WO2020127790A1

WO2020127790A1 - Flexible pipe for transporting a hydrocarbon fluid within a body of water, and associated method

Info

Publication number: WO2020127790A1
Application number: PCT/EP2019/086387
Authority: WO
Inventors: Anh-Tuan DO
Original assignee: Technip France
Priority date: 2018-12-21
Filing date: 2019-12-19
Publication date: 2020-06-25
Also published as: FR3090799A1; FR3090799B1

Abstract

A flexible pipe (10) with a central axis (A) intended for transporting, within a body of water, a hydrocarbon fluid comprising gas particles, the flexible pipe (10) comprising a tubular anti-corrosion barrier (16) intended to prevent the gas particles from passing from the internal passage to outside the flexible pipe (10), the anti-corrosion barrier (16) comprising a polymer matrix (24) formed by a first material having a melting temperature (Tf1) and fillers (26) in the solid state arranged within the polymer matrix, comprising a second material having a melting temperature (Tf2) higher than the melting temperature (Tf1), wherein the second material of the fillers (26) is chosen from semi-crystalline thermoplastic polymer materials.

Description

DESCRIPTION

FLEXIBLE PIPE FOR TRANSPORTATION, WITHIN A BODY OF WATER, OF A HYDROCARBON FLUID AND ASSOCIATED METHOD

Technical field of the invention

The invention relates to the technical field of flexible pipes intended for the transport, within a body of water, of a hydrocarbon fluid.

More particularly, the flexible pipes according to the invention are used in the exploitation and production of hydrocarbons in an underwater environment.

State of the art

In the context of the exploitation and production of hydrocarbons in an underwater environment, flexible pipes are deployed within a body of water in order to convey a hydrocarbon fluid from an underwater installation to a surface installation across a body of water.

The body of water can be a lake, sea or ocean. The depth of the extent is generally between 200 m and 5000 m, more generally between 1000 m and 2500 m.

The subsea installation to which a first flexible pipe end can be directly or indirectly connected is, for example, a wellhead intended to control the production of hydrocarbon fluid leaving the well or a collector intended to collect and / or distribute the fluid from one or more wellheads, for example to one or more additional or surface subsea installations. The surface installation to which a second flexible pipe end is generally connected directly or indirectly and to which the fluid in raw or pretreated form is routed, is for example a floating platform such as a Floating Production Unit, of Storage and Unloading (FPSO for Floating, Production, Storage and Offloading in English) or a tensioned cable platform (TLP for Tension Leg Platform in English). The hydrocarbon fluid is a multiphase mixture comprising at least one liquid phase formed of linear and / or cyclic carbon compounds, saturated and / or unsaturated, of variable density and / or a liquid phase formed of water, at least one gas phase formed by example of methane (CH ₄ ), carbon dioxide (CO2), hydrogen sulfide (HS), and optionally at least one solid phase comprising sand for example. Depending on the characteristics of the reservoir, at the outlet of the well, the temperature of the hydrocarbon fluid is between 25 ° C and 130 ° C. In general, the temperature of the hydrocarbon fluid decreases during transport.

Flexible pipes in the technical field of the invention are for example described in the normative documents API 17J (4 ^th edition, May 2014) and API 17B (5 ^th edition, March 2014) published by the American Petroleum Institute.

A flexible pipe generally comprises several sections of pipes connected to each other by connection end pieces.

Furthermore, the flexible pipe extends along a longitudinal axis and includes an internal passage for circulation of the hydrocarbon fluid. The passage is for example delimited by an internal tubular sheath. The internal sheath generally comprises a polymeric material chosen from polyolefins such as a polyethylene, a polyamide such as a polyamide 11 or a fluorinated polymer such as a polyvinylidene fluoride. The material of the internal sheath is chosen according to the conditions of pressure, temperature and the nature of the fluid transported.

In addition, the flexible pipe comprises at least one metallic reinforcing layer arranged coaxially around the internal sheath and intended to reinforce the flexible pipe against axial forces and / or internal radial forces exerted on the flexible pipe. The reinforcing layer comprises an anti-bursting sheet, called a pressure vault, intended to reinforce the flexible pipe against the internal radial forces exerted on the flexible pipe. The anti-burst sheet is formed by a helical winding of metal wires of cross-section, for example in the form of Z, T, U, K or I. The metal wires of the anti-burst sheet are wound in a short pitch. By short pitch, it is understood an absolute helix angle between 75 ° and 90 °, typically 90 °. The metallic reinforcing layer also comprises a superposition of at least two plies of tensile armor arranged around the anti-burst ply and intended to reinforce the flexible pipe against the axial forces exerted on the flexible pipe. The tensile armor plies are generally formed by a helical winding of metallic wires of rectangular section for example. The metallic wires of the tensile armor plies are wound in a long pitch. By long pitch is meant an absolute helix angle between 20 ° and 55 °. Typically, the wires of a first layer of tensile armor are wound at an angle opposite to the winding angle of the wires of a second layer of tensile armor. For example, when the first layer of tensile armor is wound at an angle of + 25 °, the second layer of tensile armor is wound at an angle of -25 °.

