阅读说明：本技术 废弃井塞及堵塞和废弃系统 (Abandonment well plug and jam and abandonment system ) 是由 J·克莱默 于 2018-12-11 设计创作，主要内容包括：本发明涉及一种用于堵塞和废弃井的废弃井塞,所述废弃井塞包括可封闭的或封闭的第一端部部件、为管状并具有在内表面上的凹槽的第二端部部件、布置在这两个端部部件之间的可膨胀金属套筒,这两个端部部件的刚性大于所述可膨胀金属套筒的刚性,和可释放地连接至第二管状端部部件的单元,所述单元包括至少一个可径向突伸的紧固元件、单元套筒、和能在所述单元套筒中移动的活塞,以便在第一位置,该活塞迫压可径向突伸的紧固元件并且在第二位置活塞相对于可径向突伸的紧固元件偏置,从而允许可径向突伸的紧固元件径向向内移动。此外,本发明涉及一种堵塞和废弃系统,其包括根据本发明的废弃井塞。(The present invention relates to a waste well plug for plugging and abandoning a well, comprising a closable or closed first end part, a second end part being tubular and having a groove on an inner surface, an expandable metal sleeve arranged between the two end parts, the two end parts being more rigid than the expandable metal sleeve, and a unit releasably connected to the second tubular end part, the unit comprising at least one radially projectable fastening element, a unit sleeve, and a piston movable in the unit sleeve, such that in a first position the piston presses the radially projectable fastening element and in a second position the piston is biased against the radially projectable fastening element, thereby allowing the radially projectable fastening element to be moved radially inwards. Furthermore, the invention relates to a plugging and abandonment system comprising a abandoned well plug according to the invention.)

1. A abandonment well plug (1) for plugging and abandoning a well (2), the abandonment well plug comprising:

-a closed or closable first end part (3);

-a second end part (4) being tubular and having a groove (5) on an inner surface (6);

-an expandable metal sleeve (7) arranged between the two end parts, the two end parts being more rigid than the expandable metal sleeve; and

-a unit (8) releasably connected to the second tubular end part, the unit comprising:

-at least one radially projectable fastening element (9);

-a unit sleeve (10); and

-a piston (11) movable in the unit sleeve to force the radially projectable fastening elements radially outwardly into engagement with the grooves in a first position and to be biased against the radially projectable fastening elements in a second position to allow the radially projectable fastening elements to move radially inwardly.

2. The abandoned well plug of claim 1, further comprising a first breakable element (12) for maintaining the piston in the first position relative to the unit sleeve until the breakable element breaks at a predetermined force.

3. An abandoned well plug according to claim 1 or 2 wherein the expandable metal sleeve is mounted end to the first and second end members.

4. An abandoned well plug according to any of the preceding claims wherein the piston is tubular.

5. A abandonment well plug as claimed in any of the preceding claims, wherein the piston has a first piston part (16) and a second piston part (17) that are movable relative to each other.

6. The abandoned well plug of claim 5 wherein the first piston member is tubular and the second piston member is bore-free.

7. An abandoned well plug according to any of the preceding claims, further comprising a second breakable element (18) located between the unit sleeve and the second end part.

8. An abandoned well plug according to any of the preceding claims, wherein the unit sleeve has unit grooves (19) in which the radially projectable fastening elements are arranged.

9. An abandonment well plug as claimed in any of the preceding claims, wherein the piston has a ball seat (21) for receiving a ball (22) thrown into the well.

10. An abandoned well plug according to any of the preceding claims wherein the first end member has an opening (23) for receiving a wiper plug (24) or ball to close the second end member.

11. An abandoned well plug according to any of the preceding claims, wherein the abandoned well plug is configured to be connected to a workover tubular, a drill pipe (25), a coiled tubing or a similar disconnectable tubular.

12. An abandoned well plug according to any of the preceding claims wherein the unit sleeve has a through bore (26) within which the piston slides.

13. A plugging and abandonment system comprising an abandoned well plug according to any of the preceding claims and a cement supply device (31) for supplying cement above, below and/or in the abandoned well plug.

14. The plugging and abandonment system of claim 13, further comprising a stroking tool (32) connected to the unit for providing an axial force for expanding the expandable metal sleeve.

