Submarine course tool

Description

1 / 26 SUBMARINE COURSE TOOL Technical field

[001] The present invention relates to the field of subsea oil or gas production, and more specifically to a subsea stroke tool. The invention also relates to a well control package comprising the subsea stroke tool. Finally, the invention relates to a method of using the subsea stroke tool to establish or retrieve a plug comprised in the pipe hanger of a subsea well, or in other applications such as milling and hydrate removal. Technical background

[002] During the construction of subsea production and injection wells, before the subsea tree is installed on the wellhead, a blowout preventer (BOP) is placed on top of the wellhead. It is necessary to temporarily suspend the well to allow the BOP to be removed. After the well has been safely plugged, the BOP is removed so that the tree can be installed on top of the wellhead, and production or injection can begin.

[003] One temporary barrier method consists of establishing a wire plug on the subsea pipeline hanger. The current drawback of this method is the need to retrieve the plug after installation and commissioning of the tree. In the past, this required installing a well control package on the tree to safely retrieve the pipe hanger plug through the tree. Deploying a well control package from a rig or light well restoration vessel is expensive considering the daily cost. The intervention can be done with or without a riser.

[004] Document US8672037 discloses a removal system and Petition 870250111136, dated 03 / 12 / 2025, page 12 / 56 2 / 26 establishment of buffers.

[005] Document WO2015074042 discloses a subsea course device for underwater restoration.

[006] Document US9291016 discloses a method for pulling a crown plug from a subsea tree.

[007] All these existing solutions consist of providing a long hydraulic piston for a stroke of more than 6 meters, deep enough to reach through a subsea tree to set or retrieve a wire plug for a vertical Christmas tree (VXT) or a crowning plug for a horizontal Christmas tree (HXT). The main problem is that there is a high risk of leakage along the entire stroke length of this long piston mandrel.

[008] In this context, there is still a need for an improved solution to establish or repair a plug in a tree, with reduced risk of leakage. Summary of the invention

[009] The present invention relates to a subsea course tool having a longitudinal axis and comprising: - accommodation; - a hydraulic piston assembly; - a rod having a proximal end and a distal end, at least partially arranged within the housing and movable along the longitudinal axis relative to the housing; - a set of rollers engaged with the rod; where both the roller assembly and the hydraulic piston assembly are configured to move the rod along the longitudinal axis. [ 010] In some variations, the stem has a retracted position, a Petition 870250111136, dated 03 / 12 / 2025, page 13 / 56 3 / 26 extended position and an intermediate position between the retracted position and the extended position, wherein the roller assembly is configured to move the rod between the retracted position and the intermediate position, and the hydraulic piston assembly is configured to move the rod between the intermediate position and the extended position. [ 011] In some variations, the roller assembly is configured to be driven by an ROV. [ 012] In some variations, the hydraulic piston assembly is configured to be actuated by an ROV. [ 013] In some variations, the hydraulic piston assembly comprises: - a camera in the accommodation; - a hydraulic piston having a distal end (which may, for example, be attached to the proximal end of the rod) and a proximal end, the hydraulic piston sliding through the chamber along the longitudinal axis; - at least one seal on the periphery of the hydraulic piston; and - at least one hydraulic port, configured to supply hydraulic fluid to the chamber.

[014] In some variations, the hydraulic piston comprises at least a distal portion closer to the rod and a proximal portion farther from the rod, wherein the distal portion has a cross-section orthogonal to the longitudinal axis smaller than the proximal portion; and, preferably, the hydraulic piston comprises an intermediate portion between the distal and proximal portions, wherein the intermediate portion has a cross-section orthogonal to the longitudinal axis smaller than the proximal portion and a cross-section orthogonal to the longitudinal axis larger than the distal portion. Petition 870250111136, dated 03 / 12 / 2025, page 14 / 56 4 / 26

[015] In some variations, the hydraulic piston comprises a blind orifice extending along the longitudinal axis from its proximal end.

[016] In some variations, the rod is sliding inside the hydraulic piston (instead of being fixed to the hydraulic piston).

[017] In some variations, the rod comprises a proximal shoulder and the hydraulic piston comprises a plurality of load segments having a locked position and an unlocked position, the rod and hydraulic piston being configured so that the load segments can engage with the proximal shoulder when the load segments are in the locked position, and the rod can slide freely within the hydraulic piston when the load segments are in the unlocked position.

[018] In some variations, the underwater course tool additionally comprises a connecting element affixed to the distal end of the rod.

[019] In some variations, the subsea course tool further comprises an end tool attached to the connector element, said end tool preferably being configured to establish or retrieve a plug within a subsea well pipe hanger.

[020] The invention is further related to a well control package configured to be placed on top of a subsea tree, comprising the subsea course tool described above.

[021] The invention is further related to a method for operating the underwater stroke tool, as described above, comprising a step of moving the rod along the longitudinal axis, actuating the roller assembly, and a step of moving the rod along the axis Petition 870250111136, dated 03 / 12 / 2025, page 15 / 56 5 / 26 longitudinal, actuating the hydraulic piston assembly.

[022] In some variations, the method comprises a step of moving the rod distally along the longitudinal axis, actuating the roller assembly, followed by a step of moving the rod distally along the longitudinal axis, actuating the hydraulic piston assembly.

