Well tool device with supporting elements for supporting a sealing element in a radially expanded state

Abstract

The present invention relates to a well tool device (1) for use in a well. The well tool device (1) has a sealing device (20) with a first supporting device (40) for supporting a first side (S1) of the sealing element (21) in the radially expanded state. The first supporting device (40) comprises a plurality of first arms (41) having a first end (41a) and a second end (41b), the first end (41a) comprising a first supporting element (42) with a first front surface (42f) having a first outer edge (42oe). The first supporting device (40 comprises a plurality of second arms (51) having a first end (51a) and a second end (51b), the first end (51a) comprising a second supporting element (52) with a second front surface (52fs) having a second outer edge (52oe). The first front surfaces (42f) and the second front surfaces (52f) together are forming an extrusion-preventing surface provided circumferentially around the mandrel (2) for supporting the first side (S1) of the sealing element (21) in the radially expanded state. In the radially retracted state, the first outer edges (42oe) are provided in a first plane (P1) and the second outer edges (52oe) are provided in a second plane (P2); wherein the first plane (P1) is longitudinally displaced with respect to the second plane (P2). In the radially expanded state, the first outer edges (42oe) and the second outer edges (52oe) are provided in a common, third plane (P3).

Description

[0001] WELL TOOL DEVICE WITH SUPPORTING ELEMENTS FOR SUPPORTING A SEALING ELEMENT IN A RADIALLY EXPANDED STATE

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a well tool device for use in a well.

[0004] BACKGROUND OF THE INVENTION

[0005] Several types of well tool devices for sealing of hydrocarbon well pipes are known. In US 7,178,602 it is shown a well tool device having an anchoring device for anchoring the well tool device to the inner surface of the well pipe to prevent longitudinal movement of the well tool device. The well tool device also comprises a sealing device with an elastomeric sealing element for preventing longitudinal fluid flow past the well pipe.

[0006] The sealing element may be deformed or extruded by higher pressure differences over the sealing element when set in the well pipe. This increases the risk of a fluid leakage. This situation increases at higher temperatures, as the material of the sealing element becomes softer.

[0007] The well tool device in US 7,290,603 comprises a number of supporting elements which are radially expanded together with the sealing element. These supporting elements provides a mechanical support for the sealing element and hence reduces the risk of deformation of the sealing element. WO 2021 / 043582 and WO 2012 / 164051 describe extrusion-preventing devices which are incorporated into the sealing element itself, in order to reduce the risk of deformation of the sealing element.

[0008] A so-called high expansion well tool device has a relatively narrow diameter in retracted state, allowing the well tool device to pass restrictions in the well pipe. At the same time, it has a relatively large diameter in the expanded state in order to seal the well pipe below the restriction.

[0009] A so-called retrievable well tool device is designed to be retrieved again after use by means of a retrieval tool or pulling tool. For such tools it is important that they can be radially retracted again in order to pull it past restrictions in the well pipe again.

[0010] WO 2012 / 079913 a plugging device having a first cone and a second cone, each having their base faced towards each other and each comprising a tapering surface. A first supporting device is provided on a first side of the cone device, a second supporting device is provided on a second side of the cone device . The first and second supporting devices comprise supporting arms having a first end movably connected to the plugging device and a second end connected to either a front supporting element or a rear supporting element. A sliding surface is provided on the first and second packer supporting device for sliding up and down the tapering surface of the first or second cone, thereby bringing the packer device between its expanded and retracted position respectively. The front supporting element are provided in contact with the sealing element, while the rear supporting element is provided behind and is supporting the rear surface of its two adjacent front supporting elements in the radially expanded position.

[0011] US 7,017,670 describes an apparatus for securing a tubular member within a liner or borehole has a seal means connected within the tubular member, and a pressure control device operable to increase the pressure within the tubular member, such that operation of the pressure control means causes the tubular member to move radially outwardly to bear against the inner surface of the liner or borehole wall. Also, a packer for use in a downhole annular space and an isolation plug for plugging a downhole tubular are disclosed.

[0012] The object of the present invention is to provide an improved well tool device.

[0013] SUMMARY OF THE INVENTION

[0014] The present invention relates to a well tool device for use in a well, wherein the well tool device comprises:

[0015] - a mandrel;

[0016] - a housing provided outside of the mandrel;

[0017] - a sealing device provided radially outside of the mandrel, wherein the sealing device is configured to be brought from a radially retracted state to a radially expanded state by a relative longitudinal displacement between the mandrel and the housing; wherein the sealing device comprises a sealing element for preventing longitudinal fluid flow past the sealing element along the well in the radially expanded state, wherein the sealing element circumferentially surrounds the mandrel; wherein the sealing device comprises a first supporting device for supporting a first side of the sealing element in the radially expanded state; characterized in that the first supporting device comprises:

[0018] - a plurality of first arms having a first end and a second end, the first end comprising a first supporting element with a first front surface having a first outer edge;

[0019] - a plurality of second arms having a first end and a second end, the first end comprising a second supporting element with a second front surface having a second outer edge; wherein the first front surfaces and the second front surfaces together are forming an extrusion-preventing surface provided circumferentially around the mandrel for supporting the first side of the sealing element in the radially expanded state; wherein in the radially retracted state, the first outer edges are provided in a first plane and the second outer edges are provided in a second plane; wherein the first plane is longitudinally displaced with respect to the second plane; and wherein in the radially expanded state, the first outer edges and the second outer edges are provided in a common, third plane.

