EP4631635A1

EP4631635A1 - A submarine line cleaning unit, related decommissioning facility, and corresponding method

Info

Publication number: EP4631635A1
Application number: EP24305596.9A
Authority: EP
Inventors: Henri Morand
Original assignee: TechnipFMC Subsea France SAS
Current assignee: TechnipFMC Subsea France SAS
Priority date: 2024-04-12
Filing date: 2024-04-12
Publication date: 2025-10-15
Also published as: WO2025215152A1

Abstract

The submarine line cleaning unit comprises:- a submarine line section handling system comprising at least a support surface configured to receive, along a submarine line cleaning axis, a submarine line section (12) to be cleaned; and- a cleaning fluid dispensing hose, configured to be introduced into the submarine line section (12) from at least one submarine line end (92, 94) of the submarine line section (12) to dispense cleaning fluid in the submarine line section (12).The submarine line section handling system comprises a submarine line lifting mechanism (104), configured to lift at least a region of the or of each support surface to tilt the submarine line section (12) with regards to a horizontal plane.

Description

The present invention concerns a submarine line cleaning unit, comprising:

a submarine line section handling system, comprising at least a support surface configured to receive, along a submarine line cleaning axis, a submarine line section to be cleaned;
a cleaning fluid dispensing hose, configured to be introduced into the submarine line section from at least one submarine line end of the submarine line section to dispense cleaning fluid in the submarine line section.

The submarine line cleaning unit is generally part of an onshore decommissioning plant, configured to process submarine line sections recovered from offshore sites, in order to recycle the metals and plastics contained in the submarine line sections.
The decommissioning of offshore fluid production sites after the termination of fluid production is currently a challenge for operators.
An offshore production site generally comprises fluid collection equipment located at the bottom of a body of water. Numerous fluid injection and/or production lines extend from the fluid collection equipment to the surface to transport fluids to be injected in the ground below the bottom of the body of water and/or to collect fluids produced from the ground.
In some instances, fluid production is carried out in shallow or mid-shallow waters with lengths of the fluid lines being less than 600 m. In some cases, the production is carried out in deep waters, in which the fluid lines have a more significant length.
Given the number of lines required to inject or/and produce fluids in several wells, the decommissioning of the production site generally requires recovering very significant lengths of submarine lines, in particular flexible lines such as flexible pipes.
The submarine lines are retrieved using vessels, onto which they may be cut into short sections. The submarine line sections generally have a length ranging from 6 m to 20 m.
Alternatively, the retrieved submarine lines are stored onto reels or carousels installed on the deck of the vessel. The submarine lines can then be cut offshore on the vessel or onshore at the deconstruction site.
Recycling the materials of the submarine line sections recovered from fluid production sites has a strong interest to generate revenue, in particular from the recovered metals. It is also beneficial for the environment, as the amount of non-reusable waste is minimized.
The recovered submarine line sections for example comprise submarine lines which have been used to carry fluids for long periods of times, such as production pipes. A production pipe generally conveys not only production fluids such as oil and gas, but also materials from the reservoirs in which the production fluids are extracted.
Consequently, as time elapses, materials such as scales, deposits, sand or sludge accumulate on the inner walls of the production submarine line. These accumulated materials may contain trace amounts of naturally occurring radioactive material (or "NORM"), such as uranium, thorium, and decay products. These radionuclides can be in a gaseous phase such as radon or can be water soluble such as the isotopes of radium.
It is thus necessary to clean the inner passage of the submarine line sections before they are fully deconstructed to be recycled, in particular to recover and process solid materials accumulated on the inner wall of the submarine line sections.
WO 2018/234551 discloses a submarine line retrieving method in which the full length of the production line is cleaned offshore before the submarine line is wound to the surface.
Such a method involves leaking to the seabed potentially contaminated sediments from the bottom of the submarine line. In addition, the method is tedious to carry out, especially for a submarine line of very long length.
One aim of the invention is thus to obtain a submarine line decommissioning facility, in which sections of retrieved offshore production submarine lines can be easily and efficiently cleaned in particular to be deconstructed and recycled.
To this aim, the subject matter of the invention is a submarine line cleaning unit, of the above mentioned type, characterized in that the submarine line section handling system comprises a submarine line lifting mechanism, configured to lift at least a region of the or of each support surface to tilt the submarine line section with regards to a horizontal plane.
The submarine line cleaning unit according to the invention may comprise one or more of the following feature(s), taken solely, or according to any technical feasible combinations:

