EXPANDABLE TUBULAR ELEMENT BEARING ONE OR MORE SWELLING SEALS

Abstract

A radially expandable metallic tubular element has at least one annular sealing module on its external face. The sealing module includes at least one annular seal made out of a swelling material, called a swelling seal, disposed between two annular stops attached to the external face of the tubular element.

Description

2. FIELD OF THE INVENTION

The invention relates to the field of drilling and especially oil and geothermal drilling

The invention relates to a device comprising a radially expandable tubular element that is designed to tightly seal or close off a well or pipeline and comprises one or more annular sealing modules on its external face.

3. PRIOR-ART SOLUTIONS

Here below in the description, the invention shall be described, by way of an example, with reference to the field of oil production.

The working of wells, vertical or horizontal, requires the ability to seal off certain parts of these wells from other parts, for example in order to demarcate an area in which action can subsequently be taken.

To illustrate the prior art on this subject, FIGS. 1 and 2 appended hereto depict a portion of a metal tubular conduit BP, known as a casing, that is placed inside a well A. (this portion could however be a tubing).

On the external surface of the conduit BP, there extends a cylindrical liner C made of metal (or a radially expandable tubular element), the extremities of which are attached, in such a way as to be tightly sealed on the face, to the external surface of the conduit BP, for example by means of annular elements or rings B.

An aperture 0 is made in the wall of the conduit BP (several apertures can be planned), so as to make the internal space of the conduit BP communicate with the annular space made between the wall of the conduit BP and the liner C.

Classically, the liner C is covered on all or part of its length with a layer of elastically deformable material, for example made of elastomer that constitutes an annular sealing “sheet” or “strip”, with a thickness of a few millimeters. In one variant, illustrated in FIG. 1, the liner can be covered with several sealing modules D spaced out relative to one another.

The liner C and especially the sealing modules D are fixed against the internal face of the tubing, at the zone to be sealed, by radial expansion. This operation of expansion is carried out in the example illustrated by hydroforming of a fluid under pressure.

In FIG. 1, the liner C is represented in its initial state when its wall is not yet deformed.

As illustrated in FIG. 2, when a predetermined pressure of fluid (preferably a liquid such as water) is applied inside the conduit BP (this is illustrated by arrows), this pressure is communicated to the interior of the liner C, via the aperture O which expands radially (relatively to the axis X-X′) beyond its limit of elastic deformation. In doing so, the sealing modules D made of elastomer material come into contact with the internal wall of the well A and get compressed against this wall so as to tightly seal off the annular spaces EA1 and EA2 which are disposed on either side of the liner.

The reference Z in FIG. 2 refers to a zone represented in a magnified view in FIG. 3.

It can then happen that during the operation for expanding the liner C illustrated in FIG. 2, one or more sealing modules D made of elastomer are in a cavity F or facing this cavity F formed in the internal wall of the well A. In this example, there is no longer any contact between the internal wall of the well A and the sealing module D, so that a communications space is thus created between the annular spaces EA1 and EA2 mentioned here above. In other words, under these conditions, the sealing quality is not satisfactory.

In addition, independently of the shape of the internal wall of the well A, it can happen that the differential pressure between the annular spaces EA1 and EA2 prompt the extrusion and the irreversible deformation of one or more of the sealing modules D, thus consequently reducing the efficiency of the sealing modules D.

4. SUMMARY OF THE INVENTION

The invention manages to fulfill all or part of these goals through a radially expandable metallic tubular element comprising at least one annular sealing module on its external face.

According to the invention, said sealing module comprises at least one annular seal made out of a swelling or swellable material, called a swelling or swellable seal, positioned between two annular stops attached to said external face of said tubular element.

The invention thus proposes a radially expansible tubular element, by hydroforming especially, equipped on its external face with one or more sealing modules that are to be applied to the wall of a tubing or of a well.

Each sealing module is constituted by at least one annular seal (or sealing ring) made of a swelling or self-swelling material such as a swelling elastomer which swells in contact with a fluid present in the well (water, sludge or oil especially).

Such a seal is capable of widening axially (within the limit set by the stops which are fixed to the expandable tubular element) and widening radially to come into contact with the wall of a tubing or of a well and tightly seal the annular space between the tubular element and the wall.

In addition, such a seal is capable of filling any cavities that may be present in the wall.

Besides, such a seal is capable of mechanically, thermally and chemically withstanding aggression and coping with the different constraints related to the application considered, while ensuring perfect sealing quality when it is applied with force against a tubing or a formation.

It may for example be made out of nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR) or again fluoroelastomers (FKM) such as Viton (registered mark).

