OA20778A - Protection system of the mouth of a pipeline and method of implementing such a system. - Google Patents

Abstract

The present invention relates to a system (1) for protecting the mouth (4) of a pipeline (2), the system (1) comprising a protective piece (10) having a central part (20) provided with at least an opening (22) for the passage of a fluid (F) circulating in the pipe (2), and a peripheral part (30) provided with skirts (31, 32, 33, 34) provided to protect surfaces (61, 62, 63, 64) of the mouth (4) against the fluid (F), the protective piece (10) being made of deformable material in order to be able to be removed from the inside of the pipe (2).

Description

PROTECTION SYSTEM FOR THE MOUTH OF A PIPELINE, AND METHOD FOR IMPLEMENTING SUCH A SYSTEM

TECHNICAL AREA

The present invention relates to a system for protecting the mouth of a pipeline, in particular of the “l-Tube” type for oil exploitation. The invention also relates to a method for implementing such a system.

PRIOR ART

Various systems are known for protecting pipes against solid bodies or fluids during their transport or storage.

US2977993A describes an example of a protection system consisting of a cover made of plastic material, in particular elastomer, intended to be arranged at the end of a pipe to protect its interior. The cover includes a closed central part, in the shape of a dome, to prevent the entry of dust, water or other foreign bodies into the pipe.

US5004016 describes another example of a protection system consisting of a piece of elastomeric material, intended to be arranged at the end of a tube to protect its thread. The part comprises a skirt intended to cover the threaded outer surface of the tube. The part is equipped with a hook for its removal from the outside. The hook is arranged in a central orifice allowing the passage of fluid through the part.

DISCLOSURE OF THE INVENTION

The object of the present invention is to provide a protection system for pipelines intended to be submerged, in particular for oil exploitation by a floating production, storage and offloading unit (FPSO: "Floating Production Storage and Offloading" in English), a tension-leg platform (TLP; “Tension-leg platform”), or a floating complex for liquefied natural gas (FLNG; “Floating Liquefied Natural Gas”).

To this end, the subject of the invention is a system for protecting the mouth of a pipeline, the system comprising a protective part having a central part provided with at least one opening for the passage of a fluid circulating in the pipe, and a peripheral part provided with skirts provided to protect the surfaces of the mouth against the fluid, the protective part being made of deformable material in order to be able to be removed from the inside of the pipe.

Thus, the invention makes it possible to protect the mouth of the pipe against fluid and foreign bodies (sea water and marine organisms such as algae, shells, etc.), while offering the possibility of removing the protective part selectively by inside or outside the pipe.

The protective part is designed to withstand transport of the pipe, for example connected to an FPSO unit, likely to be towed at sea between two continents.

At the same time, the protective part is designed to allow non-manual removal, that is, by mechanized means.

This removal can be carried out from the outside with a remotely operated underwater vehicle (ROV: "Remotely Operated Underwater Vehicle" in English) under several meters of water, with a low traction force. However, such an operation is expensive and complex. Removal from the outside by a diver is totally prohibited given the fatal risks.

Particularly advantageously, the removal can be carried out from inside the pipeline, from a floating unit, a platform or a boat, using a winch pulling on a rope or strap fixed to the protective part. This then deforms and folds back on itself, so that it can go up along the pipe. This mode of withdrawal is much simpler and less costly than the intervention of an underwater robot.

According to other advantageous characteristics of the invention, taken individually or in combination:

- The protective piece has thinned areas to facilitate deformation and removal. - The thinned zones are formed on the peripheral part.

- The thinned zones comprise lines distributed in axial planes on the peripheral part.

- The thinned areas include at least some of the junction angles between the skirts of the peripheral part.

- The thinned areas are formed on the central part.

- The thinned areas include thinned sections formed on the radii of the central part.

- The central part has a wheel shape, with at least two spokes connected to the peripheral part and separated by fluid passage openings.

- The spokes have a cylindrical section.

- The spokes are inclined with respect to a radial plane of the protective part.

- The peripheral part is provided with at least three skirts designed to respectively protect an inner surface, a front surface and an outer surface of the mouth of the pipe.

- The peripheral part is provided with four skirts designed to respectively protect an inner surface, a front surface, an outer surface and a rear surface of the mouth of the pipe.

- The system includes attachment means designed to attach traction means to the protective part for its removal.

- The attachment means are designed to attach traction means to the protective part from above and below, with a view to its removal selectively from the inside or the outside of the pipe.

- The attachment means include an anchor fixed to the hub of the central part.

- The anchoring part is made of a harder material than the protective part.

- The attachment means comprise an anchoring member secured to the hub of the central part.

- The attachment means include the hub of the central part, directly receiving the traction means.

- The attachment means comprise elements arranged on the peripheral part of the protective part and designed to receive the traction means.

- The protective piece is made of polyurethane material, preferably Courbhane (registered trademark).

- The anchoring piece is made of polyurethane material, preferably Courbhane (registered trademark), which is harder than the material of the protective piece.

