandable metal sleeve 8 has a second axial extension 23 along the first axial extension, which represents the length of the expandable metal sleeve. Each end 31, 32 of the expandable metal sleeve 8 is connected to the tubular metal part 6 to enclose an annular space 11 between the expandable metal sleeve and the tubular metal part. An expansion opening 12 is arranged in the tubular metal part 6, through which a fluid can enter the annular space 11 to expand the expandable metal sleeve 8. The annular barrier also includes a eutectic material 14. The eutectic material is arranged on the outer surface 7 of the tubular metal part 6 in a first state at a first axial position 51. This first axial position is different from the axial position of the expandable metal sleeve, that is, the first axial position 51 is different from the second axial extension 23 of the expandable metal sleeve 8 along the first axial extension 2, so that the eutectic material 14 is arranged outside the annular space 11 and the expandable metal sleeve.

[0089] By placing eutectic material 14 on outer surface 7 of tubular metal component 6, the sealing capability of annular barrier 1 can be easily reestablished by heating the eutectic material, as the eutectic material then changes state to a flowable state and rearranges itself between expandable metal sleeve 8 and wellbore 5. As the eutectic material changes state to a solid state, the volume of the eutectic material expands and provides a new, adequate seal. Thus, the flowable or even liquefied eutectic material 14 is able to enter smaller gaps than when the eutectic material is in its solid state, and upon solidification, the eutectic material increases in volume and fills the gap even better. Consequently, annular barriers having such eutectic material are suitable for implementation in salt formations, as the annular barrier can still provide an adequate seal even after a period of time when the salt formation has expanded.

[0090] Instead of having a eutectic material, the annular barrier may have a bentonite material 14B. Bentonite material 14B is in powder form in a first state, and in a second state, bentonite material 14B is an absorbent, swelling clay primarily composed of montmorillonite (smectite family), which may be sodium montmorillonite or calcium montmorillonite. Sodium montmorillonite has a much greater swelling capacity than calcium montmorillonite. Bentonite material 14B is in powder form and arranged in chamber 19B. Then, at an intermediate position, the powder reacts with a liquid, which may be a wellbore fluid, and in the second state, the bentonite material has absorbed the liquid and has formed into a solid clay mass that clings to the surface of the expandable metal sleeve of the annular barrier 1.

[0091] When a downhole tool string 50 including a heating unit 54 for heating the eutectic material 14 is introduced from within the first metal wellbore structure 3a or tubular metal component 6, the eutectic material 14 becomes flowable and flows downward relative to the top 61 of the well and toward the expanded expandable metal sleeve 8, so as to rest on top of the sealing unit 27 along the circumference of the annular barrier 1, as shown by the dashed lines and reference numeral 14', which represents the eutectic material in a second state. This may occur after the annular barrier 1 has been set for many years to plug and abandon the well, or when the sealing of the annular barrier has become less effective due to formation changes (e.g., salt formations).

[0092] exist Figure 2A In the first state, the eutectic material 14 is located on the outer surface 7 of the tubular metal part 6 at a first axial position 51, which is different from the second axial extension 23 of the expandable metal sleeve 8 along the first axial extension 2. After heating, the eutectic material 14 becomes flowable and flows to the second axial position 52 and enters a second state, in which the eutectic material clings to the surfaces 9, 10 of the expandable metal sleeve 8, as shown in FIG. Figure 2B When in the flowable state, the eutectic material 14 is in an intermediate state, wherein the eutectic material is located between the first axial position 51 and the second axial position 52 .

