The present invention relates to a supporting device for a sealing element in a well plug.
Many well tools, such as well plugs (bridge plugs, packers, etc.) comprise a sealing device and an anchor device connected to a mandrel. The plug has a radially retracted, or run, state and a radially expanded, or set, state. In the set state, the anchoring device is in contact with the inner surface of the well pipe, and prevents the plugging device from moving axially within the well pipe. In the set state, the sealing device is sealing off the annular space between the mandrel of the plug and the inner surface of the well pipe in order to prevent fluid flow between the lower side of the sealing element and the upper side of the sealing element.
The sealing device comprises a sealing element designed to retract and expand between its run and set states and must also be designed to withstand a high pressure difference and also to be able to seal the annular area at high temperatures. In order to do so, the sealing element, typically made from an elastomer, a rubber material etc., must be supported by supporting devices in the set state.
One such plug is shown in U.S. Pat. No. 7,178,602. Here, the sealing device comprises a sealing element and supporting devices on its upper and lower sides. Each supporting device comprises a number of first supporting arms and a number of second supporting arms having their first ends pivotably connected to a supporting ring provided around the mandrel and where their second ends are pivotably connected to each other. This principle is used in the commercially available High Expansion Retrievable Bridge plug (HEX plug), sold and marketed by Interwell (http://www.interwell.com/hex-retrievable-bridge-plug/category178.html).
One of the HEX plugs is made for use in a 7″ 29 pounds/feet well pipe, where the specification for such pipes allows the inner diameter of the pipe to vary in a range between ca 154.6-159.8 mm, i.e. a variation in the distance between the outside of the supporting arms of the plug in its set state to the inner surface of the well pipe up to 3 mm. The supporting devices can not be made to expand to the largest possible diameters of these pipes, because then, when set in a narrower pipe (i.e. close to 154.6 mm), the supporting devices will contact the pipe surface before a sufficient compression of the sealing element has been achieved.
The HEX is tested and approved for a differential pressure of 4000 psi at a temperature T=110° C. according to ISO 14310:2008 up to validation grade V0.
At higher temperatures and/or higher pressures, the material of the sealing element may be extruded into the gap between the supporting devices and the inner surface of the well pipe in particular if the plug is set in an well pipe having a large inner diameter (i.e. close to 159.9 mm).
One common way to reduce the extrusion of the sealing element is to incorporate a supporting ring within the sealing element itself, such as shown in
One or more embodiments of the present invention may provide a sealing device which can be used to seal well pipes at higher pressures and/or higher temperatures than the above sealing device. In particular, is to one or more embodiments may provide a sealing device which can be used to seal well pipes having a varying inner diameter and to provide a sealing device where the extrusion of the sealing element is reduced and/or prevented in such well pipes.
One or more embodiments of the present invention may relate to a sealing device for a well plug, comprising:
a mandrel device;
a sealing element provided circumferentially around the mandrel device;
a first supporting device provided on a first side of the sealing element;
a second supporting device provided on a second side of the sealing element;
where each supporting device comprises proximal supporting elements provided proximal to the sealing element and distal supporting elements, where first ends of the respective proximal and distal supporting elements are pivotably connected to each other;
where second ends of the proximal supporting elements are pivotably connected to a connector of a proximal supporting ring;
where second ends of the distal supporting elements are connected to a distal supporting ring;
where the sealing device is configured to be brought from a run state to a first set state by relative axial movement of the distal supporting rings towards each other and relative axial movement of the proximal supporting rings towards each other;
characterized in that the connector comprises an expansion section in the radial direction of the proximal supporting ring, the expansion section allowing the proximal supporting element to be displaced at a radial distance from the first set state to a second set state.
Accordingly, if there is available space radially outside of the supporting devices in the first set state, the proximal supporting element may expand further radially outwards, and may occupy this available space. Hence, the available space for the sealing element to be extruded is considerably reduced.
According to one aspect of the invention, the connector of the proximal supporting ring comprises a slit and a curved recess and where the expansion section is being provided as a radial expansion of the curved recess.
According to another aspect of the invention, the second end of the proximal supporting element comprises a spherical-like connector, where the spherical-like connector, the curved recess and the expansion section of the connector are adapted to each other.
According to one aspect of the invention, the sealing device further comprises a delay mechanism for each supporting device, where the delay mechanism is configured to delay the radial expansion of the supporting devices in relation to the radial expansion of the sealing element when moving from the run state to the set state.
According to one aspect of the invention, the delay mechanism comprises an axially displaceable sealing element setting sleeve provided radially between the proximal supporting ring and the mandrel device, a shear pin connecting the proximal supporting ring to the axially displaceable sealing element setting sleeve in the run state.
According to one aspect of the invention, the sealing device further comprises a first cone ring provided around the mandrel device axially between the first supporting device and the sealing element and a second cone ring provided around the mandrel device axially between the second supporting device and the sealing element, where the first and second cone rings each comprise an abutment surface in abutment with a front expansion surface of the respective proximal supporting elements in the first set state and in the second set state.
According to one aspect of the invention, the first abutment surface has an angle α11a in relation to the longitudinal direction of the sealing device and the second abutment surface has an angle α12a in relation to the longitudinal direction of 30-90°.
According to one aspect of the invention, each of the proximal supporting elements comprises a rear expansion surface provided on the opposite side of the front expansion surface, where the angle αexp between the front and rear expansion surfaces is between 20-60°.
