Downhole tool with cone assembly

Abstract

The present invention relates to a downhole tool comprising a main body having an upstream end and a downstream end, wherein the downstream end is provided with a cone assembly comprising a plurality of pivotally supported cone segments, wherein the cone assembly is operational between a retracted position in which a total diameter of the cone assembly is smaller than or equal to an inner diameter of the main body and an extended position in which the cone assembly forms a cone shape having a total diameter that is larger than the outer diameter of the main body.

Description

[0001] DOWNHOLE TOOL WITH CONE ASSEMBLY

[0002] The present invention relates to a downhole tool. In particular, the present invention relates to a downhole tool with a cone assembly for engaging with fish.

[0003] In the field of downhole operations, particularly in oil and gas exploration and extraction, it is not uncommon for components such as wirelines to become unintentionally left within a wellbore. These components, often referred to as "fish", can become stuck due to various factors, including mechanical failures, operational errors, or unexpected well conditions. The presence of such fish can impede further operations and pose significant challenges to the efficiency and safety of downhole activities.

[0004] Wirelines, which are commonly used for conveying tools and possibly also to supply power and / or transmit data to and from the surface and downhole environments, are particularly susceptible to becoming stuck due to their elongated and flexible nature. Once lodged, they can be difficult to retrieve.

[0005] Existing solutions for fish retrieval often involve complex and time-consuming procedures that may not effectively resolve the issue or could potentially lead to further complications. Therefore, there is a continuous need for improved methods and tools that can reliably and efficiently retrieve stuck wirelines, minimising operational downtime and ensuring the safety and integrity of downhole operations.

[0006] The present invention seeks to at least to some extent mitigate the drawbacks of prior art solutions. The idea of the present invention is to provide a downstream end of a downhole tool with a cone assembly. The cone assembly, having a funnel shape, can be selectively arranged in a collapsed position and in an expanded position. In the expanded position, the cone assembly has a diameter larger than the diameter of the downhole tool, and preferably such that it matches the diameter of the borehole in which the downhole tool is running. By pushing the downhole tool further down the borehole, any wireline present ahead of the downhole tool will be pushed forward by the cone assembly, thereby collecting the

[0007] P2981PC00wireline in a more compact and possibly entangled bundle. It has been proven that it is much easier to catch the wireline when it is in such bundle, as compared to when it is freely oriented in the borehole.

[0008] According to a first aspect, a downhole tool is provided. The downhole tool comprises a main body having an upstream and a downstream end. The downstream end comprises a cone assembly. The cone assembly comprises a plurality of pivotally supported cone segments. The cone assembly is configured to be operational in a retracted position in which a total diameter of the cone assembly is less than, or equal to, an inner diameter of the main body, and in an extended position in which the cone assembly forms a cone shape having a total diameter that is larger than the outer diameter of the main body. The downhole tool is specifically advantageous in that it facilitates capture and retrieval of fish in a borehole, in particular when such fish comprises elongated and relatively thin structures, such as a wireline. The present invention further allows the downhole tool to operate and move without any substantial effect of the cone assembly, unless the cone assembly is arranged in the extended position.

[0009] Each cone segment may be pivotally mounted to the main body by a respective hinge mechanism. This is advantageous in that robust and articulate movement of the cone segments is ensured.

[0010] The cone segments may be symmetrically arranged around the main body. This promotes balanced expansion and retraction and also reduces the risk of the cone assembly being rotationally non-aligned with the fish.

[0011] When extended, the cone assembly may form a continuous perimeter. This increases the chance for actually engaging with the fish, which otherwise could pass through gaps between the cone segments.

[0012] The cone assembly may further be operated in an intermediate position, wherein the segments partially overlap. This offers versatile engagement capacities as well as robust and efficient adaptation to the internal diameter of the borehole.

[0013] In one example, when in the retracted position, all cone segments abut another cone segment. This prevents any gap between cone segments, thereby ensuring that the cone assembly will come into contact with the wireline to be retrieved.

[0014] P2981PC00The downhole tool may further comprise an actuator configured to control an operational position of the cone assembly between the retracted position and the extended position. This is advantageous in that precise adjustments of the cone segments may be possible.

[0015] Each cone segment may comprise a support that is configured to pivot around a pivot point supported in the main body of the downhole tool. This provides for a simple yet extremely robust connection of the cone segments to the main body, while still allowing for reliable control of the position of the cone assembly.

[0016] The support may comprise a lever extending from the pivot point and into a recess in the cone assembly actuator. This ensures that the cone segment is always pivotally connected to the cone assembly actuator, thereby improving robustness.

[0017] The lever of one of the cone segments may have a first length from the pivot point and into the recess in the cone assembly actuator, and a neighbouring cone segment may have a second length from the pivot point into another recess in the cone assembly actuator, the first length being smaller than the second length. Hence, it is possible for the cone segments to move differently, which is especially advantageous when some cone segments are intended to retract at a smaller angle than other cone segments.

[0018] The downhole tool may further comprise a longitudinal spear, the spear comprising a spear body and a plurality of hooks distributed along an outer surface of the spear body. The spear may facilitate effective engagement with the fish, especially when the fish comprises flexible and elongated structures, such as a wireline.

[0019] The downhole tool may further be configured to control the position of the spear between an idle position in which the spear is accommodated inside the main body of the downhole tool and an engagement position in which at least a distal end of the spear is arranged downstream of the cone assembly of the downhole tool. This is advantageous in that the spear is only protruding when it is controlled to retrieve and engage with fish downhole, thereby preventing any effect of the downhole tool in other operations. For this, the downhole tool may be provided with a spear actuator. Optionally, the spear is pre-mounted and fixedly attached to the downstream end of the main body of the downhole tool.

