Well tool device for releasing substance into wellbore annulus

Abstract

The present disclosure provides a well tool device (1) for releasing a substance (PM) into a wellbore (WB) and further into an annulus (AN) of a well (WE). The device comprises a storing module (10) for storing the substance and a releasing module (20). The releasing module includes a first outer housing (31) connected to the storing module, with the first outer housing having a radial opening (32) for substance exit. A valve element (25) is provided inside the first outer housing, operable between open and closed positions relative to the radial opening. Diverter arms (72; 74, 76) are connected to the first outer housing, operable between radially retracted and expanded positions. The device is operable between a storing state, 10 where the diverter arms are retracted and the radial opening is closed, and a releasing state, where the diverter arms are expanded and the radial opening is opened.

Description

[0001] WELL TOOL DEVICE FOR RELEASING SUBSTANCE INTO WELLBORE ANNULUS

[0002] FIELD OF THE INVENTION

[0003] The present disclosure relates to a well tool device for releasing a substance into a wellbore, and more particularly to a well tool device, method, and system for releasing a substance into a wellbore of a well and further into an annulus of the well.

[0004] BACKGROUND OF THE INVENTION

[0005] To meet governmental requirements during plugging and abandonment (P&A) operations in a well, a deep-set barrier must be installed as close to the potential source of inflow as possible, covering all leak paths. A permanent well barrier shall extend across the full cross section area of the well, including all annuli, and seal both vertically and horizontally in the well. Normally cement is used for the purpose of P&A operations.

[0006] Recently, an alternative method of performing P&A operations has been invented, using a heat generating mixture, e.g. a thermite mixture. This method is described in WO 2013 / 135583 where the method steps comprise providing an amount of a heat generating mixture, the amount being adapted to perform the desired operation, positioning the heat generating mixture at a desired position in the well, igniting the heat generating mixture, thereby melting the surrounding materials in the well.

[0007] In the thermite-based barrier formed by the method of WO 2013 / 135583, the heat generating mixture, e.g. the thermite mixture, when initiated, for example by ignition, will burn with a temperature of up to 3000°C and melt a great part of the proximate surrounding materials, with or without the addition of any additional metal or other meltable materials to the well. The surrounding materials may include any material normally present in the well, such as tubulars, e.g. casing, tubing and liner, cement, formation sand, etc. The heat from the ignited mixture will melt a sufficient amount of said materials. When the heat generating mixture has burnt out, the melted materials will solidify forming a sealing barrier comprising melted metal, cement, formation sand, etc. against the well formation.

[0008] The well tool for releasing the heat generating mixture into the well should store and protect its content until it has reached the intended position in the well. It was therefore believed that the tool must withstand the increasing ambient pressure exerted on it as it is lowered into the well. In the event of a collapse, the content of the tool will likely be destroyed and lost. A collapsed tool can also be difficult if not impossible to install in the well. To withstand external pressure, tools are typically made of expensive high strength materials or their wall thickness is increased which requires more material, which in turn increases cost.

[0009] NO 20190537 describes a first solution to the above. The well tool here has a first compartment in which the heat generating mixture is located, and a second compartment separated from the first compartment by means of a partition device. The second compartment is exposed to ambient pressure via a fluid line. The partition device may be a piston, a diaphragm or a bladder which moves and hence equalizes the pressure between the compartments as the well tools is lowered into the well.

[0010] NO 20210637 describes a second solution to the above. Here, the well tool has a downhole pressure equalizer formed by means of two pistons, an inner piston and an outer piston, located within the tool. Here, it was necessary to pressurize a piston compartment on one side of the pistons with a predetermined pressure, typically equal to the expected well pressure at the location of the heat generation process. This was typically performed topside before the well tool was lowered into the well.

[0011] N020210353 describes discs of metal and metal oxide, where holes are provided centrally through these discs. These discs are then inserted onto a central carrying device such as a rod or wire etc. In this application, it was stated that the pyrotechnic mixture is forming a self-supported pyrotechnic structure and hence that the outer housing could be omitted. A non-supporting coating could be applied outside of the self-supported pyrotechnic structure.

[0012] N020210354 describes a well tool used to transport heat generating mixture as a particulate matter into the well and to allow it to settle at a desired location within the well. It is also described how heat generating mixture can be moved into an annulus of the wellbore.

[0013] NO 20210355 describes a well tool used to transport heat generating mixture into the well. Above the tool itself, a replenishment string is connected, in order to supply further amounts of heat generating mixture to the heat generating process. The replenishment string may comprise a number of sections connected to each other.

[0014] NO 20191143 describes that the well tool used to transport heat generating mixture into the well may comprise a housing made of aluminium, where the aluminium housing is a constituent of the heat generating mixture.

[0015] NO 20201128 and NO 20201129 describe a well tool device for transporting heat generating mixture into the well. The tool has a lower sealing element which expands outwardly in a radial direction into contact with the well pipe, in order to prevent molten materials to flow down into the well. The tool also has an upper anchoring device which expands outwardly in a radial direction into contact with the well pipe, in order to prevent the tool to move upwardly during the heat generation process.

[0016] Interwell RockSolid™ is a well tool device for reinstating cap rock integrity across the entire cross section of the well. Information about this tool is available from the website interwell.com.

[0017] One object of the present invention is to provide a more efficient method for providing a permanent barrier in a well.

[0018] SUMMARY OF THE INVENTION

[0019] According to a first aspect, there is provided a well tool device for releasing a substance into a wellbore of a well and further into an annulus of the well. The well tool device comprises a storing module for storing the substance; a releasing module; wherein the releasing module comprises a first outer housing connected to the storing module, wherein the first outer housing comprises a radial opening for allowing the substance to exit from the well tool device into the wellbore; a valve element provided on the inside of the first outer housing and operable between an open position relative to the radial opening and a closed position relative to the radial opening; diverter arms connected to the first outer housing and operable between a radially retracted position for allowing the well tool device to be lowered into the wellbore and a radially expanded position for guiding the substance from the wellbore into the annulus; wherein the well tool device is operable between a storing state and a releasing state; wherein, in the storing state, the diverter arms are radially retracted and the radial opening is closed by the valve element; wherein, in the releasing state, the diverter arms are radially expanded and the radial openings are opened by the valve element.