[023] In some variations, the method comprises a step of moving the rod proximally along the longitudinal axis, actuating the hydraulic piston assembly, followed by a step of moving the rod proximally along the longitudinal axis, actuating the roller assembly.

[024] In some variations, the method is for establishing a plug in a pipe hanger of a subsea well and comprises successively: - Connect the cap to an end tool attached to the distal end of the rod; - Place the plug in the desired position on the pipe hanger by moving the rod distally along the longitudinal axis, actuating the roller assembly, then move the rod distally along the longitudinal axis, actuating the hydraulic piston assembly to set the plug in the desired position; - Release the end tool cap and remove the underwater stroke tool, moving the rod proximally along the longitudinal axis, actuating the hydraulic piston assembly, then move the rod proximally along the longitudinal axis, actuating the roller assembly. [ 025] In some variations, the method is for retrieving a plug in a pipe hanger of a subsea well and comprises successively: Petition 870250111136, dated 03 / 12 / 2025, page 16 / 56 6 / 26 - Move the rod distally along the longitudinal axis, actuating the roller assembly, then move the rod distally along the longitudinal axis, actuating the hydraulic piston assembly; - Connect an end tool attached to the distal end of the rod to the plug inside the pipe hanger; - Remove the underwater stroke tool, along with the plug, by moving the rod proximally along the longitudinal axis, actuating the hydraulic piston assembly, then move the rod proximally along the longitudinal axis, actuating the roller assembly.

[026] In some variations, the method additionally involves injecting fluid before moving the rod.

[027] The invention relates to a subsea travel tool that provides an improved solution for handling an object, in particular a plug, within a wellhead. In particular, thanks to this subsea travel tool, no riser is required to set or retrieve a plug. In other words, the present invention allows for riserless intervention.

[028] The invention also eliminates the need for a long piston: only a short piston can be used, thanks to the presence of the roller assembly.

[029] Traditional solutions, typically using a drilling rig, are extremely expensive, whereas the subsea course tool only requires the use of construction vessels used to install the subsea tree, which significantly lowers the cost and provides a large saving in drilling expenses.

[030] The underwater cutting tool is also preferably transportable by air, simpler to use than previous solutions and Petition 870250111136, dated 03 / 12 / 2025, page 17 / 56 7 / 26 reliable with existing cutting and sealing capabilities. Brief description of the drawings

[031] FIGS. 1A / 1B schematically show the internal structure of the subsea course tool positioned on a wellhead, according to a particular embodiment, respectively in the extended position and in the retracted position.

[032] FIGS. 2A / 2B schematically show the internal structure of the underwater course tool according to a particular embodiment, respectively in the intermediate position and in the retracted position. The vertical scale is different in FIGS. 2A and 2B.

[033] FIGS. 3A / 3B / 3C / 3D are various schematic views of the internal structure of part of the subsea tool, according to a particular embodiment. The sectional view of FIG. 3B corresponds to a 90° rotation of the sectional view of FIG. 3A. FIG. 3C is another sectional view similar to FIG. 3A, showing another part of the tool. FIG. 3D is a perspective view.

[034] FIG. 4 schematically shows the internal structure of a part of the underwater course tool, according to a particular embodiment, focusing on the roller assembly.

[035] FIG. 5 schematically shows the subsea course tool positioned on a wellhead and operated by a single remotely operated underwater vehicle (ROV), according to a particular embodiment.

[036] FIGS. 6A / 6B schematically show the hydraulic piston of the subsea stroke tool, according to a particular embodiment, respectively in the extended and retracted positions.

[037] FIGS. 7A / 7B / 7C / 7D are various schematic views of the structure. Petition 870250111136, dated 03 / 12 / 2025, page 18 / 56 8 / 26 internal part of the underwater course tool, according to a particular modality, in various configurations. Detailed Description

[038] The invention will now be described in greater detail and without limitation in the following description. General description of the underwater course tool.

[039] An object of the present invention is a subsea stroke tool having a longitudinal axis and comprising a housing. The subsea stroke tool comprises a hydraulic piston assembly. The subsea stroke tool further comprises a rod having a proximal end and a distal end, at least partially arranged within the housing and movable along the longitudinal axis relative to the housing. Finally, the subsea stroke tool comprises a set of rollers engaged with the rod. In the subsea stroke tool, both the roller assembly and the hydraulic piston assembly are configured to move the rod along the longitudinal axis.

[040] The rod can be made from a length of spiraled tubing, as is typically used in industry.

[041] A “submarine course tool” refers to a tool configured to perform coursework in a submerged environment. The submarine course tool could also be used in other environments.

[042] A “hydraulic piston assembly” refers to an assembly comprising at least one hydraulic piston. A hydraulic piston assembly may comprise multiple pistons and other elements.

[043] The terms “proximal” and “distal” are used in the present invention as relative positions along the longitudinal axis. “Distal” means more Petition 870250111136, dated 03 / 12 / 2025, page 19 / 56 9 / 26 near the end of the tool that is configured to interact with another object, for example, to be inserted into a pipe hanger and manipulate an object, such as a plug, while “proximal” means closer to the other, opposite end of the tool along the longitudinal axis. When a part is moved distally, it means that it moves along the longitudinal axis in a proximal-to-distal direction, and when a part is moved proximally, it means that it moves along the longitudinal axis in a distal-to-proximal direction.