[0020] P2981PC00Each hook may be pivotally supported by the spear body. This allows effective and reliable control of the hook positions in order to ensure proper operation of the spear. Each hook may be operational between an engagement position where the hook points upstream to form a barb to the spear body, and an idle position where the hooks point downstream. This configuration ensures secure capture and retrieval of the fish, thereby optimising the tool's functionality in downhole operations. This also allows the hooks to be in a disengaging state if the hooks, when acting as barbs, fail to engage with the fish, or if the fish get stuck in the borehole and cannot be retrieved by available pulling force.

[0021] Each hook may be pivotally mounted to a spear actuator for moving the hooks between the engagement position and the idle position. Hence, an effective and robust control of the hooks is enabled.

[0022] According to a second aspect, a downhole tool is provided. The downhole tool comprises a main body having an upstream end and a downstream end. The downhole tool further comprises a longitudinal spear, the spear comprising a spear body and a plurality of hooks distributed along an outer surface of the spear body. The downhole tool is thereby beneficial in that the spear may engage and catch a fish in the borehole, especially when the fish comprises flexible and elongated structures, such as a wireline.

[0023] The longitudinal spear is configured to extend longitudinally out from the downstream end of the downhole tool. The spear is thereby protruding ahead of the main body of the downhole tool, thereby allowing the retrieval of fish without the need for the main body of the downhole tool to travel all the way up to the fish.

[0024] The downhole tool may further be configured to control the position of the spear between an idle position in which the spear is accommodated inside the main body of the downhole tool and an engagement position in which at least a distal end of the spear is arranged at the downstream end of the downhole tool. This is advantageous in that the spear is only protruding when it is controlled to retrieve and engage with fish downhole, thereby preventing any effect of the downhole tool in other operations. For this purpose, the downhole tool may be provided with a

[0025] P2981PC00spear actuator. Optionally, the spear may be pre-mounted and fixedly attached to the downstream end of the main body of the downhole tool.

[0026] The downhole tool may further be configured to control the position of the spear between an idle position in which the spear is accommodated inside the main body of the downhole tool and an engagement position in which at least a distal end of the spear is arranged downstream of the cone assembly of the downhole tool. This allows for more efficient and safe operation of the downhole tool, as the spear may be in a less protruding position when the downhole tool travels to the location of the fish.

[0027] Each hook may be pivotally supported by the spear body. This allows effective and reliable control of the hook positions in order to ensure proper operation of the spear. This further improves versatility and allows for accurate control of the engagement capability of the downhole tool.

[0028] Each hook may be operational between an engagement position in which the hook is pointing upstream to form a barb to the spear body and an idle position in which the hook is pointing downstream. This allows for efficient manoeuvrability of the spear as the idle position can be utilised if the fish is not properly engaged by the spear, thereby allowing the spear to be securely withdrawn from the fish. This also allows the hooks to be in a disengaging state if the hooks, when acting as barbs, fail to engage with the fish, or if the fish get stuck in the borehole and cannot be retrieved by available pulling force.

[0029] Each hook may be pivotally mounted to a spear actuator for moving the hooks between the engagement position and the idle position. Hence, an effective and robust control of the hooks is enabled.

[0030] Optionally, the downhole tool further comprises a hook actuator configured to control the position of the hooks in any of the engagement position and the idle position.

[0031] The hook actuator may be coupled to all hooks of the spear, thereby providing efficient, consistent and simultaneous actuation of the hooks.

[0032] P2981PC00The downhole tool may also comprise a spear being releasably attached to the downstream end of the main body of the downhole tool. The spear may be formed by two parts - one central elongated part and one outer elongated part.

[0033] The outer elongated part may be made as a single piece and surrounds the central elongated part on at least two sides.

[0034] Also, the central elongated part may be fixedly attached to the downstream end of the main body, for example at the cap. The central elongated part may be centrally aligned with the longitudinal extension of the downhole tool.

[0035] Further, the outer elongated part may be slidingly engaged with the central elongated part between an idle position and an engagement position, where the outer elongated part and the central elongated part may be moved in relation to each other longitudinally in the downstream direction or upstream direction, thereby offsetting the position of the outer elongated part in relation to the central elongated part. In order to move between the positions, the central elongated part could be moving, and the outer elongated part could be stationary or vice versa.

[0036] Furthermore, the outer elongated part may be provided with a plurality of hooks, and each hook may be formed by two radial protrusions on the outer elongated part. The two radial protrusions of each hook may be identical and provided on each side of the outer elongated part. The hooks may be oriented such that they point upstream so that each hook forms a barb to the spear.

[0037] In addition, the central elongated part may be provided with a plurality of counter barbs having an inclined face extending downstream. Each counter barb may be formed as a radial projection on the central elongated part. In the idle position, each counter barb may be aligned with an associated hook such that the counter barb may fill the radial void between the hook and a main portion of the central elongated part. Hence, in an idle position the barb function of the hooks will be eliminated by the counter barbs, preventing any structure to be caught radially inside the hooks. A hook and an associated counter barb may together form a shape of a truncated triangle having no overhand to act as a barb.

[0038] In the engagement position, the hooks may be longitudinally displaced in relation to the central elongated part and the counter barbs.

[0039] P2981PC00The outer elongated part may be operated by any suitable means, e.g. a linear actuator, a hydraulic drive unit, or any other mechanical or electrical actuator known in the art. Such actuator may be arranged at an upstream end of the spear.

