Device for closing an open end of a subsea pipe and method of using the same

Abstract

The present disclosure relates to a device 1 for closing an open end of a subsea pipe having a radially protruding edge at the open end and to a method of closing an open end of a subsea pipe 10. The device 1 and method of the present disclosure allow efficient sealing of potentially pressurized subsea pipes 10. Unlocking insights from Geo-Data, the present invention further relates to improvements in sustainability and environmental developments: together we create a safe and liveable world.

Description

DEVICE FOR CLOSING AN OPEN END OF A SUBSEA PIPE AND METHOD OF USING THE SAMEFIELD OF THE INVENTION

[0001] The present disclosure generally relates to the field of subsea operations, and more specifically to a device for closing an open end of a subsea pipe having a radially protruding edge at the open end, and to a method of closing an open end of a subsea pipe. Unlocking insights from Geo-Data, the present invention further relates to improvements in sustainability and environmental developments: together we create a safe and liveable world.BACKGROUND OF THE INVENTION

[0002] There is a general and ongoing need to improve the efficiency and quality of subsea operations. Subsea operations become an increasingly important part to the energy transition. However, these operations also face an increase demand on efficiency and safety, leading to a wish for faster operations without the need for human intervention.

[0003] There is a specific need to improve the efficiency and quality of sealing subsea piping. In various cases, subsea piping needs to be terminated, for example when a section of a subsea field is abandoned and / or decommissioned. In such cases, certain pipes which link to the rest of a potentially operational field need to be isolated. These pipes can be pressurized, increasing the difficulty in providing a reliable seal. This is particularly challenging when the subsea piping is pressurized. The application of a terminating flange to an open end of a subsea pipe can be a challenging and often dangerous procedure. In addition, providing a system that can adequately seal a piping system, especially when pressurized has been an ongoing challenge.

[0004] Conventional approaches to terminating subsea piping is done through the provision of a flange which is bolted to the open end of a subsea pipe using a plurality of bolts extending through apertures in both the flange and a radially protruding edge extending from the subsea pipe. The bolts are provided around the periphery and can often amount to ten, or even more, bolts.

[0005] These bolts must be tightened in a specific pattern to ensure a uniform application of force of the sealing flange to the open end of the subsea pipe. If the bolts are not adequatelytightened, or if they are tightened in the wrong order, the flange will not seal the pipe properly, causing, e.g., leakage of hazardous material.

[0006] Attempts to address these problems have seen remote operations be introduced, for example using remotely operated vehicles (RO Vs) to apply the flange to the open end of the subsea pipe. However, these ROVs still have to tighten several bolts and may require intervention from divers or multiple other ROVs. These attempts have not provided a solution to safely and efficiently sealing open ends of subsea piping, particularly of pressurized subsea piping.

[0007] There is thus a need for an improved device and method for closing the open end of a subsea pipe. This disclosure aims to solve at least one of the abovementioned problems associated with sealing subsea piping.BRIEF SUMMARY OF THE INVENTION

[0008] In one aspect of the disclosure there is provided a device for closing an open end of a subsea pipe. In an advantageous implementation, the subsea pipe has a radially protruding edge at the open end. The device comprises a pressure plate comprising an engagement side, arranged to engage with the open end of the subsea pipe, and a rear side.

[0009] The device further comprises a torque connector, arranged to engage with a torque tool. The device further comprises a lead screw comprising a threaded section extending between a distal and a proximal end, the distal end being connected to the rear side of the pressure plate, the lead screw longitudinally extending away from the rear side of the pressure plate towards and extending into the torque connector such that a torque can be applied to the proximal end of the lead screw when the torque tool is engaged with the torque connector.

[0010] Further, the device comprises a drive unit provided between the pressure plate and the torque connector and engaging with the threaded section of the lead screw, such that rotation of the lead screw results in movement of the drive unit along the lead screw in relation to the pressure plate.

[0011] The device further comprises a plurality of fingers extending longitudinally from the drive unit to beyond the pressure plate, the plurality of fingers having a first connection with the drive unit, and having a second connection with the pressure plate, such that relative movement between the pressure plate and the drive unit moves the fingers such that theyengage with the radially protruding edge of the subsea pipe to press the pressure plate against the open end.

[0012] The pressure plate of the device is arranged to provide a sealing to the open end of a subsea pipe. The pressure plate is pressed against the open end of the subsea pipe through a clamping force generated by the fingers, which engage with the subsea pipe. The fingers generate a longitudinal pulling force, driving the pressure plate tightly against the open end of the subsea pipe. The pulling force exerted by the fingers is generated through the connection between the fingers and the pressure plate and the drive unit. In an implementation, as the drive unit is longitudinally moved away from the pressure plate by rotation of the lead screw, the fingers close radially inward and longitudinally towards the pressure plate. This movement is reversed as the drive unit is longitudinally moved towards the pressure plate, causing the fingers to move away from the pressure plate and open radially outward to release the radially protruding edge of the subsea pipe.