[044] The rod can have a retracted position (most proximal position), an extended position (most distal position), and an intermediate position, between the retracted and extended positions. The roller assembly can be configured to move the rod between the retracted and intermediate positions, and the hydraulic piston assembly can be configured to move the rod between the intermediate and extended positions.

[045] A part (i.e., a roller assembly or a hydraulic piston assembly) configured to move the rod between two positions means that the part can move the rod from one position to another, but the part can also, conversely, move the rod from the other position to the original position.

[046] The action of moving the rod from the retracted position to the extended position, moving the rod first from the retracted position to the intermediate position and then moving the rod from the intermediate position to the extended position, is referred to as a stroke.

[047] The roller assembly is preferably configured to perform most of the stroke, since the distance between the retracted position and the intermediate position is preferably greater than the distance between the intermediate position and the extended position. More generally, the roller assembly is preferably configured to move the rod along a distance Petition 870250111136, dated 03 / 12 / 2025, page 20 / 56 10 / 26 larger than the hydraulic piston assembly.

[048] Preferably, taking as a reference, for example, one end of the rod, the distance between the retracted position and the intermediate position can be 1 m 10 m, preferably 2 m 8 m; and the distance between the intermediate position and the extended position can be 0.3 m 1 m.

[049] The hydraulic piston assembly can be configured to move the rod between the intermediate and extended positions. For this, the hydraulic piston assembly needs to exert high forces. Thus, preferably, during the stroke, the final stroke is performed by the hydraulic piston assembly which can provide a higher load than the roller assembly. This higher load may be necessary, for example, to loosen or place a plug in a pipe hanger, as will be further explained below.

[050] The underwater course tool may additionally comprise a connecting element affixed to the distal end of the rod.

[051] The connecting element makes it possible to connect the rod to an end tool. This end tool can engage with and manipulate an external object, such as a plug.

[052] The end tool may comprise locking pins and a spring. Specifically, the end tool may be configured to set or remove a plug in the pipe hanger of a subsea well.

[053] A pipe hanger is a device installed on a Christmas tree (Xmas tree or XT) or wellhead that suspends piping and / or casing. The pipe hanger is configured to seal the production or injection piping, so as to stop the flow. Petition 870250111136, dated 03 / 12 / 2025, page 21 / 56 1 1 / 26 of fluid (usually oil or gas) inside the well. The tubing hanger is generally located inside or under the well's Christmas tree. The Christmas tree is an assembly of valves, casing spools, and fittings used to regulate fluid flow in the well. The Christmas tree can be a VXT or an HXT. The plug mentioned above is a component that can be placed inside the tubing hanger to provide a barrier during well completion or maintenance.

[054] An example of a subsea stroke tool according to the invention is shown in Figures 2A and 2B. In this example, the housing 200 of the subsea stroke tool 100 contains the hydraulic piston assembly 203 as well as the roller assembly 202. The roller assembly 202 may be located distally relative to the hydraulic piston assembly 203. The rod 201 is partially inside the housing 200 and partially outside the housing 200. The extent to which the rod 201 projects out of the housing 200 depends on whether it is in the retracted, intermediate, or extended position (or in any other position between these positions). The connecting element 204 at the distal end of the rod 201 comprises a fastener for attaching to an end tool (not shown). This fastener may be, for example, a threaded member or a threaded hole. In FIG. 2A, rod 201 of the underwater travel tool 100 is in the intermediate position and, in FIG.Figure 2B is in the retracted position. The roller assembly 202 makes it possible for the rod to transition from the retracted position to the intermediate position or vice versa. Rod 201 projects further out of housing 200 during this transition. The extended position of rod 201 is not shown in Figures 2A or 2B.

[055] The underwater course tool may also include a Petition 870250111136, dated 03 / 12 / 2025, page 22 / 56 12 / 26 fluid circulation hose, which can run along the longitudinal axis of the tool, for example, to or beyond the distal end of the housing, for example, externally to the housing. The circulation fluid hose can be configured to supply circulation fluid, such as methanol, to the restoration area of ​​the subsea stroke tool. Roller assembly

[056] The roller assembly comprises a plurality of rollers, for example, 2, 3, 4, 5, 6, 7, 8, 9 or more than 10 rollers. The rollers are configured to engage with the rod so as to move the rod along the longitudinal axis (for example, between the retracted position and the intermediate position) when rotated.

[057] The rollers are replaceable. They can be of any diameter to fit any diameter of rod used.

[058] An example of the roller assembly is disclosed in more detail by referring to FIG. 4. It may comprise two or more rollers aligned longitudinally. It may also comprise a first group of one or more rollers and a second group of one or more rollers, the two groups engaging the rod at different circumferential positions around the longitudinal axis of the rod. The roller assembly 202 may comprise circulation channels 401 configured to allow fluid to circulate through them. The circulation channels 401 may allow the circulation of fluids (such as methanol or seawater) to bypass the rollers.

[059] The roller assembly 202 may additionally comprise a rotating ROV interface 402. The rotating ROV interface 402 is configured so that an ROV connects to and drives the roller assembly 402, in order to move the rod along the longitudinal axis.