15. A plugging and abandonment system according to claim 13, further comprising a disconnectable tube (25) connecting the cement supply device with the well plug.

Technical Field

The present invention relates to a abandonment well plug for plugging and abandoning a well and a plugging and abandonment system.

Background

When the well is less productive and all attempts to improve hydrocarbon production from the reservoir fail, the non-producing portion of the well (if not the entire well) is plugged and abandoned. Plugging and abandonment are a significant part of the life of a well. This is also an expensive process, as authorities have high requirements on plugging operations to ensure that the well does not contaminate the environment. Most regulatory agencies require placement of cement plugs and testing across any open hydrocarbon-bearing formation, across all casing shoes, across fresh water aquifers, and possibly also across multiple other areas near the surface (including the top 6-15m of the wellbore). Well designers often choose to set the bridge plug to cooperate with the cement slurry to ensure that the higher density cement does not fall too far into the wellbore. In this case, the bridge plug will be set and cement pumped through the drill pipe string to the top of the well plug, and then the drill pipe string will be withdrawn before the slurry hardens. In other cases, the plug is set and cement is pumped down through the plug, and thus cement is disposed below the plug, after which the plug is permanently closed from flowing therethrough. Most well plugs have a complex design for providing flow therethrough during insertion of the well plug, and as such, well plugs are provided with shear pins, pistons, sealing arrangements, and the like.

In planning a well, the costs for plugging and abandonment must be guaranteed so that the authorities do not make a lot of money to pay for plugging and abandonment of the well, and therefore, well operators are always looking for more economical solutions for plugging and abandonment in order to guarantee that less money is spent. However, known well plugs are expensive and some known plugs may fail to provide flow therethrough because of the complexity of the plug and, later, the plug may not close as desired and a new plug may have to be inserted.

Disclosure of Invention

It is an object of the present invention to wholly or partly overcome the above disadvantages and drawbacks of the prior art. More particularly, it is an object to provide an improved plugging and abandonment system that is not as complex and expensive as the known solutions.

The above objects, together with numerous other objects, advantages, and features, which will become evident from the below description, are accomplished by a solution in accordance with the present invention by a discard plug for plugging and abandoning a well, comprising:

-a closed or closable first end part;

-a second end piece being tubular and having a groove on an inner surface;

-an expandable metal sleeve arranged between the two end parts, the two end parts being more rigid than the expandable metal sleeve; and

-a unit releasably connected to the second tubular end part, the unit comprising:

-at least one radially projectable fastening element;

-a cell sleeve; and

-a piston movable in the unit sleeve, in a first position the piston pressing the radially projectable fastening element and in a second position the piston being biased with respect to the radially projectable fastening element so as to allow the radially projectable fastening element to move radially inwards.

The abandoned well plug according to the invention may further comprise a first breakable element for maintaining the piston in the first position with respect to the unit sleeve until the breakable element breaks at a predetermined force.

Further, the expandable metal sleeve may be mounted end-to-end to the first end component and the second end component.

Furthermore, the expandable metal sleeve may be the only element connecting the first end part with the second end part.

Furthermore, the expandable metal sleeve may have a circumferential projection.

Furthermore, the expandable metal sleeve may have a sealing element arranged between two protrusions.

Furthermore, the piston may be tubular.

Furthermore, the piston may have a first piston part and a second piston part which are movable relative to each other.

Furthermore, the first piston part may be tubular and the second part may be bore-free.

Furthermore, the unit releasably connected to the tubular second end part may be an expansion unit facilitating expansion of the expandable metal sleeve.

The abandoned well plug according to the invention may further comprise a second breakable element between the unit sleeve and the second end part for maintaining the unit sleeve in the first position relative to the second end part until the breakable element breaks at a predetermined force.

Furthermore, the unit sleeve may have unit grooves in which the radially projectable fastening elements are arranged.

The unit sleeve may include a sealing element disposed between the unit sleeve and the second end member.

Further, the piston may have a ball seat for receiving a ball dropped into the well.

Further, the second end member may have an opening for receiving a wiper dart or a ball to close the second end member.