[0013] The plurality of fingers advantageously comprise an engagement surface provided at a distal end of the fingers. In an implementation, the engagement surface is directed towards the drive element such that the fingers can exert a longitudinally directed clamping force between the subsea pipe and the pressure plate such that the pressure plate is tightly pressed against the open end of the subsea pipe. The device of the present disclosure allows for easy installing of the pressure plate and providing sufficient sealing force such that pipes having internal pressure can also be sealed. Advantageously, by providing an arrangement which can be clamped using a single torque being provided to the lead screw, the risk of incorrect installment is reduced. Finally, since the device is operated through the torque connector, a single remotely operated vehicle or a single diver having a torque tool can close a pressurized subsea pipe.

[0014] Advantageously, the device of the present disclosure can withstand maximum working pressure and test pressures in accordance to API17D (API6A) or other applicable standards. In and advantageous implementation, the device of the present disclosure can withstand a pressure of 7500 psi (517 bar). In an implementation, the device is able to withstand a pressure of at least about 50 bars, advantageously of at least about 100 bars, more advantageously of at least about 200 bars, still more advantageously of at least about 400 bars.

[0015] In a preferred implementation, the subsea pipe comprises a radially protruding edge, and wherein the plurality of fingers are arranged to clamp around the radially protruding edge of the subsea pipe. Subsea piping often has a radially protruding edge at the end of a pipe section, this radially protruding edge, or pipe flange, is usually provided with a number ofapertures such that two sections of pipe can be longitudinally aligned and connected with a plurality of nuts and bolts, which are tightened to provide a seal between the two pipe segments. In an implementation, the fingers of the device are arranged to clamp over the protruding edge of subsea pipe such that a clamping force can be exerted by the fingers and the pressure plate. In other implementations, the fingers are arranged to engage with the subsea pipe in another fashion, such as magnetically, or with indentations in the pipe wall. As such, in an implementation, the relative movement between the pressure plate and the drive unit moves the fingers such that they engage with the subsea pipe to press the pressure plate against the open end.

[0016] In an implementation, the plurality of fingers are substantially equally spaced around the pressure plate and the drive unit. By providing the fingers in an equally spaced manner around the pressure plate and the drive unit, the engagement of the fingers with the protruding edge of the subsea pipe is as uniform as possible. This improves the sealing of the subsea pipe with the pressure plate since the longitudinal (i.e., pressing force) of the pressure plate to the open end of the subsea pipe is more uniformly provided.

[0017] In an implementation, the plurality of fingers comprises at least three fingers, advantageously wherein the at least three fingers are provided such that the at least three fingers are substantially equally spaced around the pressure plate and the drive unit.

[0018] Advantageously, having at least three fingers provided in an equally spaced manner. By providing three fingers, which are substantially equally spaced around the pressure plate and the drive unit, the circumference of the radially protruding edge of the subsea pipe does not have a region of at least 180 degrees over which it is not engaged by one of the fingers. As a result, it is not possible for the device to laterally move away from the open end of the subsea pipe. Having at least three fingers thus has the extra advantage that the open end of the subsea pipe is secured in relation to the device.

[0019] In an implementation, the plurality of fingers comprises at least six fingers. In a preferred implementation, the plurality of fingers comprises at least eight fingers. In an optional implementation, the plurality of fingers comprises ten fingers. An increase of fingers provides a more stable provision of pressure to the protruding edge of the subsea pipe. However, having too many fingers introduces a limitation to their dimensions, which could result in a system having limited mechanical stability.

[0020] The inventors have determined that six or eight fingers provides sturdy fingers while having sufficient engagement surfaces between the fingers and the protruding edge of the subsea pipe such that a uniform force is provided to the protruding edge. By providingequally spaced fingers, the clamping force between the pressure plate and the radially protruding edge of the open end of the subsea pipe is uniformly distributed. Additionally, providing at least six fingers reduces the area of the pressure plate and radially protruding edge of the subsea pipe which lack a clamping force. Such regions can elastically deform if no clamping force is applied. By providing at least six fingers, the space between the fingers is reduced, thereby limiting the amount of potential deformation of both the pressure plate and the radially protruding edge of the subsea pipe. As a result, the quality of the seal between the pressure plate and the open end of the subsea pipe is improved.

[0021] In an implementation, each of the plurality of fingers extends between a proximal end at the first connection with the drive unit and a distal end, the distal end comprising a radially inwardly directed curved section, arranged to clamp around the radially protruding edge of the subsea pipe.

[0022] By providing each of the plurality of fingers with a radially inwardly directed curved section, the fingers can reach around the radially protruding edge of the subsea pipe and provide a clamping force between the pressure plate and the laterally protruding edge of the subsea pipe. The inwardly directed curved section of the fingers are provided such that the fingers form a hook-shape and forming an engagement surface which is directed towards the drive element such that the fingers can exert a clamping force between the radially protruding edge and the pressure plate. In another implementation, the fingers are arranged to connect to the subsea pipe in a different manner, such as magnetically, or by engaging with indentations provided in the subsea pipe.