[0093] exist Figure 2A and 2B In the embodiment, the annular barrier 1 further comprises a fluid communication channel 15 having a first opening 16 at a first axial channel position 21 and extending toward a second opening 17 at a second axial channel position 22. Figure 2A and 2BIn the middle position, the second axial channel position 22 overlaps with the axial position 23 of the expandable metal sleeve 8 and is in close contact with the expandable metal sleeve. In the first state, the eutectic material 14 is arranged upstream of the first opening 16, and in the second state, the eutectic material is in close contact with the inner surface 10 of the expandable metal sleeve 8 downstream of the second opening 17. In the intermediate position, the eutectic material 14 flows in the fluid communication channel 15 so as to move to the second axial channel position 22. The first axial channel position 21 is closer to the first axial position 51 than to the second axial position 52. The fluid communication channel 15 can be as follows Figure 2A The tube 18 shown. The tube 18 is connected to the tubular metal part 6 (such as Figure 3 A metal tube (not shown), such as a hollow heat pipe, such as a cobber tube, is provided so that a heating unit of the downhole tool string 50 can heat the tube, thereby keeping the eutectic material flowable. The first metal wellbore structure 3a has a higher melting point than the eutectic material 14, so that only the eutectic material becomes flowable. Although not shown, the tube 18 can also be heated by other means, such as electrical wire or thermite.

[0094] At the second axial position 52 and the second state of the eutectic material 14, Figure 2B In the embodiment, the eutectic material is located within the annular space 11, but may also be located outside the expandable metal sleeve 8, thereby providing a seal between the outer surface 9 of the expandable metal sleeve and the inner surface 4 of the wellbore 5 or another metal well tubular structure 3 (e.g., Figure 6 As shown in FIG. 1 , the eutectic material 14 can be disposed both inside and outside the expandable metal sleeve 8 in the second state, which is suitable for plugging and abandoning a well or portion of a well when sidetracking above the abandoned portion. Because the eutectic material 14, such as a bismuth alloy, is metallic, the eutectic material provides a very strong, complete metal-to-metal seal in the second state when located between the expandable metal sleeve 8 and the first metallic well tubular structure 3 a. When the eutectic material 14 is located between the expandable metal sleeve 8 and the wall of the wellbore 5, the sealing ability of the eutectic material is less effective.

[0095] exist Figure 2A In the illustrated first state, eutectic material 14 has a first volume V1. In the intermediate state, the eutectic material has a second volume smaller than the first volume. Eutectic material 14 includes bismuth or a bismuth alloy. Thus, the eutectic material is a late transition metal material, such as bismuth or a bismuth alloy, in a bulk or powdered form.

[0096] In the first state, the eutectic material 14 extends at least partially around the circumference of the tubular metal component 6, which may be in the form of a separate element, an annular element with an open end, or a complete ring. In the second state, the eutectic material 14 extends around the entire circumference of the tubular metal component 6 because the eutectic material flows in the intermediate state and evenly distributes itself around the circumference of the tubular metal component 6 when positioned within the annular space 11, or evenly distributes itself around the circumference of the expandable metal sleeve 8 when positioned outside the expandable metal sleeve.

[0097] like Figure 3 As shown, one of the ends of the expandable metal sleeve 8 is connected to the tubular metal member 6 via connecting members 41, 42. Figure 2A and 2B The first end 31 and the second end 32 of the expandable metal sleeve 8 are connected to the tubular metal member 6 through the first connecting member 41 and the second connecting member 42. Figure 5 In the embodiment, the fluid communication channel 15 extends through the connecting parts 41, 42 to provide fluid communication to the annular space 11. Figure 3 and 4 In the second state, the fluid communication channel 15 is arranged to partially abut a portion of the outer surface 9 of the expandable metal sleeve 8 so as to guide the eutectic material 14 in its flowable intermediate state to the outside of the expandable metal sleeve over the top of the sealing unit 27. Thus, in the second state, the eutectic material 14 overlaps with the second axial extension 23. The second opening 17 is arranged to overlap with the second axial extension 23 of the expandable metal sleeve 8.