the submarine line cleaning unit is an onshore submarine line cleaning unit;
the submarine line lifting mechanism comprises a jack;
the submarine line lifting mechanism comprises an elongated swivel member holding the or each support surface, the jack being configured to lift the swivel member;
the submarine line lifting mechanism comprises a base, a first end of the elongated swivel member being hinged on the base, the jack being positioned at a second end of the elongated swivel member;
the elongated swivel member comprises a beam, and several lifting pillars protruding from the beam, each lifting pillar defining one support surface;
the submarine line section handling system comprises at least one transverse conveyor having a belt and at least a power unit powering the belt, the transverse conveyor comprising at least a submarine line loading region or evacuation region located transversely away from the cleaning axis, and at least a submarine line cleaning region, located in alignment with the submarine line cleaning axis;
the or each transverse conveyor defines a plurality of transverse slots separate from one another, each slot being configured to receive a region of a single submarine line section;
the submarine line section handling system comprises several transverse conveyor having parallel belts, each belt defining successive slots, the power unit being configured to power the parallel belts to maintain the successive slots of successive parallel belts aligned along an axis parallel to the submarine line cleaning axis to form lines of slots parallel to the submarine line cleaning axis;
the power unit is configured to move the lines of slots selectively in a first direction towards to the submarine line cleaning axis and in a second direction away from the submarine line cleaning axis;
the or each belt comprises successive cleats, each pair of adjacent cleats defining a slot;
the submarine line lifting mechanism comprises at least one transverse conveyor having an upward curved shape to cause the tilting of the submarine line section, the support surface being delimited on the at least one transverse conveyor;
the submarine line lifting mechanism comprises an articulated robotic arm configured to grab the submarine line section on a support surface to cause the tilting of the submarine line section or wherein the submarine line lifting mechanism comprises a pulley system comprising at least a cable wound on at least a pulley and at least a support surface for the submarine line section configured to be lifted by the cable to cause the tilting of the submarine line section;
the submarine line cleaning unit can be fixed or mobile, in particular carried on at least one truck.

The invention also concerns a decommissioning facility, comprising a plurality of submarine line sections; and a submarine line cleaning unit as defined above, configured to successively receive and tilt the submarine line sections.
The decommissioning facility according to the invention may comprise the following feature :

the plurality of submarine line sections comprises flexible pipe sections, each flexible pipe section including at least an internal polymer sheath and at least an armor layer wound around the internal polymer sheath, the internal polymer sheath defining at least an inner central passage, the hose being configured to be introduced into the inner central passage.

The invention also concerns a decommissioning method comprising the following steps:

positioning a submarine line section to be cleaned on at least a support surface of a handling system along a submarine line cleaning axis;
lifting the or of each support surface with a submarine line lifting mechanism of the submarine line section handling system and tilting the submarine line section which regards to a horizontal plane before, during or/and after cleaning the submarine line section with a cleaning fluid dispensing hose introduced into the submarine line section from at least one submarine line end of the submarine line section.

The decommissioning method according to the invention may comprise the following feature:

positioning a submarine line section to be cleaned on at least a support surface of a handling system comprises placing the submarine line section on at least one transverse conveyor having a belt and a power unit powering the belt, in a submarine line loading region located transversely away from the cleaning axis, and conveying the submarine line section on the transverse conveyor to a submarine line cleaning region.

The invention will be better understood, based on the following description, given solely as an example, and made in reference to the appended drawings, in which:

figure 1 is an exploded view of first section of an example of submarine line (here a flexible pipe) containing accumulated solids to be cleaned in a submarine line cleaning unit according to the invention;
figure 2 is an upper perspective view of relevant parts of an onshore decommissioning facility comprising the submarine line cleaning unit according to the invention;
figure 3 is an enlarged view of a detail of the facility of figure 2;
figure 4 is a side view of a submarine line section, mounted on a submarine line lifting mechanism, the mechanism maintaining the submarine line section in a horizontal configuration;
figure 5 is a view similar to figure 4, the mechanism maintaining the submarine line section in a tilted configuration;
figure 6 is a flow chart of a decommissioning method according to the invention.