The invention also relates to a method for implementing a protection system as mentioned above, the method comprising a step of mounting the protective part on the mouth of the pipe, and a step of removing of the protective piece, selectively from the inside or from the outside of the pipe.

During the assembly stage, the protective piece is force-fitted onto the mouth of the pipe. This operation does not require tools in contact with the mouthpiece to be protected.

During the removal step, the protective piece is pulled and deformed so as to release it from the mouth of the pipe. For its removal from the inside, the part is folded back on itself, so that its outside diameter (or its largest outside dimension) becomes smaller than the inside diameter of the pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood on reading the following description, given solely by way of non-limiting example and made with reference to the appended drawings in which:

[Fig 1] is an exploded perspective view of a pipe mouth protection system, showing said pipe mouth, and the system consisting of two parts, namely a protective part and an attachment part.

[Fig 2] is an axial view of the system without the pipe.

[Fig 3] is a cross-section of the system and the pipeline, along line III-III in Figure 2.

[Fig 4] is a larger scale view of detail IV in Figure 3, showing a first side of the protective piece.

[Fig 5] is a larger scale view of detail V in Figure 3, showing a second side of the protective piece.

[Fig 6] is a perspective view of the attachment piece.

[Fig 7] is a larger scale view of detail VII in figure 2, showing the attachment piece.

[Fig 8] is a larger scale view of detail VIII in figure 3, showing the attachment piece.

[Fig 9] is a perspective and cross-sectional view of a protection system according to a second embodiment of the invention.

[Fig 10] is a perspective view of a protection system according to a third embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

In Figures 1 to 8 is shown a system (1) mouth protection (4) pipe (2).

In the example of the figures, the pipe (2) is of the “l-Tube” type, designed to equip an FPSO floating unit, a TLP platform or an FLNG complex. The pipe (2) comprises a tubular body (3) and a mouth (4) provided with a frustoconical part (5) and an annular flange (6). As an indication, an FPSO unit can comprise twentyfour pipes (2) of this type to be protected.

The collar (6) forms a flange for attaching the pipe (2) to another pipe, for example a bend stiffener for a flexible or umbilical conduit.

The collar (6) comprises four surfaces (61,62,63,64) whose protection by the system (1) is desired, namely an inner cylindrical surface (61), a frontal annular surface (62), a cylindrical surface exterior (63) and a rear annular surface (64). The flange (6) comprises a plurality of through bores (65) provided between the front surface (62) and the rear surface (64).

A fluid (F) circulating in the pipe (2) is represented by a double arrow in FIG. 3. The fluid (F) is for example seawater, circulating freely in one direction or the other while the mouth (4) of the pipe (2) is submerged, during its transport or on the operating site.

The system (1) comprises a protective part (10) and an anchoring part (40). The protective part (10) comprises a central part (20) and a peripheral part (30).

The central part (20) has a wheel shape. The central part (20) includes a set of spokes (21), openings (22) formed between the spokes (21), and a central hub (23). The openings (22) allow the passage of the fluid (F) through the system (1).

It is obvious that in order not to hinder the passage of the fluid (F) through the system (1), the central part (20) does not include any additional element such as a membrane closing off the openings (22) , The openings (22) of the central part (20) represent a total area corresponding to at least 30% of the section of the pipe (2), and preferably more than 50%.

The spokes (21) extend between the hub (23) and the peripheral part (30). The spokes (21) have a cylindrical section, minimizing the hydrodynamic resistance to the fluid (F), compared to a flat section. The spokes (21) are inclined with respect to a radial plane (P10) of the part (10), minimizing the hydrodynamic resistance to the fluid (F), with respect to spokes (21) which would all be arranged in the same radial plane (R10).

The central part (20) comprises a collar of stiffening ribs (24) arranged between the spokes (21), all around the hub (23). The central part (20) also comprises a series of stiffening elements (25) arranged on either side of the spokes (21) and against the peripheral part (30). These stiffening means (24, 25) make it possible to ensure that the protective part (10) does not give way when it is removed.

The peripheral part (30) comprises four skirts (31, 32, 33, 34) designed to protect four surfaces (61, 62, 63, 64) of the mouthpiece (4) against fluid (F) and foreign bodies. More specifically, the peripheral part (30) comprises a cylindrical inner skirt (31), a front annular skirt (32), an outer cylindrical skirt (33) and a rear annular skirt (34) respectively protecting the inner cylindrical surface (61) , the front annular surface (62), the outer cylindrical surface (63) and the rear annular surface (64) of the mouth (4) of the pipe (2). In practice, the geometry of the peripheral part (30) is adapted to the geometry of the collar (6). The skirts (31-34) cover the surfaces (61-64), preferably by being pressed against these surfaces (61-64).

The protective piece (10) is made of deformable material so as to be intended to be removed from the inside of the pipe (2). The folded piece (10) has an outside diameter which is smaller than the inside diameter of the pipe (2). The part (10) exhibits elastomeric behavior, with the ability to deform for shrinkage, and return to the initial shape and dimensions after shrinkage.

Preferably, the protective piece (10) is made of Courbhane polyurethane material (registered trademark).