[0023] In an implementation, each of the first and second connections are rotational connections comprising a rotation pin, and wherein one of the first and second connections comprises a slot, such that the pin of the first or second connection can move laterally through the slot.

[0024] In an implementation, the first and second connections are rotational connections. In an advantageous implementation, one of the connections is provided with a slot such that the pin which forms one of the rotational connections can move through the slot. The slot can be provided in the fingers or in the drive unit or in the pressure plate. By providing a slot in one of the connections, the relative movement of the pressure plate and the drive unit results in lateral movement of the plurality of fingers.

[0025] In an implementation, the second connection comprises a slot such that the pin of the second connection can move laterally through the slot. In an implementation, the slot is provided in each of the plurality of fingers.

[0026] In an implementation, the slot in each of the plurality of fingers comprises an angled section, the angled section defining an angle with a centerline of the lead screw, such that movement of the pin through the slot results in a radial and longitudinal movement of the plurality of fingers.

[0027] In an implementation, the slot further comprises a longitudinal section which is parallel to the centerline of the lead screw, such that movement of the pin through the slot results solely in longitudinal movement of the plurality of fingers.

[0028] In an implementation, the proximal end of the lead screw extending into the torque connector comprises a square cross-sectional shape. Having a square cross-sectional section allows for the transfer of a torque from the torque tool to the lead screw, such that the fingers can be driven from a single operating tool.

[0029] In an implementation, the pressure plate further comprises at least one alignment pin longitudinally protruding away from the engagement side of the pressure plate, the at least one alignment pin being arranged to protrude through an aperture provided in the radially protruding edge of the subsea pipe.

[0030] By providing at least one alignment pin, the radial position of the pressure plate and the open end of the subsea pipe is fixed. In such an implementation, the radially protruding edge of the subsea pipe comprises a plurality of longitudinally extending apertures, through which the alignment pin can extend. That is, the alignment pin provides a fixed point between the radially protruding edge and the pressure plate. In an advantageous implementation, the pressure plate comprises at least two alignment pins, longitudinally protruding away from the engagement side of the pressure plate. Such an arrangement allows for a radially fixed position of the pressure plate with the open end of the subsea pipe, such that they are concentrically aligned. This advantageously allows for a fixed position of sealing elements, such as gasket seals and / or grooves in the surface of the pressure plate with the open end of the subsea pipe, leading to an improved sealing of the subsea pipe.

[0031] In an advantageous implementation, the pressure plate comprises a metal gasket ring. This metal gasket ring allows a strong seal between the device and the open end of the subsea pipe. In an implementation, the metal gasket ring is a standard seal ring for use on open ends of subsea pipes. Advantageously, the device is able to use these standard seal ring flanges, already being proven in industry, in a more efficient manner by application using the single lead screw to clamp the metal gasket ring of the pressure plate to the open end of the subsea pipe.

[0032] In an implementation, the distal end of the lead screw comprises a radially protruding edge, which is contained in the rear side of the pressure plate, such that the lead screw can exert a pulling and a pushing force to the pressure plate.

[0033] In an implementation, the device further comprises a bearing plate, provided between the rear side of the pressure plate and the lead screw. The bearing plate is arranged to provide a bearing surface for the rotation between the pressure plate and the lead screw. Advantageously, the bearing plate can be replaced as it wears out. In an advantageous implementation, the bearing plate comprises a nickel steel alloy.

[0034] In an implementation, the pressure plate comprises a passage extending from the engagement side to a test receptacle at a lateral region of the pressure plate.

[0035] The test receptacle is used to test the sealing quality of the engagement of the pressure plate with the open end of the subsea pipe. Such tests are referred to as hot stab tests. The hot stab pressure test is a procedure designed to evaluate the integrity and performance of subsea hydraulic connections. This test is performed using a device known as a hot stab, which is a tool used to pressurize the test receptacle. The design and manufacturing of hot stabs typically adhere to standards, including ISO 13628-8 and API 17H, ensuring their reliability and safety under subsea conditions.

[0036] During a hot stab pressure test, the procedure involves the application of pressure through the hot stab to the test receptacle. The passage through the pressure plate is pressurized through the test receptacle. The pressure is maintained for a set period of time, such as, for example, 15 minutes. The hot stab tool can measure whether the pressure is decreased after the set period of time, to measure whether there is a drop in pressure in the passage, indicating a leak or improper seal. This is done to verify the device’s capacity to withstand the specified pressures, a critical factor in subsea operations. The hot stabs are equipped with, for example, integrated check valves to minimize fluid spill and water ingress, and they come in various configurations with different port options to suit a wide range of requirements. The pressure ratings of these devices can reach up to 20,000 psi, with the ability to handle significant flow rates while maintaining minimal pressure drop, which leads to efficient and safe subsea operations.