In addition, the flexible pipe comprises a tubular external sheath arranged coaxially around the reinforcing layer intended to limit the penetration of water into the flexible pipe. The outer sheath comprises a polymeric material chosen for example from polyolefins such as polyethylene, polypropylene or polyamide.

In addition, an annular space is located between the outer sheath and the inner sheath. The annular space is defined as the volume between the outer sheath and the inner sheath. The reinforcing layer is generally arranged within the annular space.

Furthermore, in the technical field of the invention, the reinforcing layer is configured to move longitudinally relative to the layers of the flexible pipe during bending of the flexible pipe. The flexible pipe is called "unbound" in the technical field of the invention. This guarantees the flexibility of the flexible pipe.

Although the internal sheath is impermeable to liquids, under specific pressure and temperature conditions, certain gas molecules such as hydrogen sulfide, carbon dioxide molecules can migrate through the internal sheath and accumulate on within the annular space. These gas molecules, combined with the presence of water within the annular space are factors favoring various types of corrosion of the reinforcing layer such as for example uniform corrosion, stress corrosion (SSC for Stress Corrosion Cracking in English) or hydrogen cracking (HIC for Hydrogen Induced Cracking in English). The integrity of the reinforcing layer is then affected, which reduces the service life of the flexible pipe.

The document WO20081 13362 describes a flexible pipe of the aforementioned type further comprising an anti-corrosion barrier making it possible to limit the passage of gas particles towards the annular space. This corrosion barrier includes a formed polymer matrix of a first material having a melting temperature Tfi and fillers formed of a second material having a melting temperature Tf greater than Tfi. In particular, according to document WO20081 13362, the fillers are cationic clay silicates.

The mechanical properties of clay silicates and matrix polymers are far apart. In particular, the presence of charges of cationic clay silicates increases the stiffness of a polymeric sheath with constant thickness. For example, adding 30% of cationic clay silicate fillers to polypropylene increases the elastic modulus of polypropylene by six. This creates difficulties in installing and using the flexible pipe, especially during dynamic applications for which considerable flexibility is required. In addition, the elongation at break of these fillers is lower than the elongation at break of the polymer matrix. This variation in mechanical properties leads to concentrations of local stresses in the charges of clay silicates within the anti-corrosion barrier where cracks can arise and propagate through said anti-corrosion barrier. The anti-corrosion barrier thus cracked no longer fulfills its role of barrier with respect to gas particles which can diffuse and concentrate within the annular space thus weakening the reinforcing layer. In addition, during manufacturing processes, the charges of cationic clay silicates tend to agglomerate and not to distribute themselves homogeneously within the polymer matrix. Additional manufacturing steps for treating the charges must be carried out to ensure a uniform distribution of the charges within the polymer matrix, which makes the manufacture of the anti-corrosion barrier complex.

There is then a need to provide a flexible pipe intended for the transport, within a body of water, of a hydrocarbon fluid comprising an anti-corrosion barrier having properties compatible with dynamic applications and the manufacture of which is simplified.

Disclosure of invention

The present invention relates to a flexible pipe of central axis A intended for the transport, within a body of water, of a hydrocarbon fluid comprising gas particles, said flexible pipe comprising:

- an internal passage for circulation of the hydrocarbon fluid, a tubular anti-corrosion barrier intended to limit the passage of gas particles from the internal passage towards the outside of the flexible pipe, said anti-corrosion barrier comprising a polymer matrix formed from a first material having a melting temperature Tfi and solid state fillers arranged within the polymer matrix, comprising a second material having a melting temperature Tf higher than the melting temperature Tfi,

- at least one metallic external reinforcement layer arranged around the anti-corrosion barrier and intended to reinforce the flexible pipe against axial forces and / or internal radial forces exerted on the flexible pipe,

- a tubular external sheath arranged coaxially around the external reinforcing layer making it possible to limit the penetration of water from the body of water within the flexible pipe, characterized in that the second filler material is chosen from polymers semi-crystalline thermoplastics.