[0040] It should be noted that specific features of the first aspect, in particular those relating to the cone assembly, are also applicable to the second aspect.

[0041] In one exemplary embodiment, the cone assembly comprises a plurality of pivotally supported cone segments, wherein each cone segment has a first end that is pivotally connected to the main body and a second free end that is moveable in the radial direction upon actuation. The actuating members are connected to the cone segments and are configured to perform a longitudinal movement in a direction towards the upstream end of the main body, thereby pulling the cone segments and causing the cone assembly to expand from the retracted position to the extended position. This has the effect of translating a simple linear actuation stroke into a reliable radial expansion of the cone assembly, thereby allowing precise control of the diameter of the receiving opening by controlling the stroke length of the actuating members.

[0042] In one exemplary embodiment, the actuating members are connected to a spring or to an actuator, such that the cone assembly is biased towards the extended position during downhole operations. This has the advantage that the cone assembly automatically assumes the extended position when the downhole tool approaches the fish, without requiring continuous active control, thereby simplifying operations and reducing the power consumption of the downhole tool.

[0043] In one exemplary embodiment, the cone segments are symmetrically arranged around the central axis of the main body, preferably at equal angular intervals. This has the effect of ensuring that the expansion of the cone assembly is radially balanced, preventing any net lateral force from being exerted on the main body during the transition between the retracted and the extended position, and ensuring that the receiving opening remains centered on the central axis.

[0044] In one exemplary embodiment, the total diameter of the cone assembly in the extended position is substantially equal to the inner diameter of the casing in which the downhole tool is deployed, such that each cone segment may come into contact

[0045] P2981PC00with the inner face of the casing. This has the effect of allowing the cone assembly to sweep substantially the entire cross-sectional area of the casing, thereby maximising the probability of the cone assembly coming into contact with the fish and directing it towards the receiving opening.

[0046] In one exemplary embodiment, the inclined surface of each cone segment, when in the extended position, is oriented at an angle relative to the central axis, preferably between 20° and 60°, and more preferably approximately 45°.

[0047] In one exemplary embodiment, the downhole tool further comprises a locking part arranged within the main body.

[0048] In one exemplary embodiment, the locking part comprises a plurality of fingers that are capable of radially expanding inside the main body when the locking part is in a first longitudinal position and that are prevented from radially expanding when the locking part is in a second longitudinal position.

[0049] In one exemplary embodiment, the outer face of the fingers is configured to engage with an inclined inner face of the main body when the locking part is in the second longitudinal position.

[0050] The invention and its many advantages will be described in more detail below with reference to the accompanying schematic drawings, which for the purpose of illustration show some non-limiting embodiments and in which:

[0051] Fig. 1 is a schematic view of a borehole with a fishing tool approaching a fish, according to one example,

[0052] Fig. 2a is a schematic cross-sectional view of a downhole tool according to an embodiment, shown in an upstream position prior to engaging with a fish,

[0053] Fig. 2b is a schematic cross-sectional view of the downhole tool shown in Fig. 2a, prepared to move further downhole to engage with the fish,

[0054] Fig. 2c is a schematic cross-sectional view of the downhole tool shown in Figs. 2a-b, shown in a downstream position where it is aligned with the fish,

[0055] P2981PC00Fig. 2d is a schematic cross-sectional view of the downhole tool shown in Figs. 2a-c, shown in a position where it is engaging with the fish,

[0056] Fig. 2e is a schematic cross-sectional view of the downhole tool shown in Figs. 2a-d, shown in a position where it is retrieving the fish,

[0057] Fig. 3a is a perspective view of parts of a downhole tool in a retracted position according to one example,

[0058] Fig. 3b is a perspective view of parts of the downhole tool shown in Fig. 3a but in an extended position,

[0059] Fig. 4a is a side view and a partially cross-sectional view of a downhole tool according to one example, shown in a retracted position,

[0060] Fig. 4b is a side view and a partially cross-sectional view of the downhole tool shown in Fig. 4a, but in an extended position,

[0061] Fig. 5a is a cross-sectional view of a downhole tool according to one example, shown in a retracted position,

[0062] Fig. 5b is a front view of the downhole tool shown in Fig. 5a,

[0063] Fig. 6a is a cross-sectional view of a downhole tool according to one example, shown in an extended position,

[0064] Fig. 6b is a front view of the downhole tool shown in Fig. 6a,

[0065] Fig. 7 is an isometric view of a downhole tool according to one example,

[0066] Figs. 8 is a schematic cross-sectional view of a spear forming part of a downhole tool according to one example,

[0067] Fig. 9a is a cross-sectional view of a spear forming part of a downhole tool according to one example, the spear being arranged in an engagement position,

[0068] P2981PC00Fig. 9b is a cross-sectional view of the spear shown in Fig. 9a, but in an idle position,

[0069] Fig. 10a is a cross-sectional view of a downhole tool according to one embodiment shown in a position where the tool is run into a hole,

[0070] Fig. 10b is a cross-sectional view of the same, shown in a position where the tool is adapted to receive a fish,

[0071] Fig. 10c, is a cross-sectional view of the same, shown in a position where the tool is receiving the fish, and

[0072] Fig. lOd is a cross-sectional view of the same, shown in a position where the downhole tool has engaged the fish.

[0073] Hereinafter, certain embodiments will be described more fully with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention, such as it is defined in the appended claims, to those skilled in the art.