[0037] The hot stab, or a similar zero leak connector is inserted into the test receptacle. A pressure is applied through the hot stab to a gasket between the pressure plate and the subsea pipe. The pressure is held for a duration to confirm no leaks are present. The pressure can be monitored throughout or can be reviewed after the test to confirm the pressure has not droppeddue to a leak. The pressure may be monitored using a gauge or a pressure transducer. Once it has been confirmed no leaks are present, the hot stab will disengage from the test receptacle.

[0038] According to an aspect of the present disclosure, there is provide a method of closing an open end of a subsea pipe having a radially protruding edge, the method comprising the steps of providing a device for closing an open end of a subsea pipe according to any of the preceding claims, providing a torque tool, attaching the torque connector of the device to the torque tool such that the lead screw connects to the torque tool, moving the torque tool and the device towards the open end of the subsea pipe, positioning the pressure plate of the device in front of the open end of the subsea pipe, providing a closing torque using the torque tool to drive the lead screw such that the plurality of fingers of the device engage with the radially protruding edge of the subsea pipe, and disengaging the torque tool from the torque connector of the device.

[0039] The connection between the torque tool and the lead screw through the torque connector may be provided indirectly. The torque tool is provided to the torque connector in such a way that it is able to transfer a rotational force, i.e., a torque to the lead screw, which extends at least partly through the torque connector.

[0040] In an implementation, the torque tool is connected to a remotely operated vehicle, further comprising the step of deploying the remotely operated vehicle to the sea after connecting the torque connector to the torque tool.

[0041] In an advantageous implementation, the device is operated using a remotely operated vehicle (ROV), which may be deployed from a surface vessel to execute subsea operations.

[0042] In an implementation, the method further comprises the steps of re-engaging the torque tool with the torque connector of the device, providing a release torque to the lead screw using the torque tool, rotating the lead screw such that the fingers disengage from the radially protruding edge of the subsea pipe, releasing the device from the open end of the subsea pipe, and retrieving the device.BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to describe the manner in which the above-recited and other advantages and features of the disclosure can be obtained, a more particular description of the principles briefly described above will be rendered by reference to specific implementations thereof which areillustrated in the appended drawings. Understanding that these drawings depict only exemplary implementations of the disclosure and are therefore not to be considered to be limiting of its scope, the principles herein are described and explained with additional specificity and detail through the use of the accompanying drawings in which:

[0044] FIG. l is a side view of an implementation of the disclosure showing the device in an open position;

[0045] FIG. 2 is a side view of an implementation of the disclosure showing the device in a closed position, and engaged with the open end of a subsea pipe;

[0046] FIG. 3 is a three-dimensional view of an implementation of the disclosure showing one of the plurality of fingers;

[0047] FIG. 4 is a three-dimensional view of an implementation of the disclosure showing the device in an open position; and

[0048] FIG. 5 is a three-dimensional cross-sectional view of an implementation of the disclosure showing the device in an open position.DESCRIPTION OF ILLUSTRATIVE IMPLEMENTATIONS

[0049] The following is a description of certain implementations of the invention, given by way of example only and with reference to the drawings.

[0050] Various implementations of the disclosure are discussed in detail below. While specific implementations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without parting from the spirit and scope of the disclosure. Thus, the following description and drawings are illustrative and are not to be construed as limiting. Numerous specific details are described to provide a thorough understanding of the disclosure. However, in certain instances, well-known or conventional details are not described in order to avoid obscuring the description. A reference to an implementation in the present disclosure can be a reference to the same implementation or any other implementation. Such references thus relate to at least one of the implementations herein.

[0051] Reference to “one implementation” or “an implementation” means that a particular feature, structure, or characteristic described in connection with the implementation is included in at least one implementation of the disclosure. The appearances of the phrase “in one implementation” in various places in the specification are not necessarily all referring to thesame implementation, nor are separate or alternative implementations mutually exclusive of other implementations. Moreover, various features are described which may be exhibited by some implementations and not by others.

[0052] The terms used in this specification generally have their ordinary meanings in the art, within the context of the disclosure, and in the specific context where each term is used. Alternative language and synonyms may be used for any one or more of the terms discussed herein, and no special significance should be placed upon whether or not a term is elaborated or discussed herein. In some cases, synonyms for certain terms are provided. A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification including examples of any terms discussed herein is illustrative only and is not intended to further limit the scope and meaning of the disclosure or of any example term. Likewise, the disclosure is not limited to various implementations given in this specification.

[0053] Without intent to limit the scope of the disclosure, examples of instruments, apparatus, methods and their related results according to the implementations of the present disclosure are given below. Note that titles or subtitles may be used in the examples for convenience of a reader, which in no way should limit the scope of the disclosure. Unless otherwise defined, technical and scientific terms used herein have the meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. In the case of conflict, the present document, including definitions will control.

[0054] Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or can be learned by practice of the herein disclosed principles. The features and advantages of the disclosure can be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the disclosure will become more fully apparent from the following description and appended claims or can be learned by the practice of the principles set forth herein.