Furthermore, the second end part may have a closing unit for closing the opening. The closed cell may comprise a tubular cell member having an open first cell end and a closed second cell end; a sliding sleeve disposed on an outer surface of the tubular cell component so as to define a chamber; at least one first opening in the tubular cell member; at least one second opening on the tubular cell member opposite the chamber, the at least one second opening being disposed closer to the first cell end than the at least one first opening; and a ball seat disposed in the tubular unit member between the at least one first opening and the at least one second opening.

The sliding sleeve may uncover/uncover the at least one first opening in the first position and the sliding sleeve may cover the at least one first opening in the second position.

Further, the sliding sleeve is movable from the first position to the second position by means of fluid entering the chamber, the chamber increasing with movement of the sliding sleeve away from the first end.

Furthermore, the sliding sleeve may act as a piston.

Furthermore, the closing unit may comprise at least one shear pin for maintaining the sleeve in the first position until a predetermined pressure is reached.

Furthermore, the outer surface at the end of the second unit may comprise a pawl in the form of a ratchet system engaging an end member of the sliding sleeve.

Furthermore, the sliding sleeve may comprise an opening, which in the first position is aligned with the at least one first opening on the tubular unit part.

The closure unit may further comprise first and second sealing means between the sliding sleeve and the tubular unit part on both sides of the at least one first opening and a third sealing means arranged between the sliding sleeve and the tubular unit part between the first unit end and the at least one second opening.

The abandoned well plug according to the invention may further comprise a unit housing surrounding the tubular unit member and the sliding sleeve, whereby the sliding sleeve slides between the unit housing and the tubular unit member.

The abandoned well plug may also include an end cap having perforations and connected to the unit housing.

Further, the unit housing may include a projection on an inner surface for receiving the flange of the tubular unit member to prevent the tubular unit member from moving beyond the projection.

Further, the tubular cell member may have a third cell section having a third outer diameter greater than the second outer diameter.

Further, the third outer diameter may be larger than the outer diameter of the second sleeve part, thereby forming a space for allowing the second sleeve part to slide.

Furthermore, the second sleeve part may be allowed to slide until the protrusion is reached.

Further, the outer diameter of the first sleeve member may be smaller than the inner diameter of the protrusion, allowing the first sleeve member to slide freely through the protrusion.

Furthermore, the diameter of the at least one second opening may be smaller than the diameter of the at least one first opening.

Furthermore, the sliding sleeve may have a first sleeve part having a first sleeve inner diameter and a second sleeve part having a second sleeve inner diameter, the tubular cell part having a first cell section and a second cell section of the tubular cell part, the first cell section having a first outer diameter corresponding to the first sleeve inner diameter, the second cell section having a second outer diameter corresponding to the second sleeve inner diameter.

Further, the tubular unit member may have a tapered inner diameter at the first unit end for guiding a ball towards the ball seat.

Further, the tubular cell member may be mounted within the cell housing.

Furthermore, the plug may be connected to a well casing, drill pipe, coiled tubing or similar disconnectable pipe.

Further, the unit sleeve may have a through hole in which the piston slides.

Further, the abandoned well plug may include a vent port in the tubular second end member for equalizing pressure within the well when running the well plug.

Further, the abandoned well plug may include a base member connecting the first end member with the second end member.

Further, the expandable metal sleeve may surround the base component.

Further, the base member may have an opening.

The invention also relates to a plugging and abandonment system comprising a abandoned well plug according to the invention and a cement supply device for supplying cement above, below and/or in the well plug.

Furthermore, the plug may be releasably connected to a well casing, drill pipe, coiled tubing or similar disconnectable tubing.

The plugging and abandonment system according to the invention may further comprise a stroking tool connected to the unit for providing an axial force for expanding the expandable metal sleeve.

The plugging and abandonment system according to the invention may further comprise a disconnectable pipe connecting the cement supply with the well plug.

Drawings

The invention and many of its advantages will be described in more detail below with reference to the accompanying schematic drawings, which show, for purposes of illustration, only some non-limiting embodiments, in which:

FIGS. 1a-1e show cross-sectional views of a abandoned well plug before, during and after setting/deployment of the plug;

FIGS. 2a-2e show cross-sectional views of another abandoned well plug before, during and after setting of the plug;

3a-3d show cross-sectional views of another abandoned plug before, during and after setting of the plug;

4a-4c illustrate a plugging and abandonment system during cementing via a drill pipe, during expansion of a well plug, and after the well plug and cement are installed;

FIGS. 5a and 5b illustrate a plugging and abandonment system with a stroking tool during plug expansion and cement installation;

FIGS. 6A and 6B show cross-sectional views of another abandoned well plug before and during setting of the well plug; and

figures 7A and 7B show cross-sectional views of another abandoned plug before and after the plug is set.