Advantageously, the protective piece (10) may include thinned areas to facilitate its deformation, its folding and its removal. The thinned zones can be formed on the peripheral part (30) and/or on the central part (20). In the example of the figures, the thinned zones comprise lines (35) distributed in axial planes (P30) on the peripheral part (30), as well as the junction angles (36) between the skirts (32, 33) and the function angles (37) between the skirts (33, 34). In a variant not shown, the thinned zones can comprise thinned sections formed on the spokes (21) of the central part (20).

The anchoring part (40) constitutes hooking means for hooking traction means to the part (10) with a view to its removal. The anchoring piece (40) is secured to the hub (23), for example by overmoulding. In the example of the figures, the anchoring piece (40) comprises an upper portion (41) provided with an upper fixing orifice, a lower portion (42) provided with a lower fixing orifice, and a middle portion (43) thinner than the portions (41,42) and provided with several orifices (44) for receiving the material of the hub (23).

The traction means can comprise a metal hook (50) fixed to the upper portion (41) of the anchoring piece (40), and a rope or strap fixed to the hook (50) and going up through the inside of the pipe. (2), to remove the protective piece (10) from the inside. If necessary, a hook (50) and a rope can be attached to the lower portion (42) of the anchoring part (40), to remove the protective part (10) from the outside.

The anchoring part (40) can be made of a harder material than the protective part (10), in order to better withstand the tensile forces. Preferably, the anchoring part (40) is made of polyurethane material, which is harder than the protective part (10). Still preferably, the anchoring piece (40) can be made of Courbhane polyurethane material (registered trademark).

Other embodiments of a protection system (1) in accordance with the invention are shown in FIGS. 9 and 10. Certain constituent elements are comparable to those of the first embodiment described above and, for the purpose of simplification , bear the same reference numerals.

Figure 9 shows a protection system (1) consisting of a single protective piece (10). The center of the hub (23) comprises an anchoring member (26) integral with the central part (20). Two cords (51, 52) or straps can be attached to the member (26), respectively above and below. A first rope (51) goes up through the pipe (2) to allow the protective part (10) to be retrieved from the inside. A second rope (52) can be fixed under the protective part (10) to remove it from the outside, if necessary.

Figure 10 shows a protection system (1) consisting of a single protective piece, the central part (20) of which is completely hollowed out. The peripheral part (30) has four attachment points (38) provided for attaching ropes or straps. These ropes go up through the pipe (2) to allow the part (10) to be recovered from the inside. Alternatively, the ropes can remain on standby under the part (10) for removal by an underwater vehicle.

The part (10) is generally monobloc, so that the system (1) is mainly made from a single material.

Furthermore, the protection system (1) and the pipe (2) can be shaped differently from FIGS. 1 to 10 without departing from the scope of the invention, which is defined by the claims. In addition, the technical characteristics of the various embodiments and variants mentioned above can be, in whole or for some of them, combined with each other. Thus, the system (1) can be adapted in terms of cost, functionalities and performance.

Claims (10)

1. System (1) for protecting the mouth (4) of a pipe (2), the system (1) comprising a protective part (10) having a central part (20) provided with at least one opening ( 22) for the passage of a fluid (F) circulating in the pipe (2), and a peripheral part (30) provided with skirts (31, 32, 33, 34) provided to protect surfaces (61, 62, 63 , 64) of the mouth (4) against the fluid (F), the protective piece (10) being made of deformable material, in order to be able to be removed from the inside of the pipe (2), 2. System (1) according to any one of the preceding claims, characterized in that the part (10) has thinned areas (35, 36, 37) to facilitate deformation and shrinkage. 3. System (1) according to any one of the preceding claims, characterized in that the central part (20) has the shape of a wheel, with at least two spokes (21) connected to the peripheral part (30) and separated by openings (22) for passage of fluid (F). 4. System (1) according to claim 3, characterized in that the spokes (21) have a cylindrical section. 5. System (1) according to claim 3 or 4, characterized in that the spokes (21) are inclined with respect to a radial plane (P10) of the protective part (10). 6. System (1) according to any one of the preceding claims, characterized in that the peripheral part (30) is provided with at least three skirts (31, 32, 33) provided to respectively protect an inner surface (61) , a front surface (62) and an outer surface (63) of the mouth (4) of the pipe (2). 7. System (1) according to any one of the preceding claims, characterized in that the system (1) comprises attachment means (26; 38; 40) designed to attach traction means to the protective part (10 ) for removal. 8. System (1) according to claim 7, characterized in that the attachment means (26; 38; 40) are designed to attach traction means to the protective part (10) above and below, for its removal selectively from the inside or from the outside of the pipe (2). 9. System (1) according to any one of the preceding claims, characterized in that the protective part (10) is made of polyurethane material. 10. Method for implementing a protection system (1) according to any one of claims 1 to 9, characterized in that the method comprises a step of mounting the protective part (10) on the mouthpiece (4) of the pipe (2), and a step of removing the protective part (10), selectively from the inside or from the outside of the pipe (2).