According to one particular characteristic, said tubular element furthermore comprises two anti-extrusion rings each disposed between one of said annular stops and said at least one swelling seal.

These anti-extrusion rings eliminate or at the very least limit the extrusion of the swelling seal when it is compressed against the inner wall of a cavity or a tubing. The rings therefore maintain optimum sealing quality.

According to one particular characteristic, each anti-extrusion ring is formed out of two parts and comprises two beveled surfaces made respectively in each of said parts, said beveled surfaces being situated so as to be facing each other and being capable of sliding relative to each other under the effect of an axial movement (along the longitudinal axis of the tubular element) of said swelling seal so as to prompt a radial shift (perpendicularly to the longitudinal axis of the tubular element) of one of said two parts.

According to one particular characteristic, each anti-extrusion ring is made out of polytetrafluoroethylene (PTFE) or polyether ether ketone (PEEK).

According to one particular characteristic, said seal made of a swelling material is sandwiched between two seals made of non-swelling material, called non-swelling seals.

According to one particular characteristic, each seal made of non-swelling material is formed by two parts, called a first part and a second part, having different hardness values.

According to one particular characteristic, the part having the lowest hardness, called the first part is juxtaposed with said seal made of swelling material.

According to one particular characteristic, the first part has a hardness of 75 to 80 shore A.

According to one particular characteristic, the second part has a hardness of 85 to 90 shore A.

According to one particular characteristic, the first and second parts are made separately and are placed in contact with said tubular element.

According to one particular characteristic, the first and second parts are bonded.

According to one particular characteristic, the first and second parts are formed as a single block (in other words, they are vulcanized together).

According to one particular characteristic, said seal made of swelling material and the seals made out of non-swelling material are manufactured separately and placed in contact on said tubular element.

According to one particular characteristic, said seal made of swelling material and the seals made of non-swelling material are manufactured separately and are bonded.

According to one particular characteristic, said seal made of swelling material and the seals made of non-swelling material are formed as a single block (in other words, they are vulcanized together).

According to one particular characteristic, said annular stops are made of metal.

Thus, the invention proposes an assembly of elements in association with the swelling sealing element to prevent the axial extrusion of the swelling material (elastomer for example) and make sure that there is particularly efficient sealing.

The sealing module can comprise a stack of three layers, or more, of swelling elastomer and non-swelling elastomer. Thus, a seal made out of swelling material can be sandwiched coaxially between two seals made out of non-swelling material.

The seal can be constituted by an annular joint made of swelling material placed between a first anti-extrusion ring and a second anti-extrusion ring.

According to one particular characteristic, the seal or seals are connected to said tubular element by a sliding pivot link.

The swelling seal is thus capable of moving axially on the expandable tubular element.

According to one particular characteristic, said swelling seal is capable of passing from a retracted mode in which it has a first volume to a dilated mode in which it has a second volume that is greater than the first volume, said swelling seal having a thickness smaller than or equal to the thickness between the two annular stops in the retracted mode.

Such a swelling seal can pass from a non-swelled mode in which it has a first volume to a dilated mode in which it has a second volume that is greater than the first volume and in which it seals off the annular space between the expandable tubular element and the wall of a well or tubing.

According to a particular characteristic, said tubular element is radially expandable by hydroforming.

5. LIST OF FIGURES

Other characteristics and advantages of the invention shall appear more clearly from the following description of several preferred embodiments, given by way of simple illustratory and non-exhaustive examples, and from the appended drawings of which:

FIGS. 1 and 2 are schematic views in a longitudinal section of a device for sealing off or isolating according to the prior art, respectively in its original state and in the state it takes once it is deformed radially;

FIG. 3 is a detailed view of the zone Z of FIG. 2;

FIGS. 4A to 4C are schematic views in longitudinal section of a device for sealing off or isolating a part of a drilling well according to a first embodiment of the invention;

FIGS. 5A to 5D represent a second embodiment of the device of the invention;

FIG. 6 represents a third embodiment of the device of the invention;

FIGS. 7A to 7C represent a fourth embodiment of the device according to the invention;

FIGS. 8A to 8D represent a fifth embodiment of the device of the invention.

6. DESCRIPTION

Here below, we present five embodiments of the tubular element 1 according to the invention.

The tubular element comprises, on its external face 10, one or more sealing modules 2 spaced out from one another.

However, in the figures only one part, namely the upper part of the tubular element 1 and of a sealing module 2 is shown.

These figures illustrate one particular application of the tubular element 1 according to the invention, namely the isolating of a bore well.

Referring to FIGS. 4A to 4C, a first embodiment of the invention is described.