All the figures are highly schematic and not necessarily to scale, and they show only those parts which are necessary for the elucidation of the invention, other parts being omitted or merely suggested.

Detailed Description

Figure 1a shows a abandonment plug 1 for plugging and abandoning a well. The abandoned well plug 1 comprises a first end part 3, which is closed and forms the bottom of the well plug, and a second end part 4, which is tubular and has a groove 5 on its inner surface 6. The second end member is closest to the top of the well. The abandoned well plug 1 also comprises an expandable metal sleeve 7 arranged between the two end parts, whereby the expandable metal sleeve is the only element connecting the first end part with the second end part. The end members 3, 4 are more rigid than the expandable metal sleeve 7, so that when a pressurised fluid is applied, the expandable metal sleeve radially expands to permanently deform and conform to the borehole wall or well tubular metal structure, thereby forming a well plug in the borehole or well tubular metal structure. The abandoned well plug 1 also comprises a unit 8 releasably connected within the second tubular end member. The unit comprises at least one radially projectable fastening element 9, a unit sleeve 10 and a piston 11 movable therein. The piston 11 is movable between a first position, shown in fig. 1a and 1b, in which the piston 11 forces the radially projectable fastening elements 9 radially outwardly into engagement with the grooves 5, and a second position, shown in fig. 1c-1e, in which the piston is biased relative to the radially projectable fastening elements 9, thereby allowing the radially projectable fastening elements to move radially inwardly.

The abandoned well plug 1 has a length of less than 5 meters, preferably less than 3 meters. A waste plug 1 is typically arranged in the well tubular metal structure for stopping cement poured into the well to provide a cement plug of 50-100 meters length.

In fig. 1a, the piston 11 has a first piston part 16 and a second piston part 17. The first piston part 16 and the second piston part 17 are two independent pistons movable relative to each other. After the ball is thrown as shown in fig. 1b, the second piston part 17 can be moved downwards and the fluid below the ball expands the expandable metal sleeve 7 as shown in fig. 1 c. The abandonment well plug 1 further comprises a first breakable element 12 for maintaining the first piston part 16 of the piston 11 in the first position relative to the unit sleeve 10 shown in fig. 1a-1B until the breakable element 12 breaks at a predetermined force (shown in fig. 1 c) applied by a pressure difference between the annular pressure acting on the first piston part 16 at the unit groove 19 and the expansion pressure inside the first piston part acting on the piston flange 44 below the sealing element 37B. By a further increase in pressure the piston 11 and the unit sleeve 10 are moved downwards, releasing the unit sleeve by breaking the second breakable element 18 (as shown in fig. 1 d), and the unit 8 is then withdrawn from the well as shown in fig. 1 e.

As can be seen in fig. 1e, the expandable metal sleeve 7 is mounted end-to-end to the first and second end parts 3, 4 such that the expandable metal sleeve 7 is the only element connecting the first end part 3 with the second end part 4. The unit has been released and pulled out and the plug is ready to be filled with cement to place cement over the plug 1. The expandable metal sleeve 7 has circumferential protrusions 14 and a sealing element 15 arranged between two protrusions to make a better seal against the borehole or in the well tubular metal structure.

By expanding the abandoned plug 1 and then pulling the unit 8 out by means of only simple mechanical functions such as breaking the shear pin, no complicated structure can get stuck and hinder plugging and abandonment. The plug left in the well is very simple but sufficient to hold the cement until it hardens. When the plug is lowered, fluid can easily pass through the plug and need not flow forward through the plug because cement is applied on top of the set plug. If for some reason the plug is expanded but the unit is not released, the unit can just remain in the well and be part of the cement filled plug.