Semi-crystalline thermoplastic polymers have an elongation at break of at least 10% as measured at 23 ° C. This minimizes stress concentrations within the corrosion barrier and thus preserves its integrity for 20 years or more. In addition, semi-crystalline thermoplastic polymers have a tensile modulus between 0.7 and 4 GPa as measured at 23 ° C which keeps the stiffness of the anti-corrosion barrier at a level compatible with the use of flexible pipe. Thus, the flexible pipe can be rolled up, unwound for storage and installation and used in dynamic applications. Also, semi-crystalline thermoplastics are easily distributed within the polymer matrix of the anti-corrosion barrier without any specific implementation process for the presence of fillers, which makes the manufacture of the anti-corrosion barrier simpler. The charges are generally dispersed within the polymer matrix.

Advantageously, the melting temperature Tf2 of the second material of the fillers is greater than or equal to 250 ° C and preferably between 300 ° C and 400 ° C. The melting point corresponds to the temperature from which the crystalline phase of semi-crystalline thermoplastics changes from a crystalline state to a viscous state. This charge melting temperature makes it possible to maintain the charges in the solid state during the manufacture of the anti-corrosion barrier which notably involves the melting of the first material forming the polymer matrix. The solid charges thus make it possible to increase the diffusion path of the transported gases such as carbon dioxide and / or hydrogen sulfide within the polymer matrix of the anti-corrosion barrier to limit the diffusion coefficient of the transported gases. such as carbon dioxide and / or hydrogen sulfide within the matrix of the anti-corrosion barrier.

Advantageously, the second filler material is chosen from a polyaryletherketone such as a polyetherketone or a polyetheretherketone or a polyetherketone ketone or a polyetheretherketone ketone, or a polyetherketoneetherketoneketone. Polyaryletherketones represent a family of semi-crystalline thermoplastic polymers whose crystalline phase, composed of ether and ketone units, confers good barrier properties with respect to gases such as carbon dioxide and / or hydrogen sulfide. . This family of materials thus makes it possible to improve the sealing of the anti-corrosion barrier with respect to gases such as carbon dioxide and / or hydrogen sulfide.

Advantageously, the fillers are in the form of powder particles. By “powder particles” is meant particles for which the length ratio is preferably less than 3. The length ratio (“aspect ratio” in English) corresponds to the ratio of the longest diameter of the particle to the diameter the shortest, the longest diameter and the shortest diameter being measured in directions perpendicular to each other.

In the sense of demand, the diameters of the particles are measured by dynamic light scattering (DLS) according to ISO 22412 of 2017.

Preferably, the powder particles have a volume diameter d _v 50 of less than 1 mm. The powder particles can be implemented by a conventional extrusion process which facilitates the manufacturing process of the anti-corrosion barrier.

Alternatively, the fillers are in the form of fibers, preferably having an average length of less than 1 mm. A fiber generally has a length ratio (length / diameter ratio of the fiber) greater than 5, in particular greater than 10. The length and the diameter of the fibers can be measured by image analysis, for example by using the Zéphyr LDA device, averaging on at least 50 fibers. The fibers make it possible to increase the diffusion path within the anti-corrosion barrier, which makes it possible to reduce more significantly the diffusion coefficient of gases such as carbon dioxide and / or hydrogen sulfide within the matrix of the anti-corrosion barrier. In addition, such an average length of fibers allows a better distribution of the charges within the matrix.

Advantageously, the volume concentration of the charges within the anti-corrosion barrier is at least 30% and even more advantageously between 30% and 50% and preferably between 30% and 40%. The volume concentration can for example be measured by scanning electron microscopy (SEM). This concentration makes it possible to improve the barrier properties of the anti-corrosion barrier with respect to gases such as carbon dioxide and / or hydrogen sulfide while preserving the mechanical properties of the polymer matrix.

Advantageously, the charges comprise a metallic external coating. This metallic external coating can partially or totally coat the surface of the second material. The permeability of metallic materials is lower than polymeric materials. Thus, the external metallic coating of the charges makes it possible to reduce the diffusion of gases within the charges. In addition, the thickness of the metal coating is of the order of a micrometer so as not to affect the stiffness of the anti-corrosion barrier and that the hardness of the metal does not cause concentration of stress within the anti-corrosion barrier.

According to the present invention, the melting temperatures Tf 1 and Tf2 are measured by differential scanning calorimetry (DSC) according to ISO standard 1 1357-3 of 2018, typically at atmospheric pressure. The first material forms the polymer matrix of the corrosion barrier. It is therefore a polymer. This first material has a melting temperature Tf1. It is therefore a semi-crystalline polymer.

The first material which forms the polymeric matrix of the anti-corrosion barrier may comprise a single semi-crystalline polymer. The first material which forms the polymeric matrix of the anti-corrosion barrier can comprise a mixture of semi-crystalline polymers. In this case, the melting temperature Tf1 i of each of these is lower than the temperature Tf2 of the second material of the fillers.