[0020] According to the above, it is achieved a well tool device that can be lowered to a desired location in the wellbore of the well, which can release the substance into the wellbore of the well, and which, when the substance is released, can guide the substance further from the wellbore of the well into the annulus of the well in an efficient way.

[0021] The substance may be a particulate material, a fluid, a slurry, or a heat generating mixture. A density of the substance may be larger than a density of the well fluid within the well, where the substance may exit from the storing module by means of gravity. When the well tool device is in the releasing state, the substance moves downwardly inside the storing module and further out of the radial opening of the first outer housing down towards the diverter arms. In this case, the storing module typically will be located above the releasing module. In this case, the diverter arms typically will be located below the radial opening. The substance may also be released by a piston movable within the storing module, for pushing the substance out of the storing module. In this case, the storing module may be located above or below the releasing module. If the density of the substance is less than the density of the well fluid within the well, the diverter arms should be located above the radial opening of the first outer housing.

[0022] The storing module may comprise a storage sleeve protruding into the first outer housing.

[0023] The storage sleeve may protrude into the first outer housing at a first end of the releasing module.

[0024] The valve element may be connected to an end of the storage sleeve and wherein the storage sleeve may comprise a radial opening for allowing the substance to exit from the storage sleeve of the storing module to the wellbore via the radial opening of the first outer housing when the well tool device is in the releasing state.

[0025] An inside of the storage sleeve may be referred to as a storage compartment for the substance.

[0026] The valve element may be operable between the open position relative to the radial opening and the closed position relative to the radial opening by relative longitudinal movement between the storage sleeve and the first outer housing.

[0027] When the valve element is the closed position, the radial opening of the storage sleeve is out of alignment with the radial opening of the outer housing. When the valve element is the open position, the radial opening of the storage sleeve is in alignment with the radial opening of the outer housing.

[0028] The valve element may comprise a tapering surface for guiding the substance outwardly towards the radial opening of the storage sleeve.

[0029] The well tool device may comprise a restrainer for restraining the relative movement between the valve element and the first outer housing.

[0030] The restrainer may comprise a restraining sleeve and a recess into which the restraining sleeve protrudes. The recess may be defined with an upper ledge and a lower ledge which limits the longitudinal movement of the restraining sleeve within the recess. The restraining sleeve may be secured radially outside of the storage sleeve and / or radially outside of the valve element. The recess may be formed in an inwardly facing surface of the first outer housing. Alternatively, the restraining sleeve is secured to the inside of the first outer housing and the recess may be formed in an outwardly facing surface of the storage sleeve and / or the valve element.

[0031] The valve element may be biased towards the closed position.

[0032] The first outer housing may comprise a first spring-supporting ledge, wherein the valve element may comprise a second spring-supporting ledge, and wherein the well tool device may comprise a first spring supported between the first springsupporting ledge and the second spring-supporting ledge, wherein the first spring is configured to bias the valve element towards the closed position.

[0033] The releasing module may comprise an inner housing; a second outer housing secured outside of a first section of the inner housing; wherein a second section of the inner housing is protruding into the first outer housing; wherein the diverter arms are connected between the first outer housing and the second outer housing; wherein the diverter arms are operable between their radially retracted position and their radially expanded position by relative longitudinal movement between the first outer housing and the second outer housing.

[0034] The inner housing and the second outer housing may be provided as one single body. The inner housing and the second outer housing may be provided as two different bodies connected to each other. The diverter arms may comprise a number of arms distributed circumferentially outside of the inner housing. The diverter arms may comprise flexible arms configured to be bent outwardly in the radially expanded position. The diverter arms may comprise flexible or rigid arms configured to be wedged outwardly in the radially expanded position.

[0035] The diverter arms in the radially expanded position together may form a continuous diverting surface protruding radially out into the wellbore.

[0036] The diverter arms may be distributed circumferentially around the inner housing.

[0037] The diverter arms in the radially expanded position may be brought into physical contact with a surface defining the wellbore.

[0038] The surface may be an inner surface of a casing, a tubing or other type of well pipe.

[0039] The diverter arms may comprise a main arm comprising a diverting surface and a supporting arm; wherein the main arm has a first end pivotably connected to a lower end of the first outer housing and a second end; wherein the supporting arm has a first end pivotably connected to the second outer housing and a second end, wherein the second end of the main arm is pivotably connected to the second end of the supporting arm.

[0040] The diverting surface of each main arm may together form the continuous diverting surface protruding radially out into the wellbore in the radially expanded position. In the radially retracted position, the main arm and the supporting arm are oriented substantially in parallel with the inner housing and / or in parallel with the first outer housing and / or in parallel with the second outer housing. Here, the diverting surface may be oriented with an angle of approximately 0° relative to the longitudinal direction. In the radially expanded position, the continuous diverting surface may be oriented with an angle of approximately 20° - 85° relative to the longitudinal direction.

[0041] The diverter arms may be biased towards the radially retracted position.

[0042] The valve element may comprise a first spring-supporting surface, wherein the inner housing may comprise a second spring-supporting surface, wherein the well tool device may comprise a second spring supported between the first spring -supporting surface and the second spring-supporting surface, wherein the second spring is configured to bias the valve element longitudinally away from the inner housing.

[0043] As the valve element is biased longitudinally away from the inner housing, also the first outer housing will be biased longitudinally away from the second outer housing due to the restrainer, thereby biasing the diverter arms towards the radially retracted position.

[0044] The inner housing may be protruding into a bore of the valve element and wherein the second spring may be located inside of the inner housing and protrudes into the bore of the valve element.

[0045] The well tool device may be brought between the storing state and the releasing state by relative longitudinal movement between the first outer housing and the second outer housing and by relative longitudinal movement between the valve element and the outer housing.

[0046] The releasing module may comprise a first shear mechanism for preventing longitudinal movement between the first outer housing and second outer housing. The releasing module may comprise a second shear mechanism for preventing longitudinal movement between the first outer housing and the valve element. In this way, it is achieved that the radial opening is closed and that the diverter arms are radially retracted during lowering of the well tool device down to the desired location in the well. The first shear mechanism may be secured directly between the first outer housing and the inner housing. The second shear mechanism may be secured directly between the first outer housing and the valve element.