[0020] The well tool device is defined with a longitudinal centre axis. As used herein, the term “longitudinal direction” is a direction aligned with, or in parallel with, the longitudinal centre axis. As used herein, the term “radial direction” is a direction perpendicular to the longitudinal centre axis.

[0021] As used herein, the term “front surface” refers to a surface being faced towards the sealing element and which purpose is to support the sealing element in the radially expanded state, i.e. to prevent, or at least considerably reduce, extrusion of the sealing element. The risk of such extrusion is highest during periods with relatively higher temperature and / or during periods of relatively higher pressure difference between the first side or upper side of the sealing element and a second side or lower side of the sealing element.

[0022] The first supporting element may be connected to the first arm. The first supporting element may be an integral part of the first arm, i.e. they are formed as one single body. Similarly, the second supporting element may be connected to the second arm. The second supporting element may be an integral part of the second arm, i.e. they are formed as one single body.

[0023] The first plane may be longitudinally displaced relative to the third plane. The second plane may be longitudinally displaced relative to the third plane. The first plane, the second plane and the third plane may be parallel to each other. The first plane, the second plane and / or the third plane may be oriented in the radial direction, i.e. perpendicular to the longitudinal center axis.

[0024] The first supporting device is longitudinally displaceable relative to the mandrel, together with the housing. By relative longitudinal displacement between the mandrel and the housing also the first supporting device will be displaced relative to the mandrel.

[0025] The extrusion-preventing surface may be a continuous surface.

[0026] The first front surfaces in the radially retracted state together may be forming a continuous surface circumferentially around the mandrel. The first supporting elements and the second supporting elements may be arranged to be contiguous circumferentially around the mandrel in the radially expanded state.

[0027] The first front surfaces and the second front surfaces may be contiguous circumferentially around the mandrel in the radially expanded state.

[0028] As used herein, the term “contiguous” is used to denote that the first supporting elements and the second supporting elements are not overlapping other first supporting elements nor second supporting elements in the radially expanded state.

[0029] The first supporting elements and the second supporting elements may be arranged in sequence circumferentially around the mandrel in the radially expanded state.

[0030] Hence, each first supporting element has two neighbouring supporting elements and each second supporting element has two neighbouring supporting elements.

[0031] Preferably, every other first supporting element has two second supporting elements as its neighbour and every other second supporting element has two first supporting elements as its neighbour. Hence, each first supporting element is located between two second supporting elements and each second supporting element is located between two first supporting elements.

[0032] However, other arrangements are possible. For example, there may be two or more second supporting elements located between two first supporting elements, and / or there may be two or more first supporting elements located between two second supporting elements.

[0033] The sealing device may comprise a first cone device radially outside of the mandrel adjacent to the sealing element; wherein the first cone device may comprise a tapering surface along which the first end of the first arms and the first end of the second arms travel between the radially retracted state and the radially expanded state.

[0034] The first supporting elements and the second supporting element may be travelling along the tapering surface between the radially retracted state and the radially expanded state.

[0035] As the first ends of the first arms may be traveling along the tapering surface of the cone device, a circumferential space between the first supporting elements may increase, thereby allowing one of the second supporting elements to move into the circumferential space.

[0036] The first cone device may comprise a sealing element supporting surface for supporting the sealing element; wherein the sealing element supporting surface together with the extrusion-preventing surface formed by the first front surfaces and the second front surfaces together may be forming a continuous extrusion - preventing surface in the radially expanded state.

[0037] The sealing element supporting surface may support the sealing element in both the radially retracted state and in the radially expanded state. The sealing element supporting surface may support the sealing element in only the radially expanded state.

[0038] The first front surface may be level or even. The second front surface may be level or even. The sealing element supporting surface may be level or even. The extrusion-preventing surface formed by the first front surface and the second front surface may be level or even. The extrusion-preventing surface formed by the first front surface, the second front surface and the sealing element supporting surface may be level or even.

[0039] The extrusion-preventing surface formed by the first front surface and the second front surface may be shaped as a spherical cap having an opening for the mandrel. The extrusion-preventing surface formed by the first front surface, the second front surface and the sealing element supporting surface may be shaped as a spherical cap having an opening for the mandrel.

[0040] The extrusion-preventing surface formed by the first front surface and the second front surface may be shaped as a cone having an opening for the mandrel. The extrusion-preventing surface formed by the first front surface, the second front surface and the sealing element supporting surface may be shaped as a cone having an opening for the mandrel.

[0041] The first arms may be moved longitudinally a first distance from the radially retracted state to the radially expanded state; the second arms may be moved longitudinally a second distance from the radially retracted state to the radially expanded state, wherein the second distance may be longer than the first distance.

[0042] The second ends of the first arms may be secured to each other by means of a first sleeve. The first sleeve may be longitudinally displaceable relative to the mandrel.

[0043] The second ends of the second arms may be secured to each other by means of a second sleeve. The second sleeve may be longitudinally displaceable relative to the mandrel. The second sleeve may be longitudinally displaceable relative to the first sleeve.