The waste plug 1 is typically connected to a workover tubular, a drill pipe (drill pipe string), coiled tubing or similar disconnectable tubular to provide pressurized fluid from the surface for expanding the waste plug 1 and to separate after completion of the setting of the plug. In another embodiment, the abandoned well plug 1 is connected to a wireline tool having a pump for providing pressurized fluid.

The piston 11 is a tube structure provided by the inner bore 36 and therefore has a very simple design. The piston of fig. 1a-1d has a first piston part 16 and a second piston part 17, which are movable relative to each other. The first piston part 16 is tubular so that a ball can flow through it and the second piston part is bore-free so that the ball 22 can be seated in a ball seat 21 in the second piston part 17 and it serves as a piston 11 which can expand the expandable metal sleeve 7.

The abandoned well plug 1 further comprises a second breakable element 18 located between the cell sleeve 10 and the second end part 4, as a means for maintaining the cell sleeve in a first position relative to the second end part during expansion of the expandable metal sleeve until the second breakable element 18 breaks at a predetermined force. However, the second breakable element can be broken by exerting a downward force on the cell sleeve 10, for example by increasing the pressure, and thus the cell 8 can always be easily retrieved. The unit sleeve 10 of fig. 1a has unit recesses 19 in which the radially projectable fastening elements 9 are arranged. The cell sleeve 10 further comprises a sealing element 37 arranged between the cell sleeve 10 and the second end part 4.

The waste well plug 1 of figures 2a-2e has an opening 23 in the first end member 3 for receiving a wiper plug 24 (or ball) to close the first end member. By having an opening 23 in the first end piece, cement can be injected below the plug 1 before the expandable metal sleeve 7 is expanded and the setting of the plug is completed. After applying cement via the opening 23, a wiper plug 24 is thrown and seated in the first end piece 3, as shown in fig. 2b, thereby closing the first end piece 3. Subsequently, cement may be applied via a string of drill pipe connected to the drill pipe of the well plug, and the expandable metal sleeve 7 is expanded as shown in fig. 2 c. In this step, the first breakable element 12 is broken by a slight downward movement of the piston 11, so that the radially projectable fastening elements 9 are free to move radially inward. This is due to the same pressure difference over the first piston member 16 as described in relation to fig. 1a-1 e. By continuing to increase the pressure, the piston 11 and the unit sleeve 10 are moved downwards, whereby the second fracturable element 18 is also fractured, and the drill pipe/drill pipe string can be retrieved with the unit 8, as shown in fig. 2e, while cement is pumped down the drill pipe and then the unit applied above the well plug when required by the operator. The plug 1 is thus set in an intermediate position in the cemented area to contribute to the curing process in the desired position, as the plug 1 can apply cement below, in and above the plug. In fig. 2a-2d, the piston 11 is one part that is only moved from the first position to the second position.

In fig. 6A and 6B, the opening 23 in the first end part 3 of the waste plug 1 of fig. 2a-2e is closed by a closing unit 20 instead of a wiper plug. The closure unit 20 has a first position as shown in fig. 6A and a second position as shown in fig. 6B. In which first position the closing unit is arranged to allow flow through the first end part 3 and in which second position the closing unit is arranged to close the first end part 3. The closure unit 20 comprises a tubular unit member 121 having a first unit end 122 which is open and in fluid communication with the interior 55 of the waste plug 1.

As shown in fig. 6A and 6B, the tubular cell member has a closed second cell end 123. The closure unit further comprises a sliding sleeve 124 arranged on an outer surface 125 of the tubular unit part, thereby defining a chamber 126 therebetween. The tubular cell element 121 further comprises at least one first opening 27 and at least one second opening 28 opposite the chamber 126. The at least one second opening is disposed closer to the first unit end than the at least one first opening. The closure unit further comprises a ball seat 29 arranged in the tubular unit part between the first and second openings for receiving a ball. When the waste plug 1 is lowered into the wellbore, the closure unit in its first position allows flow therethrough, meaning that wellbore fluid around the waste plug 1 is allowed to enter the first end member 3 of the waste plug 1 via the perforations 23 in the end cap 136, as shown in fig. 6A.