[0098] like Figure 4 As shown, the annular barrier 1 further comprises a chamber 19 arranged on the outer surface 7 of the tubular metal component 6, and in a first state, the eutectic material 14 is in powder form and arranged in the chamber. The chamber 19 has a chamber opening 20 in fluid communication with the first opening 16 of the fluid communication channel 15. The tube 18 forming the fluid communication channel 15 may also contain the powdered eutectic material 14. In the first state, the first opening 16 abuts the eutectic material 14. Figure 1 、 2A , 3, 5 and 6, the eutectic material 14 is a solid block of eutectic material. Figure 5 In the embodiment, the first opening 16 and the second opening 17 are both arranged in the first connecting member 41, and the first opening 16 includes a plug 28, which can be made at least partially of a eutectic compound or alloy so that the plug is removed when heated, for example by a heating unit 54 (e.g., a heating unit 54 of a downhole tool string 50) Figure 1 The heating may be performed by other means such as thermite or wire.

[0099] like Figure 2A and 2BAs shown, the annular barrier 1 may further include a pressure equalizing fluid channel 24. The pressure equalizing fluid channel 24 provides fluid communication between the annular space 11 and the annulus 103, and is used to allow the fluid in the annular space to flow out of the annular space when the eutectic material 14 displaces the fluid. Figure 1 As shown, the pressure equalizing fluid channel 24 can be fluidly connected to the valve unit 25, so that the pressure equalizing fluid channel 24 also serves as a conduit 38, controlling the fluid communication between the expansion opening and the annular space 11 via the conduit 38, as shown in FIG. Figure 1 In another annular barrier 1, a portion of the conduit 38 is used as a fluid communication channel 15. Figure 2A and 2B In the embodiment, the pressure equalizing fluid channel 24 has a first hole 33 in fluid communication with the annular space 11 and a second hole 34 in fluid communication with the second region.

[0100] In order to provide better sealing when the expandable metal sleeve 8 is expanded to fit closely against the inner surface 4 of the wellbore 5 or another metal well pipe structure, the expandable metal sleeve is provided with a plurality of sealing units 27 on the outer surface 9 of the expandable metal sleeve 8, such as Figure 1 As shown. The sealing unit 27 is arranged in a circumferential groove 29 of the expandable metal sleeve 8. At the groove 29, the expandable metal sleeve 8 has a first thickness t1, and between the two grooves, the expandable metal sleeve has a second thickness t2 that is greater than the first thickness. The sealing unit 27 also includes an annular sealing element 35 and a retaining element 36. The retaining element 36 is a winding ring so that when the expandable metal sleeve 8 is expanded, the retaining element can be partially unfolded, thereby providing appropriate support / backbearing for the annular sealing element 35. Figure 6 In the embodiment of the invention, an intermediate sealing element 37 is arranged between annular sealing element 35 and retaining element 36 so that the retaining element does not rupture the annular sealing element when deployed during expansion. To retain annular sealing element 35 in groove 29, the annular sealing element has different widths w1, w2, and w3, where w2 is greater than w1 but less than w3. In one annular barrier 1, retaining element 36 comprises a late transition metal material, such as bismuth or a bismuth alloy. Annular sealing element 35 is made of an elastomer, natural or synthetic rubber, a polymer, or a similar material.

[0101] like Figure 3-5 As shown, the eutectic material 14 has a first outer diameter O1 when in the first state, and the first outer diameter is less than or equal to the outer diameter O2 of the expandable metal sleeve 8 in the unexpanded state. In this manner, the eutectic material 14 does not hinder the insertion of the annular barrier 1 into the well. In the intermediate state, the eutectic material 14 can be at least partially in a liquid state.

[0102] The first region 101 may be a producing region, and the eutectic material 14 is disposed in the second region 102 such that when the eutectic material enters the annular space 11 to displace fluid in the annular space, the lower pressure in the first region, due to the lower pressure in the producing region, will facilitate flow of the fluid out of the annular space through the pressure-equalizing fluid passage 24. In some wells, the pressure in the non-producing region is lower than the pressure in the producing region, and in such wells, the eutectic material is disposed in its first state in the second non-producing region.