[0044] The second sleeve may be located at least partially inside the first sleeve.

[0045] The second sleeve may be protruding longitudinally from the first sleeve in the radially retracted state; and wherein the sealing device may be brought from the radially retracted state to the radially expanded state by moving the second sleeve longitudinally relative to the first sleeve.

[0046] The second sleeve may be moved longitudinally relative to the first sleeve on the inside of the first sleeve.

[0047] The first supporting device may comprise a movement restrainer for restraining the relative longitudinal displacement between the first sleeve and the second sleeve.

[0048] The movement restrainer may comprise a pin secured to the second sleeve and a slot provided in the first sleeve, wherein the pin is engaged in the longitudinal slot. Relative longitudinal displacement between the first sleeve and the second sleeve is allowed only as long as the pin is movable within the longitudinal slot.

[0049] The maximum allowed relative longitudinal displacement between the first sleeve and the second sleeve may be referred to as a maximum longitudinal movement.

[0050] The outer edges of the first front surfaces are together forming a first circle in the radially retracted state. The diameter of the first circle may be equal to an outer diameter of the well tool device in the radially retracted state.

[0051] The outer edges of the second front surfaces are together forming a second circle in the radially retracted state. A diameter of the second circle may be equal to an outer diameter of the well tool device in the radially retracted state.

[0052] The outer edges of the first front surfaces and the outer edges of the second front surfaces are together forming a third circle in the radially expanded state. A diameter of the third circle is less than an expected inner diameter of the well. A difference between an expected inner diameter of the well and the diameter of the third circle may be referred to as a gap.

[0053] The sealing element may comprise an elastomeric body and an extrusion -preventing element incorporated into the elastomeric body. The extrusion -preventing element may be torus-shaped. The extrusion-preventing element may have a minor radius being substantially equal to or larger than the gap. The extrusion -preventing element may have a major radius in the radially expanded state being substantially equal to the diameter of the third circle.

[0054] The first supporting device may comprise a guiding arrangement for guiding of the first arms and the second arms along the tapering surface of the cone device.

[0055] The guiding arrangement may be a protrusion and track type of guiding arrangement. The protrusion and track type of guiding arrangement may comprise tracks, for example in the form of recesses, provided in the tapering surface and protrusions protruding from the first arms and the second arms, wherein each protrusion is engaged in a respective one of the tracks. The guiding arrangement may be a dovetail type of guiding arrangement. Here, the supporting elements of the arms are forced radially inwardly when moving the supporting device from the radially expanded state to the radially retracted state.

[0056] The first front surfaces and the second front surfaces together may be forming an extrusion-preventing surface provided circumferentially around the mandrel for supporting the second side of the sealing element in the radially expanded state; wherein in the radially retracted state, the first outer edges may be provided in a fourth plane and the second outer edges may be provided in a fifth plane; wherein the fourth plane may be longitudinally displaced with respect to the fifth plane; and wherein in the radially expanded state, the first outer edges and the second outer edges may be provided in a common, sixth plane.

[0057] According to the above, it is achieved a retrievable well tool device with a relatively high expansion ratio, which may be rated to a relatively high pressure and / or a relatively high temperature.

[0058] The well tool device may be referred to as a well plug. The well tool device is a retrievable well tool device. The well tool device may comprise an upper connection interface for connection to a setting tool being used to displace the mandrel and the housing longitudinally relative to each other in order to bring the well tool device from the radially retracted state to the radially expanded state. The connection interface may be used by a retrieval tool in order to bring the well tool device from the radially expanded state to a retrieval state, in order to retrieve the well tool device from the well. The sealing device and / or the anchoring device may be radially retracted also in the retrieval state. The retrieval state is similar to, but not necessarily identical to, the radially retracted state.

[0059] The terms “upper”, “above”, “below” and “lower” are used herein to define parts of the well tool device, when the well tool device is used in a well. “Upper” and “above” refer to a position relatively closer to the well opening and “below“ and “lower” refer to a position relatively further away from the well opening. These terms apply both when the well has a vertical and horizontal orientation.

[0060] As used herein, the terms “radially retracted state” and “run state” are used interchangeably for the state in which the well tool is lowered to a desired location in the well. The terms “radially expanded state” and “set state” are used interchangeably for the state in which the well tool is engaged with the inner surface of the well at the desired location in the well.

[0061] As used herein, the term “anchoring device” is referring to a part of the well tool which is radially expanded to be engaged with the inner surface of the well at the desired location in the well. The anchoring device may comprise a serrated surface which prevents the well tool from moving longitudinally within the well when engaged with the inner surface of the well.

[0062] As used herein, the term “sealing device” is referring to a part of the well tool which is radially expanded into contact with the inner surface of the well at the desired location of the well. The function of the sealing device is to prevent or reduce longitudinal fluid flow at the desired location in the well, i.e. to prevent or reduce fluid from flowing between a location above the well tool device and a location below the well tool device.

[0063] It is commonly known that the anchoring device and / or sealing device are only capable of performing their function in their radially expanded state in the well. Moreover, it should be noted that a well tool is rated to a pressure level or pressure interval and / or a temperature level or temperature interval.

[0064] The term “well” may refer to a hydrocarbon producing well, such as a gas well or an oil well. The term “well” may also refer to a water well, a thermal well or other types of wells.

