The present invention relates to a plugging device. More specific, the invention relates to a plugging device for sealing against an inner surface of a pipe. The invention also relates to a packer body for sealing against an inner surface of a pipe.
Many types of plugging devices for sealing against the inner wall of a pipe are known. Typically such plugging devices are used in the pipes of oil and/or gas wells or oil and/or gas production equipment, but they may also be used in other applications. Such plugging devices comprise a packer device provided circumferentially around the plugging device.
The packer device is in a retracted state during the transportation of the plugging device to the desired location in the pipe. At the desired location, the packer device is brought to an expanded state, for sealing against the inner wall of the pipe. The packer device comprises a packer body made of an elastic or ductile material in order to be brought between the retracted and the expanded states, and in order to seal against the inner wall of the pipe. The packer body is subjected to extrusion forces which may deform the packer body so much that it becomes damaged. In order to reduce the extrusion of the packer body, a supporting device or so-called backup ring is often incorporated into the packer body. The supporting device is also provided circumferentially around the plugging device.
One typical supporting device is a coil spring. However, when a spring is expanded due to the movement from the retracted state to the expanded state, the distance between each turn of the spring increases, allowing the ductile material of the packer body to extrude in between the openings between the respective turns. Moreover, the ductile material which has extruded into the openings between the respective turns will obstruct the spring to return to its retracted state when there is a need to retrieve the plugging device from the pipe. Hence, the plugging device may have a larger outer diameter during transportation out from the pipe than during transportation into the pipe, which may cause the plugging device to get stuck.
It is known to provide a core unit inside a spring, for example as in US 2006/0290066. Here the core unit comprises several interlinked elements, each having a first end connected to a second end of an adjacent element. Also here the distance between each element increases in the expanded state, allowing the material of the packer body to extrude between the openings of the spring and the opening between the elements.
From U.S. Pat. No. 4,379,558 it is also known to provide a flat wire spring on the outside of the coiled spring, where the flat wire spring has overlapping contiguous elements forming a tubular encasement for the spring. It is difficult to provide the flat wire spring sufficiently strong, and the production of it is complex.
The object of the invention is to provide a packer device with a supporting device where the disadvantages above are avoided. One object of the present invention is to avoid the use of a coil spring in the supporting device.
The present invention relates to a plugging device comprising:
In one aspect, the packer body and the supporting device are provided as one body made of the same material.
In one aspect, the material of the packer body and the supporting device is a ductile or semi-ductile material.
In one aspect, the packer body is provided in a groove in the supporting device.
In one aspect, the first side of the packer device comprises at least one first contact area in which the packer device is in contact with the first supporting assembly in the retracted state;
In one aspect, the first side of the packer device comprises two first contact areas and where the second side of the packer device comprises two second contact areas.
In one aspect, the first side of the packer device comprises six first contact areas and where the second side of the packer device comprises six second contact areas.
In one aspect, the supporting device comprises a chain comprising interconnected chain elements.
In one aspect, the chain elements comprises an outwardly curved front end and an inwardly curved rear end, where the front end is adapted to be received by the rear end of an adjacent chain element.
In one aspect, the front end is outwardly hemispherical and the rear end is inwardly hemispherical.
In one aspect, the chain elements comprises:
In one aspect, the chain elements comprises a substantially cylindrical side surface between the front end and the rear end.
In one aspect, a connection bore is provided between the front end and the rear end of each chain and where a connection wire is inserted through the connection bores of each chain element.
In one aspect, the supporting device is incorporated into the packer body.
In one aspect, the packer device is oval or wave-shaped in the retracted state, and cylindrical in the expanded state.
In one aspect, the packer body is oval or wave-shaped in the retracted state, and cylindrical in the expanded state.
The invention also relates to a packer body for sealing against an inner surface of a pipe, where:
Embodiments of the invention will now be described with reference to the enclosed drawings, where:
a illustrates a perspective view of a first embodiment of a packer device;
b illustrates a cross sectional view of the first embodiment in
a illustrates a perspective view of a first embodiment of the supporting device;
b illustrates a cross sectional side view of a link element of the first embodiment of the supporting device;
c illustrates a perspective view of the link element of
d illustrates a perspective rear view of the link element of
a and 12b illustrate a cross sectional front view and side view of a second embodiment of the supporting device respectively;
c and 12d illustrate the link elements of the second embodiment of the supporting device.
It is now referred to
A plugging device 1 comprises a housing 10 and a packer device 2 provided circumferentially around the housing 10.
The packer device 2 is configured to be provided in a retracted state and in an expanded state, where the outer radial radius R2 of the packer body 20 in the expanded state is larger than the outer radial radius R1 of the packer body 20 in the retracted state.
The housing 10 has an outer circumference C10 indicated in
In
The packer device 2 may be connected to the first supporting assembly 3 and the second support assembly 4 in order to pull the packer device 2 back to its retracted state. Alternatively, the packer device 2 may return to its initial (i.e. retracted state) state by itself due to the properties of the material of the packer device when the first and second supporting assemblies 3 and 4 are returned to their retracted positions.
In addition, the plugging device 1 may comprise first and second gripping assemblies 5, 6 which also have a retracted state (as in
Embodiments of the packer device 2 will now be described in detail. The packer device 2 comprises a packer body 20 and a supporting device 30. The main purpose of the packer body is to seal against the inner wall of the pipe, while the main purpose of the supporting device 30 is to support the packer body 20 in the expanded state, i.e. to avoid extrusion of the packer body 20.