The melting temperature of the second material of the fillers is higher than the melting temperature Tf 1 of the first material which forms the polymer matrix. Generally, the difference between Tf2 and Tf 1 is greater than 10 ° C, in particular greater than 20 ° C, typically greater than 50 ° C, for example greater than 100 ° C.

Advantageously, the first material of the polymer matrix is chosen from polyolefins such as polypropylene or polyethylene. The polyolefins have a melting temperature below 200 ° C. which makes them extrudable at temperatures below the melting point of the fillers. Furthermore, the polyolefins have a flexural elasticity module, a chemical resistance as well as a mechanical resistance compatible with the use of the flexible pipes according to the invention.

Advantageously, the flexible pipe comprises an internal tubular sheath arranged inside or around the anti-corrosion barrier. The internal sheath makes it possible to create a sealed space with respect to the liquid phase of the fluid transported at least. The internal sheath thus makes it possible to reduce the physical-chemical attacks and the mechanical stresses within the anti-corrosion barrier, in particular when the internal tubular sheath is arranged inside the anti-corrosion barrier.

Advantageously, the anti-corrosion barrier and the internal sheath are linked. Preferably, the anti-corrosion barrier and the internal sheath are bonded or bonded. The diffusion coefficient of gases such as carbon dioxide and / or hydrogen sulfide within the anti-corrosion barrier is lower than the diffusion coefficient of these gases within the internal sheath. Bonding therefore keeps the anti-corrosion barrier and the internal sheath intimately linked in order to prevent the accumulation of gases at the interface and to avoid damage within the flexible pipe.

Optionally, the flexible pipe includes an internal reinforcement structure making it possible to limit the crushing of the flexible pipe under the effect of external radial forces exerted on the flexible pipe.

Optionally, the external reinforcement layer of the flexible pipe comprises an anti-bursting sheet intended to reinforce the flexible pipe against the radial forces. internal around which is wound a superposition of at least two plies of tensile armor intended to reinforce the flexible pipe against the axial forces exerted on the flexible pipe.

Advantageously, the external reinforcing layer is configured to move longitudinally relative to any of the layers of the flexible pipe when the flexible pipe is bent. This increases the flexibility of the flexible pipe which can be wound on smaller radii of curvature during installation and storage of the flexible pipe.

The invention also relates to a method for manufacturing a flexible pipe with a central axis intended for transporting, within a body of water, a hydrocarbon fluid comprising gas particles, said flexible pipe comprising a passage internal circulation of the hydrocarbon fluid, the method comprising the following steps:

forming a tubular anti-corrosion barrier intended to limit the passage of gas particles from the internal passage towards the outside of the flexible pipe, said anti-corrosion barrier comprising a polymer matrix formed from a first material having a melting temperature Tfi and fillers in the solid state arranged within the polymer matrix comprising a second material having a melting temperature Tf higher than the melting temperature Tfi,

- have a layer of metallic external reinforcement around the anti-corrosion barrier intended to reinforce the flexible pipe against axial forces and / or internal radial forces exerted on the flexible pipe,

- arrange coaxially around the outer reinforcing layer a tubular outer sheath intended to limit the penetration of water within the flexible pipe, characterized in that the second filler material is chosen from semi-crystalline thermoplastic polymers.

The process of the invention is simplified compared to the process of document WO20081 13362 in that the semi-crystalline thermoplastic materials of the fillers can be extruded and dispersed easily within the polymer matrix of the anti-corrosion barrier without aggregation of the fillers. The flexible pipe manufacturing process comprising the anti-corrosion barrier therefore does not require any additional or specific material in order to add the charges within the anti-corrosion barrier.

Description of the figures

Other features and advantages of the invention will emerge on reading the description given below of particular embodiments of the invention, given by way of indication but not limitation, with reference to the figures, in which:

- Figure 1 is a perspective view of a central section of a flexible pipe according to the invention;

- Figure 2 is a schematic view of a matrix comprising fillers according to an embodiment of the invention and

- Figure 3 is a view similar to Figure 2 illustrating an alternative embodiment of the charges.

Detailed description of embodiments of the invention

Figure 1 shows an example of a flexible pipe (10) according to the invention. The flexible pipe (10) is intended for the transport of a hydrocarbon fluid within a body of water. Generally, the transport is carried out from an underwater installation to a surface installation across the body of water.

The body of water can be a lake, sea or ocean. The depth of the body of water is generally between 200 m and 5000 m, more generally between 1000 m and 2500 m.

The subsea installation to which a first end of the flexible pipe (10) can be directly or indirectly connected is, for example, a well head intended to control the production of hydrocarbon fluid at the well exit. According to another example, the underwater installation is a collector intended to collect and / or distribute the fluid from one or more well heads, for example to one or more additional underwater or surface installations. The surface installation to which a second end of the flexible pipe (10) is generally connected directly or indirectly and to which the fluid, in raw or pretreated form, is routed, is for example a platform floating such as a Floating Production, Storage and Unloading Unit (FPSO for Floating, Production, Storage and Offloading in English) or a tensioned cable platform (TLP for Tension Leg Platform in English).

