ELEMENTS IN A BODY OF WATER"

CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority from Italian patent application no. 102020000002776 filed on 12/02/2020, the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD The present invention relates to an apparatus and a system for joining elongated elements in a body of water.

The present invention further relates to a method for joining elongated elements by means of said apparatus.

BACKGROUND ART In the oil & gas sector, recent technological developments in underwater devices suitable for operating at great depths and the great interest of oil companies have facilitated the spread of underwater systems for the extraction, production or transport of hydrocarbons. Such underwater systems can be placed onto the bed of a body of water or at intermediate positions depending on the configuration of the well or field of wells. In addition, underwater systems can be placed in shallow or very deep waters and in all geographic areas regardless of whether the environmental conditions are easy or extreme. In the steps of installation and maintenance of underwater systems there is currently a need to join elongated elements, such as for example to join shells or cups or floats to pipes, or cables and pipes, in order to form bundles of pipes or mixed bundles of pipes (rigid or flexible) and cables.

In particular, in currently known underwater systems, some pipes, especially risers or jumpers or spools, are equipped with floating shells in order to reduce the weight of the risers or jumpers or spools, or with shells equipped with fins shaped so as to mitigate the wake turbulence and reduce the vibrations induced by these wakes on said pipes. The shells are formed by a series of facing half-shells.

According to the prior art, the joining between the shells and the pipe involves removing the pipe from the underwater system, placing the pipe above the body of water, and joining the half-shells to the pipe. This operation is costly in terms of downtime of the underwater system.

DISCLOSURE OF INVENTION One object of the present invention is to provide an apparatus for joining elongated elements, which can overcome the drawbacks of the prior art.

Therefore, according to the present invention, there is provided an apparatus for joining elongated elements in a body of water, the apparatus comprising: a frame;

- a strap feeding device; two arms moveable with respect to the frame and configured to guide a strap around the elongated elements; - a clamping device configured to retain an end portion of the strap;

- a driving device configured to advance and tighten the strap around the elongated elements;

- a junction device configured to join two overlapping portions of the strap so as to close the strap around the elongated elements; and

- a cutting device configured to separate the strap upstream of the joined portion.

The present invention allows straps to be applied around elongated elements in an underwater environment, thus avoiding bringing the elongated elements to the surface, with consequent saving of time and resources.

In particular, if the elongated elements are an integral part of an underwater system for the production or transport of hydrocarbons, the underwater system can be kept in operation during the operations involved in applying the straps around the elongated elements.

Moreover, the apparatus is flexible, adaptable to different types of elongated elements, and not bulky.

In particular, each arm comprises a guide configured to allow the strap to advance along the arm. Each guide is bounded by facing fins, which are mounted on the arm, are shaped to define a guide channel for the strap and have a stiffness so as to allow the facing fins to be opened wide and the strap to be pulled out of the guide when the strap is tightened around the elongated elements.

In this way, the strap can be guided around the elongated elements and pulled out of the guide in a simple and reliable manner, thus limiting the number and complexity of the components of the apparatus.

In particular, the apparatus comprises actuators to operate the arms and an emergency device configured to deactivate the actuators or release the actuators from the arms so that the apparatus can be decoupled from the elongated elements.

In this way, the apparatus can be removed from the elongated elements in a simple and quick way. A further object of the present invention is to provide a system for joining elongated elements in a body of water, which allows the drawbacks described above to be overcome or at least mitigated. Therefore, according to the present invention, there is provided a system for joining elongated elements in a body of water, the system comprising:

- the apparatus as previously described; - an underwater vehicle;

- an articulated arm connected to the underwater vehicle and to the apparatus, to control the position of the apparatus.

In this way, straps can be applied around elongated elements in an underwater environment, in a simple and cheap way.

In particular, the underwater vehicle is a ROV.

In this way, the underwater vehicle can be controlled remotely. In particular, the control device comprises a first sensor, which is coupled to one of the two movable arms and is configured to monitor the position of the apparatus with respect to the elongated elements and/or to monitor the relative position of the two movable arms; in particular, the first sensor may be a linear probe or a magnetic or ultrasonic presence sensor or a camera.

In this way, the articulated arm and the arms of the apparatus can be controlled and monitored in real time.

In particular, the control device comprises a second sensor coupled to the frame to monitor the presence of the strap in a given position, the junction device being controlled as a function of the signals provided by the second sensor. In this way, the junction device and the outcome of the strap application operations can be controlled and monitored in real time.

A further object of the present invention is to provide a method for joining elongated elements in a body of water, which allows the drawbacks described above to be overcome or at least mitigated.