[0065] LIST OF DRAWINGS

[0066] Fig. 1 is a side view of a well tool device 1 in the form of a plug in the radially retracted state;

[0067] Fig. 2a is a perspective view of the sealing device of the plug in the radially retracted state;

[0068] Fig. 2b is a perspective view of the sealing device of fig. 2a in the radially expanded state;

[0069] Fig. 3a is a side view of the sealing device of the plug in the radially retracted state; Fig. 3b is a perspective view of the sealing device of fig. 3a in the radially expanded state;

[0070] Fig. 4a is an enlarged view of the first supporting device, the first cone device and the mandrel in the radially retracted state, where the sealing element has been removed;

[0071] Fig. 4b is an enlarged view of the first supporting device, the cone device, the mandrel and the second supporting device in the radially expanded state, where the sealing element has been removed;

[0072] Fig. 5a is a cross sectional view of the sealing device of the plug in the radially retracted state;

[0073] Fig. 5b is an enlarged view of the dashed box in fig. 5a;

[0074] Fig. 5c is a cross sectional view of the sealing device of fig. 5a in the radially expanded state;

[0075] Fig. 5d is an enlarged view of the dashed box in fig. 5c;

[0076] Fig. 6a is an enlarged view of the second supporting device, the second cone device and the mandrel in the radially retracted state, where the sealing element has been removed;

[0077] Fig. 6b is an enlarged view of the second supporting device, the second cone device, the mandrel and the first supporting device in the radially expanded state, where the sealing element has been removed;

[0078] Fig. 7a illustrates schematically the radius of the well tool device in the radially retracted state;

[0079] Fig. 7b illustrates schematically the radius of the well tool device in the radially expanded state;

[0080] Fig. 8 shows an alternative embodiment to the one shown in fig. 5c.

[0081] DETAILED DESCRIPTION

[0082] It is now referred to fig. 1, where a retrievable well plug device 1 in the form of a well plug is shown. The well tool device 1 comprises a mandrel 2 (fig. 5a), a housing 3, a sealing device 20 and an anchoring device 10.

[0083] A longitudinal center axis is indicated as a dashed line LCA in fig. 1. A longitudinal direction is a direction aligned with, or parallel to the longitudinal center axis LCA. A radial direction RD shown in fig. 1 is a direction perpendicular to the longitudinal center axis LCA. A circumferential direction CD shown in fig. 2a is a direction circumferentially around the longitudinal center axis LCA.

[0084] An outer diameter of the well tool device 1 in the radially retracted state is indicated as a diameter DRR.

[0085] The housing 3 is provided radially outside of the mandrel 2 and comprises three housing sections as indicated in fig. 1.

[0086] The purpose of the anchoring device 10 is to anchor the well tool device 1 to the well in the radially expanded state to prevent longitudinal movement of the well tool device 1 within the well. The anchoring device 1 is considered to be well known for a skilled person and will not be described further in detail below.

[0087] The sealing device 20 is provided radially outside of the mandrel 2 and comprises a sealing element 21, a first or upper supporting device 40 for supporting a first or upper side SI of the sealing element 21 in the radially expanded state and a second or lower supporting device 80 for supporting a second or lower side S2 of the sealing element 21 in the radially expanded state. In addition, the sealing device 20 comprises a first or upper cone device 31 longitudinally above the sealing element 21 and a second or lower cone device 35 longitudinally below the sealing element 21. The sealing device 20 and the anchoring device 10 are configured to be brought from the radially retracted state to the radially expanded state by a relative longitudinal displacement between the mandrel 2 and the housing 3.

[0088] The purpose of the sealing device 20 is to prevent longitudinal fluid flow past the sealing element 21 along the well in the radially expanded state.

[0089] In addition to the above, the well tool device 1 comprise an upper connection interface UCI for connection to a setting tool (not shown) being used to displace the mandrel 2 and the housing 3 longitudinally relative to each other in order to bring the well tool device from the radially retracted state to the radially expanded state. The connection interface UCI may be used by a retrieval tool in order to bring the well tool device from the radially expanded state to a retrieval state, in order to retrieve the well tool device 1 from the well. The sealing device and / or the anchoring device may be radially retracted also in the retrieval state. The retrieval state is similar to, but not necessarily identical to, the radially retracted state.

[0090] The sealing element 21

[0091] It is now referred to fig. 5a and 5c. The sealing element 21 is here shown to comprise a body 22 provided circumferentially around the mandrel 2. The body 22 is made of an elastomeric material, which has sealing properties when forced towards the outer surface of the mandrel 2 and when forced towards the inner surface of the well. In addition, the sealing element 21 comprises two extrusion - preventing elements 23 incorporated into the elastomeric body 22.

[0092] The extrusion-preventing elements 23 are torus -shaped and are typically located near or along the periphery of the body 22 and in the upper end and in the lower end of the body 22 respectively. As is known, a torus may be defined with a major radius and a minor radius. In fig. 5b and 5d, the major radius of one of the extrusion elements 23 is indicated as r23major and the minor radius is indicated as r23minor. The minor radius r23minor in the retracted state is similar to, or is equal to, the minor radius r23minor in the expanded state, while the major radius r23major is larger in the expanded state than in the retracted state.