[0055] Referring to FIG. 1, a side view of an implementation of the disclosure is shown. In the shown implementation, the device 1 is provided in an open position. The shown device 1 is arranged for closing an open end 11 of a subsea pipe 10 having a radially protruding edge 12 at the open end. The subsea pipe 10 having an open end 11 and a radially protruding edge 12 is shown in FIG. 2 of the drawings. The device 1 comprises a pressure plate 2 comprising an engagement side 21, arranged to engage with the open end of the subsea pipe, and a rear side 22. The device 1 further comprises a torque connector 4, arranged to engage with a torque tool. The device 1 further comprises a lead screw 5 comprising a threaded section 51 extendingbetween a distal end 52 and a proximal end 53, the distal end 52 being connected to the rear side 22 of the pressure plate 2, the lead screw 5 longitudinally extending away from the rear side 22 of the pressure plate 2 towards and extending into the torque connector 4 such that a torque can be applied to the proximal end 53 of the lead screw 5 when the torque tool is engaged with the torque connector 4.

[0056] The device 1 further comprises a drive unit 3, provided between the pressure plate 2 and the torque connector 4, and engaging with the threaded section 51 of the lead screw 5, such that rotation of the lead screw 5 results in movement of the drive unit 3 along the lead screw 5 in relation to the pressure plate 2. The device 1 further comprises eight fingers 6 extending longitudinally from the drive unit 3 to beyond the pressure plate 2, the plurality of fingers 6 having a first connection 61 with the drive unit 3, and having a second connection 62 with the pressure plate 2, such that relative movement between the pressure plate 2 and the drive unit 3 moves the fingers 6 such that they engage with radially protruding edge 12 of the subsea pipe 10 to press the pressure plate 2 against the open end 11.

[0057] The fingers 6 of the device 1 are spaced around the periphery of the pressure plate 2. In the shown implementation, the device 1 comprises a total of eight fingers 6. The fingers 6 define a proximal end 63 and a distal end 64. The first connection 61 between the fingers 6 and the drive unit 3 is positioned at the proximal end 63 of the fingers 6. The distal end 64 of the fingers 6 comprises a radially inwardly directed curved section 65, which is arranged to clamp around the radially protruding edge 12 of the subsea pipe 10.

[0058] In the shown implementation of FIG. 1, the device 1 is in an open position. The drive unit 3, driven by the lead screw 5, is positioned close to the pressure plate 2, which results the first connection 61 and the second connection 62 to be positioned closely together. In the shown implementation, the relative position of the first connection 61 and the second connection 62 ensure the movement of the fingers 6, causing them to open laterally and longitudinally. When the lead screw 5 is rotated by the torque tool through the torque connector 4, the rotation of the threaded section 51 of the lead screw 5 will move the drive unit 3 away from the pressure plate 2. This will cause the first connection 61 and the second connection 62 to move away from one another, which causes the fingers 6 to move inwards and downwards such that they can clamp around the radially protruding edge 12, of a subsea pipe 10, as shown in FIG. 2 of the drawings.

[0059] In the shown implementation, the first connection 61 and the second connection 62 comprises a rotation pin 66. At the first connection 61, the pin 66 extends through a section of the drive unit 3, and traverses an indentation made in the periphery of the drive unit, whichaccommodates the proximal end 63 of the fingers 6. The pin extends through the proximal end 63 of the fingers 6 to connect the fingers 6 to the drive unit 3.

[0060] The pressure plate 2 comprises a set of outwardly directed prongs 23, between which the fingers 6 are positioned. In the shown implementation, the prongs 23 are positioned in a fixed manner, relative to the pressure plate 2. The prongs 23 can either be connected to the pressure plate 2, or integrally formed with the pressure plate 2. The second connection 62 also comprises a rotation pin 66, which connects the pressure plate 2 with the fingers 6. In the shown implementation, the fingers 6 comprise an angled slot 67, through which the rotating pin 66 of the second connection 62 extends. The free movement of the rotation pin 66 through the slot results in the movement of the fingers 6 relative to the pressure plate 2 as the drive unit 3 moves relative to the pressure plate 2 through actuation of the lead screw 5.

[0061] In another implementation, the prongs 23 have a rotational coupling with the pressure plate 2, such that they can hinge at the point where they connect to the pressure plate. This would also allow the fingers 6 to move radially and longitudinally in relation to the pressure plate 2 if the drive unit 3 is moved relative to the pressure plate 2. In yet another alternative implementation, the fingers 6 comprise a slot section provided at the proximal end 63, such that the rotating pin 66 of the first connection 61 can move in the slot of the proximal end of the fingers 6. In an implementation where the second connection 62 comprises a fixed rotational connection, the movement of the rotating pin 66 of the first connection 61 would allow radial movement of the fingers 6 around the rotation pin 66 of the second connection 62 between the fingers 6 and the pressure plate 2.

[0062] In still another implementation, both the first connection 61 and the second connection 62 comprise a slotted arrangement such that a rotation pin 66 of both connections is able to move through a slot and provide relative movement of the fingers 6 in relation to both the pressure plate 2 and the drive unit 3.