[0074] The term "coupled" is defined as connected, although not necessarily directly, and not necessarily mechanically. Similarly, the term "connected", or "operatively connected", is defined as connected, although not necessarily directly, and not necessarily mechanically. Two or more items that are "coupled" or "connected" may be integral with each other. The terms "a" and "an" are defined as one or more, unless this disclosure explicitly requires otherwise. The terms "substantially", "approximately" and "about" are defined as largely, but not necessarily wholly what is specified, as understood by a person of ordinary skill in the art. The terms "comprise" (and any forms thereof), "have" (and any forms thereof), "include" (and any form thereof) and "contain" (and any forms thereof) are open-ended linking verbs. As a result, a method that "comprises", "has", "includes" or "contains" one or more steps and possesses those one or more steps, but is not limited to possessing only those one or more steps.

[0075] P2981PC00Within this specification, reference is made to "upstream" and "downstream". The term "upstream" should be interpreted as "facing the surface", i.e. a direction inside the borehole but facing the surface, or an uphole direction. Consequently, the term "downstream" should be interpreted as facing further down the borehole, i.e. a downhole direction.

[0076] Starting in Fig. 1, a drilled well 1 is shown. The well 1 consists of a drilled hole 3 leading down into the bedrock to extract gas and / or oil. The well 1 may be reinforced and / or cased or lined as is well-known in the art.

[0077] Fig. 1 also shows a downhole tool 100 submerged in the well 1. The downhole tool 100 is configured to perform a fishing operation and to engage a fish 200 left downhole. While the fish 200 may be in any suitable form, in this example it is represented as a portion of a wireline or other thin and flexible structure which has been lost in hole.

[0078] The downhole tool 100 is connected to a wireline 20, i.e. a cable adapted to power and / or pull the downhole tool 100 up the well 1. The wireline 20 is attached to the downhole tool 100 at one end, while the other end of the wireline 20 is connected to some equipment 30 above the well 1. In this way, the position of the downhole tool 100 in the well can be controlled by manoeuvring the wireline 20. The wireline 20 may be electrically coupled to the downhole tool 100 so that the downhole tool 100 can be powered via the wireline 20. The wireline 20 thus provides the downhole tool 100 with the necessary power so that the downhole tool 100 can perform its intended fishing operation downhole. Alternatively or additionally, the downhole tool 100 may be powered by a battery 101 comprised in the downhole tool 100.

[0079] In the shown example, the wireline 20 forms a running structure used in connection with the downhole tool 100 up and down the borehole 3. It should, however, be realised that the running structure 20 may be implemented in many different ways, such as by a coiled tubing, drill pipe, etc.

[0080] The downhole tool 100 may be a solitary component connected to the wireline 20, or it may form a portion of a larger tool string comprising one or more additional downhole tools such as tractors, intervention tools, measurement tools, etc.

[0081] P2981PC00With reference to Figs. 2a-e, the general construction of a downhole tool 100 will be described as well as its intended functionality. Starting in Fig. 2a, the downhole tool 100 is shown having a main body 110 and an upstream end 112 as well as a downstream end 114. The downstream end 114 is provided with a cone assembly 120. In this position, the cone assembly 120 is arranged in a retracted position. In the retracted position, the diameter of the cone assembly 120 at its distal or downstream end is smaller than, or equal to, the outer diameter of the main body 110 of the downhole tool 100.

[0082] The downhole tool 100 is shown moving in a downstream direction (indicated by the block arrow), thus approaching a fish 200.

[0083] In Fig. 2b, the cone assembly 120 is moved from the retracted position to an extended position. In this position, the distal diameter of the cone assembly 120 is extended such that it is larger than the outer diameter of the main body 110. Preferably, the outer and total diameter of the cone assembly 120 is increased to match the inner diameter of the borehole 3.

[0084] In Fig. 2c, the downhole tool 100 has been moved further downstream such that the fish 200, i.e. the lost wireline 200, is pushed by the cone assembly 120. By pushing onto the wireline 200, the thin and flexible structure 200 will be forced to bundle in a more compact volume, as illustrated schematically in Fig. 2c. By making a bundle of wireline, it is much easier to fish the wireline from the well as it is very difficult to get a grab in a wireline extending freely in the well, but when forced to bundle, this bundle of wireline is retrievable.

[0085] When the wireline 200 is re-arranged in the more compact distribution, the downhole tool 100 is operated by projecting a spear 140 in the downstream direction, i.e. towards the wireline 200. Optionally, the spear 140 is pre-mounted at the downstream end 114 of the downhole tool 100. In such case, the downhole tool 100 is operated by moving the entire downhole tool 100, including the spear 140, towards the fish 200. This is shown in Fig. 2d. This will cause the spear 140 to penetrate through the thin and flexible structure 200. The spear 140 is provided with several hooks 142 that protrude backwards, or in the upstream direction. The hooks 142 act as barbs to the spear 140 to grab into the bundle of wireline.

[0086] P2981PC00In order to retrieve the fish 200, the downhole tool 100 is moved upstream as indicated by the block arrow in Fig. 2e. The hooks 142 will ensure that the downhole tool 100 is engaged with the fish, i.e. the bundle of wireline 200, as it is pulled up hole. In this retrieval mode, the cone assembly 120 may be in the extended position or in the retracted position where the cone helps grabbing around the bundle of wireline as shown in Fig. 2e.

[0087] The cone assembly 120 is further shown in Figs. 3a and 3b. In Fig. 3a, the cone assembly 120 is shown in a retracted position, while in Fig. 3b the cone assembly 120 is shown in an extended position.