[0103] As shown in FIG7a , the pressure-equalizing fluid channel 24 is arranged at the same end as the fluid communication channel 15, so that when the eutectic material 14 enters the annular space 11, it displaces the fluid in the annular space 11 through the pressure-equalizing fluid channel 24. When the annular space 11 is filled with the eutectic material 14, the eutectic material 14 enters through the pressure-equalizing fluid channel 24 and settles at the top of the annular barrier 1, as shown in FIG7b . The annular barrier 1 also includes a valve unit 25 that controls fluid communication between the expansion opening 12 and the annular space 11 via the conduit 38 during expansion of the expandable metal sleeve 8.

[0104] like Figure 1 As shown, a downhole system 100 is disclosed, which includes an annular barrier 1 and a downhole tool string 50 , the downhole tool string 50 including a heating unit 54 for heating the eutectic material 14 .

[0105] exist Figure 8 , the annular barrier 1 includes a heating unit 54 for heating the eutectic material 14. The heating unit 54 is arranged on the outer surface of the tubular metal part 6 close to the eutectic material 14. The annular barrier 1 also includes an insulator 43 arranged to surround the heating unit 54 and the eutectic material 14.

[0106] Figure 9 A portion of a downhole system 100 is shown, wherein a tool string 50 includes a heating unit 54 and a fluid displacement section 55. The fluid displacement section 55 has a first portion 55a arranged on one side of the heating unit 54 along the longitudinal extension of the tool string 50 and a second portion arranged on the other side of the heating unit 54 along the longitudinal axis, such that the heating unit 54 is arranged opposite the eutectic material 14 arranged in the chamber 19, and the first and second portions 55a, 55b of the fluid displacement section 55 are arranged to displace fluid, i.e., to block the passage of fluid and cool the heated area. Thus, the fluid displacement section 55 has the function of blocking the metallic well tubular structure 3a near the heating unit 54, so that the fluid flowing in the well does not flow through the heated area, and cools the heated area before heat is transferred to the eutectic material 14.

[0107] exist Figure 10In the embodiment of the present invention, an annular barrier 1 includes a heating unit 54 disposed on the outer surface of a tubular metal component 6 near the eutectic material 14, and a downhole tool string 50 includes a fluid displacement section 55. Thus, the auxiliary tool section operates within the metal well tubular structure 3a to displace wellbore fluid from the heated area, thereby mitigating any heat loss due to convection within the metal well tubular structure 3a. Thus, when the heating unit 54 is activated and heats the eutectic material 14, the fluid displacement section 55 simultaneously prevents the fluid within the metal well tubular structure 3a from cooling the heated area. The heating unit 54, the chamber 14 containing the eutectic material, and the fluid communication channel 15 are encapsulated by insulation 43.

[0108] The heating unit 54 may include an activation unit with three positions. The first position places the activation unit in a safe state and deactivated mode, the second position places the activation unit in a safe state and armed mode, and the third position places the activation unit in armed mode. The second position ensures that the activation unit cannot be accidentally activated, but setting the activation unit to "armed mode" requires two movements, not just an intentional bump during completion. In the second position, the activation unit can be programmed to signal that the unit is operating as intended before it is set to armed mode.

[0109] exist Figure 11A and 11B In the case of annular barriers, Figure 11A The illustration only includes the eutectic material 14 in the first state and first axial position, and in the Figure 11B In the second state and second axial position shown, the annular barrier forms a solidified plug on the outside and is in close contact with the outer surface of the expandable metal sleeve. In another embodiment, the annular barrier comprises only bentonite material 14B in chamber 19B. Bentonite material 14B is as described with respect to Figure 12A and 12B The expandable metal sleeve is released as described to form a solidified plug external to and adjacent to the outer surface of the expandable metal sleeve.