[060] The circulating fluid hose (optional) 307 is also visible. Petition 870250111136, dated 03 / 12 / 2025, page 23 / 56 13 / 26 in FIG. 4. Hydraulic piston assembly

[061] The hydraulic piston assembly may comprise a chamber within the housing. Hydraulic fluid may be fed into or withdrawn from the chamber in order to regulate hydraulic pressure. The hydraulic piston assembly may comprise a hydraulic piston that slides within the chamber. When the rod is in the retracted position, the hydraulic piston may be outside the chamber, proximal to the chamber. When the rod is in the intermediate or extended position, the hydraulic piston may be wholly or partially inside the chamber. The chamber may comprise two or more portions along the longitudinal axis having different cross-sectional areas (internal). Similarly, the hydraulic piston may comprise two or more portions along the longitudinal axis having different cross-sectional areas (external). All cross-sectional areas, as defined in the present invention, are orthogonal to the longitudinal axis.

[062] For example, the hydraulic piston may comprise at least one distal portion closer to the rod and a proximal portion further from the rod. The distal portion may have a smaller cross-sectional area than the proximal portion. Similarly, the chamber may comprise at least one distal portion and one proximal portion, and the distal portion may have a smaller cross-sectional area than the proximal portion. Preferably, the hydraulic piston may comprise an intermediate portion between the distal and proximal portions. In this case, the intermediate portion may have a smaller cross-sectional area than the proximal portion and a larger cross-sectional area than the distal portion. Similarly, the chamber may comprise an intermediate portion between the distal and proximal portions, and the intermediate portion may have a smaller cross-sectional area than the proximal portion. Petition 870250111136, dated 03 / 12 / 2025, page 24 / 56 14 / 26 proximal and a larger cross-sectional area than the distal portion.

[063] The hydraulic piston may comprise another part located proximal to the proximal portion, and having an even larger cross-sectional area: this is the piston centralizer mentioned elsewhere. Similarly, the chamber may comprise another space located proximal to the proximal portion, and having an even larger cross-sectional area.

[064] In this case, the cross-sectional area of ​​the portions (both of the hydraulic piston and of the chamber) decreases, preferably, gradually from the proximal direction to the distal direction.

[065] The hydraulic piston may have a distal end and a proximal end, the distal end of the hydraulic piston being attached to the proximal end of the rod.

[066] The hydraulic piston assembly may also comprise at least one seal fixed to the periphery of the hydraulic piston. When the hydraulic position is in the chamber, each seal on the periphery of the hydraulic piston may define two zones on each side of it, along the longitudinal axis, within the chamber. The respective zones on each side of a seal may be fluidically isolated, so that a hydraulic pressure differential between the zones may be applied, so as to displace the hydraulic piston.

[067] The hydraulic piston assembly may also comprise at least one hydraulic port, configured to supply hydraulic fluid to the chamber (or withdraw hydraulic fluid from the chamber). The hydraulic piston may be configured to be actuated by the hydraulic pressure supplied by the hydraulic fluid entering the chamber from at least one hydraulic port. The hydraulic piston assembly may comprise a plurality of hydraulic ports in different positions along the longitudinal axis. One or more Petition 870250111136, dated 03 / 12 / 2025, page 25 / 56 15 / 26 hydraulic ports can be configured to apply hydraulic pressure to move the hydraulic piston distally, for example, from the intermediate position to the extended position. One or more hydraulic ports can be configured to apply hydraulic pressure to move the hydraulic piston proximally, for example, from the extended position to the intermediate position. In some cases, the same hydraulic port can be used to move the hydraulic fluid in both directions.

[068] The hydraulic piston may comprise a blind orifice extending along the longitudinal axis from its proximal end.

[069] An example of the hydraulic piston assembly is disclosed in more detail by referring to FIGS. 3A / 3B / 3C / 3D. The hydraulic piston assembly 203 of the subsea stroke tool is shown when the rod 201 is in the intermediate position in FIGS. 3A / 3B. The hydraulic piston assembly 203 comprises a hydraulic piston 301 configured to slide through the chamber 300. The hydraulic piston 301 may comprise a piston centralizer 306 at its proximal end. Between the piston centering device 306 and the point where the rod 201 is attached to the hydraulic piston 301, the hydraulic piston 301 may successively comprise, in the proximal to distal direction: a proximal portion 311, an intermediate portion 312, and a distal portion 313. The cross-sectional (external) area of ​​the hydraulic piston 301 gradually decreases from the proximal portion 311 to the intermediate portion 312 and then to the distal portion 313.

[070] The chamber 300 may similarly comprise a proximal portion 314, an intermediate portion 315 and a distal portion 316. The cross-sectional (internal) area of ​​the chamber 300 gradually decreases from the proximal portion 314, to the intermediate portion 315 and then to the distal portion 316. Petition 870250111136, dated 03 / 12 / 2025, page 26 / 56 16 / 26

[071] In the intermediate position, as illustrated in FIGS. 3A / 3B, the proximal portion 311 of the hydraulic piston 301 may be substantially or totally outside the chamber 300, the intermediate portion 312 of the hydraulic piston 301 may be substantially or totally in the proximal portion 314 of the chamber 300, and the distal portion 313 of the hydraulic piston 301 may be substantially or totally in the intermediate portion 315 of the chamber 300.

[072] In the extended position, the proximal portion 311 of the hydraulic piston 301 may be substantially or totally in the proximal portion 314 of the chamber 300, the intermediate portion 312 of the hydraulic piston 301 may be substantially or totally in the intermediate portion 315 of the chamber 300, and the distal portion 313 of the hydraulic piston 301 may be substantially or totally in the distal portion 316 of the chamber 300.