[0088] The cone assembly 120 comprises a plurality of cone segments 130. In the shown example, all cone segments 130 are identical. Each cone segment 130 comprises a support 132 that is pivotally supported at the downstream end 114 of the main body 110 of the downhole tool 100. For this, the downstream end 114 of the main body 110 comprises a cap 116 that provides a pivot joint 118 for each cone segment 130. The pivotal support forms a hinge mechanism for the cone segment 130.

[0089] The support 132 extends in a downstream direction from the cone segments 130 and is integrally formed with a curved segment portion 134. The segment portion 134 extends from an upstream end 134a to a downstream end 134b. As can be seen especially in Fig. 3b, each segment portion 134 has the shape of a curved truncated triangle, whereby the width of the upstream end 134a is smaller than the width of the downstream end 134b. When the cone assembly 120 is in the extended position, shown in Fig. 3b, the upstream ends 134a of all cone segments 130 form a closed circle having a diameter that is larger than the diameter of the main body 110.

[0090] Again referring to Fig. 3a, the cone assembly 120 comprises six cone segments 130. In the retracted position, three cone segments 130 are pivoted radially inwards such that the upstream ends 134a meet at their respective corners. The remaining three cone segments 130 are also pivoted radially inwards, but to a less pivoting angle as the inner cone segments 130 will form a radial stop for the outer cone segments 130. In the retracted position, the segments 130 abut so that if meeting the lost wireline, the wireline will be pushed forward in front of the tool without inducing the risk of the wireline being squeezed in between two cone

[0091] P2981PC00segments 130. When moving to the extended position, shown in Fig. 3b, as the outer cone segments 130 pivot radially outwards, there will be a circumferential space for accommodating the inner cone segments 130, and the cone segments 130 abut, forming a continuous perimeter so that the wireline is pushed in front of the tool to force the wireline to bundle, and since the cone segments abut each other, the wireline cannot be squeezed in between two cone segments. In the extended position, the cone segments may have a small mutual distance between two adjacent cone segments 130, but this distance is smaller than a thickness of the wireline.

[0092] Further details of the downhole tool 100 is shown in Fig. 4a and in Fig. 4b. In Fig.

[0093] 4a, the downhole tool 100 is shown having a cone assembly 120 in a retracted position, while in Fig. 4b the downhole tool 100 is shown with the cone assembly 120 arranged in the extended position.

[0094] With reference to these figures, the main body 110 has a longitudinal extension. The main body 110 preferably has a circular cross-section. The downstream end 114 comprises the required components for controlling the position of the cone assembly 120.

[0095] Examples of these required components are further shown in Figs. 5a and 5b and in Figs. 6a and6b. The downstream end 114 of the main body 110 forms a tubular sleeve 160. The sleeve 160 terminates at the cap 116, which is inserted in the sleeve 160. A cone assembly actuator 170 is arranged inside the sleeve 160. The cone assembly actuator 170 is in the shape of a longitudinal rod that extends along the sleeve 160 and further radially inside the cap 116. The distal end of the cone assembly actuator 170 is provided with a plurality of radial recesses 172. These recesses 172 are aligned longitudinally and distributed, preferably evenly, along the circumferential surface of the cone assembly actuator 170. Each recess 172 is configured to accommodate a lever 131 of the support of a cone segment 130. The lever 131 of one of the cone segments 130 has a first length Li from the pivot point and into a recess 172 in the cone assembly actuator 170, and a neighbouring cone segment 130 has a second length L2 from the pivot point into another recess 172 in the cone assembly actuator 170, the first length Li being smaller than the second length L2.

[0096] P2981PC00The cone assembly actuator 170 is connected at its upstream end to a shift sleeve 180. The shift sleeve 180 is configured to move longitudinally, and for such motion any suitable drive mechanism may be used. For example, the shift sleeve 180 may be controlled mechanically, electrically, hydraulically, etc. In Fig. 5a, the cone assembly 120 is in a retracted position. Upon actuation to move the cone assembly 120 into the extended position as shown in Fig. 6a, the shift sleeve 180 is moved longitudinally towards the cone assembly 120. This will cause a corresponding motion of the cone assembly actuator 170. Hence, the radial recesses 172 will move accordingly, which causes a corresponding movement of the levers 131 of the cone segments 130.

[0097] The lever 131 extends approximately perpendicularly from the cone segment support 132 (support 132). The cone segment support 132 is pivotally supported by the cap 116 at a pivot joint 118. The lever 131 extends from the pivot joint 118 radially inwards. Hence, as the cone assembly actuator 170 moves longitudinally, the levers 131 will be pushed longitudinally, thereby forcing the cone segment supports 132 to pivot. This also means that the cone assembly actuator 170 is configured to arrange the cone assembly 120 in any intermediate position between the retracted position and the extended position, simply by controlling the stroke length of the longitudinal movement of the shift sleeve 180.

[0098] As is shown in Fig. 5a, the cone segments 130 shown in a cross-sectional view are the ones folding completely inwards. In order to allow the outer cone segments 130 to fold at a smaller angle, the corresponding radial recesses 172 may be slightly bigger so that in a forward motion of the cone assembly actuator 170, the upstream wall of the radial recess 172 will not push the lever 131 over the same stroke length.

[0099] The cap 116 is provided with a central through-hole 190. Although not shown in Figs. 5a and 5b and in Figs. 6a and6b, the through-hole 190 may extend into a central cavity of the cone assembly actuator 170. The downhole tool 100 may further comprise a longitudinal spear 140 arranged inside the through-hole 190. The longitudinal spear 140 is further shown in Fig. 7.