The hydrocarbon fluid is a multiphase mixture comprising at least one liquid phase formed of linear and / or cyclic carbon compounds, saturated and / or unsaturated, of variable density and / or a liquid phase formed of water, at least one gas phase formed by example of methane, carbon dioxide, hydrogen sulfide and optionally at least one solid phase comprising sand for example. Depending on the characteristics of the reservoir, at the outlet of the well, the temperature of the hydrocarbon fluid is between 25 ° C and 130 ° C. In general, the temperature of the hydrocarbon fluid decreases during transport.

The flexible pipe (10) extends along a central axis (A) and includes an internal passage for circulation of the hydrocarbon fluid.

According to the invention, the flexible pipe (10) comprises a tubular anti-corrosion barrier (16) intended to limit the passage of gas particles from the internal passage towards the outside of the flexible pipe (10).

As shown in the examples of Figures 2 and 3, the corrosion barrier (16) includes a polymer matrix (24) and fillers (26). The polymer matrix (24) is formed from a first material. The first material is chosen from polyolefins such as polypropylene or polyethylene. Polyolefins have the advantage of being able to be shaped by conventional manufacturing means such as extrusion. Alternatively, the first material is chosen from polyamides or fluorinated polymers such as a polyvinylidene fluoride (PVDF). The first material has a melting temperature Tfi. The latter is between 100 ° C and 200 ° C. The volume concentration of the first material within the anti-corrosion barrier (16) is preferably greater than or equal to 50% and generally between 50% and 70%.

The anti-corrosion barrier (16) further comprises fillers (26) in the solid state arranged within the polymer matrix (24). The fillers (26) comprise a second material whose melting temperature Tf ₂ is higher than the melting temperature Tfi of the first material of the polymer matrix (24). Preferably, the difference between the melting temperature Tf ₂ of the second material and the melting temperature Tfi of the first material is at least 50 ° C. For example, the melting temperature Tf ₂ is higher or equal to 250 ° C and preferably between 300 ° C and 400 ° C. The melting temperature Th of the second filler material (26) is higher than the melting temperature Tfi of the first material of the polymer matrix (24) which allows, by choosing an intermediate temperature for manufacturing the anti-corrosion barrier ( 16), to carry out the extrusion of the anti-corrosion barrier (16) while maintaining the charges (26) in the solid state. The result is an anti-corrosion barrier (16) with barrier properties superior to an anti-corrosion barrier (16) in which the charges would have been fused during manufacture. In addition, the second material forming the fillers (26) is chosen from semi-crystalline thermoplastic polymers. Semi-crystalline thermoplastic polymers have an elongation at break of at least 10% as measured at 23 ° C according to ISO standard 527-1 2012. These fillers (26) therefore make it possible to limit the stress concentrations at the level of the anti-corrosion barrier (16) and thus preserve its integrity during the service of the flexible pipe (10). In addition, semi-crystalline thermoplastic polymers have a tensile elasticity modulus of between 0.7 GPa and 4 GPa as measured at 23 ° C according to ISO standard 527-1 2012, which makes it possible to provide the anti-corrosion barrier ( 16) with a stiffness compatible with the use of the flexible pipe (10). Also, the semi-crystalline thermoplastics are easily distributed within the matrix (24) without an implementation process specific to the presence of fillers (26), which simplifies the manufacture of the anti-corrosion barrier (16). According to an advantageous embodiment of the invention, the fillers (26) are chosen from polyaryletherketone such as a polyetherketone or a polyetheretherketone or a polyetherketone ketone or a polyetheretherketoneketone, or a polyetherketoneetherketoneketone. The polyaryletherketone family have good barrier properties with respect to gas particles such as carbon dioxide and / or hydrogen sulfide, which makes it possible to effectively limit the diffusion of gas particles through the anti-barrier. -corrosion (16), and consequently, to reduce the corrosion of the external reinforcing layer (18, 20).