[0093] The sealing element 21 and / or the extrusion -preventing element 23 may be waveshaped or sinusoidal along its circumference to allow a larger difference between the radially expanded state and the radially retracted state. Such wave-shaped or sinusoidal sealing elements are described in EP2715048.

[0094] The extrusion-preventing element 23 may comprise a spiral spring. The extrusionpreventing element 23 may comprise a canted spiral spring formed as a torus, as described in EP 4025764. The extrusion-preventing element 23 may comprise thimble- shaped elements inserted into each other to form a torus, as described in EP 2715048.

[0095] The first cone device 31

[0096] The first cone device 31 will now be described in detail with reference to fig. 4a. Here it is shown that the first cone device 31 comprises a sealing element supporting surface 32 for supporting the first side SI of the sealing element 21 in the radially expanded state. It should be noted that the sealing element supporting surface 32 may be in physical contact with the sealing element 21 both in the radially retracted state and in the radially expanded state.

[0097] The first cone device 31 further comprises a tapering surface 33 along which at least parts of the first supporting device 40 moves between the radially expanded state and the radially retracted state.

[0098] In the tapering surface 33, tracks 33a are provided. These tracks 33a may be engaged by protrusions protruding radially inwardly from the from the first supporting device 40, wherein the tracks 33a and protrusions are forming a guiding arrangement for the at least parts of the first supporting device 40 moving along the tapering surface 33.

[0099] The second cone device 35

[0100] The second cone device 33 will now be described in detail with reference to fig. 6a. The second cone device 35 is identical to the first cone device 31, and therefore the same reference numbers have been used for the sealing element supporting surface 32, the tapering surface 33 and the track 33a.

[0101] It should be noted that the sealing element supporting surface 32 of the second cone device 35 is supporting the second side S2 of the sealing element 21 in the radially expanded state. Hence, the sealing element supporting surface 32 of the second cone device 35 is faced longitudinally towards the sealing element supporting surface 32 of the first cone device 31, as shown in fig. 3a. The tapering surface 33 of the second cone device 35 is a surface along which at least parts of the second supporting device 80 moves between the radially expanded state and the radially retracted state. Also this tapering surface 33 comprises tracks 33a.

[0102] The first supporting device 40

[0103] The first supporting device 40 will now be described in detail. In fig. 2a and fig. 3a, it is shown that the first supporting device 40 comprises a number of first arms 41 having a first end 41a and a second end 41b. In the present embodiment, there are six first arms 41.

[0104] Each first end 41a comprises a first supporting element 42 with a first front surface 42f faced towards the sealing element 21. The front surface 42f is defined with an outer edge 42oe referred to as a first outer edge 42oe. The second ends 41b of the first arms 41 are secured to each other by means of a first sleeve 45.

[0105] The first supporting device 40 further comprises a number of second arms 51 having a first end 51a and a second end 51b. In the present embodiment, there are six second arms 51.

[0106] Each first end 51a comprises a second supporting element 52 with a second front surface 52f faced towards the sealing element 21. The front surface 52f is defined with an outer edge 52oe referred to as a second outer edge 52oe. The second ends 51b of the second arms 51 are secured to each other by means of a second sleeve 55.

[0107] The first arms 41, the first supporting element 42 and the first sleeve 45 may be machined as one single part. Similarly, the second arms 51, the second supporting element 52 and the second sleeve 55 may be machined as one single part.

[0108] The second sleeve 55 is located at least partially inside the first sleeve 45 and the second sleeve 55 is longitudinally displaceable relative to the first sleeve 45. As shown in fig. 3a, the inner second sleeve 55 protrudes upwardly (i.e. to the left) from the inside of the outer first sleeve 44, while in fig. 3b, the inner second sleeve 55 has been moved entirely inside of the outer first sleeve 45. It is further shown in fig. 3a that the second sleeve 55 is secured to the housing 3 above the sealing device 20.

[0109] The longitudinal displacement is limited by a movement restrainer 60 shown in fig. 3a and fig. 3b. The movement restrainer 60 here comprise a pin 56 secured to the second sleeve 55 and a slot 46 provided in the first sleeve 45, wherein the pin 56 is engaged in the longitudinal slot 46. Relative longitudinal displacement between the first sleeve 45 and the second sleeve 55 is allowed only as long as the pin 56 is movable within the longitudinal slot 46.

[0110] In fig. 3a, the pin 56 is in the leftmost position within the slot 46, while in fig. 3b, the pin 56 is in the rightmost position within the slot 46. The maximum allowed relative longitudinal displacement between the first sleeve 45 and the second sleeve 55 is shown in fig. 3a as a maximum longitudinal movement D60.

[0111] It is now referred to fig. 2a and fig. 4a. Here it is shown that in the circumferential direction CD, every other arm is a first arm 41 and every other arm is a second arm 51. Hence, each first arm 41 has two second arms 51 as its neighbour, and each second arm 51 have two first arms 41 as its neighbour.

[0112] It is now referred to fig. 3b. Here it is shown apertures provided in the first end 41a of the first arms 41 and apertures provided in the first end 51a of the second arms 51, in which pins 43, 53 are inserted. These pins 43, 53 forms the above protrusions being engaged in the tracks 33a of the tapering surface 33 of the first cone device 31, i.e. the pins 43, 53 and the tracks 33a are together forming the above guiding arrangement.