[0063] In an implementation not shown in the figure, the slot 67 may be provided in the drive unit 3 and / or in the pressure plate 2. For example, the prongs 23 of the pressure plate 2 may comprise a slot through which a pin, optionally attached to the fingers 6 can freely move. The inventors have found that having at least three degrees of freedom provides the movement of the fingers 6 required to seal an open end 11 of a subsea pipe 10. In the shown implementation, these degrees of freedom are rotational movement of the rotation pins 66 in the first connection 61 and the section connection 62, and translational movement of the rotation pin 66 of the second connection 62 through the slot 67 provided in the fingers 6. It is understood that other approaches to providing these degrees of freedom are also covered in thisdisclosure. Mechanical inversions such as the ones described above are considered to be covered in this disclosure, and the shown implementation of FIG. 1 is not a limitation to the scope of this disclosure. Similarly, the prongs 23 could be rotationally coupled to the pressure plate 2, the prongs 23 could comprise a slot, similar to the slot 67 provided in the fingers 6. The drive unit 3 can comprise a slot connection similar to the shown implementation, in which the slot is either provided in the proximal end 63 of the fingers 6 or in the drive unit 3 itself.

[0064] Now referring to FIG. 2, a side view of an implementation of the disclosure is shown. The device 1 of the shown implementation of FIG. 2 shows the device in a closed position and engaged with the open end 11 of a subsea pipe 10. The device 1 arranged for closing an open end 11 of a subsea pipe 10 having a radially protruding edge 12 at the open end is shown. In relation to FIG. 1, discussed above, FIG. 2 shows the device 1 in a closed position, where the drive unit 3 is moved away from the pressure plate 2 using the lead screw 5. The distal end 52 of the lead screw 5 is connected with the pressure plate 2. In an advantageous implementation, the lead screw 5 is connected to the pressure plate 2 such that relative movement between the lead screw 5 and the pressure plate 2 in the longitudinal direction is not possible, while allowing rotational movement between the lead screw 5 and the pressure plate 2. This advantageously allows the pressure plate 2 to be rotationally fixed in relation to the open end 11 of the subsea pipe 10.

[0065] As the lead screw 5 is rotated, the drive unit 3 is moved towards the proximal end 53 of the lead screw, and away from the distal end 52 of the lead screw 5, and the pressure plate 2. As a result of increased distance between the pressure plate 2 and the drive unit 3, the fingers 6 move radially inward and longitudinally towards the drive unit 3. In the shown implementation, the slot 67 comprises an angled section 68 and a longitudinal section 69. This is shown in more detail in relation to FIG. 3 of the drawings. The first part of the movement between the drive unit 3 and the pressure plate 2 results in both longitudinal movement and lateral movement of the fingers 6 in relation to the pressure plate 2. This is the result of the angled section 68 of the slot 67. The rotation pin 66 of the second connection 62 then moves into the longitudinal section 69 of the slot of the fingers 6, which causes longitudinal movement of the fingers 6 relative to the pressure plate 2. Without radial movement. The inwardly directed curved section 65 of the fingers 6 then only longitudinally moves towards the radially protruding edge 12 of the subsea pipe 10 such that uniform pressure is provided to the edge 12, without an inwardly directed component of the force exerted by the fingers 6. This advantageously improves the engagement of the pressure plate 2 with the open end 11 of the subsea pipe 10, and as a result the quality of the seal.

[0066] The torque connector 4 of the shown implementation comprises a torque bucket 41, which is arranged to receive a torque tool from, for example, a remotely operated vehicle (ROV). Such an ROV may be deployed from a surface vessel. Such a surface vessel may be a conventional manned vessel, or it may be an uncrewed surface vessel (USV). The torque bucket 41 comprises a hollow region 42 for receiving the torque tool. Advantageously, torque bucket 41 further comprises an aperture 43. The torque tool may engage with the aperture 43 in the torque bucket 41 to prevent the torque bucket 41 to start rotating as a result of the torque applied to the lead screw 5. The device 1 further advantageously comprises at least one strut 7, arranged between the torque connector 4 and the drive unit 3. In the shown implementation, most clearly shown in FIG. 1 and FIG. 5, the device 1 comprises a plurality of struts 7. Advantageously, struts 7 extend between the torque bucket 41 and the drive unit 3. This arrangement prevents rotation between the drive unit 3 and the torque bucket 41 as a torque is provided to the lead screw 5. As will be described in more detail below, in an advantageous implementation, the at least one strut 7, advantageously the plurality of struts 7 extend from the torque connector 4 through the drive unit 3, to the pressure plate 2. This prevents rotation between any of the torque connector 4, the drive unit 3, and the pressure plate 2. Only the lead screw 5 is then able to rotate, which ensures that the longitudinal movement of the drive unit 3 along the threaded section 53 of the lead screw 5 is the only movement resulting from the actuation of the torque tool driving the lead screw 5. In an alternative implementation, the connection between the drive unit 3 and the pressure plate 2 provided by the fingers 6 is sufficient to prevent relative rotation between the drive unit 3 and the pressure plate 2. In the shown implementation, the struts 7 provide additional strength in the connection between the drive unit 3 and the pressure plate 2, in addition to that provided by the fingers 6.