Thus, in this first position, the sliding sleeve 124 does not cover the first opening and in the second position, the sliding sleeve covers the first opening and thus closes the end of the abandoned well plug 1. Movement of the sliding sleeve 124 from the first position to the second position is achieved by dropping a ball and increasing the chamber 126 by forcing fluid into the chamber 126 via the second opening 28 and onto the sliding sleeve, thereby increasing the chamber 126 as the sliding sleeve moves away from the first unit end 122 towards the second unit end 123. The sliding sleeve thus acts as a piston. The ball is obstructed behind the second opening so that fluid is directed into the chamber 126.

As can be seen in fig. 6A, the closing unit comprises a shear pin 131 for maintaining the sliding sleeve in the first position until a predetermined pressure is reached on the interior 55 of the abandoned well plug 1 and this predetermined pressure presses on the sliding sleeve, whereby the shear pin breaks and the sliding sleeve can thus start to move towards the second position, as shown in fig. 6B.

In order to prevent the closure unit from returning to the first position, but still remaining closed, the outer surface at the end of the second unit comprises a circumferential groove 47, which circumferential groove 47 engages with a pawl 132 in the form of a ratchet system of the end part 48 of the sliding sleeve 124. In another embodiment, the collet may be released as a result of the sliding sleeve moving and the collet falling into the space formed behind the sliding sleeve as a result of the movement of the sleeve towards the second position, and thus preventing the sliding sleeve from returning to its first position.

In fig. 6A, the sliding sleeve may comprise an opening 33 which, in the first position, is aligned with and therefore uncovered by the first opening 27 in the tubular cell part 121. In another embodiment, the sliding sleeve does not overlap the first opening 27 in the first position, but covers the first opening in the second position.

In order to properly seal the first opening, the closure unit 20 further comprises a first sealing mechanism 34A and a second sealing mechanism 34B arranged between the sliding sleeve 124 and the tubular unit part 121 on both sides of the first opening. In fig. 6A, the first and second sealing mechanisms 34A, 34B are disposed in the circumferential groove 49 in the tubular unit member 121. In order to provide a reliable sliding of the sliding sleeve 124, the closure unit 20 further comprises a third sealing mechanism 34C arranged between the sliding sleeve 124 and the tubular unit part 121 between the first unit end 122 and the second opening 28.

In fig. 6A-6B, the closure unit 20 further comprises a unit housing 135 that surrounds the tubular unit member 121 and the sliding sleeve 124 such that the sliding sleeve is located between the unit housing 135 and the tubular unit member 121.

The cell housing 135 may include a protrusion 138 on an inner surface 139 for receiving a flange 141 of the tubular cell member, thereby preventing the tubular cell member 121 from moving beyond the protrusion 138 and beyond the first opening 27. In this way it is ensured that the sliding sleeve does not slide too far and thus also that the sliding sleeve can again uncover/uncover the first opening 27. As can be seen in fig. 6A-6B, the second opening has a smaller diameter than the at least one first opening.

The sliding sleeve has a first sleeve portion 142 having a first sleeve inner diameter ID1 and a second sleeve portion 143 having a second sleeve inner diameter ID2, and the tubular cell member 121 has a first cell section 144 having a first outer diameter OD1 corresponding to the first sleeve inner diameter ID1 and a second cell section 145 having a second outer diameter OD2 corresponding to the second sleeve inner diameter ID 2. The first sleeve inner diameter is smaller than the second sleeve inner diameter, thereby providing the possibility of forming the chamber 126.

The tubular cell member 121 has a third cell section 152 having a third outer diameter OD3 that is greater than the second outer diameter OD 2. The third outer diameter OD3 is larger than the outer diameter of the second sleeve section 143, thereby creating a space for allowing the second sleeve section to slide until reaching the protrusion 138. The outer diameter of the first sleeve portion 142 is smaller than the inner diameter of the protrusion, allowing the first sleeve portion 142 to slide freely through the protrusion.

The tubular unit member may have an inner diameter decreasing from the open end at the first unit end towards the ball seat for guiding the ball 146 towards the ball seat.

As shown in fig. 6A-6B, the tubular cell member may be mounted within the cell housing, but in another embodiment, the cell housing and tubular cell member are combined into one member having an elongated groove in which the sliding sleeve slides. In the event that the sliding sleeve simply pushes any element away from the outer surface of the tubular cell member 121 when the sleeve is slid towards the second position, the closed cell may operate without a cell housing or an outer member surrounding the sliding sleeve 124.