A first onshore decommissioning facility 10 according to the invention is schematically depicted in figure 2. The onshore decommissioning facility 10 is configured to receive successive submarine line sections 12 to clean and deconstruct the submarine line sections 12 and allow for example the recycling of the metal and polymer materials obtained from the submarine line sections 12.
The submarine line sections 12 are obtained from an offshore decommissioning installation (not shown), and retrieved with a recovery vessel equipped with a submarine line recovery system.
The submarine line recovery system for example comprises a spooling and/or a recovery tower to lift and wind the submarine line. It may comprise a submarine line end working section configured to cut or rework the submarine line into submarine line sections 12 having a length advantageously comprised between 6 m and 20 m.
Alternatively, it may comprises reel(s) or carrousel(s) configured to receive the submarine line into complete length to be further cut onshore or offshore at a separate time than the recovery.
The submarine line sections 12 are transported from their offshore recovery site to the onshore decommissioning facility 10 where they are processed to form the deconstructed sections to be recycled.
In the example shown on figure 1, the submarine line section 12 is a section of flexible pipe, in particular built according with the standards API 17J (Specification for Unbonded Flexible Submarine line, 4th edition - May 2014) and API RP 17B (Recommended Practice for Flexible Submarine line, 5th edition - March 2014) established by the American Petroleum Institute. The flexible submarine line is here an unbonded submarine line. At least two adjacent layers of the flexible submarine line are free to move longitudinally with respect to each other during flexure of the submarine line.
Alternatively, the submarine line is a Hybrid Flexible Pipe (HFP), in particular built according with the standards DNV-ST-F119 (Thermoplastic Composite Pipes, Edition September 2019) established by the DNV (Det Norske Veritas). The hybrid flexible pipe is advantageously an unbonded flexible pipe. At least two adjacent layers of the hybrid flexible pipe are free to move longitudinally with respect to each other during flexure of the pipe.
Alternatively, the submarine line is another type of flexible pipe, such as a Fibre Reinforced 'composite' Pipe (FRP).
Alternatively, the submarine line is another type of flexible pipe, such as a bonded flexible pipe. The bonded flexible pipe is designed, manufactured and used according with the standards API RP 17B (Recommended Practice for Flexible Pipe, 5th edition - March 2014), API 7K (Drilling and Well Servicing Equipment, 6th edition - December 2015), API 16C (Choke and Kill Equipment, 3rd edition - March 2021) and API 17K (Specification for Bonded Flexible Pipe, 3rd edition - August 2017) established by the American Petroleum Institute.
Alternatively, the submarine line is a drill pipe or tubing as defined, designed and manufactured according to the standard API SPEC 5A (Specification for Casing, Tubing and Drill Pipe, 39th edition - May 1987) established by the American Petroleum Institute
Again alternatively, the submarine line is a an umbilical, as defined in ISO 13628-5 "Petroleum and natural gas industries - Design and operation of subsea production systems - Part 5: Subsea umbilicals" published in December 2009 by the International Organization for Standardization, API 17E "Specification for Subsea Umbilicals", 5th Edition - July 2017, established by the American Petroleum Institute, and IEC60183:2015, January 2015, IEC60840:2020, May 2020 and/or IEC63026:2019, December 2019 , established by the International Electrotechnical Commission (IEC), all provide standards for the design and manufacture of umbilicals and power cables.
Umbilical includes for example steel/thermoplastic/composite tube electrohydraulic umbilical, Integrated Service/Production Umbilical (ISU^™ / IPU^™) and subsea power umbilical/cable.
As well, the submarine line is a single rigid metallic pipe including for example mechanically lined pipe (MLP), concrete coated pipe or polymer lined pipe (PLP), or is a rigid metallic pipe-in-pipe (PiP), as defined in the offshore standard DNV-ST-F101 "Submarine Pipeline Systems", August 2021, established by the DNV (Det Norske Veritas).
In the example of figure 1, depicting a flexible pipe, each submarine line section 12 has an axis A-A' and delimits an inner central passage 16 for circulation of a fluid, advantageously a petroleum fluid.