[0100] The spear 140 may be mounted as fixed in relation to the main body 110 and comprising a spear actuator 150 (shown in Fig. 8) which is driven by the cone assembly actuator 170 through a J-slot guide so that the cone assembly actuator

[0101] P2981PC00170 acts alone until it has been moved a predetermined number of times, after which it engages and moves the spear actuator 150.

[0102] The spear 140 is provided with a plurality of hooks 142. The hooks 142 are distributed longitudinally along the length of the spear 140, as well as circumferentially. For example, the plurality of hooks 142 may be distributed in sets 144 of four hooks 142. Each set 144 may comprise a number of hooks 142 aligned longitudinally and evenly spaced around the circumference of the spear 140. In the shown example, the spear 140 is provided with five sets 144 of hooks 142 evenly spaced along the length of the spear 140, and each set 144 of hooks 142 comprises four hooks 142 spaced by 90°.

[0103] The spear 140 may be accommodated inside the main body 110 of the downhole tool in an idle position when not needed and may be projected out from the main body 110, as shown in Fig. 7, in an extended position when the cone assembly 120 has been extended and when the fish is ready to be retrieved. For this, the spear 140 may be connected to a spear actuator (shown in Fig. 8). Due to the substantial length of the spear 140, the spear actuator may e.g. be realised using a gearing or other mechanical mechanism configured to translate a comparatively small stroke length, or motion, to a linear motion of greater magnitude.

[0104] In the position shown in Fig. 7, the hooks 142 form barbs for the fish to be retrieved. Hence, when the spear 140 is inserted through the fish being a bundle of thin or flexible structure, such as a wireline, the hooks 142 will ensure proper engagement with the fish as the downhole tool 100 is pulled up hole.

[0105] In order to provide further functionality of the spear 140, the hooks 142 may be manoeuvrable between an engagement position where they form barbs, shown in Fig. 8, and an idle position where the hooks do not form barbs, shown by dotted lines in Fig. 8.

[0106] In order to enable the desired control of the hooks 142, the hooks 142 may be allowed to pivot relative to a spear body 146. In Fig. 8, a hook 142 is shown in an extended position, i.e. the hook 142 is pointing upstream. This is indicated by the hook 142 drawn in solid lines. At an intermediate position radially inside the spear body 146, the hook 142 is pivotally connected to a spear actuator 150. For

[0107] P2981PC00example, the radially inner end of the hook 142 may be attached to the spear actuator 150 via a pivot joint 148.

[0108] Hence, when the spear actuator 150 is moved longitudinally in an upstream direction, as indicated by the block arrow in Fig. 8, the pivot joint 148 will move longitudinally as well. As the hook 142 may protrude out from the spear body 146 via a cutout 149, the upstream end of this cutout 149 will prevent the hook 142 from moving longitudinally. Instead, the hook 142 will pivot around the pivot joint 148, forcing the hook 142 to enter the idle position where it points downstream. This is indicated by the dashed hook 142 in Fig. 8. Preferably, in one example the hook 142, when in the idle position, is pivoted completely such that the entire hook 142 is accommodated radially inside the outer surface of the spear 140. This allows the spear 140 to be fully moveable in and out from the main body 110 of the downhole tool 100, without the hooks 142 causing any radial extension.

[0109] The change of position between the extended position and the idle position may be particularly useful if the spear 140 is unable to engage with the fish properly. The hooks 142 can then be pivoted to the idle position, and the spear 140 can be moved inside the main body 110 before another attempt is made.

[0110] Another example of a downhole tool 100 is shown in Figs. 9a and 9b, in particular with regards to a specific example of a spear 140. In this example, the spear 140 is releasably attached to the downstream end 114 of the main body 110 of the downhole tool 100. The spear 140 is generally formed by two parts - one central elongated part 1401 and one outer elongated part 1402. As shown in Fig. 9a, the outer elongated part 1402 is made as a single piece and surrounds the central elongated part 1401 on at least two sides.

[0111] The central elongated part 1401 is fixedly attached to the downstream end 114 of the main body 110, for example at the cap 116. The central elongated part 1401 is preferably centrally aligned with the longitudinal extension of the downhole tool 100.

[0112] The outer elongated part 1402 is slidingly engaged with the central elongated part 1401. From an idle position shown in Fig. 9b, the outer elongated part 1402 can be moved longitudinally in the downstream direction, thereby offsetting the position of the outer elongated part 1402 in relation to the central elongated part

[0113] P2981PC001401. In order to move between the positions shown in Figs. 9a and 9b, the central elongated part 1401 could be moving, and the outer elongated part 1402 could be stationary.

[0114] The outer elongated part 1402 is provided with a plurality of hooks 142. As is shown in Fig. 9a, each hook 142 is formed by two radial protrusions 1421 on the outer elongated part 1402. The two radial protrusions 1421 of each hook 142 are identical and provided on each side of the outer elongated part 1402. The hooks 142 are oriented such that they point upstream. Hence, each hook 142 forms a barb to the spear 140.

[0115] The central elongated part 1401 is provided with a plurality of counter barbs 1422 having an inclined face extending downstream. Each counter barb 1422 is formed as a radial projection on the central elongated part 1401. In the idle position, shown in Fig. 9b, each counter barb 1422 is aligned with an associated hook 142 such that the counter barb 1422 fills the radial void between the hook 142 and a main portion of the central elongated part 1401. Hence, in an idle position the barb function of the hooks 142 will be eliminated by the counter barbs 1422, preventing any structure to be caught radially inside the hooks 142. A hook 142 and an associated counter barb 1422 will together form a shape of a truncated triangle having no overhand to act as a barb.