[0047] The first shear mechanism is configured to be sheared off before or simultaneously as the second shear mechanism, in order to ensure that the diverter arms become radially expanded before the substance is arriving out of the openings and further to the location of the diverter arms. The well tool device may be considered to be in an intermediate state when the first shear mechanism has been sheared off, but before the second shear mechanism has been sheared off. In this intermediate state, the diverter arms are radially expanded and the radial opening is closed.

[0048] The first shear mechanism and / or the second shear mechanism may be sheared off by the weight of the well tool device above the shear mechanisms. Hence, when the lower end of the well tool device is supported onto the platform, the first shear mechanism and the second shear mechanism will be sheared off.

[0049] Alternatively, a setting tool is connected to the connection interface. The setting tool is first anchored to the wellbore and us used to push the storing module downwardly into the releasing module in order to shear off the first shear mechanism and / or the second shear mechanism.

[0050] The storing module may be connected above the releasing module. Hence, the first end of the releasing module may be referred to as an upper end of the releasing module, while the second end may be referred to as a lower end of the releasing module.

[0051] The well tool device may comprise a distance module connected to the second end of the releasing module. The distance module may be configured to be supported on a platform within the well. The distance module may have a length determined by a height between the platform and an opening providing access to the annulus from the wellbore of the well, in order to ensure a desired location of the diverter arms relative to the opening.

[0052] An alternative restrainer for limiting the movement of the valve element towards the inner housing may be formed by an end surface of the inner housing and a bore surface of the bore of the valve element. When these surfaces engage each other, no further movement is possible.

[0053] A first distance may indicate a distance between the first spring -supporting ledge and the second spring-supporting ledge. The first distance may indicate a length of the first spring. The first distance is shorter in the releasing state than in the storing state. The first distance is equal in the releasing state and in the intermediate state.

[0054] A second distance may indicate a distance between the first spring -supporting surface of the valve element and the second spring-supporting surface of the inner housing. The second distance may indicate a length of the second spring. The second distance is shorter in the releasing state than in the storing state. The second distance is shorter in the intermediate state than in the storing state.

[0055] The well tool device may be defined with an upper end and a lower end. The well tool device may comprise a connection interface in its upper end. The well tool device may comprise an EJC interface in its lower end, the EJC interface being an interface to manipulate an expandable junk catcher. In some cases, an amount of the substance which are released to the wellbore will not be diverted into the annulus. One reason may be that the diverter arms are not brought into contact with the surface around the entire circumference of the well tool device. This amount of the surface will then be caught by the expandable junk catcher. The expandable junk catcher may be retrieved together with the well tool device to surface after release of the substance.

[0056] According to a second aspect, there is provided a method for releasing a substance into a wellbore of a well and further into an annulus of the well. The method comprises the steps of providing a well tool device having a storing module and a releasing module, wherein the substance is stored within the storing module; providing a platform within a wellbore of the well at a location below openings between the wellbore and the annulus; lowering the well tool device onto the platform; opening radial openings of the releasing module to allow the substance to be released into the wellbore; radially expanding diverter arms of the releasing module to guide the substance from the wellbore into the annulus.

[0057] The method may further comprise an initial step of providing the opening between the wellbore of the well and the annulus of the well.

[0058] The platform may be a substance collector for collecting any substance bypassing the diverter arms.

[0059] According to a third aspect, there is provided a method for forming a thermite -based downhole well barrier in a well. The method comprises the steps of using the method according to the second aspect for releasing a substance in the form of a heat generating mixture into an annulus of the well; lowering a further amount of the substance in the form of the heat generating mixture to the wellbore of the well adjacent to the heat generating mixture of the annulus; igniting the heat generating mixture of the wellbore and the heat generating mixture of the annulus, thereby melting the surrounding materials in the well.

[0060] When the heat generating mixture has burnt out, the melted materials will solidify and form a permanent barrier sealingly engaged against the well formation.

[0061] According to the above, there is a larger amount of heat generating mixture per height unit of the well. Hence, the heat generating process may be more efficient and may obtain a wider range out into the well formation.

[0062] Definitions

[0063] The well tool device is defined with a longitudinal centre axis. As used herein, a longitudinal direction is a direction perpendicular to or aligned with the longitudinal centre axis. As used herein, a radial direction is a direction perpendicular to the longitudinal centre axis.

[0064] 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.

[0065] As used herein, the terms “radially retracted state / position” and “run state / position” are used interchangeably for the state / position in which the well tool is lowered to a desired location in the well. The terms “radially expanded state / position” and “set state / position” are used interchangeably for the state / position in which the well tool is engaged with the inner surface of the well at the desired location in the well.

[0066] 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.

[0067] The heat generation mixture and the heat generating process

[0068] As used herein, the term “heat generating mixture” is a mixture of a metal oxide of a first type of metal and a metal of a second type of metal, which when heated to an ignition temperature will react spontaneously in an exothermic and self-sustained chemical reaction where the metal oxide of the first type of metal is reduced to elementary metal and the metal of the second type of metal is oxidized to a metal oxide. This type of heat generating mixture is often referred to as thermite, and the heat generating reaction is often referred to as a thermite reaction.

[0069] The metal oxide may be ferric oxide and the metal may be aluminum:

[0070] Fe2O3 + 2 Al 2 Fe + A12O3 + heat

[0071] The result is here iron, aluminum oxide and heat.

[0072] The metal oxide may be bismuth oxide and the metal may be aluminum:

[0073] Bi2O3 + 2 Al -> A12O3 + 2Bi + heat

[0074] The result is here bismuth, aluminum oxide and heat.

[0075] It should be noted that there are several alternatives to the above. The metal may be magnesium Mg, calcium Ca and / or silicon Si in addition to, or as an alternative to aluminium Al. The metal oxide may be tin oxide, copper oxide etc.