[0067] Now referring to FIG. 3, a three-dimensional view of one of the plurality of fingers 6 according to an implementation of the disclosure is shown. The finger 6 defines a proximal end 63 and a distal end 64. The proximal end 63 of the shown implementation comprises an aperture 601, arranged to receive a rotation pin 66 which forms part of the first connection 61. The distal end 64 of the fingers 6 comprises a radially inwardly directed curved section 65, which is arranged to clamp around the radially protruding edge 12 of the subsea pipe 10. The inwardly directed curved section 65 comprises an engagement surface 602 which faces in the direction of the proximal end 63 of the finger 6. The engagement surface 602 is arranged to provide a longitudinally directed force to the radially protruding edge 12 of the subsea pipe 10 such that the pressure plate 2 is pressed against the open end 11 of the subsea pipe 10. Thefinger 6 further comprises an abutment surface 603, which is arranged to engage with a side surface of the radially protruding edge 12 of the subsea pipe 10.

[0068] In the shown embodiment, the finger 6 comprises a slot 67 such that the connection pin 66 of the second connection 62 can move through the slot 67. In an advantageous implementation, the connection pin 66 can move through the slot 67 at least partially in a lateral direction in relation to the lead screw 5 such that the finger 6 moves radially as the distance between the drive unit 3 and the pressure plate 2 is altered. In the shown embodiment, the slot 67 comprises an angled section 68 and a longitudinal section 69. The angled section 68 defines an angle in relation to a centerline of the lead screw 5, such that movement of the connection pin 66 moving through the slot 67 results in a radial and longitudinal movement of the finger 6. The longitudinal section 69 of the slot 67 is provided substantially parallel to the centerline of the lead screw 5. This longitudinal section 69 of the slot 67 is provided such that the movement of the connection pin 66 of the second connection 62 through the slot results solely in longitudinal movement of the finger 6 in relation to the pressure plate 2.

[0069] In the shown embodiment, the slot 67 further comprises a locking section 604, which is provided towards the proximal end 63 of the finger 6. This section is provided such that the first movement of the finger 6 when moving from the open position towards the closed position is solely longitudinal. This way, the movement of the fingers 6 as a result of the torque provided to the lead screw 5 can be tested prior to lateral movement of the fingers 6 occurring.

[0070] Now referring to FIG. 4, a three-dimensional view of the device 1 in an open position is shown according to an implementation of the disclosure. A device 1 is shown having a pressure plate 2 and a drive unit 3, which are driven by the lead screw 5, not shown. The device 1 comprise a torque connector 4 and a plurality of fingers 6. In the shown implementation, the device 1 comprises eight fingers. The pressure plate 2 of the device 1 of the shown implementation further comprises at least one alignment pin 24 which longitudinally protrudes away from the engagement side 21 of the pressure plate 2, the at least one alignment pin 24 being arranged to protrude through an aperture provided in the radially protruding edge 12 of the subsea pipe 10. In the shown implementation, the pressure plate 2 comprises two radially opposed alignment pins 24.

[0071] Now referring to FIG. 5, a three-dimensional cross-sectional view of the device 1 according to an implementation of the disclosure is shown in an open position. The shown device 1 comprises a plurality of fingers 6, a pressure plate 2 and a drive unit 3. The device 1 further comprises a lead screw 5 comprising a threaded section 51 extending between a distal end 52 and a proximal end 53, the distal end 52 being connected to the rear side 22 of thepressure plate 2, the lead screw 5 longitudinally extending away from the rear side 22 of the pressure plate 2 towards and extending into the torque connector 4 such that a torque can be applied to the proximal end 53 of the lead screw 5 when the torque tool is engaged with the torque connector 4. The torque connector 4 comprises a torque bucket 41, a hollow region 42 for receiving the torque tool, and an aperture 43 in the torque bucket 41, with which the torque tool may engage to prevent the torque bucket 41 to start rotating as a result of the torque applied to the proximal end 53 of the lead screw 5. The device 1 further comprises at least one strut 7 to connect the torque connector 4 with the drive unit 3 and the pressure plate 2.

[0072] The proximal end 53 of the lead screw 5 extending into the torque connector 4 comprises a square cross-sectional shape, making it easier to exert a torque force by the torque tool to the lead screw 5. The distal end 52 of the lead screw 5 comprises a radially protruding edge 54 which is contained in the rear side 22 of the pressure plate 2. As a result, the lead screw 5 can exert a pulling and a pushing force to the pressure plate 2, while allowing rotation between the lead screw 5 and the pressure plate 2.

[0073] Advantageously, the pressure plate 2 comprises a passage 8 extending from the engagement side to a test receptacle 81 at a lateral region of the pressure plate 2. This test receptacle 81 is used to test the quality of the seal once the device 1 is installed to the open end 11 of a subsea pipe 10.