It is now referred to
The packer body 20 and the supporting device 30 have the same circumference C in the retracted state and the expanded state. More specifically, the central circumference C (indicated in
It should be noted that it would be difficult or impossible to retract the packer device 2 of the first embodiment back to its retracted state. Hence, the plugging device 1 having such a packer device 2 will be a permanent plugging device.
It should also be noted that in an alternative embodiment, the packer body 20 and the supporting device 30 may be provided as one body made of the same ductile or semi-ductile material such as tin or lead, i.e. there are no grooves and no rubber material. Here, the material of such a packer device 2 will provide the sealing against the inner wall of the pipe and will also provide properties which avoid the extrusion.
In
There are also six non-contact areas 22 longitudinally opposite of the respective first contact areas 21 and six non-contact areas 24 longitudinally opposite of the respective second contact areas 23 where there is no contact between the packer device 2 and the first and second supporting assemblies 3, 4 respectively. Hence, there is a distance (i.e. an axial distance) between each non-contact area 22 and the second supporting assembly 4 which is larger than zero and there is a distance (i.e. an axial distance) between each non-contact area 24 and the first supporting assembly 3 which is larger than zero.
The first side 2a of the packer device 2 is parallel to the second side 2b of the packer device 2 along the circumference of the packer device in the retracted state, i.e. the normal N1 is parallel to the normal N2 in
It is now referred to
In
There are also a non-contact area 22 longitudinally opposite of the first contact area 21 and a non-contact area 24 longitudinally opposite of the second contact area 23 where there is no contact between the packer device 2 and the first and second supporting assemblies 3, 4 respectively. Hence, there is a distance D22 (i.e. an axial distance) between the non-contact area 22 and the second supporting assembly 4 which is larger than zero and there is a distance D24 (i.e. an axial distance) between the non-contact area 24 and the first supporting assembly 3 which is larger than zero.
In
Consequently, in the retracted state, the first and second supporting devices 30, 60 are substantially oval, while in the expanded state, they are substantially ring-shaped. In the retracted state, the packer device 2 (and hence the packer body 20) is shaped as an oblique or inclined cylinder. More specifically, it is shaped as an inclined, circular cylinder. As the packer body 20 is provided circumferentially around the plugging device, an opening is provided through the packer body 20, i.e. the packer body is hollow. In a preferred embodiment, the packer body 20 is unstrained in the retracted state.
Consequently, the first and second supporting devices 30, 60 have the same circumference C in the retracted state and the expanded state. Hence, there is no radial expansion of the first and second supporting devices 30, 60, and no openings occur in the supporting device in which the packer body 20 may extrude. By the term “there is no radial expansion” it is referred to
During the movement of the packer device from the retracted state to the expanded state the material of the packer body and the supporting device will be twisted and bent due to the axial compression, however, the strain on the materials will be reduced when compared to a prior art plugging device.
The material of the packer body 20 may be a flexible, elastic, ductile or semi-ductile material, such as rubber PEEK (polyether ether ketone), PTFE (polytetrafluoroethylene), or other suitable materials. Also other materials may be added, as described above.
It is now referred to
In
There are also a non-contact area 22 longitudinally opposite of each first contact area 21 and a non-contact area 24 longitudinally opposite of each second contact area 23 where there is no contact between the packer device 2 and the first and second supporting assemblies 3, 4 respectively. Hence, there is a distance D22 (i.e. an axial distance) between the non-contact area 22 and the second supporting assembly 4 which is larger than zero and there is a distance D24 (i.e. an axial distance) between the non-contact area 24 and the first supporting assembly 3 which is larger than zero.
In
Consequently, the first and second supporting devices 30, 60 have the same circumference C in the retracted state and the expanded state.
The embodiment in
It is now referred to
Also the fourth embodiment comprises first and second supporting devices 50, 60 incorporated into the packer body 20.
In
There are also a non-contact area 22 longitudinally opposite of each first contact area 21 and a non-contact area 24 longitudinally opposite of each second contact area 23 where there is no contact between the packer device 2 and the first and second supporting assemblies 3, 4 respectively. Hence, there is a distance D22 (i.e. an axial distance) between the non-contact area 22 and the second supporting assembly 4 which is larger than zero and there is a distance D24 (i.e. an axial distance) between the non-contact area 24 and the first supporting assembly 3 which is larger than zero.
As shown in
Also here the first and second supporting devices 30, 60 have the same circumference C in the retracted state and the expanded state.
The embodiment on
In all the embodiments above, the circumference C is larger than the circumference C10 of the housing 10. This is achieved due to the oval shaped or wave shaped packer device 2 in the retracted state.
This embodiment of the packer device is used on the plugging device in
A first embodiment of the supporting device 30 will now be described with reference to
In
A second embodiment of the supporting device 30 will now be described with reference to
The outwardly curved front end 57 of the second chain element 55 is adapted to be received by the inwardly curved rear end 53 of the first chain element 50 and the outwardly curved rear end 58 of the second chain element 55 is adapted to be received by the inwardly curved front end 42 of the first chain element 50.
Also here a connection bore 54, 59 is provided between the front end 52, 57 and the rear end 53, 58 of the respective first and second chain elements 50, 55, where a connection wire 70 is inserted through the connection bores 54, 59 of the respective chain elements and the ends of the connection wire 70 is connected to each other, thereby forming the chain as shown in
In
It should be noted that the supporting device 30 described above with reference to
The supporting devices 30 described above are non-stretchable or substantially non-stretchable, i.e. its circumference will not be increased when the packer device 2 is axially compressed by the first and second supporting assemblies 3, 4.
Number | Date | Country | Kind |
---|---|---|---|
20110809 | Jun 2011 | NO | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2012/060321 | 5/31/2012 | WO | 00 | 11/22/2013 |