[0116] In the engagement position, the hooks 142 will be longitudinally displaced in relation to the central elongated part 1401 and the counter barbs 1422. This is shown in Fig. 9a, where the counter barbs 1422 are "hidden" by the hooks 142. Hence, the hooks 142 will point upwards and form barbs to the spear 140.

[0117] The outer elongated part 1402 may be operated by any suitable means, e.g. a linear actuator, a hydraulic drive unit, or any other mechanical or electrical actuator known in the art. Such actuator may preferably be arranged at an upstream end of the spear 140.

[0118] Fig. 10a is a cross-sectional view of a downhole tool 301 according to one embodiment shown in a position where the downhole tool 301 is run into a hole. The downhole tool 301 comprises a main body 303 having an upstream end 305 and a downstream end 307, where the downstream end 307 is provided with a cone assembly 309 comprising a plurality of pivotally supported cone segments

[0119] P2981PC00311. The cone segments 311 have a first end 313 that is pivotally connected with the main body 303 and a second free end 315. The pivotally supported cone segments 311 may be pivoted from a retracted position, as seen in Fig, 10a, to an extended position, as seen in Fig. 10b, where the second end 314 of the cone segments are moved in a radial direction outwards by a pivotal movement of cone segments 311, where the pivotal movement of the cone segments 311 is performed by a longitudinal movement of actuating members 317 in a direction towards the upstream end, which pulls on the cone segments 311 and causes the cone assembly 309 to expand, thereby increasing the diameter of the cone assembly 309, and thereby increasing the diameter of a receiving opening 319 of the cone assembly 309. Thus, the cone assembly 309 is operational between a retracted position as seen in Fig. 10a, where the total diameter of the cone assembly 309 is smaller than or equal to an inner diameter of the main body 303, and in an extended position as seen in Fig. 10b, in which the cone assembly 309 forms a cone shape having a total diameter that is larger than the outer diameter of the main body 303. The actuating members 317 may be connected to an actuator or a spring so that when the downhole tool 301 is in a position where a fish 401 is to be retrieved, (as seen in Fig. 10c) the actuator members 317 may be manoeuvred in a longitudinal direction, and thereby pulling onto the cone segments 311, and expanding the cone assembly 309 to its expanded position.

[0120] The actuating members 317 may be connected to a spring-loaded mechanism, such that the cone assembly 309 is biased towards the extended position during normal downhole operations and is only returned to the retracted position when sufficient axial force is applied by the fish 401 or by a deliberate retraction stroke of the actuator. This has the effect of ensuring that the cone assembly 309 remains open and ready to receive the fish 401 without requiring continuous active control of the actuator, thereby simplifying the operational procedure and reducing the power consumption of the downhole tool 301.

[0121] The increase in diameter of the cone assembly 309 allows the cone segments NR to come into contact with an inner face 405 of a casing 407 so that if a fish, such as coiled tubing, is expanded inside the casing 407, the cone segments 311 can have a diameter similar to that of the fish 401 to be received. Furthermore, the expanded cone assembly 309 may function as a funnel, allowing easier access of the fish 401 into the main body 303, as seen in Fig. 10c, as the funnel-shaped (cone-shaped) cone assembly 309 will have an inclined surface 321 directing a first

[0122] P2981PC00end 403 of the fish 401 towards a central axis A of the main body 303 and allowing the fish 401 to be directed towards the receiving opening 319 of the downhole tool 301. The outer diameter of the cone assembly 309 may be substantially equal to the inner diameter of the casing 407, ensuring that each cone segment 315 may come into contact with the inner face 405 of the casing 407, allowing the cone assembly 309 to scoop up at least a part of the fish and direct it towards the receiving opening 319.

[0123] The cone assembly 309 and a locking part 323 may be operated so that in a first step, the cone assembly 309 is expanded from the run-in position, as shown in Fig.

[0124] 10a, to the extended position, as seen in Fig. 10b, so that the inclined surfaces 321 of the cone segments 311 guide the fish 401 into the receiving opening 319. In a second step, as the fish 401 is received within the main body 303, as seen in Fig. 10c, by moving the downhole tool 301 in a direction towards the fish 401, the locking part 323 is moved from the first longitudinal position to the second longitudinal position, causing the fingers 325 to be radially constrained by the inclined inner face 331 and to grip the outer surface of the fish 401. At the same time, or during a subsequent step, the cone assembly 309 may be retracted towards the retracted position, reducing the total diameter of the cone assembly 309 for ease of withdrawal from the borehole, as seen in Fig. lOd. This coordinated sequence has the advantage of allowing the downhole tool 301 to adapt its geometry throughout the retrieval operation, maximising the probability of successfully capturing the fish 401 while minimising the risk of the fish 401 escaping from the downhole tool 301 during the upward retrieval stroke.

[0125] The downhole tool 301 may further comprise the locking part 323, where the locking part 323 may be arranged to lock the fish 401 inside the main body 303, ensuring that the downhole tool 301 and the fish 401 are securely attached to each other when the downhole tool 301 is used to retrieve the fish 401. The locking part 323 may be in the form of fingers 325 that are capable of expanding inside the main body 303 when the locking part 323 is in a first longitudinal position, while in a second longitudinal position, the fingers 325 may be prevented from expanding, allowing an inner face 327 of the fingers 325 to grip an outer part 409 of the fish 401, as seen in Fig. lOd. The longitudinal movement of the fingers 325 may be performed by an actuator or a spring. When the fingers 325 are in a second longitudinal position, an outer face 329 of the fingers 325 may be in contact with

[0126] P2981PC00an inner face 331 of the main body 303, such as an inclined inner face 331, ensuring that the fingers cannot radially expand.