[073] In the example illustrated, a first seal 308 may be provided on the periphery of the proximal portion 311 of the hydraulic piston 301, preferably at or near the distal end of this portion; a second seal 309 may be provided on the periphery of the intermediate portion 312 of the hydraulic piston 301, preferably at or near the distal end of this portion; and a third seal 310 may be provided on the periphery of the distal portion 313 of the hydraulic piston 301, preferably at or near the distal end of this portion.

[074] Preferably, each seal engages with chamber 300 in order to fluidically isolate the respective zones on both sides of the seal and thus apply a hydraulic pressure differential across the seal (at least when the rod is in the intermediate position, in the extended position or in any position between these).

[075] In the example illustrated, a first hydraulic port 305 can be provided proximally in relation to the proximal portion 314 of chamber 300; a Petition 870250111136, dated 03 / 12 / 2025, page 27 / 56 17 / 26 A second hydraulic port 304 may be provided in the proximal portion 314 of chamber 300 (preferably near its distal end); a third hydraulic port 303 may be provided in the intermediate portion 315 of chamber 300 (preferably near its distal end); and a fourth hydraulic port 302 may be provided in the distal portion 316 of chamber 300 (preferably near its distal end).

[076] In order to move the hydraulic piston 301 distally, starting from the intermediate position illustrated in FIGS. 3A / 3B, it is possible to supply hydraulic fluid via the first hydraulic port 305 and withdraw hydraulic fluid via one or more of the other hydraulic ports. Alternatively, it is possible to supply hydraulic fluid via the second hydraulic port 304 and withdraw hydraulic fluid via the third hydraulic port 303 and / or the fourth hydraulic port 302. The second hydraulic port 304 can thus function as a backup for the first hydraulic port 305. It is also possible to supply hydraulic fluid via both the first hydraulic port 305 and the second hydraulic port 304, and withdraw hydraulic fluid via the third hydraulic port 303 and / or the fourth hydraulic port 302.

[077] In order to move the hydraulic piston 301 proximally, from the extended position to transition to the intermediate position illustrated in FIGS. 3A / 3B, it is possible to supply hydraulic fluid via the third hydraulic port 303 and withdraw hydraulic fluid via the second hydraulic port 304 and / or the first hydraulic port 305. Alternatively, it is possible to supply hydraulic fluid via the second hydraulic port 304 and withdraw hydraulic fluid via the first hydraulic port 305. The second hydraulic port 304 can thus function as a backup for the third hydraulic port 303. It is also possible to supply hydraulic fluid via the third hydraulic port 303 and the second hydraulic port 304, and withdraw hydraulic fluid via the first hydraulic port 305.

[078] In each case, the hydraulic piston 301 can be made to move Petition 870250111136, dated 03 / 12 / 2025, page 28 / 56 18 / 26 along the longitudinal axis, applying a hydraulic pressure differential through the first seal 308 and / or the second seal 309.

[079] The third seal 310 can provide a pumping area if hydraulic pressure is applied distally to it. The third seal 310 also provides a sealing point for the second seal 309 to push proximally when hydraulic fluid is injected via the third hydraulic port 303.

[080] The piston centering device 306 may include a blind hole to collect any debris and prevent interference with the operation of the hydraulic piston 301. The circulating fluid hose 307 mentioned above is also visible in FIGS. 3A / 3C / 3D.

[081] FIGS. 6A / 6B also show, more schematically, the hydraulic piston 301 inside the chamber 300, in the intermediate position (FIG. 6A) and in the extended position (FIG. 6B). In these two drawings, part of the proximal portion 311 of the hydraulic piston, as well as the piston centering device, are not depicted.

[082] Another example of a hydraulic piston assembly is disclosed in more detail by referring to FIGS. 7A / 7B / 7C / 7D.

[083] As in the case of FIGS. 3A / 3B / 3C / 3D, the underwater stroke tool comprises a housing 200, a hydraulic piston assembly 203, a rod 201 and a set of rollers 202 engaged with the rod 201, the hydraulic piston assembly 203 comprises a hydraulic piston 301 configured to slide through a wear sleeve 300'. However, unlike the case of the chamber in FIGS. 3A / 3B / 3C / 3D, the wear sleeve 300' does not comprise several portions of different internal cross-sections. Instead, the wear sleeve 300' may have a relatively constant cross-section along the longitudinal axis. The rod 201 may slide within the hydraulic piston 301 (therefore, it is not permanently fixed to the Petition 870250111136, dated 03 / 12 / 2025, page 29 / 56 19 / 26 hydraulic piston 301).

[084] The rod 201 may have a proximal shoulder 701 at its proximal end, and the hydraulic piston 301 may comprise a plurality of load segments 702, such as 2 to 16 load segments, preferably 4 to 10 load segments, for example, 6 load segments. The load segments 702 may be arranged circumferentially around the longitudinal axis, in a position along the longitudinal axis. The load segments 702 may be radially movable between a locked and an unlocked position. In the unlocked position, the load segments 702 are radially collapsed outwards, while in the locked position, they extend radially inwards, within the internal space through which the rod 201 is able to slide. The load segments 702 are configured to cooperate with the shoulder 701 of the rod 201 when in the locked position.