As shown in the example in FIG. 2, the fillers (26) are for example in the form of powder particles (28). The powder particles (28) have a diameter D _v 50 of less than 1 mm, for example between 50 μm and 600 μm. The particle size of the powder particles (28) is between 20 μm and 500 μm. The higher the volume concentration of fillers (26) within the anti-corrosion barrier (16), the smaller the particle size will be preferred in order to guarantee the mechanical properties of the anti-corrosion barrier (16). The powder particles (28) make it easier to manufacture the anti-corrosion barrier (16). Another exemplary embodiment is shown in FIG. 3. The fillers (26) are for example in the form of fibers (30) having an average length of less than 1 mm. The fibers (30) make it possible to increase the diffusion path of gases such as carbon dioxide and / or hydrogen sulfide within the anti-corrosion barrier (16) compared to an anti-corrosion barrier comprising fillers in powder form. In addition, taking into account the flexibility of the fibers (30), after the extrusion, the fillers (26) are in the form of entangled structures as shown in FIG. 3 which further increase the path of diffusion of the gases at the within the anti-corrosion barrier (16) with respect to straight structures such as glass fibers for example. The entanglement of the fibers may be in the form of islands or spider webs for example. The average diameter of the fibers is for example between 0.05 mm and 3 mm.

Furthermore, the volume concentration of the charges (26) within the anti-corrosion barrier (16) is at least 30%, advantageously between 30% and 50% and preferably between 30% and 40%. Such a concentration in volume of the charges (26) within the anti-corrosion barrier (16) makes it possible to effectively reduce the diffusion path of gases such as carbon dioxide and / or hydrogen sulfide within the barrier anti-corrosion (16).

According to yet another embodiment of the invention, the charges (26) comprise an external metallic coating. The metal is, for example, chosen from aluminum, nickel, copper or any other suitable metallic material. The metallic external coating makes it possible to reinforce the tightness of the anti-corrosion barrier (16) with respect to gas molecules such as carbon dioxide and / or hydrogen sulfide. Generally, the metallic coating is applied by electrostatic deposition.

The corrosion barrier (16) may include additives such as anti-UV agents. The mass concentration of additives within the anti-corrosion barrier (16) is less than 10%, advantageously less than 5%. The mass concentration of first material (or mixture of first materials) within the anti-corrosion barrier is generally greater than 50%, in particular 75%, preferably greater than 80% by weight. The mass concentration of the first material (or mixture of first materials) within the anti-corrosion barrier. The mass concentration of fillers (26) within the anti-corrosion barrier is generally from 1 to 50%, in particular 5

For example, the anti-corrosion barrier (16) can comprise, or even consist of: - from 50 to 99% by weight, in particular from 75 to 90% by weight of the first material (or of a mixture of first materials),

- from 1 to 50% by weight, in particular from 10 to 25% of fillers (26),

- from 0 to 10% by weight of additives.

The anti-corrosion barrier (16) is for example formed by a superposition of strips wound in a tubular structure. Advantageously, the turns of a lower strip and the turns of an upper strip are welded to each other to seal the anti-corrosion barrier (16) with respect to the gases transported such as dioxide carbon and / or hydrogen sulfide. According to another example, the anti-corrosion barrier (16) is formed by extrusion of a continuous tube which makes it possible to reduce the assembly steps of the anti-corrosion barrier (16) during manufacture.

According to the invention, around the anti-corrosion barrier (16), the flexible pipe (10) comprises at least one metallic external reinforcement layer (18, 20) intended to reinforce the flexible pipe (10) against axial forces and / or internal radial forces exerted on said flexible pipe (10).

As shown in the embodiment of the invention of FIG. 1, the external reinforcing layer (18, 20) comprises an anti-bursting sheet (18) intended to reinforce the flexible pipe (10) against the internal radial forces . The bursting sheet (18), also called pressure vault in the technical field of the invention, comprises a helical winding of metal wires. The metal is, for example, chosen from carbon steel, stainless steel. The section of the son of the anti-bursting sheet (18) is for example in the form of Z, T, U, K or I. The son of the anti-bursting sheet (18) are wound in a short pitch. By short pitch, it is understood an absolute helix angle between 75 ° and 90 °. Advantageously, the external reinforcing layer (18, 20) also comprises a superposition of at least two plies of tensile armor (20) wound around the anti-burst ply (18) and intended to reinforce the flexible pipe (10 ) against the axial forces exerted on said flexible pipe (10). The tensile armor plies (20) include a first tensile armor ply (20a) and a second tensile armor ply (20b). The tensile armor plies (20) are generally formed by a helical winding of metal wires. The turns of the tensile armor plies (20) are contiguous. The metal is, for example, chosen from carbon steel, stainless steel. The section of the wires of the tensile armor plies (20) are rectangular, circular or of any geometry suitable for the present application. The metallic wires of the tensile armor plies are wound in a long pitch. By long pitch is meant an absolute helix angle between 20 ° and 55 °. Typically, the wires of the first tensile armor ply (20a) are wound at an angle opposite to the winding angle of the wires of the second tensile armor ply (20b).