Therefore, according to the present invention, there is provided a method for joining elongated elements in a body of water by means of an apparatus as previously described; the method comprising the steps of:

- placing the apparatus in a body of water at a given zone of the elongated elements;

- coupling the apparatus to the elongated elements by means of an underwater vehicle and an articulated arm placed between the underwater vehicle and the apparatus at the said zone; guiding the strap around the elongated elements by means of two arms of the apparatus; - tightening the strap around the elongated elements; and

- joining two overlapping portions of the strap so that the strap is closed around the elongated elements. In this way, a strap can be applied in the body of water around a selected zone of the elongated elements in an inexpensive and reliable manner.

In accordance with a particular embodiment of the present invention, the method comprises: - launching a first elongated element into a body of water;

- launching a second elongated element into the body of water near the first elongated element;

- placing the first and the second elongated element close together in the said body of water by means of at least one underwater vehicle; and

- joining the first and the second elongated element by means of straps.

In this way, the first and the second elongated element are joined to each other as they are launched by a laying vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will be apparent from the following description of a non-limiting embodiment thereof, with reference to the accompanying drawings, wherein:

- Figure 1 is a side elevation view, with parts removed and parts schematized, of a system for joining elongated elements in accordance with the present invention;

- Figure 2 is an enlarged, side elevation view of an apparatus of the system of Figure 1;

- Figure 3 is a further enlarged, side elevation view, with parts removed for clarity and parts in section, of a detail of Figure 2;

- Figure 4 is a further enlarged, sectional view, with parts removed for clarity, of a detail of Figure 3 sectioned along a plane parallel to the plane of the sheet;

- Figures 5 and 6 are further enlarged, sectional views, with parts removed for clarity, of a detail of Figure 3 in accordance with the section lines V-V and in two operating configurations, respectively;

- Figures 7, 8 and 9 are perspective views, with parts removed for clarity, of respective elongated elements joined to each other by means of the system and method object of the present invention; and

Figures 10, 11 and 12 are schematic, side elevation views, with parts removed, of an application of the system and method of the present invention for joining elongated and continuous elements in a body of water.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to Figure 1, number 1 indicates, as a whole, a system used for joining elongated elements 2 and G in a body of water 3, and in particular for linking elongated elements 2 and G located in a body of water 3.

The system 1 comprises an apparatus 4 for applying straps around the elongated elements 2 and G; an underwater vehicle 5, which is movable in the body of water 3; and an articulated arm 6, which is connected to the underwater vehicle 5 and to the apparatus 4 to control the position of the apparatus 4 in the body of water 3.

In the example described and illustrated herein, the underwater vehicle 5 is a ROV. Within the scope of the present description, the term "ROV" refers to a Remote Operated Vehicle. The underwater vehicle 5 comprises a hydraulic unit 8, configured to transmit power to the apparatus 4 and to the arm 6 through one or more supply pipes and/or cables 9.

Furthermore, the system 1 comprises a surface station 10, which is preferably located on a support vessel 11 and is connected to the underwater vehicle 5 by means of an umbilical 12, and a control device 13 comprising a control unit 14 located at the surface station 10 to control the underwater vehicle 5, the apparatus 4 and the articulated arm 6.

The umbilical 12 is configured to supply electrical power to the underwater vehicle 5 and to exchange signals with the underwater vehicle 5, which in turn exchanges signals with the apparatus 4.

In a preferred embodiment, the control unit 14 supplies the signals exchanged with the underwater vehicle 5 to an operator, who gives commands to the control unit 14, which are transmitted to the underwater vehicle 5 through the umbilical 12.

Moreover, the system 1 comprises a support underwater vehicle 18 configured to check the strap R application operations and/or to intervene in case of emergency.

In particular, the underwater vehicle 18 is configured to provide the control unit 14 with images and/or videos of the operations of application of the strap R around the elongated elements 2 and G, and to decouple the apparatus 4 from the elongated elements 2 and G in case of failure or malfunction of the apparatus 4.

In the example described and illustrated herein, which does not limit the present invention, the underwater vehicle 18 is a ROV. In accordance with a variant of the preferred embodiment, not shown in the accompanying drawings, the underwater vehicle 18 is an AUV.

With reference to Figure 2, the articulated arm 6 comprises a plurality of elements 16 articulated with each other, and a plurality of hydraulic actuators 17 to control the position of the elements 16 with respect to each other, to the underwater vehicle 5 and to the apparatus 4.

In particular, the elements 16 are coupled so as to give the articulated arm 6 seven degrees of freedom.