The metal tubular element 1 is radially expandable by hydroforming. Although this is not illustrated, the tubular element 1 is attached in a tightly sealed way at its extremities to the external face of a conduit, by means of annular elements or rings. At least one aperture is made in the wall of the conduit so as to make its internal space communicate with the space made between the external wall of the conduit and the tubular element.

The tightly sealing annular module herein comprises two annular metal stops 21 between which an annular seal 22 is inserted, this seal 22 being advantageously made of a swelling elastomer material.

The two metallic annular stops 21 are fixed to the external face of the metallic tubular element 1, by welding for example. The seal 22 is not fixed to the tubular element 1 and is thus free to pivot about the tubular element 1 and move axially (along the longitudinal axis of the tubular element 1).

The metallic tubular element 1 and the annular metal stops 21 are for example made of steel and are capable of getting elastically deformed.

The annular seal 22 has an appreciably rectangular cross-section, two of its opposite corners that face the internal wall of the well A being beveled.

Each of the annular metal stops 21 has a substantially triangular cross-section.

FIG. 4A shows the radially expanded metallic tubular element 1 expanded beyond its limit of elastic deformation.

The seal 22, which herein is retracted (i.e. not swelled) comes into contact with the internal wall of the well A and is situated so as to be facing the cavity F formed in the internal wall of the well A.

It can be noted that the lateral surfaces of the seal 22 are not in contact with the metallic annular stops 21 (there is therefore a clearance between the seal 22 and the stops 21) and that its upper surface is plane.

FIG. 4B shows the seal 22 in the expanded position of the metallic tubular element 1, in its swelled state, the upper surface of the seal 22 being incurvated. This seal 22 has swelled in contact with the fluid (water, petrol) present in the well A and has filled the space of the cavity F.

Besides, the seal 22 is in contact with the metallic annular stops 21.

In other words, in contact with the fluid, the seal 22 gets dilated radially outwards, (i.e. towards the internal wall of the well A) and axially towards the annular metallic stops 21.

Once swelled, the seal 22 gets applied in a tightly sealed manner against the internal wall of the well A.

The annular space EA1 is thus isolated in fluid communication and in pressure from the annular space EA2.

If the pressure in the annular space EA1 and EA2 is different, the seal 22 is subjected to differential pressure. To prevent the differential pressure from causing any irreversible extrusion and deterioration of the seal 22 (and therefore any deterioration of the tight sealing between the annular spaces EA1 and EA2), the annular metallic stops 21 are configured to axially maintain the seal in a sealing position.

In FIG. 4C, it can be seen that the application of differential pressure (illustrated by the arrows to the right) between the annular spaces EA1 and EA2 has the effect of shifting the seal 22 axially towards the stop 21 situated to the left. The seal 22 thus behaves dynamically.

In FIG. 4C, the seal 22, which has swelled, is placed against/compressed in the axial sense against the stop 22 situated to the left. The material constituting the seal 22 is subjected to a new distribution of volume or shape in a controlled, reversible way by the stop 21. It can be understood that when the axial pressure is eliminated, the seal 22 resumes its position and its shape of FIG. 4B.

It can be noted that there is a small extrusion clearance “j” between the annular metallic stop 21 and the internal wall of the well A. This small extrusion clearance “j” maintains optimum sealing quality, even when the differential *pressure is relatively high.

Referring to FIGS. 5A to 5D, we describe a second embodiment of the invention.

This alternative embodiment differs from the previous one only by the implementation of a non-swelling seal 24 (made of elastomer for example) on either side of the swelling seal 22. The non-swelling seals 24 do not lose their mechanical characteristics in contact with the fluid and in the course of time and thus prevent the extrusion of the swelling seal 22.

In other words, the non-swelling seals 24 serve as an anti-extrusion barrier for the swelling seal 22.

FIG. 5A shows the tubular element 1 when it is not yet deformed before it is positioned in the well A. The seals 22, 24 are mounted around the tubular element 1 without being fixed to it. They are spaced out by stops 21.

According to a first approach, the seal 22 made of swelling material and the seals 24 made of non-swelling material are manufactured separately and placed in contact on said tubular element.

According to a second approach, the seal 22 made of swelling material and the seals 24 made of a non-swelling material are manufactured separately and are bonded.

According to a third approach, the seal 22 made of swelling material and the seals 24 made of a non-swelling material are formed in a single block (in other words, they are vulcanized together).

FIG. 5B shows the expanded metallic tubular element 1 in the well A.