The axial forces exerted on the flexible pipe (10) are the forces exerted along the central axis (A) during the installation of the flexible pipe (10) and / or during the service of the pipe. flexible (10). The axial forces generally result from the weight of the flexible pipe (10). The internal radial forces exerted on the flexible pipe (10) are the forces which are exerted radially with respect to the central axis (A) from the inside to the outside of the flexible pipe (10), generally during the flexible pipe service (10). The internal radial forces result for example from the internal pressure of the transported hydrocarbon fluid exerted on the internal surface of the flexible pipe (10).

In addition, the flexible pipe (10) comprises a tubular external sheath (22) arranged coaxially around the external reinforcing layer (18, 20) intended to limit the penetration of water into the flexible pipe (10). The outer sheath (22) includes a polymeric material. The polymeric material is for example chosen from polyolefins such as polyethylene, polypropylene or polyamide or a mixture of these materials. The outer sheath (22) has a thickness of between 0.5 mm and 10 mm. The outer sheath (22) is watertight from the body of water. The outer sheath (22) is also intended to protect the reinforcing structure (18, 20) from friction with the seabed when the flexible pipe (10) extends over the seabed and / or with laying equipment used during installing the flexible pipe (10) such as clamps.

Typically, the flexible pipe (10) according to the invention comprises an annular space delimited by the external sheath (22) and the anti-corrosion barrier (16), the reinforcing layer (18, 20) being arranged within said annular space. . In particular, the annular space is the volume between the internal face of the external sheath (22) and the external face of anti-corrosion barrier (16). By internal face is meant the face of the sheath oriented towards the inside of the flexible pipe (10), that is to say as close as radially to the axis (A). By external face, it is understood the face of the sheath oriented towards the outside of the flexible pipe (10), that is to say the face of the sheath most radially distant from the axis (A). According to the present invention, the annular space can comprise several annular sub-spaces. For example, when the flexible pipe (10) comprises an additional tubular sheath arranged between the anti-corrosion barrier (16) and the external sheath (22), the annular space comprises a first annular sub-space included between the anti-corrosion barrier (16) and the additional tubular sheath and a second annular sub-space between the additional tubular sheath and the outer sheath (22).

Furthermore, according to the embodiment of Figure 1, the flexible pipe (10) comprises an inner tubular sheath (14). According to this example, the internal sheath (14) is arranged inside the anti-corrosion barrier (16). According to another embodiment not shown, the internal sheath (14) is arranged around the anti-corrosion barrier (16).

The internal sheath (14) extends along the central axis (A). The internal sheath (14) comprises a polymeric material. The polymeric material is chosen from polyolefins such as a polyethylene, a polyamide such as a polyamide 11 or a fluorinated polymer such as a polyvinylidene fluoride. Optionally, the polymeric material can be reinforced with long fibers. Long fibers are defined here as fibers of average length greater than 10 mm. For example, long fibers are carbon fibers embedded in the polymeric material. The internal sheath (14) has a thickness of between 0.5 mm and 5 mm. The nature of the material and the thickness of the internal sheath (14) are chosen as a function of the pressure, temperature and nature of the fluid transported conditions. The internal sheath (14) can be formed by extruding a tube, or extruding strips which are then wound up to form a tube which is leaktight towards at least the liquid phase of the transported hydrocarbon fluid.

According to an exemplary embodiment, the internal sheath (14) and the anti-corrosion barrier (16) are linked. This is particularly advantageous when the anti-corrosion barrier (16) is located around the internal sheath (14). In fact, the speed of diffusion of gas particles such as carbon dioxide and / or hydrogen sulfide being higher within the internal sheath (14) than within the anti-diffusion barrier (16), gases can accumulate within the space between these two layers, and the pressure at the interface of these two layers can increase and damage the flexible pipe (10). The connection thus reduces the risk of damage since the gases can no longer accumulate at the interface. For example, the anti-corrosion barrier (16) and the internal sheath (14) are bonded or bonded. Preferably, the first material of the polymer matrix of the anti-corrosion barrier (16) and the second material of the internal sheath (14) are of the same nature. By the same nature, it it is understood that the mixing of the materials after melting, form a single phase. This makes it possible to improve the bonding force between the internal sheath (14) and the anti-corrosion barrier (16).