The inner central passage 16 diameter advantageously ranges from 76 mm to 60 cm.
The submarine line section 12 delimits a plurality of concentric layers around the axis A-A'. The submarine line section 12 includes at least one first tubular sheath 20 formed of a polymeric material. The first tubular sheath 20 is a pressure sheath.
The submarine line section 12 further includes at least one layer of tensile armors 24, 25 positioned externally with respect to the first sheath 20.
The submarine line section 12 further optionally includes an internal carcass 26 positioned inside the pressure sheath 20, and/or a pressure vault 27 inserted between the pressure sheath 20 and the layer(s) of tensile armors 24, 25, and/or an external sheath 30, intended for protecting the submarine section 12 .
In a known way, the pressure sheath 20 is intended to tightly confine the fluid transported in the passage 16. It is formed of a polymeric material, for example based on a polyolefin such as polyethylene, based on a polyamide such as PA11 or PA12, or based on a fluorinated polymer such as polyvinylidene fluoride (PVDF).
The thickness of the pressure sheath 20 is for example comprised between 5 mm and 20 mm.
When present, the carcass 26 is formed for example with a first helicoidally wound profiled metal strip 28. The successive turns of the strip 28 are stapled with each other.
The strip 28 has a thickness advantageously comprised between 0.8 mm and 3.5 mm and a width advantageously comprised between 40 mm and 140 mm.
The main function of the carcass 26 is to absorb the squeezing radial forces.
The carcass 26 is positioned inside the pressure sheath 20. It is able to come into contact with the fluid circulating in the pressure sheath 20.
The helicoidal winding of the first profiled strip 28 forming the carcass 26 is with a short pitch, i.e. it has a helix angle with an absolute value close to 90° in relation to the axis A-A', typically comprised between 75° and 90°.
When present, the pressure vault 27 is intended to absorb the radial forces related to the pressure prevailing inside the pressure sheath 20. For example it is formed with a helicoidally wound metal profiled wire around the sheath 20. The profiled wire generally has a complex geometry, in particular Z-shaped, T-shaped, U-shaped, K-shaped, X-shaped or I-shaped.
The pressure vault 27 is helicoidally wound with a short pitch around the pressure sheath 20, i.e. with a helix angle of an absolute value close to 90° in relation to the axis A-A', typically comprised between 75° and 90°.
The flexible submarine line according to the invention comprises at least one layer of armors 24, 25 formed with a helicoidal winding of at least one elongated armor element 29.
In the example illustrated in Figure 1, the flexible submarine line includes a plurality of layers of armors 24, 25, in particular an inner layer of armors 24, applied on the pressure vault 27 and an outer layer of armors 25 around which is positioned the outer sheath 30.
Each layer of armors 24, 25 includes longitudinal armor elements 29 wound with a long pitch around the axis A-A' of the submarine line.
By "wound with a long pitch", is meant that the absolute value of the helix angle in relation to the axis A-A' is less than 60°, and is typically comprised between 25° and 55°.
The armor elements 29 of a first layer 24 are generally wound according to an opposite angle with respect to the armor elements 29 of a second layer 25. Thus, if the winding angle of the armor elements 29 of the first layer 24 is equal to + α, α being comprised between 25° and 55°, the winding angle of the armor elements 29 of the second layer of armors 25 positioned in contact with the first layer of armors 24 is for example equal to - α°.
The armor elements 29 are for example formed with metal wires, in particular steel wires, or with strips in composite material, for example strips reinforced with carbon fibers.
The external sheath 30 is intended to prevent ingress of fluid from the outside of the flexible submarine line towards the inside. It is advantageously made in a polymeric material, in particular based on a polyolefin, such as polyethylene, or on in a polyamide, such as PA11 or PA12.
The thickness of the external sheath 30 is for example comprised between 5 mm and 20 mm.
The submarine line sections 12 in some instances comprise accumulated sediments 70 present in the central passage 16, in particular between the tubular sheath 20 and the carcass 26 or within the carcass 26. The accumulated solids 70 for example form an inside layer within the carcass 26. The layer can be solid, similar to quartz or can be powdery, similar to sand.