[085] FIG. 7A shows rod 201 in the retracted position. In this position, the shoulder is proximal to the load segments 702. The hydraulic piston 301 lies inside the wear sleeve 300'.

[086] FIG. 7B shows rod 201 in the intermediate position. Hydraulic piston 301 is still in the same position as in FIG. 7A. Shoulder 701 is positioned slightly distally in relation to load segments 702. The detail in FIG. 7B shows load segments 702 in the unlocked position. As described elsewhere, rod 201 transitions from the retracted position to the intermediate position due to the roller assembly 202.

[087] FIG. 7C and the detail thereof show the hydraulic piston 301 with the load segments in the locked position, the hydraulic piston 301 having moved slightly distally so that it engages with the shoulder 701 of the rod 201 via the load segments 701. The tool is then ready to Petition 870250111136, dated 03 / 12 / 2025, page 30 / 56 20 / 26 transition rod 201 from the intermediate position to the extended position by moving hydraulic piston 301 further distally and thus pushing rod 201.

[088] FIG. 7D shows rod 201 in the extended position.

[089] In the illustrated example, a first hydraulic port (proximal) 703 and a second hydraulic port (distal) 704 may be provided in the wear sleeve 300'. The hydraulic piston 301 may have a seal on its periphery, located between the first hydraulic port 703 and the second hydraulic port 704, and engaging with the inner wall of the wear sleeve 300' so as to fluidically isolate the respective zones on either side of the seal within the wear sleeve 300' and thus apply a hydraulic pressure differential across the seal.

[090] In order to move the hydraulic piston 301 distally, starting from the intermediate position illustrated in FIGS. 7B / 7C, it is possible to supply hydraulic fluid via the first hydraulic port 703 and / or remove hydraulic fluid via the second hydraulic port 703.

[091] In order to move the hydraulic piston 301 proximally, starting from the extended position illustrated in FIG. 7D, it is possible to supply hydraulic fluid via the second hydraulic port 704 and / or remove hydraulic fluid via the first hydraulic port 703.

[092] In each case, the hydraulic piston 301 can be made to move along the longitudinal axis by applying a hydraulic pressure differential to the wear sleeve 300' through the seal of the hydraulic piston 301.

[093] The load segments must be in the unlocked position when rod 201 moves proximally to the retracted position so that rod 201 can slide proximally within hydraulic piston 301,

[094] In all the above configurations, the hydraulic piston assembly Petition 870250111136, dated 03 / 12 / 2025, page 31 / 56 21 / 26 can be configured to be triggered by an ROV.

[095] In this case, the hydraulic piston assembly preferably additionally comprises an ROV interface. The ROV interface may enable the connection of the ROV to the hydraulic piston assembly. The ROV may comprise a hydraulic fluid circuit, which may be fluidically connected to one or more hydraulic ports of the hydraulic piston assembly. As a result, the ROV may supply hydraulic fluid to the chamber and / or withdraw hydraulic fluid from the chamber via one or more of these hydraulic ports, as described above.

[096] The ROV interface may comprise one or more hot stab receptacles, each of which may include one or more ports, for example, 1, 2 or 4 ports. Once the ROV is connected to the ROV interface, hydraulic fluid may be applied to each port individually to operate the tool in the desired sequence.

[097] The ROV can also operate the payload segments, if present, from the unlocked position to the locked position and vice versa. Integration of the subsea course tool into a well control package.

[098] The subsea course tool can be integrated into a well control package to be placed on top of a subsea tree. Referring to FIG. 1A and FIG. 1B, the subsea course tool 100 is integrated into a well control package (WCP) 104 placed on top of a subsea tree 103. A connector 102 connects the subsea course tool 100 within the well control package 104 placed on top of the subsea Christmas tree 103 via an XTAC (Christmas Tree Adapter Connector) 105.

[099] An example of the well control package is presented in more detail by referring to FIG. 5. The subsea course tool 100 is Petition 870250111136, dated 03 / 12 / 2025, page 32 / 56 22 / 26 integrated into well control package 104 via connector 102. Well control package 104 is placed on top of subsea Christmas tree 103. The subsea course tool is configured to extend into wellhead 503. Method for operating

[100] Another object of the present invention is a method for operating the underwater stroke tool. The method comprises a step of moving the rod along the longitudinal axis, actuating the roller assembly, and a step of moving the rod along the longitudinal axis, actuating the hydraulic piston assembly. The method may comprise, firstly, the step of moving the rod along the longitudinal axis, actuating the roller assembly, and then the step of moving the rod along the longitudinal axis, actuating the hydraulic piston assembly, or, firstly, the step of moving the rod along the longitudinal axis, actuating the hydraulic piston assembly, and then the step of moving the rod along the longitudinal axis, actuating the roller assembly.

[101] The method may comprise a step of moving the rod distally along the longitudinal axis, actuating the roller assembly, followed by a step of moving the rod distally along the longitudinal axis, actuating the hydraulic piston assembly. In such a case, the subsea stroke tool rod may extend out of the tool housing when the rod reaches its extended position. In such a case, the method may be used in a process of connecting an object. The method may also be used in a process of setting an object in another device. For example, the method may be used to reach the interior of a pipe hanger in a wellhead. The method may therefore be used to set a plug previously connected to the rod (via the Petition 870250111136, dated 03 / 12 / 2025, page 33 / 56 23 / 26 end tool) inside the pipe hanger of a subsea tree.