[0074] The device of any preceding claim, wherein the distal end of the lead screw comprises a radially protruding edge, which is contained in the rear side of the pressure plate, such that the lead screw can exert a pulling and a pushing force to the pressure plate.

[0075] The invention has been described by reference to certain implementations discussed above. It will be recognized that these implementations are susceptible to various modifications and alternative forms well known to those of skill in the art.

[0076] Further modifications in addition to those described above may be made to the structures and techniques described herein without departing from the spirit and scope of the invention. Accordingly, although specific implementations have been described, these are examples only and are not limiting upon the scope of the invention.

Claims

CLAIMS1. A device for closing an open end of a subsea pipe having a radially protruding edge at the open end, the device comprising: a pressure plate comprising an engagement side, arranged to engage with the open end of the subsea pipe, and a rear side; a torque connector, arranged to engage with a torque tool; a lead screw comprising a threaded section extending between a distal and a proximal end, the distal end being connected to the rear side of the pressure plate, the lead screw longitudinally extending away from the rear side of the pressure plate towards and extending into the torque connector such that a torque can be applied to the proximal end of the lead screw when the torque tool is engaged with the torque connector; a drive unit provided between the pressure plate and the torque connector, and engaging with the threaded section of the lead screw, such that rotation of the lead screw results in movement of the drive unit along the lead screw in relation to the pressure plate; and a plurality of fingers extending longitudinally from the drive unit to beyond the pressure plate, each of the plurality of fingers having a first connection with the drive unit, and having a second connection with the pressure plate, such that relative movement between the pressure plate and the drive unit moves the fingers such that they engage with the radially protruding edge of the subsea pipe to press the pressure plate against the open end.

2. The device of any preceding claim, wherein the plurality of fingers are substantially equally spaced around the pressure plate and the drive unit.

3. The device of any preceding claim, wherein the plurality of fingers comprises at least three fingers, advantageously wherein the at least three fingers are provided such that the at least three fingers are substantially equally spaced around the pressure plate and the drive unit.

4. The device of any preceding claim, wherein the plurality of fingers comprises at least six fingers.

5. The device of any preceding claim, wherein each of the plurality of fingers extends between a proximal end at the first connection with the drive unit and a distal end, the distal end comprising a radially inwardly directed curved section, arranged to clamp around the radially protruding edge of the subsea pipe.

6. The device of any preceding claim, wherein each of the first and second connections are rotational connections comprising a rotation pin, and wherein one of the first and second connections comprises a slot, such that the pin of the first or second connection can move laterally through the slot.

7. The device of claim 6, wherein the second connection comprises a slot provided in each of the plurality of fingers such that the pin of the second connection can move laterally through the slot.

8. The device of claim 7, wherein the slot in each of the plurality of fingers comprises an angled section, the angled section defining an angle with a centerline of the lead screw, such that movement of the pin through the slot results in a radial and longitudinal movement of the plurality of fingers.

9. The device of claim 8, wherein the slot further comprises a longitudinal section which is parallel to the centerline of the lead screw, such that movement of the pin through the slot results solely in longitudinal movement of the plurality of fingers.

10. The device of any preceding claim, wherein the pressure plate further comprises at least one alignment pin longitudinally protruding away from the engagement side of the pressure plate, the at least one alignment pin being arranged to protrude through an aperture provided in the radially protruding edge of the subsea pipe.

11. The device of any preceding claim, wherein the distal end of the lead screw comprises a radially protruding edge, which is contained in the rear side of thepressure plate, such that the lead screw can exert a pulling and a pushing force to the pressure plate.

12. The device of any preceding claim, wherein the pressure plate comprises a passage extending from the engagement side to a test receptacle at a lateral region of the pressure plate.

13. Method of closing an open end of a subsea pipe having a radially protruding edge, the method comprising the steps of: a. providing a device for closing an open end of a subsea pipe according to any of the preceding claims; b. providing a torque tool; c. attaching the torque connector of the device to the torque tool such that the lead screw connects to the torque tool; d. moving the torque tool and the device towards the open end of the subsea pipe; e. positioning the pressure plate of the device in front of the open end of the subsea pipe; f. providing a closing torque using the torque tool to drive the lead screw such that the plurality of fingers of the device engage with the radially protruding edge of the subsea pipe; and g. disengaging the torque tool from the torque connector of the device.

14. The method according to claim 13, wherein the torque tool is connected to a remotely operated vehicle, the method further comprising the step of deploying the remotely operated vehicle to the sea after attaching the torque connector to the torque tool.

15. The method according to claim 13 or 14, further comprising the steps of a. re-engaging the torque tool with the torque connector of the device; b. providing a release torque to the lead screw using the torque tool; c. rotating the lead screw such that the fingers disengage from the radially protruding edge of the subsea pipe; d. releasing the device from the open end of the subsea pipe; and e. retrieving the device.

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