[0110] like Figure 12A and 12B As shown, the annular barrier may include eutectic material 14 and bentonite material 14B. Bentonite material 14B is disposed in chamber 19B, eutectic material 14 is disposed in chamber 19, and both chambers are disposed on the outer surface of the tubular metal component. Figure 12BAs shown, bentonite material 14B can be in powder form in a first state and disposed within chamber 19B, then released into the annulus to react with the wellbore fluid and form an annular plug atop and adjacent to expandable metal sleeve 8. Eutectic material 14 is heated and then flows into annular space 11 via fluid communication passage 15 to move to second axial passage position 22. By disposing bentonite material 14B on outer surface 7 of tubular metal component 6, the sealing capability of annular barrier 1 can be easily reestablished simply by exposing bentonite material 14B to the wellbore fluid. Furthermore, by including the eutectic material, annular space 11 can be filled with the eutectic material, displacing the fluid within the annular space, and forming a suitable plug as the eutectic material solidifies. Bentonite material can then be applied to the exterior of the annular barrier, and eutectic material can be applied to the interior of the annular barrier. However, in another embodiment, this can be reversed. Thus, the flowable bentonite material 14B and the flowable eutectic material 14 are able to enter smaller gaps than the eutectic material in its solid state, and upon solidification, the eutectic material and the bentonite material increase in volume, filling the gaps even better. Thus, an annular barrier having such a eutectic material and bentonite material is suitable for implementation in salt formations because the annular barrier can still provide an adequate seal even after a period of time when the salt formation has expanded.

[0111] exist Figure 13 In the embodiment, annular barrier 1 includes a heating unit 54 for heating eutectic material 14. Heating unit 54 comprises a chamber containing thermite material 26, liquid 30, and a heater 39 in the form of a heating channel 40 extending into chamber 19 containing eutectic material 14. Ignition of thermite heats the liquid, which then flows through heating channel 40 of heater 39, heating eutectic material 14 before flowing through a channel at the end of expandable metal sleeve 8 into the annular space of annular barrier 1. A heating unit / heating device is disposed on the outer surface of tubular metal component 6 to heat eutectic material 14, with a pump 44 being arranged to assist in circulating the heated liquid within heating channel 40. Annular barrier 1 also includes insulating material 43 disposed to surround heating unit 54 and eutectic material 14.

[0112] Figure 14AThe annular barrier comprises only bentonite material 14B, which is disposed on the outer surface of the tubular metal component at a first axial position 51 in a first state. The first axial position 51 is distinct from and does not overlap the second axial extent of the expandable metal sleeve, and in a second state and a second axial position 52, the bentonite material abuts surfaces 9 and 10, as shown in FIG14B . The bentonite material has an intermediate state between the first and second axial positions. In the first state and the first axial position 51, the bentonite material 14B is in a powdered form within chamber 19B. When in the intermediate state, the bentonite material is released into the wellbore fluid, reacts with the wellbore fluid, and expands to a second state in the form of clay. The clay is located on top of the expanded expandable metal sleeve and forms a secure plug 52 in the second axial position. Cement can then be placed on top of the bentonite plug before abandoning the well or well portion. Bentonite material 14B is disposed in chamber 19B on one side of a piston 45 that divides the chamber into a first chamber portion containing the bentonite material 14B in a first state and a second chamber portion having some kind of pressurized charge 48, such as thermite, a gas cartridge, or the like, which when activated generates sufficient force to break the piston holding the chamber in place. Figure 14A 14B and forces the bentonite material out of chamber 19B and into the annulus to react with the wellbore fluid and solidify into a plug.

[0113] "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 gaseous 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.

[0114] "Annular barrier" refers to an annular barrier comprising a tubular metal component installed as part of a metal well tubular structure and an expandable metal sleeve surrounding and connected to the tubular component to define an annular barrier space.

[0115] "Casing" or "metal well tubular structure" means any type of pipe, tubing, tubular structure, liner, tubing string, etc. used downhole in connection with oil or natural gas production.