The accumulated solids result from materials such as scales, sand or sludge. They may contain radioactive elements, in particular uranium, thorium and decay products, or radium. These elements are Naturally Occurring Radioactive Material (or "NORM"). These accumulated deposits may also contain other hazardous substances such as mercury or hydrocarbons.
As shown in figure 2, the onshore decommissioning facility 10 comprises a submarine line cleaning unit 52 according to the invention, to clean the inside of a plurality of submarine line sections 12, in particular the inner central passage 16, from accumulated solids 70. The line sections 12 are received from the offshore decommissioning installation and may temporarily be stored in a dedicated area on site.
Once cleaned in the line cleaning unit 52, the cleaned line sections may be reused, may be deconstructed in a deconstructing unit to recover metal layers and polymeric layers from layers 20 to 30 of the deconstructed sections, or may be dumped.
The submarine line cleaning unit 52 comprises a submarine line section handling system 82 comprising a submarine line lifting mechanism 104, a cleaning fluid dispensing hose 86 (shown schematically in figure 2), and a fluid recovery system (not shown).
The cleaning fluid can be water, chemical or a combination of water and chemical suitably selected to achieve an efficient cleaning for the specific submarine line section 12 to be cleaned.
The submarine line section handling system 82 is configured to receive a submarine line section 12 in a loading region (here on the right of figure 2), and to transport it to a cleaning region along a submarine line cleaning axis B-B'.
In the cleaning region, the submarine line section 12 longitudinal axis A-A' aligns with the submarine line cleaning axis B-B', in projection in a horizontal plane.
In the cleaning region, the submarine line section 12 is tiltable from a horizontal configuration, shown in figure 4, to a tilted configuration, shown in figure 5, in which the submarine line section 12 longitudinal axis A-A' is titled upwardly with regard to a horizontal plane, for example by an angle greater than 1° and up to 90°. The angle is generally comprised between 1° and 45°.
The submarine line section handling system 82 comprises at least a transverse conveyor 100, to carry submarine line sections 12 from the loading region to the cleaning region, at least a transverse support member (not shown), to horizontally support the submarine line sections 12 and the submarine line lifting mechanism 104 (shown in particular in figures 4 and 5), configured to lift a submarine line section 12 in the cleaning region from the horizontal configuration to the tilted configuration.
In the example of figure 2, the submarine line section handling system 82 comprises several parallel transverse conveyors 100, for example between 2 and 5 transverse conveyors 100. Each transverse conveyor 100 extends perpendicular to the submarine line cleaning axis B-B'.
Each transverse conveyor 100 comprises a continuous belt 106 forming a loop, and at least two wheels 108A, 108B, onto which the belt 106 is wound. One of the at least two wheels 108A, 108B is for example a drive wheel.
The submarine line section handling system 82 further comprises a power unit 110, configured to drive the wheels 108A, 108B in rotation around their axis to move the belt 106 in either direction perpendicularly to the submarine line cleaning axis B-B' for example the wheels 1 08A, 108B comprise drive sprockets to interact with the belt.
As shown in figures 2 and 3, the belt 106 can be for example of the cleated belt type equipped in which case at regular intervals it possesses longitudinal cleats 112 acting as stoppers. Each pair of adjacent cleats 112 define between them a slot 114 dimensioned to receive a region of a submarine line section 12, and to maintain it substantially parallel to the submarine line cleaning axis B-B'.
The cleats 112 here are made of rigid longitudinal plates parallel to each other. When a region of the submarine line section 12 is received into the slot 114, it follows the movement of the transverse conveyor 100 towards and away from the cleaning axis B-B'.
The successive slots 114 of successive parallel transverse conveyors 100 are aligned along an axis parallel to the submarine line cleaning axis B-B' to form lines of slots 114 parallel to the submarine line cleaning axis B-B'.
When received in a line of slots 114 parallel to the submarine line cleaning axis B-B', the submarine line section handling system 82 is configured to transversely move a submarine line section 12 in either direction relative to the submarine line cleaning axis B-B'.