In the example shown herein, the elements 16 are articulated with each other around the following axes of rotation Al, A2, A3, A4, A5, A6 and A7.

The apparatus 4 comprises a frame 19; two arms 20 movable with respect to the frame 19 and configured to guide the strap R around the elongated elements 2 and G; a clamping device 21 configured to retain an end portion of the strap R; a driving device 22 configured to advance and tighten the strap R around the elongated elements 2 and G; a junction device 23 configured to join two overlapping portions of the strap R so as to close the strap R around the elongated elements 2 and G; and a cutting device 24 configured to separate the strap R upstream of the joined portion.

The two arms 20 are hinged to the frame 19 and are moveable between an open position to enable the apparatus 4 to be arranged around the elongated elements 2 and G, and a closed position, in which the said arms 20 and the frame 19 form a closed ring around the elongated elements 2 and G.

In particular, each arm 20 is moved by a hydraulic cylinder 25, which is mounted on the frame 19.

Moreover, each arm 20 comprises a guide 26 configured to allow the strap R to advance along the arm 20.

In addition, the apparatus 4 comprises two spacers 27, mounted on the frame 19, two spacers 28, each mounted on a respective arm 20, and an emergency device 29 configured to decouple the apparatus 4 from the elongated elements 2 and G.

The spacers 27 and 28 are configured to rest on the elongated elements 2 and G when the arms 20 are arranged in the closed position around the elongated members 2 and G, so as to space the guide 26 from the elongated elements 2 and G.

The number and position of the spacers 27 and 28, shown in the accompanying drawings, are given purely by way of example and should not be construed as limiting the scope of protection of the present invention. The emergency device 29 is configured to be actuated by the underwater vehicle 18, and by means of a release mechanism, not shown in the accompanying drawings, moves the arms 20 from the closed position to the open position, so as to release the apparatus 4 from the elongated elements 2 and G. In practice, the emergency device 29 is configured to discharge the hydraulic actuators 25 that operate the arms 20 or to decouple the hydraulic actuators 25 from the arms 20.

The control device 13 comprises a sensor 30, which is coupled to one of the two arms 20 and is configured to monitor the position of the apparatus 4 with respect to the elongated elements 2 and G and/or to monitor the relative position of the two arms 20; and a sensor 31 coupled to the frame 19 to monitor the presence of the strap R in a given position and allow the junction device 23 to be controlled as a function of the signals provided by the sensor 31.

In the example described and illustrated herein, the sensors 30 and 31 are cameras configured to provide real time images and/or videos to the control unit 14. In particular, the sensor 30 is mounted at one end of one of the two arms 20. The sensor 31 is mounted at the junction device 23 and checks whether the strap R is correctly inserted inside the guide 26 and monitors the outcome of the joining operation performed by the junction device 23.

With reference to Figure 3, the apparatus 4 is shown in the closed position around the elongated elements 2 and G. in this configuration, the arms 20 and the portion of the frame 19 between the arms 20 form a closed ring around the elongated elements 2 and G. In the example described and illustrated herein, the apparatus 4 comprises a strap feeding device 32 provided with a reel 33, on which a spool of strap R is wound, and feed rollers 34 configured to convey the strap R into the guide 26.

The driving device 22 comprises a driving roller 35 configured to selectively advance the strap R in a first direction, so as to feed the strap R to the guide 26 and unwind the strap R from the spool, and in a second direction opposite to the first direction to tighten the strap R around the elongated elements 2 and G.

With reference to Figure 4, the clamping device 21 comprises a vice 36 configured to clamp the strap R at one end of the strap R and retain the strap R, thereby enabling the driving device 22 to clamp the strap R around the elongated elements 2 and G.

The junction device 23 comprises a plurality of grippers 37 configured to join two overlapping portions of the strap R downstream of the clamping device 21. The cutting device 24 comprises a knife 38 arranged between the clamping device 21 and the junction device 23.

In accordance with the preferred, non-limiting embodiment of the present invention, the clamping device 21, the junction device 23 and the cutting device 24 are part of a machining head 39, mounted on the frame 19 between the arms 20.

With reference to Figure 5, each guide 26 is bounded by facing fins 40, which are mounted on the arm 20, are shaped to define a guide channel 41 for the strap R and have a stiffness so as to allow the facing fins 40 to be opened wide and the strap R to be pulled out of the guide 26 when the strap R is tightened around the elongated elements 2 and G.

In particular, each fin 40 is L-shaped and is fixed at one end to the arm 20. The free end of each fin 40 is arranged at a distance from the free end of the facing fin 40. When the strap R is tightened around the elongated elements 2 and G, each fin 40 deforms, thereby increasing the distance between the free ends of the facing fins 40 to allow the strap R to come out of the guides as shown in Figure 6.