[0076] In addition, the heat generating mixture may comprise additives to improve the heat generating process. As used herein, the term “materials of the surroundings of the well tool device” is used to denote parts of the well, such as casing, cement, gravel and / or sand etc., and possibly also parts of the formation radially outside of the casing and cement. Typically, it is desired to form the permanent barrier in a layer of cap rock of the formation, the cap rock itself being impermeable for the fluids located below the cap rock. Hence, the result of a heat generating process in this area will be a cap rock to cap rock permanent barrier extending across the whole cross -section of the well.

[0077] It should be noted that there may be two or more casings outside of each other. At least parts of the annulus between the casings may be fluid-filled, filled with cement, gravel or other materials. When providing the opening within the inner casing, a perforation and washing operation may be performed to create or increase an available volume for the substance in the annulus.

[0078] LIST OF DRAWINGS

[0079] Fig. 1 illustrates a cross-sectional view of a well tool device.

[0080] Fig. 2 illustrates an enlarged cross-sectional view of the releasing module, wherein the well tool device is in a storing state.

[0081] Fig. 3 illustrates an enlarged cross-sectional view of the releasing module, wherein the well tool device is in an intermediate state.

[0082] Fig. 4 illustrates an enlarged cross-sectional view of the releasing module, wherein the well tool device is in a releasing state.

[0083] Fig. 5a and fig. 5b illustrate a first embodiment of the diverter arms in their retracted and expanded states respectively.

[0084] Fig. 6a and fig. 6b illustrate schematically a second embodiment of the diverter arms in their retracted and expanded states respectively.

[0085] Fig. 7a and fig. 7b illustrate schematically a third embodiment of the diverter arms in their retracted and expanded states respectively.

[0086] Fig. 8 illustrates a well with an annulus into which a substance is to be released.

[0087] Fig. 9 illustrates a platform being set in the wellbore.

[0088] Fig. 10 illustrates schematically how the well tool device is lowered into a desired location in the wellbore, wherein the well tool device is in the storing state.

[0089] Fig. 11 illustrates schematically the well tool device in the releasing state at the desired location. Fig. 12 illustrates a well tool for performing a P&A operation being lowered to the location of the substance within the annulus.

[0090] Fig. 13 illustrates a permanent barrier formed in the well as a result of the P&A operation.

[0091] DETAILED DESCRIPTION

[0092] With reference to Fig. 1, a well tool device 1 is defined with an upper end la and a lower end lb. The well tool device 1 comprises a storing module 10, a releasing module 20, and a distance module 80 arranged in sequence along a longitudinal direction indicated as a longitudinal centre axis LCA of the well tool device 1.

[0093] The storing module 10 comprises a storage sleeve 11 that defines a storage compartment 14 for storing a substance PM (not shown in fig. 1). The releasing module 20 is connected below the storing module 10. The distance module 80 is connected to a lower end of the releasing module 20. The distance module 80 extends to the lower end lb of the well tool device 1.

[0094] The upper end la of the well tool device 1 comprises a connection interface CI for connecting the well tool device 1 to a wireline. The lower end lb of the well tool device 1 comprises an EJC interface configured to be supported on a platform or an expandable junk catcher (not shown).

[0095] In the present embodiment, the substance PM is a particulate material in the form of a thermite type of heat generating mixture, for example a particulate material containing bismuth oxide and aluminum, or a particulate material containing iron oxide and aluminum, as described in the summary of the invention section above.

[0096] With reference to Fig. 2, the releasing module 20 comprises three main parts in the form of housings: a first outer housing 31, a second outer housing 22, and an inner housing 21. The inner housing 21 comprises a first section 21a and a second section 21b, where first section 21a is located below the second section 21b. The second outer housing 22 is secured outside the first section 21a, and the second section 21b protrudes up and into the first outer housing 31. Hence, in the present embodiment, the second outer housing 22 is located below the first outer housing 31.

[0097] The storage sleeve 11 of the storing module 10 protrudes down into the first outer housing 31. The first outer housing 31 comprises a radial opening 32 for allowing the substance to exit from the well tool device 1 into a wellbore.

[0098] A valve element 25 is provided on the inside of the first outer housing 31 and is connected to a lower end of the storage sleeve 11. The valve element 25 comprises a tapering guiding surface 26 facing towards the storage compartment 14. The valve element 25 is operable between an open position and a closed position relative to the radial opening 32. The storage sleeve 11 comprises a radial opening 12 for allowing the substance to exit from the storage sleeve 11 via the radial opening 32 of the first outer housing 31. In the open position, the radial opening 12 is aligned with the radial opening 32. In the closed position, the radial openings 12, 32 are brought out of alignment with each other.

[0099] The storage sleeve 11 and the valve element 25 are movable in a longitudinal direction relative to the first outer housing 31 and relative to the second outer housing 22. In addition, the first outer housing 31 is movable in a longitudinal direction relative to the second outer housing 22.

[0100] A restrainer 40 comprises a restraining sleeve 41 connected to, or provided as a part of, the valve element 25. The restraining sleeve 41 is positioned within a recess 42 defined by an upper ledge 43a and a lower ledge 43b provided on the inside of the first outer housing 31. The restraining sleeve 41 is allowed to move longitudinally between the upper ledge 43a and a lower ledge 43b. Hence, the restrainer 40 limits relative longitudinal movement between the valve element 25 and the first outer housing 31.

[0101] The first outer housing 31 comprises a first spring-supporting ledge 37, and the valve element 25 comprises a second spring-supporting ledge 27. A first spring 57 is supported between the first spring-supporting ledge 37 and the second springsupporting ledge 27, biasing the valve element 25 towards the closed position.

[0102] Diverter arms comprising a main arm 74 and a supporting arm 76 are pivotably connected between the first outer housing 31 and the second outer housing 22. The diverter arms are operable between a radially retracted position and a radially expanded position by relative longitudinal movement between the first outer housing 31 and the second outer housing 22. Hence, also the diverter arms servs the function of a restraining mechanism, as the diverter arms limits the relative movement between the first outer housing 31 and the second outer housing 22.