This allows loading and unloading successive submarine line sections 12, or if necessary, placing again a submarine line section 12 which has already been partially cleaned in alignment with the longitudinal axis B-B'.
In the example of figure 2, the submarine line section handling system 82 comprises several parallel transverse support members.
The submarine line section lifting mechanism 104 is depicted in figures 4 and 5. It comprises a base 120, fixed with regard to the ground, and a swivel beam 122, hinged on the base 120. It further comprises several lifting pillars 124 extending at intervals along the beam 122, and a lifting jack 126.
The beam 122 extends along the submarine line cleaning axis B-B'. It is configured to rotate between a rest horizontal position, and an upper tilted position, under the actuation of the jack 126.
In the upper tilted position, a free downstream end of the beam 122 is located above an opposed upstream end of the beam 122 hinged to the base 120. The beam 122 is tilted with regard to a horizontal plane with an angle of inclination ranging from 0° to 90°, preferably between 1° and 45°.
The lifting pillars 124 protrude from the beam 122 at several locations along the length of the beam 122. They extend between the conveyors 100 and the transverse support beams.
Each lifting pillar 124 has an upper support 128 defining a support surface configured to engage a lower region of the submarine line section 12 to support and hold in place the submarine line section 12 when lifted.
In this example, the upper supports 128 comprise two lateral wings protruding transversely on both sides of the lifting pillar 124. The lateral wings are for example, U- or V-shaped. These lateral wings or pads can be made of specific materials to maximize friction.
Alternatively, one or several of the lifting pillars 124, can be fitted with mechanical and hydraulic clamps to maintain the submarine line section 12 in position during the operations.
The lifting jack 126 is here positioned near a free downstream end of the beam 122. Alternatively, the lifting jack 126 is a pneumatic or electric powered actuator.
The lifting jack 126 is operable to lift the swivel beam 122 jointly with each lifting pillar 124 and its support surface, and consequently, the submarine line section 12, in a tilted configuration with regard to a horizontal plane, with the same inclination as the swivel beam 122, as shown in figure 5.
In the tilted configuration shown in figure 5, liquids and/or solids can be evacuated from the inner passage 16 under the effect of gravity.
In a variant (not shown) of a lifting mechanism 104, the submarine line section 12 is lifted and tilted with regard to a horizontal plane through at least one automated and articulated robotic arm. The at least one robotic arm is configured to grab the submarine line section 12 outer surface e.g. with a jaw. The jaw of the robotic arm defines a support surface onto which at least a region of the submarine line section 12 rests to be lifted by the robotic arm.
In another variant (not shown), the lifting mechanism 104 comprises at least a transverse conveyor 100 which has an upward curved shape to progressively cause the tilting of the submarine line section 12. The submarine line section 12 is conveyed from the handling system 82 to the cleaning region through the at least a transverse conveyor 100.
Like so, when loaded in the slots 114 of the conveyor 100, the submarine line section 12 rests in its horizontal position and is slowly conveyed to the cleaning region. During the conveyance, the submarine line section 12 gradually passes from a horizontal position to a tilted position tilted with regard to a horizontal plane with an angle of inclination ranging from 0° to 90°, preferably between 1° and 45°.
Thus, when the cleaning region is reached, the section 12 rests on a support surface of the conveyor 100. It is already inclined and can be cleaned.
In another variant (not shown), the lifting mechanism 104 comprises a pulley system mounted on a roof structure 192 of the cleaning unit 52. The pulley system comprises at least a cable wound on at least a pulley and at least a support surface for the submarine line section 12 configured to be lifted by the cable.
The inclination of the submarine line section 12 helps to evacuate liquids and solids from the inner passage 16. Nonetheless, the submarine line section 12 may also be placed in a tilted configuration before cleaning the inner passage 16. Thus, the steps of cleaning and evacuating of liquids/solids are carried out in a tilted configuration.