FIG. 5C shows the seal 22 in its dilated state, in the expanded position of the metallic tubular element 1. This seal 22 has swelled in contact with the fluid (water, petroleum) present in the well A and fills the space of the cavity F. The seals 24 are shifted axially under the effect of the swelling of the seal 22 and press against the stops 21, thus preventing the swelling seal 22 from getting extruded and thus reducing the efficiency of the seal 22.

In FIG. 5D, it can be seen that the application of differential pressure (illustrated by the arrows to the right) between the annular spaces EA1 and EA2 has the effect of placing/compressing the seal 22 axially against the stop 21 situated to the left, the anti-extrusion barrier being formed by the non-swelling seal 24 situated to the left of the seal 22.

Referring to FIG. 6, we describe a third embodiment of the invention.

FIG. 6 shows the tubular element 1 when it is not yet deformed and installed in the well or tubing.

In this alternative embodiment, two non-swelling seals 24 (made of elastomer for example) are disposed on either side of the swelling seal 22.

Each non-swelling seal 24 is formed by two parts 24A, 24B made out of different elastomers and having different properties. Thus, the elastomer of the part 24B has a hardness of 85 to 90 shore A in this example and the elastomer of the part 24A has a hardness of 75 to 80 shore A. It can be noted that a greater hardness will confer better resistance to extrusion.

The two parts 24A, 24B can be independent and are for example manufactured separately and juxtaposed during assembly (they are left free or are bonded).

In one variant, the two parts 24A, 24B are fixedly attached together, the two elastomers that constitute them being vulcanized together and forming one and the same dual-rubber element.

In another variant, the non-swelling seal 24 can be formed by more than two parts 24A, 24B manufactured out of different elastomers having different properties.

Referring to FIGS. 7A to 7C, we describe a fourth embodiment of the invention.

In this alternative embodiment, the swelling seal 22 is placed between two anti-extrusion rings 26, each of the anti-extrusion rings 26 being placed between the seal 22 and the annular metal stop 21, in contact with this stop. The anti-extrusion rings 26 are mounted so as to be mobile on the tubular element 1.

Each anti-extrusion ring 26 comprises two parts 26A, 26B in the form of a right-angled triangle. These two parts 26A, 26B are disposed back to back so that their tilted surfaces (corresponding to the base of the triangle) respectively face each other.

The anti-extrusion rings 26 are for example made out of polytetrafluoroethylene (PTFE) or polyether ether ketone (PEEK).

FIG. 7A shows the expanded metal tubular element 1.

FIG. 7B shows the swollen seal 22 in the expanded position of the metal tubular element 1. The seal has filled the cavity F and is in contact with the anti-extrusion rings 26.

FIG. 7C shows that the application of a differential pressure (illustrated by the arrows to the right) between the annular spaces EA1 and EA2 has the effect of placing/compressing the seal 22 in the axial sense against the anti-extrusion ring 26 situated to the left. More specifically, the pressure applied in the annular space EA2 passes between the stop 21 situated to the right and the internal wall of the well A, and then between the anti-extrusion ring 26 situated to the right and the internal wall of the well A. This has the effect of placing the seal 22 against the part 26B of the ring 26 situated to the left of FIG. 7C.

The part 26B of the ring 26 and its beveled surface slide towards the left stop 21 and, by “wedge” effect, they lift the part 26A of the ring 26 and cause it to move outwards radially (towards the wall of the well A) until the part 26A gets applied against the wall.

The parts 26A, 26B of the ring 26 to the left thus cooperate perfectly with the swelling seal 22 so as to prevent the extrusion of this seal and ensure dynamic sealing between the tubular element 1 and the internal wall of the well A.

Referring to FIGS. 8A to 8D, we describe a fifth embodiment of the invention. This alternative embodiment differs from the previous one solely by the implementation of a non-swelling seal 24 (made of elastomer for example) on either side of the swelling seal 22.

FIG. 8A shows the tubular element 1 when it is not yet deformed and installed in a well or tubing.

In this alternative embodiment, the swelling seal 22 is placed between two anti-extrusion rings 26, each of the anti-extrusion rings 26 being placed between the seal 22 and an annular metal stop 21.

In addition, two non-swelling seals 24 are placed on either side of the swelling seal 22

FIG. 8B shows the expanded tubular element 1.

FIG. 8C shows the swollen seal 22 in the expanded position of the tubular element 1.

In FIG. 8D, it can be seen that the application of a differential pressure (illustrated by the arrows to the right) between the annular spaces EA1 and EA2 has the effect of placing/compressing the seal 22 and the non-swelling seal 24 situated to the left in the axial sense against the anti-extrusion ring 26 situated to the left. The part 26B of the ring 26 and its beveled surface slide towards the left stop 21 and, by “wedge” effect, they lift the part 26A of the ring 26 and cause it to move radially outwards (towards the walls of the well A) until the part 26A gets applied against the wall.