[0127] Modifications and other variants of the described embodiments will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing description and associated drawings. Therefore, it is to be understood that the embodiments are not limited to the specific example embodiments described in this disclosure, and that modifications and other variants are intended to be included within the scope of this disclosure

[0128] The use of the terms "first", "second", "third" and "fourth", "primary", "secondary", "tertiary", etc., does not imply any particular order but are included to identify individual elements. Moreover, the use of the terms "first", "second", "third" and "fourth", "primary", "secondary", "tertiary", etc., does not denote any order or importance, but rather the terms "first", "second", "third" and "fourth", "primary", "secondary", "tertiary", etc., are used to distinguish one element from another. Note that the words "first", "second", "third" and "fourth", "primary", "secondary", "tertiary", etc., are used here and elsewhere for labelling purposes only and are not intended to denote any specific spatial or temporal ordering.

[0129] Furthermore, the labelling of a first element does not imply the presence of a second element and vice versa.

[0130] It is to be noted that the word "comprising" does not necessarily exclude the presence of other elements or steps than those listed.

[0131] It is also to be noted that the words "a" or "an" preceding an element do not exclude the presence of a plurality of such elements.

[0132] It should further be noted that any reference signs do not limit the scope of the claims.

[0133] By "fluid" or "well fluid" is meant any kind of fluid that may be present in oil or gas wells downhole, such as natural gas, oil, oil mud, crude oil, water, etc. By "gas" is meant any kind of gas composition present in a well, completion or open hole, and by "oil" is meant any kind of oil composition, such as crude oil, an oil-containing

[0134] P2981PC00fluid, etc. Gas, oil and water fluids may thus all comprise other elements or substances than gas, oil and / or water, respectively.

[0135] By "casing" or "well tubular metal structure" is meant any kind of pipe, tubing, tubular, liner, string, etc., used downhole in relation to oil or natural gas production.

[0136] In the event that the tool is not submergible all the way into the casing, a downhole tractor can be used to push the tool all the way into position in the well. The downhole tractor may have projectable arms having wheels, wherein the wheels contact the inner surface of the casing for propelling the tractor and the tool forward in the casing. A downhole tractor is any kind of driving tool capable of pushing or pulling tools in a well downhole, such as a Well Tractor®.

[0137] Although the invention has been described above in connection with preferred embodiments of the invention, it will be evident to a person skilled in the art that several modifications are conceivable without departing from the invention as defined by the following claims.

[0138] P2981PC00

Claims

23Claims1. Downhole tool (100) comprising a main body (110) having an upstream end (112) and a downstream end (114), wherein the downstream end (114) is provided with a cone assembly (120) comprising a plurality of pivotally supported cone segments (130), wherein the cone assembly (120) is operational between a retracted position in which a total diameter of the cone assembly (120) is smaller than or equal to an inner diameter of the main body (110) and an extended position in which the cone assembly (120) forms a cone shape having a total diameter that is larger than the outer diameter of the main body (110).

2. The downhole tool of claim 1, wherein each cone segment (130) is pivotally mounted to the main body by a respective pivot joint (118).

3. The downhole tool of claim 1, wherein the cone segments (130) are symmetrically arranged around the main body (110).

4. The downhole tool of any of claims 1-3, wherein in the extended position the cone assembly (120) forms a continuous perimeter.

5. The downhole tool of any of claims 1-4, wherein the cone assembly (120) is further operational in an intermediate position in which the cone segments (130) are at least partially overlapping.

6. The downhole tool of claim 5, wherein in the retracted position all cone segments (130) abut another cone segment (130).

7. The downhole tool of any of claims 1-6, further comprising a cone assembly actuator (170) configured to control an operational position of the cone assembly (120) between the retracted position and the extended position.

8. The downhole tool according to claim 7, wherein each cone segment (130) comprises a support (132) that pivots around the pivot point (118) supported in the main body (110) of the downhole tool (100).P2981PC009. The downhole tool according to claim 8, wherein the support comprises a lever (131) extending from the pivot point and into a recess in the cone assembly actuator (170).

10. The downhole tool according to claim 9, wherein the lever (131) of one of the cone segments (130) has a first length (Li) from the pivot point and into the recess (172) in the cone assembly actuator (170), and a neighbouring cone segment (130) has a second length (L2) from the pivot point into another recess (172) in the cone assembly actuator (170), the first length being smaller than the second length.

11. The downhole tool of any of the preceding claims, further comprising a longitudinal spear (140), the spear (140) comprising a spear body (146) and a plurality of hooks (142) distributed along an outer surface of the spear body (146).

12. The downhole tool according to claim 11, wherein the spear (140) is configured to move between an idle position in which the spear (140) is accommodated inside the main body (110) of the downhole tool (100) and an engagement position in which at least a distal end of the spear (140) is arranged downstream of the cone assembly (120) of the downhole tool (100).

13. The downhole tool according to claim 11 or 12, wherein each hook (142) is pivotally supported by the spear body (146).

14. The downhole tool according to claim 13, wherein each hook (142) is operational between an engagement position in which the hook (142) is pointing upstream to form a barb to the spear body (146) and an idle position in which the hook (142) is pointing downstream.

15. The downhole tool according to any of claims 9-13, wherein each hook (142) is pivotally mounted to a spear actuator (150) for moving the hooks between the engagement position and the idle position.P2981PC00

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