[0103] The valve element 25 comprises a first spring-supporting surface 29a, and the inner housing 21 comprises a second spring-supporting surface 29b. A second spring 59 is supported between these surfaces, biasing the valve element 25 longitudinally away from the inner housing 21. Hence, the first outer housing 31 is biased away from the second outer housing 22 and the diverter arms are biased towards the radially retracted position. The valve element 25 includes a bore 28, and the inner housing 21 protrudes into this bore. The second spring-supporting surface 29b is provided in the upper end of this bore 28.

[0104] A first shear mechanism 91 prevents longitudinal movement between the first outer housing 31 and the second outer housing 22, while a second shear mechanism 92 prevents longitudinal movement between the first outer housing 31 and the valve element 25.

[0105] A first distance D57 indicates the distance between the first spring -supporting ledge 37 and the second spring-supporting ledge 27, while a second distance D59 indicates the distance between the first spring-supporting surface 29a and the second spring-supporting surface 29b.

[0106] With reference to Fig. 3, the releasing module 20 is shown in an intermediate state between the storing state of Fig. 2 and the releasing state. In this intermediate state, several key changes have occurred:

[0107] The first shear mechanism 91 has been sheared off, allowing relative longitudinal movement between the first outer housing 31 and the second outer housing 22. However, the second shear mechanism 92 remains intact, preventing relative movement between the first outer housing 31 and the valve element 25.

[0108] As a result of the first shear mechanism 91 being sheared, the diverter arms, comprising the main arm 74 and the supporting arm 76, have moved to their radially expanded position. The main arm 74 now extends outward, with its diverting surface 74ds positioned to guide substances in the wellbore.

[0109] Despite the movement of the diverter arms, the radial openings 12 and 32 remain misaligned. This is because the second shear mechanism 92 is still intact, maintaining the valve element 25 in its closed position relative to the first outer housing 31.

[0110] The first distance D57, which indicates the distance between the first springsupporting ledge 37 and the second spring-supporting ledge 27, remains unchanged from Fig. 2. This is due to the second shear mechanism 92 still preventing relative movement between the valve element 25 and the first outer housing 31.

[0111] However, the second distance D59, which indicates the distance between the first spring-supporting surface 29a of the valve element 25 and the second springsupporting surface 29b of the inner housing 21, has decreased compared to Fig. 2. This reduction in D59 is a result of the relative movement between the first outer housing 31 (to which the valve element 25 is still fixed) and the inner housing 21, caused by the shearing of the first shear mechanism 91.

[0112] In this intermediate state, the well tool device is prepared for substance release with its diverter arms expanded, but the substance is still contained within the storage compartment as the valve element 25 maintains its closed position. With reference to Fig. 4, the releasing module 20 is shown in its releasing state, which represents a further progression from the intermediate state depicted in Fig.

[0113] 3. Several significant changes have occurred:

[0114] The second shear mechanism 92 has now been sheared off, allowing relative longitudinal movement between the first outer housing 31 and the valve element 25. This is in addition to the previously sheared first shear mechanism 91.

[0115] As a result of the second shear mechanism 92 being sheared, the valve element 25 has moved relative to the first outer housing 31. This movement has caused the radial openings 12 and 32 to align, allowing the substance to flow from the storage compartment through these openings and into the wellbore.

[0116] The diverter arms, comprising the main arm 74 and the supporting arm 76, remain in their radially expanded position as in Fig. 3. The diverting surface 74ds is as in fig. 3 positioned to guide the released substance from the wellbore into the annulus.

[0117] The first distance D57, which indicates the distance between the first springsupporting ledge 37 and the second spring-supporting ledge 27, has decreased compared to Fig. 3. This reduction is due to the relative movement between the valve element 25 and the first outer housing 31, enabled by the shearing of the second shear mechanism 92.

[0118] The second distance D59, which indicates the distance between the first spring - supporting surface 29a of the valve element 25 and the second spring -supporting surface 29b of the inner housing 21, has further decreased compared to Fig. 3. This additional reduction in D59 is a result of the valve element 25 moving closer to the inner housing 21 after the shearing of the second shear mechanism 92.

[0119] In this releasing state, both the first spring 57 and the second spring 59 are further compressed compared to their states in Fig. 3. The restrainer 40, with its restraining sleeve 41 positioned within the recess 42, now limits the extent of the relative movement between the valve element 25 and the first outer housing 31.

[0120] The well tool device is now in its fully operational state for substance release, with the diverter arms expanded and the substance flowing through the aligned radial openings 12 and 32 (dashed arrow Al) and further guided by the diverting surface 74ds (dashed arrow A2) into the annulus of the well (described further in detail below).

[0121] It should be noted that a downwardly directed force is applied to the valve element 25 during the transition from the storing state SS to the intermediate state IS and further to the releasing state RS. This downwardly directed force is in the present embodiment caused by the weight of the storage module 10 (i.e. the weight of the sleeve 11, and possibly other parts of the storage module 10 above the valve element 25). This force is sufficient to shear off the shear mechanisms 91, 92 and is sufficient to counteract the upwardly directed biasing forces of the springs 57, 59. This allows the well tool device 1 to be lowered into the well by wireline connected to the connection interface CI in the upper end la of the well tool device 1.

[0122] With reference to Fig. 5a and Fig. 5b, the two states of the diverter arms are illustrated further in detail.

[0123] Fig. 5a shows the diverter arms in a retracted state. A plurality of diverter arms, each comprising a main arm 74 and a supporting arm 76, are arranged circumferentially between the housings 31, 22. In this retracted state, the main arms 74 with their diverting surfaces 74ds are oriented substantially parallel to the longitudinal axis of the device, as indicated by the angle a~0°. The diverter arms are radially retracted allowing the device to be lowered into a wellbore.

[0124] Fig. 5b illustrates the diverter arms in an expanded state. The main arm 74 extends radially outward and includes a diverting surface 74ds oriented at an angle of approximately 85 degrees relative to the longitudinal axis. The supporting arm 76 connects between the main arm 74 and the second outer housing 22 to provide structural support for the expanded configuration. The diverting surface 74ds forms part of a continuous surface around the circumference of the device when multiple diverter arms are arranged side by side around the circumference of the inner housing 21.