In fig. 3a, the unit sleeve 10 has a through hole 26, and the piston 11 slides in the through hole 26, as shown in fig. 1a to 1d and fig. 2a to 2 d. The unit sleeve 10 of the waste plug 1 of figures 3a-3d is connected to the housing of a stroking tool 32 (shown in figure 5 a). The stroking tool has a stroking rod which pushes the second piston member 17 downwards in a first downward stroke to expand the expandable metal sleeve 7 by fluid trapped under the second piston member 17. In a second stroke, the stroke tool engages the recess 38 (shown in fig. 3 a) in the tubular piston 11 and moves the first piston member 16 downwards, thereby breaking the breakable element 12. In another embodiment, as shown in fig. 3b, the stroking tool may provide a pressurized fluid to move the second piston member 17 in order to expand the expandable metal sleeve 7. Thereafter, the stroking tool provides another downward stroke to displace the piston 11 and the unit sleeve 10 downwards, thereby breaking the second breakable element, i.e. the shear pin 18, and releasing the unit 8 from the second end part 4 (as shown in fig. 3 c) and withdrawing the tool (as shown in fig. 3 d).

Sealing mechanisms 37 are provided at various locations (as shown in figures 1a-3 d) to ensure an adequate seal between moving parts of the waste plug 1. As shown in fig. 3d, the expandable metal sleeve 7 is mounted to an end 42 of the first end part 3 and an end 43 of the second end part 4 by means of a connection part 41. Thus, the connecting member overlaps the end portions 42, 43, thereby connecting the expandable metal sleeve 7 end-to-end to the first and second end members 3, 4.

In fig. 4a-4c a plugging and abandonment system 100 is shown in the well 2, comprising a abandoned well plug and a cement supply device 31 for supplying cement above, below and/or in the well plug depending on the plugging scheme selected. The plugging and abandonment system 100 is arranged in a wellbore 102 by means of a drill pipe 25 or similar disconnectable pipe from the top 103 of the well.

In fig. 5a-5b the plugging and abandonment system 100 is shown in the well 2 and comprises a stroking tool 32 connected to the unit in order to provide an axial force for expanding the expandable metal sleeve 7 (as shown in fig. 5 b), wherein the unit 8 has been withdrawn and cement 35 is applied above the well plug 1.

The first end piece 3 and the second end piece 4 may also be connected as shown in fig. 7a and 7b, such that there is a base pipe 51 below the expandable metal sleeve 7. By having such a base pipe 51 connecting the first end piece 3 with the second end piece 4, the abandoned well plug 1 is significantly stronger in the longitudinal extension of the well plug. The base pipe 51 has openings 52 for fluid to enter the annular space between the base pipe and the expandable metal sleeve 7.

The stroking tool 32 is a tool that provides an axial force. The stroking tool includes an electric motor for driving a pump. The pump pumps fluid to the piston housing to move the piston therein. The piston is disposed on the stroke rod. The pump may pump fluid into the piston housing on one side of the piston and simultaneously draw fluid on the other side of the piston.

Fluid or wellbore fluid refers to any type of fluid present downhole in an oil or gas well, such as natural gas, oil-based mud, crude oil, water, and the like. Gas refers to any type of gas component present in a well, completion, or open hole, and oil refers to any type of oil component, such as crude oil, oleaginous fluids, and the like. The gas, oil and water fluids may thus each comprise other elements or substances than gas, oil and/or water, respectively.

An annular barrier refers to an annular barrier comprising a tubular metal part mounted as part of a well tubular metal structure and an expandable metal sleeve surrounding the tubular part and connected to the tubular part to define an annular barrier space.

By a casing or well tubular metal structure is meant any type of pipe, tubing, tubular structure, liner, string etc. used downhole in connection with oil or gas production.

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 projectable arms with wheels, wherein the wheels contact an inner surface of the casing for advancing the tractor and the tool within the casing. Downhole tractors are any type of driving tool capable of pushing or pulling a tool downhole, e.g. Well

Although the invention has been described above in connection with preferred embodiments thereof, several variations will be apparent to those skilled in the art which may be made without departing from the invention as defined in the following claims.