The cleaning fluid dispensing hose 86 is configured to create at least a high-pressure water jet in the inner passage 16 of the submarine line section 12, to break the layer of accumulated solids 70 in the submarine line section, and/or to convey the solids 70 towards the upstream end 92 of the submarine line section 12.
The cleaning fluid dispensing hose 86 is configured to be introduced within the submarine line section 12 through an end 92, 94 of the submarine line section 12, to dispense a cleaning fluid in the inner passage 16.
The cleaning fluid is for example pressurized water, in particular produced by a high-pressure or ultra-high-pressure apparatus such as a high-pressure water jet generator.
Preferably, the cleaning fluid dispensing hose 86 has a length greater than 10 m, in order to be able to travel through at least 50%, preferably through at least 80% of a length of a submarine line section 12.
The cleaning fluid pressure is preferably greater than 200 bar and is generally comprised between 690 bar and 3500 bar.
The projection of pressurized cleaning fluid is configured to break the accumulated solids 70 in the submarine line section 12, and to carry the broken solids towards an end 92, 94 of the submarine line section 12, especially when the submarine line section 12 is in a tilted configuration.
A decommissioning process according to the invention will now be described in reference to figure 6.
At step 200, a submarine line, in particular a flexible submarine line, is retrieved from an offshore production site by recovering it on a vessel.
At step 202, the submarine line is preferably cut into submarine line sections 12 for example directly on the vessel, with a length comprised between 6 m and 20 m.
In a variant, the submarine line is wound around a drum, or into a basket and the cutting of the submarine line is carried out onshore during or after the unloading of the submarine line from the vessel.
If needed, at step 204, the submarine line sections 12 are transported to the onshore decommissioning facility 10. The submarine line sections 12 may temporarily be stored into the dedicated area.
At step 206, the submarine line sections 12 are then transferred to the cleaning unit 52 to be cleaned.
At step 210, the submarine line section 12 is loaded in the loading region of the submarine line section handling system 82.
The submarine line section 12 is inserted in successive aligned slots 114 of the conveyors 100. Its axis A-A' aligns parallel to the submarine line cleaning axis B-B', in the submarine line loading region.
At step 212, the power unit 110 is activated to actuate each transverse conveyor 100. The upper region of the continuous belt 106 moves the submarine line section 12 transversely towards the submarine line cleaning axis B-B'.
At step 214, the submarine line section 12 reaches the submarine line cleaning axis B-B'. The hose 86 is introduced into the inner passage 16 through an end 92, 94 of the submarine line section 12.
Cleaning fluid, in particular pressurized water is dispensed towards the inner surface of the carcass 26.
At step 222, the pressurized water breaks the accumulated solids 70 into chips and/or powder, and the ejected water carries the chips and/or powder towards an end 92, 94. The submarine line lifting mechanism 104 is activated to incline the submarine line section 12 with regard to a horizontal plane.
A fluid containing water and solids recovered from the end 92, 94 of the submarine line section is evacuated by gravity out of the inner passage 16.
The cleaned submarine line section 12 is then moved out of the submarine line section handling system 82 towards an evacuation region to be reused, to be deconstructed or/and to be dumped.
The submarine line cleaning unit 52 according to the invention is thus very easy to operate. It allows a safe and efficient treatment of a large number of submarine line sections 12 to clean them from any accumulated solid 70 they contain.
The removal of accumulated solids 70 is particularly efficient thanks to the inclination of the submarine line section 12 from the horizontal configuration to the tilted configuration.
Manual handling is minimal, as the submarine line sections 12 may comprise accumulated solids 70, which may contain trace amounts of radioactive material.
Therefore, the submarine line sections 12 are transported to the cleaning region via the conveyors 100.
Thus, staffing of the submarine line cleaning unit 52 can be reduced which makes it usable even in remote regions.