[102] The method may comprise a step of moving the rod proximally along the longitudinal axis, actuating the hydraulic piston assembly, followed by a step of moving the rod proximally along the longitudinal axis, actuating the roller assembly. In such a case, the subsea stroke tool rod may retract into the subsea stroke tool housing when the rod reaches its retracted position. In such a case, the method may be used in a process of connecting an object. The method may also be used in a process of retrieving an object in another device. For example, the method may be used to retrieve an object, such as a plug, in a pipe hanger on a wellhead.

[103] The method can be used to set a plug in a pipe hanger of a wellhead. In this case, the method may first comprise connecting the plug to the end tool affixed to the distal end of the rod. The plug may be fixed to the end tool so that it moves longitudinally along with the rod. The method may further comprise placing the plug in the desired position in the pipe hanger, moving the rod distally along the longitudinal axis, actuating the roller assembly (e.g., from the retracted position to the intermediate position), followed by moving the rod distally along the longitudinal axis, actuating the hydraulic piston assembly (e.g., from the intermediate position to the extended position).Finally, the method may involve releasing the end tool cap and removing the underwater stroke tool, moving the rod proximally along the longitudinal axis, actuating the assembly. Petition 870250111136, dated 03 / 12 / 2025, page 34 / 56 24 / 26 hydraulic piston (e.g., from the extended position to the intermediate position), followed by moving the rod proximally along the longitudinal axis, actuating the roller assembly (e.g., from the intermediate position to the retracted position). For the end tool to lock onto the plug in a releasable manner, the end tool may comprise locking pins and a spring, such that, depending on the force exerted longitudinally by said end tool when engaged with the plug, the locking pins may expand or retract, thus ensuring that the end tool locks onto the plug or is free to be separated from the plug.

[104] The method can be used to retrieve a plug in a pipe hanger of a wellhead. In this case, the method may first comprise placing the rod in the desired position in the pipe hanger, moving the rod distally along the longitudinal axis, actuating the roller assembly (e.g., from the retracted position to the intermediate position), followed by moving the rod distally along the longitudinal axis, actuating the hydraulic piston assembly (e.g., from the intermediate position to the extended position). The method may further comprise connecting the end tool affixed to the distal end of the rod to the plug (e.g., by exerting an appropriate force in the longitudinal direction).The method may further comprise removing the underwater stroke tool with the plug connected thereto, moving the rod proximally along the longitudinal axis, actuating the hydraulic piston assembly (e.g., from the extended position to the intermediate position), followed by moving the rod proximally along the longitudinal axis, actuating the roller assembly (e.g., from the intermediate position to the retracted position). Petition 870250111136, dated 03 / 12 / 2025, page 35 / 56 25 / 26

[105] FIG. 1A shows a subsea stroke tool 100, in which the subsea stroke tool rod 100 is in the extended position. The subsea stroke tool rod 100 is connected to a wire plug 101 inside the pipe hanger of a subsea Christmas tree 103. In this case, the subsea stroke tool rod 100 can release the wire plug 101 inside the pipe hanger of the subsea Christmas tree 103 or additionally retrieve the wire plug 101 from the pipe hanger of the subsea Christmas tree 103.

[106] FIG. 1B shows the underwater travel tool 100, in which the underwater travel tool rod 100 is in the retracted position. The wire plug 101 has been retrieved from the underwater Christmas tree 103, while it is still connected to the underwater travel tool rod 100.

[107] Each step of moving the rod can be done by actuating the subsea stroke tool with an ROV. The ROV can connect successively or alternately to the ROV interface of the roller assembly and the ROV interface of the hydraulic piston assembly, so as to actuate the roller assembly and the hydraulic piston assembly, respectively. As shown in FIG. 5, the ROV may, in particular, comprise a hydraulic skid 504 that can be connected to one or more hydraulic ports of the hydraulic piston assembly via one or more hydraulic hoses 501. The hydraulic skid 504 may include a pump and fluid to actuate the pistons via the hot stab receptacles. The ROV may also comprise a torque tool to rotate the roller starter unit. By alternating between the torque tool and the hot stabs, the correct operating sequence can be achieved.

[108] The method may further comprise injecting fluid (e.g., via the fluid circulation hose described above) before actuating the rod, especially around the stroke tool and spindle. By Petition 870250111136, dated 03 / 12 / 2025, page 36 / 56 26 / 26 For example, this step can be used to clean any material that may be inside the pipe hanger, such as mud or debris, as well as to displace water. Fluid injection can prevent the formation of hydrates and thus facilitate the recovery or installation of a plug.

[109] In other examples, a method for operating the subsea stroke tool may comprise a step of moving the rod along the longitudinal axis, actuating the roller assembly, and may not comprise any step of moving the rod along the longitudinal axis, actuating the hydraulic piston assembly. This may be useful in situations where a high load is not required during the stroke. Such a method may be, for example, a milling method, a hydrate removal method, or a method of setting bridge plugs below the pipe hanger. Petition 870250111136, dated 03 / 12 / 2025, page 37 / 56

Claims

1 / 5 CLAIMS 1. Subsea stroke tool (100) having a longitudinal axis characterized in that it comprises: - a housing (200); - a hydraulic piston assembly (203); - a rod (201) having a proximal end and a distal end, at least partially arranged within the housing (200) and movable along the longitudinal axis relative to the housing (200); - a set of rollers (202) engaged with the rod (201); wherein both the roller assembly (202) and the hydraulic piston assembly (203) are configured to move the rod (201) along the longitudinal axis.