In use and with reference to Figure 1, the underwater vehicle 5 is moved in the body of water 3 by the control unit 14 and arranged at the elongated elements 2 and G to be joined. The sensor 30 monitors the position of the apparatus 4 with respect to the elongated elements 2 and G and provides the relevant signals to the control unit 14.

The apparatus 4 is moved by the articulated arm 6 as a function of the signals provided by the sensor 30, so as to couple the apparatus 4 to the elongated elements 2 and G. Subsequently, the arms 20 are moved from the open position to the closed position and the sensor 30 monitors the relative position of the two arms 20.

During the operations involved in joining the elongated elements 2 and G, the underwater vehicle 18 monitors and provides the control unit 14 with images and/or videos of said operations and is ready to intervene in case of failure or malfunction of the apparatus 4.

With reference to Figure 3, when the arms 20 are in the closed position, the driving device 22 feeds the strap R into the guide 26. The sensor 31 (Figures 1 and 2) detects the presence of the strap R in the guide 26 in a given position and provides the relevant signals to the control unit 14. With reference to Figure 4, the clamping device 21 closes the vice 36 around a portion of the strap R, so as to retain the strap R after receiving consent from the sensor 31. Next, the driving device 22 tightens the strap R around the elongated elements 2 and G, extracting the strap R from the guide 26. Once the strap R has been tightened around the elongated elements 2 and G, the junction device 23 joins the two overlapping portions of the strap R by means of the grippers 37, so as to close the strap R around the elongated elements 2 and G. The sensor 31 monitors the outcome of the joining operation and provides relevant signals to the control unit 14.

Subsequently, the cutting device 24 separates the strap R upstream of the joined portion by means of the knife 38.

With reference to the preferred, non-limiting embodiment of the present invention, all the steps of the operations involved in applying the strap R around the elongated elements 2 and G are remotely controlled by the control unit 14 located at the surface station 10.

With reference to Figures 7, 8 and 9, elongated elements are shown, which are joined by means of the system 1 through the application of straps R.

In the example shown in Figure 7, a rigid or flexible pipe 42 is shown for the transport of process fluids from an underwater system. The pipe 42 is provided with a finned shell 43, which is shaped so as to mitigate the wake turbulence downstream of the pipe 42 and is formed by a series of pairs of facing half-shells 44. The pairs of half shells 44 are distributed along the longitudinal direction of the pipe 42 at substantially regular intervals. The straps R are applied between two successive fins of each pair of half-shells 44.

In the example shown in Figure 8, a rigid or flexible pipe 45 having a first diameter and a pipe or cable or optical fibre 46 having a second diameter substantially smaller than the first diameter are shown, which are joined by straps R by means of the system 1.

In the example shown in Figure 9, a rigid or flexible pipe 47 is shown, to which the system 1 applies facing half shells 48 by using straps R.

With reference to Figures 10, 11 and 12, three successive operating steps are shown for joining two elongated elements 49 and 50 in a body of water 3 following a step in which they are launched.

In the example shown in Figure 10, a laying vessel 51 progressively releases the elongated element 49 into the body of water 3 by means of a launching tower 52. In the example shown, the elongated element 49 is an underwater pipe which is released into the body of water 3 as it is assembled in the launching tower 52.

At the same time, the elongated element 50, in this case a cable, is launched into the body of water 3 by a reel 53 arranged on the deck 54 of the laying vessel 51. The two elongated elements 49 and 50 are joined in the body of water 3 by means of a discrete succession of straps

R preferably uniformly distributed along the elongated elements 49 and 50. The control unit 14 is located on the launching vessel

51, which serves as a surface station.

With reference to Figure 10, the articulated arm 6 arranges the apparatus 4 around the elongated element 50 and brings the elongated element 50 closer to the elongated element 49.

With reference to Figure 11, the underwater vehicle 5 moves the apparatus 4 so as to place the elongated element 50 alongside the elongated element 49. The arms 20 (Figures 1, 2 and 3) of the apparatus 4 are in the closed position around both elongated elements 49 and 50.

With reference to Figure 12, following the application of the strap R around the elongated elements 49 and 50, the underwater vehicle 5 moves the apparatus 4 away from the elongated elements 49 and 50.

Lastly, it is clear that the present invention can be subject to variations with respect to the embodiments described above or to the shape of the elongated element 50 which could be replaced with shells 48 launched by the crane of the vessel without however departing from the scope of protection of the attached claims.