[0116] In the event that the tool is not fully submerged in the casing, a downhole tractor may be used to push the tool fully into position in the well. The downhole tractor may have an extendable arm with wheels, wherein the wheels contact the inner surface of the casing for propelling the tractor and the tool forward within the casing. A downhole tractor is any type of driving tool capable of pushing or pulling a tool downhole, such as a Well

[0117] Although the invention has been described above in conjunction with preferred embodiments thereof, it will be obvious 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. An annular barrier (1) for expanding in an annulus (103) between a first metallic well tubular structure (3a) and an inner surface (4) of a wellbore (5) or a second metallic well tubular structure (3) for providing zonal isolation between a first region (101) and a second region (102) of the annulus, the annular barrier having a first axial extension (2), wherein the annular barrier comprises: - a tubular metal component (6) for installation as part of the first metal shaft structure, the tubular metal component having an outer surface (7); an expandable metal sleeve (8) surrounding the tubular metal part, the expandable metal sleeve having an outer surface (9) facing the inner surface of the wellbore or the second metal well tubular structure and an inner surface (10) facing the outer surface of the tubular metal part, a second axial extension (23) along the first axial extension, and each end (31, 32) of the expandable metal sleeve being connected to the tubular metal part; - an annular space (11) between the expandable metal sleeve and the tubular metal part; and an expansion opening (12) in the tubular metal part, through which a fluid can enter the annular space in order to expand the expandable metal sleeve, The annular barrier further comprises a eutectic material (14) and / or a bentonite material (14B), wherein in a first state, the eutectic material and / or the bentonite material are arranged on the outer surface of the tubular metal part at a first axial position (51) different from the second axial extension range of the expandable metal sleeve, and in a second state and a second axial position (52), the eutectic material and / or the bentonite material abuts the surface (9, 10) of the expandable metal sleeve, and in an intermediate state, the eutectic material and / or the bentonite material are located between the first axial position and the second axial position.

2. The annular barrier according to claim 1 further includes a fluid connecting channel (15), which has a first opening (16) at a first axial channel position (21) and extends toward a second opening (17) at a second axial channel position (22), wherein the second axial channel position overlaps or abuts the axial position (23) of the expandable metal sleeve, and, in a first state, the eutectic material is arranged upstream of the first opening, and in a second state, the eutectic material abuts the surface of the expandable metal sleeve downstream of the second opening.

3. The annular barrier according to claim 2, wherein: One of the ends of the expandable metal sleeve is connected to the tubular metal component via a connecting component (41, 42), and the fluid communication channel extends through the connecting component to provide fluid communication to the annular space.

4. An annular barrier according to any one of the preceding claims, wherein In the second state, the eutectic material and / or bentonite material overlaps the second axial extension.

5. The annular barrier according to claim 2, wherein: The fluid communication passage is arranged to partially abut a portion of an outer surface of the expandable metal sleeve.

6. The annular barrier according to any one of the preceding claims, further comprising a cavity (19) arranged on the outer surface of the tubular metal part; in the first state, the eutectic material and / or the bentonite material is arranged in powder form in the cavity.

7. The annular barrier according to any one of claims 1 to 5, wherein: The eutectic material is a solid block composed of eutectic material.

8. An annular barrier according to claim 7 as appended to claims 2-5, wherein The chamber has a chamber opening (20) in fluid communication with the first opening of the fluid communication passage.

9. An annular barrier according to any one of the preceding claims, wherein In the second state, the eutectic material and / or the bentonite material is at least partially disposed on the outer surface of the expandable metal sleeve.

10. The annular barrier according to any one of claims 1 to 9, wherein: In the second state, the eutectic material and / or the bentonite material is at least partially arranged in the annular space.

11. The annular barrier according to any one of the preceding claims further comprises a pressure equalizing fluid channel (24), which provides fluid communication between the annular space and the annulus, and is used to allow the fluid in the annular space to flow out of the annular space when the eutectic material and / or bentonite material displaces the fluid.

12. The annular barrier according to claim 3, wherein: The first opening and the second opening are arranged in the connecting member.

13. The annular barrier according to claim 2-5, wherein: In a first state, the first opening abuts the eutectic material.

14. An annular barrier according to any one of the preceding claims, wherein In the first state, the eutectic material and / or bentonite material extends at least partially around the circumference of the tubular metal component.

15. A downhole system (100) comprising a downhole tool string (50) and an annular barrier according to any one of claims 1 to 14, the downhole tool string comprising a heating unit (54) for heating a eutectic material.

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