[0113] It is now referred to fig. 4a. Here it is shown that the first outer edges 42oe of the first supporting elements 42 are provided in a first plane Pl. It is further shown that the second outer edges 52oe of the second supporting elements 52 are provided in a second plane P2, the first plane Pl being longitudinally displaced with respect to the second plane P2. It is further shown that the first front surfaces 42f of the first supporting elements 42 are wider (i.e. as measured in the circumferential direction CD) than the second front surfaces 52f of the second supporting elements 52.

[0114] It is further shown that the first outer edges 42oe together are shaped like a circle or substantially like a circle, as indicated by a dashed line Cl. This dashed line Cl has a diameter DC1. The first outer edges 42oe are forming a continuous circle, and hence, the front surfaces 42f are forming one continuous surface around the mandrel 2.

[0115] It is further shown that if a dashed line C2 is drawn through all second outer edges 52oe of the second supporting elements 52, also this dashed line will be shaped like a circle or substantially like a circle having a diameter DC2. It should be noted that the second outer edges 52oe are not forming a continuous circle. Still, the diameter DC1 of the first circle Cl is equal to the diameter DC2 of the second circle DC2. Preferably, these diameters DC1, DC2 are equal to, or substantially equal to, the outer diameter DRR shown in fig. 1.

[0116] Hence, as seen from the sealing element 21, the second front surfaces 52f are hidden behind the first front surfaces 42f in the radially retracted state.

[0117] The diameter DC1 is typically corresponding to the diameter of the first sleeve 45. Hence, the first arms 41 are generally oriented in the radial direction. However, as the second sleeve 55 are located inside the first sleeve 45, the second arms 52 are somewhat inclined with respect to the radial direction, as shown in fig. 3a and fig. 5a. It should be noted that the second arms 52 in the present embodiment are linear, even if the rendering of fig. 5a makes the second arms 51 appearing somewhat bent.

[0118] Above, we have described the radially retracted state with reference to fig. 4a. Now, the radially expanded state will be described with reference to fig. 3b and fig. 4b. Here, the entire supporting device 40 has been moved towards the first cone 31 and hence towards the sealing element 21. Hence, the first supporting elements 42 and the second supporting elements 52 are moving along the tapering surface 33, thereby moving the first supporting element 42 and the second supporting element 52 radially outwardly. Their movement is guided by the above-mentioned guiding arrangement.

[0119] As the first supporting elements 42 are moving along the tapering surface 33, circumferential spaces CS between each of the first supporting elements 42 increases. In addition, as the second supporting elements 52 will move a longer longitudinal distance than the first supporting elements 42 due to the relative movement D60 between the first sleeve 45 and the second sleeve 55, the second supporting elements 52 are allowed to move into the circumferential spaces CS.

[0120] Hence, in fig. 4b, it is shown that the first outer edges 42oe and the second outer edges 52oe together are provided in a common, third plane P3, the third plane P3 being different from the first plane Pl and the second plane P2.

[0121] It is further shown that the first outer edges 42oe together with the second outer edges 52oe are shaped like a circle or substantially like a circle, as indicated by a dashed line C3. This dashed line C3 has a diameter DC3 being larger than the diameter DC1 and the diameter DC2. The first outer edges 42oe and the second outer edges 52oe are together forming a continuous circle, and hence, the first front surfaces 42f and the second front surfaces 52f are forming one continuous surface around the mandrel 2.

[0122] It is further shown in fig. 4b that the continuous surface formed by the first front surfaces 42f and the second front surfaces 52f are aligned with the sealing element supporting surface 32 of the first cone device 31. The first front surfaces 42f, the second front surfaces 52f and the sealing element supporting surface 32 are together forming an extrusion-preventing surface provided circumferentially around the mandrel 2 for supporting the first side SI of the sealing element 21 in the radially retracted state.

[0123] It should be noted that the first front surfaces 42f are not supporting any surface of their neighbouring second supporting elements 52. Similarly, the second front surfaces 52f are not supporting any surface of their neighbouring first supporting elements 42. Hence, the front surfaces 42f, 52f are not overlapping in the longitudinal direction.

[0124] In fig. 5c, the shape of the extrusion-preventing surface formed by the first front surfaces 42f, the second front surfaces 52f and the sealing element supporting surface 32 are indicated. On the left side, the extrusion-preventing surface can be considered as a spherical cap SC having an opening for the mandrel 2, as indicated by the dashed shape.

[0125] Preferably, an inner edge 42ie of the first front surface 42f and an inner edge 52ie of the second front surface 52f are curved with a radius being equal to an outer radius of the cone 31, the outer radius of the cone 31 being measure at the intended point of contact between the respective inner edges 42ie, 52ie and the cone 31 in the radially expanded state. Hence, the number of gaps and / or the size of gaps are reduced in the radially expanded state.

[0126] Second supporting device 80

[0127] It is now referred to fig. 3a. The second supporting device 80 is in the present embodiment identical to the first supporting device 40. For simplicity, the same reference numbers are used as for the first supporting device 40. Hence, the description will not be repeated here for the second supporting device 80.