[0125] The main arm 74 is pivotably connected to the first outer housing 31 at one end and pivotably connected to the supporting arm 76 at the other end. The supporting arm 76 is pivotably connected to the second outer housing 22 at one end and pivotably connected to the main arm 74 at the other end. This arrangement of pivotable connections allows the diverter arms to move between the retracted and expanded states.

[0126] The configuration of the diverter arms is similar to the supporting elements described in N020031489, where arms of this type are used as supporting elements for an elastomeric sealing element of a well plug. However, in the present application, instead of supporting a sealing element, these arms are adapted to function as diverter arms for guiding substances from the wellbore into the annulus.

[0127] With reference to Fig. 6a and Fig. 6b, an alternative embodiment of the diverter arms is illustrated.

[0128] Fig. 6a shows the diverter arms 72 in a retracted position. The diverter arms 72 are connected between the first outer housing 31 and second outer housing 22. In this retracted state, the diverter arms 72 are oriented substantially parallel to the longitudinal axis of the device, with an angle a~0° relative to the longitudinal direction.

[0129] Fig. 6b depicts the diverter arms 72 in their expanded state. Unlike the embodiment shown in Fig. 5a and 5b, these diverter arms 72 do not have pivotable connections. Instead, the diverter arms 72 are flexible, allowing them to bend outwardly in the radially expanded state. In this configuration, the diverter arms 72 form a curved profile with a diverting surface 72ds oriented at an angle of approximately 50 degrees relative to the longitudinal axis.

[0130] This flexible design allows the diverter arms 72 to transition smoothly between the retracted and expanded states without the need for pivoting joints.

[0131] This alternative embodiment offers a simpler mechanical structure compared to the pivoting arms, potentially reducing complexity and increasing reliability in certain operational scenarios. The flexible nature of the diverter arms 72 allows them to adapt to varying wellbore conditions while maintaining their function of guiding substances from the wellbore into the annulus.

[0132] With reference to Fig. 7a and Fig. 7b, an alternative embodiment of the diverter arms is illustrated.

[0133] The diverter arms 72 are here also positioned between the first outer housing 31 and the second outer housing 22. The diverter arms 72 are here only connected to the first outer housing 31. In this retracted position, the diverter arms 72 are oriented substantially parallel to the longitudinal axis of the device, with an angle a=0° relative to the longitudinal direction. The diverter arms 72 are here located at a longitudinal distance from a wedge element 72b connected to the second outer housing 22.

[0134] Fig. 7b illustrates the diverter arms 72 in their expanded state. The wedging element has here been brought radially inside the diverter arms 72, thereby wedging the diverter arms radially outwardly. In this expanded configuration, the diverter arms 72 include a diverting surface 72ds that is oriented at an angle of approximately 25 degrees relative to the longitudinal axis.

[0135] This design allows for a simple yet effective mechanism for expanding the diverter arms. In the retracted state, the diverter arms 72 are held close to the device body, allowing for easy deployment into the wellbore. When expansion is required, the relative movement between the first outer housing 31 and the second outer housing 22 brings the wedging element into contact with the diverter arms 72, forcing them to expand radially outward.

[0136] It should be noted that the angles above are only examples, and that it would be possible to use the flexible arms 72 in fig. 6a and 6b and still achieve a higher angle than the one shown in fig. 6b. Similarly, it should be noted that it would be possible to use the wedged arms 72 in fig. 7a and 7b and still achieve a higher angle than the one shown in fig. 7b.

[0137] Operation of the well tool device

[0138] The operation of the well tool device 1 will now be described in detail. Initially, it is referred to fig. 8 where a well WE is shown with various components and layers. The figure depicts a wellbore WB with an inner casing IC extending vertically through the formation. An opening OP is provided in the inner casing, creating access to an annulus AN outside of the inner casing.

[0139] In fig. 8, surrounding materials S include the inner casing IC, cement CM that has been used to secure the inner casing IC in place and possibly also parts of the formation outside of the cement. Beyond the cement layer, the well structure is surrounded by cap rock CR, which is typically an impermeable layer of rock that prevents the migration of fluids.

[0140] An inner surface of the casing is denoted SU.

[0141] The opening OP in the inner casing IC has already been made, for example by a perforation operation. This opening provides a pathway for communication between the wellbore WB and the annulus AN.

[0142] Fig. 9 illustrates the well of Fig. 8. The key additions in this figure are:

[0143] A platform or expandable junk catcher PF, EJC is positioned at a lower portion of the illustrated section. This platform serves as a support structure within the wellbore and may be used to catch debris or provide a base for the further operation of the well tool device 1. The expandable junk catcher is known from N020131042.

[0144] A height dimension HOP is shown, representing the distance between the platform PF, EJC and the opening OP in the inner casing. This height is used for positioning the well tool device and ensuring proper alignment of its components, particularly the diverter arms, with the opening in the casing. Typically, the platform PF or expandable junk catcher is set before the perforation operation, and is used also during the perforation operation. Hence, the height dimension HOP is known by properties of the perforation tool (typically distance between lower end of perforation tool and perforation mechanism of perforation tool).

[0145] Fig. 10 illustrates the well tool device 1 being lowered into the wellbore WB on a wireline 2. The device 1 is shown with its lower end lb supported on the platform or expandable junk catcher PF, EJC. The storing module 10 at the upper portion of the device contains the substance, which is visible as particulate material PM within the storage compartment 14. This substance is ready for future release into the wellbore and annulus.

[0146] The well tool device 1 is depicted in its storing state, with the releasing module 20 configured to retain the substance within the storage compartment 14. The distance module 80 extends below the releasing module 20, ensuring proper positioning of the diverter arms relative to the opening OP.

[0147] Fig. 11 illustrates the well tool device 1 in the releasing state RS, where the diverter arms of the releasing module 20 are radially expanded, making contact with the inner surface of the wellbore. This expansion creates a pathway for guiding the substance from the wellbore into the annulus.

[0148] The substance PM is now flowing down from the storage compartment 14 within the storing module 10. It is guided via the tapering guiding surface 26 out through the aligned openings 12, 32 in the releasing module 20 and enters the wellbore. The expanded diverter arms then guide the substance from the wellbore into the annulus.