The parts 26A, 26B of the left ring 26 and the non-swelling seal 24 situated to the left thus cooperate perfectly with the swelling seal 22 so as to prevent its extrusion and ensure dynamic sealing between the tubular element 1 and the internal wall of the well A. It must be noted that shapes other than the ones illustrated can be envisaged for the stops, the seals and the anti-extrusion rings.

Besides, it can be envisaged to associate anti-extrusion rings 26 with the seal 22, 24 as described with reference to FIG. 6.

An embodiment of the present disclosure entirely or partly overcomes the drawbacks of the prior art.

More specifically, at least one embodiment provides a radially expandable tubular element, by hydroforming especially, equipped on its external face with one or more sealing modules which fully carry out their function when they are applied to a wall of a tubing or of a well.

This sealing function is carried out whatever the environment, whether liquid or gas, in which the expansion is implemented.

At least one embodiment sprovide such an element that:

• • is simple to implement;
  • preserves its sealing qualities over a wide range of temperatures and pressures;
  • has high resistance over time;
  • is compact and does not cause any excessive increase in the external diameter of the tubular element.

Although the present disclosure has been described with reference to one or more examples, workers skilled in the art will recognize that changes may be made in form and detail without departing from the scope of the disclosure and/or the appended claims.

Claims

1. A radially expandable metallic tubular element comprising: an external face;two annular stops attached to said external face of said tubular element;at least one annular sealing module on the external face, wherein said sealing module comprises at least one annular seal made out of a swelling material, called a swelling seal, disposed between the two annular stops attached to said external face of said tubular element.

2. The radially expandable metallic tubular element according to claim 1, further comprising two anti-extrusion rings each disposed between one of said annular stops and said at least one swelling seal.

3. The radially expandable metallic tubular element according to claim 2, wherein each anti-extrusion ring is in two parts and comprises two beveled surfaces made respectively in each of said parts, said beveled surfaces being situated so as to be facing each other and being capable of sliding relative to each other under the effect of an axial movement of said swelling seal so as to prompt a radial shift of one of said two parts.

4. The radially expandable metallic tubular element according to claim 2, wherein each anti-extrusion ring is made of polytetrafluoroethylene (PTFE) or polyether ether ketone (PEEK).

5. The radially expandable metallic tubular element according to claim 1, wherein said swelling seal is sandwiched between two seals made of non-swelling material, called non-swelling seals.

6. The radially expandable metallic tubular element according to claim 5, wherein each non-swelling seal is in two parts, called a first part and a second part, having different hardness values.

7. The radially expandable metallic tubular element according to claim 6, wherein the part having the lowest hardness, called the first part is juxtaposed with said seal made of swelling material.

8. The radially expandable metallic tubular element according to claim 6, wherein the first part has a hardness of 75 to 80 shore A.

9. The radially expandable metallic tubular element according to any claim 6, wherein the second part has a hardness of 85 to 90 shore A.

10. The radially expandable metallic tubular element according to claim 6, wherein the first and second parts are manufactured separately and are placed in contact on said tubular element.

11. The radially expandable metallic tubular element according to claim 10, wherein the first and second parts are bonded.

12. The radially expandable metallic tubular element according to claim 6, wherein the first and second parts are formed as a single block.

13. The radially expandable metallic tubular element according to claim 5, wherein said swelling seal and the non-swelling seals are manufactured separately and placed in contact on said tubular element.

14. The radially expandable metallic tubular element according to claim 5, wherein said swelling seal and the non-swelling seals are manufactured separately and are bonded.

15. The radially expandable metallic tubular element according to claim 5, wherein said swelling seal and the non-swelling seal are formed as a single block.

16. The radially expandable metallic tubular element according to claim 1, wherein said annular stops are made of metal.

17. The radially expandable metallic tubular element according to claim 1, wherein said seal or seals are connected to said tubular element by a sliding pivot link.

18. The radially expandable metallic tubular element according to claim 1, wherein said swelling seal is capable of passing from a retracted mode in which it has a first volume to a dilated mode in which it has a second volume that is greater than the first volume, said swelling seal having a thickness smaller than or equal to the thickness between the annular stops in the retracted mode.

19. The radially expandable metallic tubular element according to claim 1, wherein said swelling seal is made of nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR) or else fluoroelastomers (FKM).

20. The radially expandable metallic tubular element according to claim 1, wherein said tubular element is radially expandable by hydroforming.