[0128] It should be noted that the purpose of the second supporting device 80 is to support the second side S2 of the sealing element 21 in the radially expanded state. Hence, also the first front surface 42f and the second front surface 52f are faced towards the sealing element 21.

[0129] It should further be noted that the first supporting element 42 and the second supporting element 52 of the second supporting device 80 are moved along the tapering surface 33 of the second cone device 35.

[0130] It is now referred to fig. 6a. Here it is shown that the first outer edges 42oe of the first supporting elements 42 are provided in a fourth plane P4. It is further shown that the second outer edges 52oe of the second supporting elements 52 are provided in a fifth plane P5, the fourth plane P4 being longitudinally displaced with respect to the fifth plane P5.

[0131] It is further shown that the first outer edges 42oe together are shaped like a circle or substantially like a circle, as indicated by a dashed line C4. This dashed line C4 has a diameter DC4. Similarly, a dashed line C2 is drawn through all second outer edges 52oe of the second supporting elements 52, also forming a circle C5 having a diameter DC5. The diameter DC4 is equal to the diameter DC5. Preferably, these diameters DC4, DC5 are equal to, or substantially equal to, the outer diameter DRR shown in fig. 1.

[0132] It is now referred to fig. 6b. Here, the entire second supporting device 80 has been moved towards the second cone 35 and hence towards the sealing element 21. Hence, the first supporting elements 42 and the second supporting elements 52 are moving along the tapering surface 33, thereby moving the first supporting element 42 and the second supporting element 52 radially outwardly. Their movement is guided by the above-mentioned guiding arrangement.

[0133] The first outer edges 42oe and the second outer edges 52oe together are provided in a common, sixth plane P6, the sixth plane P6 being different from the fourth plane P4 and the fifth plane P5.

[0134] It is further shown that the first outer edges 42oe together with the second outer edges 52oe are shaped like a circle or substantially like a circle, as indicated by a dashed line C63. This dashed line C6 has a diameter DC6 being larger than the diameter DC4 and the diameter DC5.

[0135] Further details of the well tool device 1

[0136] Above, the radially retracted state and the radially expanded state of the sealing device 20 has been described in detail. It has also been described how the first supporting element 42 and the second supporting element 52 of the first supporting device 40 (and hence how the first supporting element 42 and the second supporting element 52 of the second supporting device 80) move along the tapering surface 33 of its respective cones 31, 35 between the radially expanded state and the radially retracted state.

[0137] It is now referred to fig. 5d. Here, an inner surface of the well W is indicated as a dashed line, and a gap G is indicated as the distance between the first edge 42oe of the first supporting element 42 and the inner surface of the well W. As shown, the first edge 42oe is not in contact with the well W. In case the sealing element 21 only comprised the elastomeric body 22, the elastomeric material of the body 22 would extrude into the gap G if the pressure difference between the first side SI of the sealing element 21 and the second side S2 of the sealing element 21 became to high. Such an extrusion is prevented by the extrusion -preventing element 23, as indicated in fig. 5d. Here it is shown that the extrusion -preventing element 23 is supported on the front surface 42 of the first supporting element 42 and on the well W, thereby effectively preventing deformation of the body 22 into the gap G. In fig. 5d, a diameter Dex is indicating the largest outer diameter of the well tool device 1 in the radially expanding state, and that this diameter Dex is equal to the inner diameter of the well W.

[0138] In fig. 5d, it is shown that the gap G is slightly smaller than the minor radius r23minor of the extrusion-preventing element 23.

[0139] Alternative embodiments It is now referred to fig. 7a and fig. 7b. Here, an embodiment having an even larger expansion than the first embodiment is shown.

[0140] In the radially retracted state, a radial height H31 of first cone device 31 together with an outer radius r2 of the mandrel 2 may indicate a total outer radius rTot of the well tool device 1. Here, H31 + r2 = * DC1 = * DRR.

[0141] In the radially expanded state, the total outer radius rTotEx of the well tool device may increase with a radial height H42 of the first supporting element 42 plus the minor radius r23minor of the extrusion-preventing element 23: rTotEX r2 + H31 + H42 + r23minor expansion ratio = — — — = - - — —— - rTotRR r2 + H31

[0142] The radial height H42 of the first supporting element 42 may be equal to the radial height H31 of first cone device 31. The minor radius r23minor of the extrusion - preventing element 23 may be * of the radial height H31 of first cone device 31. Hence, a ratio of expansion may be expressed as

[0143] It is now referred to fig. 8. Here it is shown that the extrusion-preventing surface formed by the first front surfaces 42f, the second front surfaces 52f and the sealing element supporting surface 32 can be considered shaped as a cone CO having an opening for the mandrel 2 as indicated by the dashed shape.