[0149] The flow of the substance PM is visually represented by the dotted pattern and dashed arrow, showing its movement from the storage compartment 14, through the releasing module 20, into the wellbore, and then being diverted into the annulus. This process effectively transfers the substance from inside the well tool device 1 to the desired location in the annulus of the well.

[0150] The use of the well tool device 1 is now finished and the well tool device 1 is retrieved topside by pulling the wireline 2. This will cause the openings 12, 32 to close and the diverter arms to go back to the radially retracted state.

[0151] During the release operation, some of the substance PM may not be fully diverted into the annulus AN by the diverter arms. This can occur if the diverter arms do not make complete contact with the wellbore surface around the entire circumference, leaving small gaps.

[0152] Any such bypassed material will fall downward in the wellbore WB due to gravity, but will be collected by the expandable junk catcher. The expandable junk catcher EJC can then be retrieved from the well WE after retrieving the well tool device 1.

[0153] Fig. 12 illustrates a sectional view of a well tool device 100 for performing a P&A (Plug and Abandonment) operation, following the use of the well tool device 1 described in previous figures.

[0154] After the initial substance release operation using the well tool device 1, a new tool

[0155] 100 is lowered into the wellbore. This new tool 100 comprises a storage chamber

[0156] 101 containing additional substance PM in the form of the heat generating mixture. The tool 100 is suspended on a wireline 102 extending vertically up from the device. The tool 100 further has an igniter 105 which is used to ignite the additional substance PM of the chamber 101. Also the tool 100 is lowered onto a platform or plug PF, PLUG that has been set in the well. This platform or plug may be the same as the previously described expandable junk catcher or a newly installed plug specifically for this stage of the operation.

[0157] Between the platform or plug PF, PLUG and the storage chamber 100, a layer of heat insulation HI material may be placed to avoid damage of the platform or plug caused by the heat generation process.

[0158] The substance PM of the annulus AN is shown to be located at the same height of the well WE as the substance PM of the chamber 101.

[0159] This configuration sets the stage for the final steps of the P&A operation, where the heat-generating mixture will be ignited to melt the surrounding materials and form a solid, permanent barrier across the wellbore and annulus.

[0160] The result of the heat generating process is shown in fig. 13. A permanent barrier PB has been formed within the wellbore WB. This barrier appears as a cross- hatched oval-shaped region extending across the entire diameter of the wellbore, i.e as a cap rock to cap rock barrier. The permanent barrier PB is the result of the heatgenerating reaction that has melted and subsequently solidified the surrounding materials S creating a solid, impermeable seal.

[0161] Alternative embodiments

[0162] In fig. 2, it is shown that the bore 28 comprises a bore surface 28s and the inner housing 21 comprises an upwardly facing end surface 2 les. These surfaces may be used to limit movement between these components. As the valve element 25 moves longitudinally relative to the inner housing 21, the bore surface 28s may come into contact with the end surface 2 les. This contact creates a physical stop that prevents further longitudinal movement of the valve element 25 towards the inner housing 21.

[0163] When these surfaces engage each other, they form an alternative restraining mechanism that limits the relative movement between the valve element 25 and the inner housing 21. This arrangement provides a secondary means of controlling the longitudinal displacement of the valve element 25, in addition to the restrainer 40. LIST OF REFERENCE NUMBERS

[0164] 1 well tool device 50 AN annulus la upper end CA casing lb lower end CI connection interface

[0165] 2 wireline CM cement

[0166] 10 storing module CR cap rock

[0167] 11 storage sleeve 55 D57 first distance

[0168] 12 radial opening D59 second distance

[0169] 14 storage compartment EJC substance collector, expandable

[0170] 20 releasing module junk catcher

[0171] 20a first end HI heat insulation

[0172] 20b second end 60 HOP height

[0173] 21 inner housing IC casing inner casing

[0174] 21a first section IS intermediate state

[0175] 21b second section LCA longitudinal centre axis

[0176] 2 les end surface OP opening

[0177] 22 second outer housing 65 PB thermite-based permanent

[0178] 25 valve element barrier

[0179] 26 tapering guiding surface PF platform

[0180] 27 second spring-supporting ledge PM substance

[0181] 28 bore RS releasing state

[0182] 28s bore surface 70 SS storing state

[0183] 29a first spring -sup porting surface SU surface

[0184] 29b second spring-supporting WB wellbore surface WE well

[0185] 31 first outer housing a angle

[0186] 32 radial opening 75

[0187] 37 first spring-supporting ledge

[0188] 40 restrainer

[0189] 41 restraining sleeve

[0190] 42 recess

[0191] 43a upper ledge

[0192] 43b lower ledge

[0193] 57 first spring

[0194] 59 second spring

[0195] 72 diverter arms

[0196] 72ds continuous diverting surface

[0197] 73 rigid arms

[0198] 74 diverter arm, main arm

[0199] 74ds continuous diverting surface

[0200] 76 diverter arms, supporting arm

[0201] 80 distance module

[0202] 91 first shear mechanism

[0203] 92 second shear mechanism

[0204] 100 well tool device

[0205] 101 chamber containing substance

[0206] 102 wireline

[0207] 105 igniter

[0208] S surrounding materials

Claims

CLAIMS1. A well tool device (1) for releasing a substance (PM) into a wellbore (WB) of a well (WE) and further into an annulus (AN) of the well (WE), comprising:- a storing module (10) for storing the substance (PM);- a releasing module (20); wherein the releasing module (20) comprises:- a first outer housing (31) connected to the storing module (10), wherein the first outer housing (31) comprises a radial opening (32) for allowing the substance (PM) to exit from the well tool device (1) into the wellbore (WB);- a valve element (25) provided on the inside of the first outer housing (31) and operable between an open position relative to the radial opening (32) and a closed position relative to the radial opening (32);- diverter arms (72; 74, 76) connected to the first outer housing (31) and operable between a radially retracted position for allowing the well tool device (1) to be lowered into the wellbore (WB) and a radially expanded position for guiding the substance (PM) from the wellbore (W) into the annulus (AN); wherein the well tool device (1) is operable between a storing state (SS) and a releasing state (RS); wherein, in the storing state, the diverter arms (72; 74, 76) are radially retracted and the radial opening (32) is closed by the valve element (25); wherein, in the releasing state, the diverter arms (72; 74, 76) are radially expanded and the radial openings (32) are opened by the valve element (25).