2. Subsea stroke tool (100), according to claim 1, characterized in that the rod (201) has a retracted position, an extended position and an intermediate position between the retracted position and the extended position, and in that the roller assembly (202) is configured to move the rod (201) between the retracted position and the intermediate position, and the hydraulic piston assembly (203) is configured to move the rod (201) between the intermediate position and the extended position.

3. Submarine course tool (100), according to claim 1 or 2, characterized in that the roller assembly (202) is configured to be actuated by an ROV.

4. Subsea travel tool (100), according to any one of claims 1 to 3, characterized in that the hydraulic piston assembly (203) is configured to be actuated by an ROV.

5. Subsea stroke tool (100), according to any one of claims 1 to 4, characterized in that the hydraulic piston assembly (203) comprises: - a chamber (300) in the housing (200); - a hydraulic piston (301) having a distal end affixed to the proximal end of the rod (201) and a proximal end, the hydraulic piston (301) being sliding through the chamber (300) along the longitudinal axis; - at least one seal (308, 309, 310) on the periphery of the hydraulic piston (301); and - at least one hydraulic port (302, 303, 304, 305), configured to supply hydraulic fluid to the chamber (300).

6. Submarine stroke tool (100), according to any one of claims 1 to 4, characterized in that the rod (201) is sliding within the hydraulic piston (301).

7. Subsea stroke tool (100), according to claim 6, characterized in that the rod (201) comprises a proximal shoulder (701) and the hydraulic piston (301) comprises a plurality of load segments (702) having a locked position and an unlocked position, the rod (201) and hydraulic piston (301) being configured such that the load segments (702) can engage with the proximal shoulder (701) when the load segments (702) are in the locked position, and the rod (201) can slide freely within the hydraulic piston (301) when the load segments (702) are in the unlocked position.

8. Subsea travel tool (100), according to any one of claims 1 to 7, characterized in that it further comprises a connecting element (204) affixed to the distal end of the rod (201); wherein, preferably, the subsea travel tool (100) further comprises an end tool affixed to the connecting element (204), said end tool more preferably being configured to establish or retrieve a plug (101) within a pipe hanger of a subsea well.

9. Well control package (104), characterized in that it is configured to be placed on top of a subsea tree (103), comprising the subsea course tool (100), defined in any one of claims 1 to 8.

10. Method for operating the subsea stroke tool (100), defined in any one of claims 1 to 8, characterized in that it comprises a step of moving the rod (201) along the longitudinal axis, actuating the roller assembly (202), and a step of moving the rod (201) along the longitudinal axis, actuating the hydraulic piston assembly (203).

11. Method according to claim 10, characterized in that it comprises a step of moving the rod (201) distally along the longitudinal axis, actuating the roller assembly (202), followed by a step of moving the rod (201) distally along the longitudinal axis, actuating the hydraulic piston assembly (203).

12. Method according to claim 10 or 11, characterized in that it comprises a step of moving the rod (201) proximally along the longitudinal axis, actuating the hydraulic piston assembly (203), followed by a step of moving the rod (201) proximally along the longitudinal axis, actuating the roller assembly (202).

13. Method, according to any one of claims 10 to 12, for establishing a plug (101) in a pipe hanger of a subsea well, characterized in that it comprises successively: - connecting the plug (101) to an end tool affixed to the distal end of the rod (201); Petition 870250111136, dated 03 / 12 / 2025, p.40 / 56 4 / 5 - Place the plug (101) in a desired position on the pipe hanger by moving the rod (201) distally along the longitudinal axis, actuating the roller assembly (202), then moving the rod (201) distally along the longitudinal axis, actuating the hydraulic piston assembly (203) to set the plug (101) in a desired position; - Release the plug (101) from the end tool and remove the subsea stroke tool (100), moving the rod (201) proximally along the longitudinal axis, actuating the hydraulic piston assembly (203), then moving the rod (201) proximally along the longitudinal axis, actuating the roller assembly (202).

14. Method, according to any one of claims 10 to 12, for retrieving a plug (101) in a pipe hanger of a subsea well, characterized in that it comprises successively: - moving the rod (201) distally along the longitudinal axis, actuating the roller assembly (202), then moving the rod (201) distally along the longitudinal axis, actuating the hydraulic piston assembly (203); - connecting an end tool affixed to the distal end of the rod (201) to the plug (101) inside the pipe hanger; - removing the subsea stroke tool (100), together with the plug (101), moving the rod (201) proximally along the longitudinal axis, actuating the hydraulic piston assembly (203), then moving the rod (201) proximally along the longitudinal axis, actuating the roller assembly (202).

15. Method according to claim 13 or 14, characterized in that it further comprises injecting fluid before moving the rod (201). Petition 870250111136, dated 03 / 12 / 2025, page 41 / 56 5 / 5 16. Product, process, system, kit, means or use, characterized in that it comprises one or more elements described in the descriptive report, claims, drawings, sequence listing, or summary of this application, when applicable. Petition 870250111136, dated 03 / 12 / 2025, pp. 42 / 56

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