Claims

CLAIMS1. A well tool device (1) for use in a well, wherein the well tool device (1) comprises:- a mandrel (2);- a housing (3) provided outside of the mandrel (2);- a sealing device (20) provided radially outside of the mandrel (2), wherein the sealing device (20) is configured to be brought from a radially retracted state to a radially expanded state by a relative longitudinal displacement between the mandrel (2) and the housing (3); wherein the sealing device (20) comprises a sealing element (21) for preventing longitudinal fluid flow past the sealing element (21) along the well in the radially expanded state, wherein the sealing element (21) circumferentially surrounds the mandrel (2); wherein the sealing device (20) comprises a first supporting device (40) for supporting a first side (SI) of the sealing element (21) in the radially expanded state; characterized in that the first supporting device (40) comprises:- a plurality of first arms (41) having a first end (41a) and a second end (41b), the first end (41a) comprising a first supporting element (42) with a first front surface (42f) having a first outer edge (42oe);- a plurality of second arms (51) having a first end (51a) and a second end (51b), the first end (51a) comprising a second supporting element (52) with a second front surface (52fs) having a second outer edge (52oe); wherein the first front surfaces (42f) and the second front surfaces (52f) together are forming an extrusion-preventing surface provided circumferentially around the mandrel (2) for supporting the first side (SI) of the sealing element (21) in the radially expanded state; wherein in the radially retracted state, the first outer edges (42oe) are provided in a first plane (Pl) and the second outer edges (52oe) are provided in a second plane (P2); wherein the first plane (Pl) is longitudinally displaced with respect to the second plane (P2); and wherein in the radially expanded state, the first outer edges (42oe) and the second outer edges (52oe) are provided in a common, third plane (P3).

2. The well tool device (1) according to claim 1, wherein the extrusion-preventing surface is a continuous surface.

3. The well tool device (1) according to claim 1 or 2, wherein the first front surfaces (42f) in the radially retracted state together are forming a continuous surface circumferentially around the mandrel (2).

4. The well tool device (1) according to any one of the above claims, wherein the first supporting elements (42) and the second supporting elements (52) are arranged to be contiguous circumferentially around the mandrel (2) in the radially expanded state.

5. The well tool device (1) according to any one of the above claims, wherein the first supporting elements (42) and the second supporting elements (52) are arranged in sequence circumferentially around the mandrel (2) in the radially expanded state.

6. The well tool device (1) according to any one of the above claims, wherein the sealing device (20) comprises a first cone device (31) radially outside of the mandrel (2) adjacent to the sealing element (21); wherein the first cone device (31) comprises a tapering surface (33) along which the first end (41a) of the first arms (41) and the first end (51a) of the second arms (51) travel between the radially retracted state and the radially expanded state.

7. The well tool device (1) according to claim 6, wherein, as the first ends (41a) of the first arms (41) are traveling along the tapering surface (33) of the cone device (31), a circumferential space (CS) between the first supporting elements (42) increases, thereby allowing one of the second supporting elements (52) to move into the circumferential space (CS).

8. The well tool device (1) according to claim 6 or 7, wherein the first cone device (31) comprises a sealing element supporting surface (32) for supporting the sealing element (21); wherein the sealing element supporting surface (32) together with the extrusion-preventing surface formed by the first front surfaces (42f) and the second front surfaces (52f) together are forming a continuous extrusion-preventing surface in the radially expanded state.

9. The well tool device (1) according to any one of the above claims, wherein the first arms (41) are moved longitudinally a first distance (DI) from the radially retracted state to the radially expanded state; the second arms (51) are moved longitudinally a second distance (D2) from the radially retracted state to the radially expanded state, wherein the second distance (D2) is longer than the first distance (DI).

10. The well tool device (1) according to any one of the above claims, wherein the second ends (41b) of the first arms (41) are secured to each other by means of a first sleeve (45).

11. The well tool device (1) according to claim 10, wherein the second ends (51b) of the second arms (51) are secured to each other by means of a second sleeve (55); wherein the second sleeve (55) is longitudinally displaceable relative to the first sleeve (45).

12. The well tool device (1) according to claim 11, wherein the second sleeve (55) is located at least partially inside the first sleeve (45).

13. The well tool device (1) according to claim 11 or 12, wherein the second sleeve (55) is protruding longitudinally from the first sleeve (45) in the radially retracted state; and wherein the sealing device (20) is brought from the radially retracted state to the radially expanded state by moving the second sleeve (55) longitudinally relative to the first sleeve (45).

14. The well tool device (1) according to any one of claims 11 - 13, wherein the first supporting device (40) comprises a movement restrainer (60) for restraining the relative longitudinal displacement between the first sleeve (45) and the second sleeve (55).

15. The well tool device (1) according to any preceding claim, comprising a second supporting device (80) the second supporting device (80) comprising:- a plurality of first arms (41) having a first end (41a) and a second end (41b), the first end (41a) comprising a first supporting element (42) with a first front surface (42f) having a first outer edge (42oe);- a plurality of second arms (51) having a first end (51a) and a second end (51b), the first end (51a) comprising a second supporting element (52) with a second front surface (52fs) having a second outer edge (52oe); wherein the first front surfaces (42f) and the second front surfaces (52f) together are forming an extrusion-preventing surface provided circumferentially around the mandrel (2) for supporting the second side (S2) of the sealing element (21) in the radially expanded state; wherein in the radially retracted state, the first outer edges (42oe) are provided in a fourth plane (P4) and the second outer edges (52oe) are provided in a fifth plane (P5); wherein the fourth plane (P4) is longitudinally displaced with respect to the fifth plane (P5); and wherein in the radially expanded state, the first outer edges (42oe) and the second outer edges (52oe) are provided in a common, sixth plane (P6).

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