2. The well tool device (1) according to claim 1, wherein the storing module (10) comprises a storage sleeve (11) protruding into the first outer housing (31).

3. The well tool device (1) according to claim 2, wherein the valve element (25) is connected to an end of the storage sleeve (11) and wherein the storage sleeve (11) comprises a radial opening (12) for allowing the substance (PM) to exit from the storage sleeve (11) of the storing module (10) to the wellbore (WB) via the radial opening (32) of the first outer housing (31) when the well tool device (1) is in the releasing state (RS).

4. The well tool device (1) according to claim 2 or 3, wherein the valve element (25) is operable between the open position relative to the radial opening (32) and the closed position relative to the radial opening (32) by relative longitudinal movement between the storage sleeve (11) and the first outer housing (31).

5. The well tool device (1) according to any one of the above claims, wherein the valve element (25) comprises a tapering surface (26) for guiding the substance (PM) outwardly towards the radial opening (12) of the storage sleeve (11).

6. The well tool device (1) according to any one of the above claims, wherein the well tool device (1) comprises a restrainer (40) for restraining the relative movement between the valve element (25) and the first outer housing (31).

7. The well tool device (1) according to any one of the above claims, wherein the valve element (25) is biased towards the closed position.

8. The well tool device (1) according to claim 7, wherein the first outer housing (31) comprises a first spring-supporting ledge (37), wherein the valve element (25) comprises a second spring-supporting ledge (27), and wherein the well tool device (1) comprises a first spring (57) supported between the first spring -supporting ledge (37) and the second spring-supporting ledge (27), wherein the first spring (57) is configured to bias the valve element (25) towards the closed position.

9. The well tool device (1) according to any one of the above claims, wherein the releasing module (20) comprises:- an inner housing (21);- a second outer housing (22) secured outside of a first section (21a) of the inner housing (21); wherein a second section (21b) of the inner housing (21) is protruding into the first outer housing (31); wherein the diverter arms (72; 74, 76) are connected between the first outer housing (31) and the second outer housing (22); wherein the diverter arms (72; 74, 76) are operable between their radially retracted position and their radially expanded position by relative longitudinal movement between the first outer housing (31) and the second outer housing (22).

10. The well tool device (1) according to any one of the above claims, wherein the diverter arms (72; 74, 76) in the radially expanded position together are forming a continuous diverting surface (72ds; 74ds) protruding radially out into the wellbore (WB).The diverter arms may be distributed circumferentially around the inner housing (21).

11. The well tool device (1) according to claim 10, wherein the diverter arms (72; 74, 76) in the radially expanded position are brought into physical contact with a surface (SU) defining the wellbore (WB).

12. The well tool device (1) according to any one of claims 9 - 11, wherein the diverter arms (72; 74, 76) comprise a main arm (74) comprising a diverting surfaceand a supporting arm (76); wherein the main arm (74) has a first end pivotably connected to a lower end of the first outer housing (31) and a second end; wherein the supporting arm (76) has a first end pivotably connected to the second outer housing (22) and a second end, wherein the second end of the main arm (74) is pivotably connected to the second end of the supporting arm (76).

13. The well tool device (1) according to any one of the above claims, wherein the diverter arms (72; 74, 76) are biased towards the radially retracted position.

14. The well tool device (1) according to claim 13, wherein the valve element (25) comprises a first spring-supporting surface (29a), wherein the inner housing (21) comprises a second spring-supporting surface (29b), wherein the well tool device (1) comprises a second spring (59) supported between the first spring -supporting surface (29a) and the second spring-supporting surface (29b), wherein the second spring (59) is configured to bias the valve element (25) longitudinally away from the inner housing (21).

15. The well tool device (1) according to claim 14, wherein the inner housing (21) is protruding into a bore (28) of the valve element (25) and wherein the second spring (59) is located inside of the inner housing (21) and protrudes into the bore (28) of the valve element (25).

16. The well tool device (1) according to any one of claims 9 - 15, wherein the well tool device (1) is brought between the storing state and the releasing state by relative longitudinal movement between the first outer housing (31) and the second outer housing (22) and by relative longitudinal movement between the valve element (25) and the outer housing (31).

17. A method for releasing a substance (PM) into a wellbore (WB) of a well (WE) and further into an annulus (AN) of the well (WE), wherein the method comprises the steps of- providing a well tool device (1) having a storing module (10) and a releasing module (20), wherein the substance (PM) is stored within the storing module (10);- providing a platform (PF; EJC) within a wellbore (WB) of the well (WE) at a location below openings (OP) between the wellbore (WB) and the annulus (AN);- lowering the well tool device (1) onto the platform (PF; EJC);- opening radial openings (32) of the releasing module (20) to allow the substance (PM) to be released into the wellbore (WB);- radially expanding diverter arms (72; 74, 76) of the releasing module (20) to guide the substance (PM) from the wellbore (WB) into the annulus (AN).

18. The method according to claim 17, wherein the method further comprises an initial step of- providing the opening (OP) between the wellbore (WB) of the well (WE) and the annulus (AN) of the well (WE).

19. The method according to claim 17 or 18, wherein the platform (PF; EJC) is a substance collector (EJC) for collecting any substance (PM) bypassing the diverter arms (72; 74, 76).

20. A method for forming a thermite-based downhole well barrier (PB) in a well (WE), wherein the method comprises the steps of:- using the method according to any one of claims 17 - 19 for releasing a substance (PM) in the form of a heat generating mixture into an annulus (AN) of the well (WE);- lowering a further amount of the substance (PM) in the form of the heat generating mixture to the wellbore (WB) of the well (WE) adjacent to the heat generating mixture of the annulus (AN);- igniting the heat generating mixture of the wellbore (WB) and the heat generating mixture of the annulus (AN), thereby melting the surrounding materials in the well.

Images