According to one aspect of the invention, where the rear expansion surface is oriented perpendicular to the longitudinal axis of the distal supporting element.
According to one aspect of the invention, where an axial compression force is used for bringing the sealing device from the run state to the set state is transferred from the distal supporting rings to the proximal supporting rings.
In the following, embodiments of the present invention will be described in detail with reference to the enclosed drawings, where:
It is now referred to
As shown in
A first supporting device 20 provided on a first side of the sealing element 10 and a second supporting device 22 provided on a second side of the sealing element 10. Each of these supporting devices 20, 22 comprises a proximal supporting element 30 provided proximal to the sealing element 10 and a distal supporting element 50 provided distal to the sealing element 10, i.e. the proximal supporting element 30 is closer to the sealing element 10 than the distal supporting element 50.
The first ends 31, 51 of the respective proximal and distal supporting elements 30, 50 are pivotably connected to each other. More specifically, the first end 31 of the proximal supporting element 30 of the first supporting device 20 is pivotably connected to the first end 51 of the distal supporting element 50 of the first supporting device 20, while the first end 31 of the proximal supporting element 30 of the second supporting device 22 is pivotably connected to the first end 51 of the distal supporting element 50 of the second supporting device 22. In
In
The connector 62 of the proximal supporting ring 60 comprises a slit 63 and a curved recess 64, adapted to receive the sphere-like body 34 and the plate-like structure 35. The plate-like structure 35 is allowed to move within the slit 63 and the sphere-like body 34 is allowed to pivot within the curved recess 64.
In
The above description, in particular the description of the distal supporting ring 58, the distal supporting element 50 and the proximal supporting element 30 are similar or even identical to the present, prior art HEX plug.
As shown in
It is now referred to
The expansion section 65 is allowing the proximal supporting element 60 to be displaced at a radial distance d from the first set state to a second set state. The second set state is illustrated in
The spherical-like connector 34 of the second end 32 of the proximal supporting element 30, the curved recess 64 and the expansion section 65 of the connector 62 are adapted to each other to allow the movement between the run state, the first set state and the second set state. The sealing device 1 comprises a first cone ring 11 provided around the mandrel device 2 axially between the first supporting device 20 and the sealing element 10 and a second cone ring 12 provided around the mandrel device 2 axially between the second supporting device 22 and the sealing element 10, as shown in
The first and second cone rings 11, 12 each comprise an abutment surface 11a, 12a as shown in
In the one or more embodiments, the angles α11a, α12a are between 30-90°, more preferably possibly for example between 60-80°. In the embodiment shown in
The abutment surfaces 11a, 12a are in abutment with a front expansion surface SB of the respective proximal supporting elements 30 in the first set state and in the second set state.
Each of the proximal supporting elements 30 also comprises a rear expansion surface SA, as indicated in
The rear expansion surface SA is supported against a corresponding surface 68 (see
In the embodiment shown in
The angle between the lines ISA and I50 may about 90° also in the second set state. Accordingly, the rear expansion surfaces SA will be in contact with the surface 68 of the respective proximal supporting ring 60 and the front expansion surfaces SB will be in contact with the respective first and second abutment surface 11a, 12a both in the first and second set states.
Consequently, due to the angle between the rear expansion surface SA and the front expansion surface SB and these surfaces SA, SB being pressed between surfaces 11a (or 12a) and 68, the proximal supporting elements 30 will be pressed outwardly.
In one or more embodiments, the sealing device 1 comprises a delay mechanism 90 for each supporting device 20, 22. The delay mechanism 90 is configured to delay the radial expansion of the supporting devices 20, 22 in relation to the radial expansion of the sealing element 10 when moving from the run state to the set state.
In one or more embodiments, the delay mechanism 90 comprises an axially displaceable sealing element setting sleeve 91 provided radially between the proximal supporting ring 60 and the mandrel device 2 and a shear pin 92 connecting the proximal supporting ring 60 to the axially displaceable sealing element setting sleeve 91 in the run state.
Accordingly, when the setting operation is initiated from the run state, the proximal supporting ring 60 of the first supporting device 20 and the proximal supporting ring 60 of the second supporting device 22 will be displaced towards each other, while the proximal supporting elements 30 of both the first and second supporting devices 20, 22 will be prevented from a full radial expansion by the delay mechanism 90.
This state is shown in
When the axial force applied to the distal supporting ring(s) 58 is above a threshold value, then the shear pin 92 will shear off, and then also the pivotal and distal supporting elements 30, 50 is allowed to expand fully to the first set state shown in
In
By this further radial expansion from the first set state to the second set state, it is achieved that the proximal supporting elements 30 on each side of the sealing element 10 to a larger extent than with the previous HEX plug will prevent extrusion of the sealing element 10 if the sealing device 1 is set in well pipes with a slightly larger diameter (for example 159.8). In well pipes with a slightly smaller diameter (for example ca 154.6 mm), the proximal supporting elements 30 will expand until they come into contact with the inner surface of the well pipe. Also here, extrusion of the sealing element 10 is prevented.
A prototype of a plug with the sealing device shown in
Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present invention. Accordingly, the scope of the invention should be limited only by the attached claims.
It should be mentioned that the invention described above could of course be used in well pipes having other diameters than the diameter(s) used in the above example.
Number | Date | Country | Kind |
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20151213 | Sep 2015 | NO | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2016/071063 | 9/7/2016 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2017/045984 | 3/23/2017 | WO | A |
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Number | Date | Country | |
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20180245423 A1 | Aug 2018 | US |