Claims

A submarine line cleaning unit (52), comprising:
- a submarine line section handling system (82), comprising at least a support surface configured to receive, along a submarine line cleaning axis (B-B'), a submarine line section (12) to be cleaned;

- a cleaning fluid dispensing hose (86), configured to be introduced into the submarine line section (12) from at least one submarine line end (92, 94) of the submarine line section (12) to dispense cleaning fluid in the submarine line section (12),
characterized in that the submarine line section handling system (82) comprises a submarine line lifting mechanism (104), configured to lift at least a region of the or of each support surface to tilt the submarine line section (12) with regards to a horizontal plane.
The submarine line cleaning unit (52) according to claim 1, wherein the submarine line lifting mechanism (104) comprises a jack (126).
The submarine line cleaning unit (52) according to claim 2, wherein the submarine line lifting mechanism (104) comprises an elongated swivel member holding the or each support surface, the jack (126) being configured to lift the swivel member.
The submarine line cleaning unit (52) according to claim 3, wherein the submarine line lifting mechanism (104) comprises a base (120), a first end of the elongated swivel member being hinged on the base (120), the jack (126) being positioned at a second end of the elongated swivel member.
The submarine line cleaning unit (52) according to claim 3 or 4, wherein the elongated swivel member comprises a beam (122), and several lifting pillars (124) protruding from the beam (122), each lifting pillar (124) defining one support surface.
The submarine line cleaning unit (52) according to any one of the preceding claims, wherein the submarine line section handling system (82) comprises at least one transverse conveyor (100) having a belt (106) and at least a power unit (110) powering the belt (106), the transverse conveyor (100) comprising at least a submarine line loading region or evacuation region located transversely away from the cleaning axis (B-B'), and at least a submarine line cleaning region, located in alignment with the submarine line cleaning axis (B-B').
The submarine line cleaning unit (52) according to claim 6, wherein the or each transverse conveyor (100) defines a plurality of transverse slots (114) separate from one another, each slot (114) being configured to receive a region of a single submarine line section (12).
The submarine line cleaning unit (52) according to claim 7, wherein the submarine line section handling system (82) comprises several transverse conveyor (100) having parallel belts (106), each belt (106) defining successive slots (114), the power unit (110) being configured to power the parallel belts (106) to maintain the successive slots (114) of successive parallel belts (106) aligned along an axis parallel to the submarine line cleaning axis (B-B') to form lines of slots (114) parallel to the submarine line cleaning axis (B-B').
The submarine line cleaning unit (52) according to claim 8, wherein the power unit (110) is configured to move the lines of slots (114) selectively in a first direction towards to the submarine line cleaning axis (B-B') and in a second direction away from the submarine line cleaning axis (B-B').
The submarine line cleaning unit (52) according to any one of claims 6 to 9, wherein the or each belt (106) comprises successive cleats (112), each pair of adjacent cleats (112) defining a slot (114).
The submarine line cleaning unit (52) according to any one of claims 6 to 10, wherein the submarine line lifting mechanism (104) comprises at least one transverse conveyor (100) having an upward curved shape to cause the tilting of the submarine line section (12), the support surface being delimited on the at least one transverse conveyor (100).
The submarine line cleaning unit (52) according to any one of the preceding claims, wherein the submarine line lifting mechanism (104) comprises an articulated robotic arm configured to grab the submarine line section (12) on a support surface to cause the tilting of the submarine line section (12) or wherein the submarine line lifting mechanism (104) comprises a pulley system comprising at least a cable wound on at least a pulley and at least a support surface for the submarine line section (12) configured to be lifted by the cable to cause the tilting of the submarine line section (12).
An assembly comprising:
- a plurality of submarine line sections (12); and

- a submarine line cleaning unit (52), according to any one of the preceding claims, configured to successively receive and tilt the submarine line sections (12).
A submarine line decommissioning method, comprising the following steps:
- positioning a submarine line section (12) to be cleaned on at least a support surface of a handling system (82) along a submarine line cleaning axis (B-B') ;

- lifting the or of each support surface with a submarine line lifting mechanism (104) of the submarine line section handling system (82) and tilting the submarine line section (12) which regards to a horizontal plane before, during or/and after cleaning the submarine line section (12) with a cleaning fluid dispensing hose (86) introduced into the submarine line section (12) from at least one submarine line end (92, 94) of the submarine line section (12).
The submarine line decommissioning method according to claim 14, wherein positioning a submarine line section (12) to be cleaned on at least a support surface of a handling system (82) comprises placing the submarine line section (12) on at least one transverse conveyor (100) having a belt (106) and a power unit (110) powering the belt (106), in a submarine line loading region located transversely away from the cleaning axis (B-B'), and conveying the submarine line section on the transverse conveyor (100) to a submarine line cleaning region.