Advantageously, the flexible pipe (10) comprises an internal reinforcement structure (12) making it possible to limit the collapse of the flexible pipe (10) under the effect of external radial forces exerted on the flexible pipe (10). The external radial forces exerted on the flexible pipe (10) are the forces which are exerted radially with respect to the axis (A) from the outside towards the inside of the flexible pipe (10), during the installation and / or service of the flexible pipe (10). The external radial forces are for example the forces resulting from the hydrostatic pressure exerted on the external surface of the flexible pipe (10) and / or resulting from the tightening efforts during the installation of the flexible pipe (10). The internal reinforcement structure (12), also called internal carcass in the field of the present invention, comprises a helical winding of self-stapled metal profiles. By self-stapled, it is understood that the profile of a turn is mechanically linked to the profile of an adjacent turn to allow a limited relative movement of the turns of the internal reinforcement structure (12) during a bending of the pipe. flexible (10) for example. The metal is for example chosen from stainless steels such as Duplex 2205 or steel 316L. The profile section is S or T shaped. The profiles of the internal reinforcement structure (12) are wound in a short pitch. By short pitch is meant an absolute helix angle between 75 ° and 90 °. When the flexible pipe (10) comprises the internal reinforcement structure (12), it is said to have a rough passage in the technical field of the present invention. When the flexible pipe (10) does not have an internal reinforcement structure, it is said to have a smooth passage.

Advantageously, the external reinforcing layer (18, 20) is configured to move longitudinally relative to any one of the layers of the flexible pipe (10) during bending of said flexible pipe (10). For example, the external reinforcing layer (18, 20) is free to move longitudinally relative to the external sheath (22), to the anti-corrosion barrier (16) and relative to the internal sheath (14) when that -This is present, in particular during a bending of the flexible pipe (10). This makes it possible to increase the minimum radius of curvature (MBR for Minimum Bend Radius in English) of the flexible pipe (10). The latter can be wound on storage coils according to smaller diameters than a pipe where the elements of the reinforcing layer are fixed, for example, embedded in a layer of elastomer. Generally, the internal sheath (14), the bursting ply (18), the tensile armor plies (20), the external sheath (22) are produced and arranged according to the normative documents API 17J, 4 ^th edition, published in May 2014 by G American Petroleum Institute and API 17B, 5 ^th edition, published in March 2014 by the American Petroleum Institute.

The flexible pipe (10) according to the invention may comprise additional polymeric or metallic layers depending on the applications. For example, the flexible pipe may comprise a pair of additional tensile armor plies wrapped around the pair of tensile armor plies (20) or even anti-wear layers of polyamide, for example arranged between the anti-ply burst (18) and each of the tensile armor plies (20).

A method for manufacturing the flexible pipe (10) described above will now be described.

Optionally, an internal reinforcement structure (12) is formed. For example, the metal profiles are wound in a helix at a short pitch as defined in the present invention.

A first polymeric material is prepared in the form of granules for example, having a melting temperature Tfi and intended to form the polymer matrix (24) of the anti-corrosion barrier (16). A second material is also prepared having a melting temperature Tf ₂ chosen from semi-crystalline thermoplastic polymers intended to form the charges (26) of the anti-corrosion barrier (16). The melting temperature Tfi of the first material is lower than the melting temperature Tf ₂ of the second material. The first material and the second material are then mixed. The mixing can be carried out during the shaping of the anti-corrosion barrier (16) for example within the extruder or upstream of the shaping for example within a hopper. The mixture is then extruded in the form of a tube or strips to form the anti-corrosion barrier (16) at a melting temperature equal to or higher than the melting temperature Tfi of the first material and lower than the melting temperature Tf ₂ of the second material. During the extrusion, the charges (26) are thus maintained in the solid state. When strips are extruded, an additional step of winding said strips is carried out according to a tubular structure forming the anti-corrosion barrier (16). Thereafter, there is arranged coaxially around the anti-corrosion barrier (16) an external reinforcing layer (18, 20) metallic intended to reinforce the flexible pipe (10) against the axial forces and / or the internal radial forces s' acting on the flexible pipe (10). For example, a plurality of metal wires are wound in a short pitch as defined in the present invention to form an anti-burst sheet (18). A pair of tensile armor plies (20) is then arranged around the anti-burst sheet (18). For example, a plurality of metallic wires are helically wound in a long pitch as defined in the present invention to form a first layer of armor (20a), then a plurality of additional metallic wires are wound in a long pitch such that defined in the present invention around the first armor ply (20a) to form a second armor ply (20b), it being understood that the value of the helix angle of the first armor ply (20a) is opposite to the value of the helix angle of the second armor ply (20b).

Then an external sheath (22) is arranged intended to limit the penetration of water within the flexible pipe (10) coaxially around the external reinforcing layer (18, 20). Advantageously, the outer sheath (22) is extruded around the reinforcing layer (18, 20).

Optionally, an internal tubular sheath (14) is formed. The internal sheath (14) is for example formed by extrusion of a tube or extrusion of strips which are then wound and welded to form a tube which is at least vis-à-vis the liquid phase of the transported fluid.

According to an exemplary embodiment, the internal sheath (14) is formed around the anti-corrosion barrier (16) after the step according to which the anti-corrosion barrier (16) is arranged and before placing the reinforcing layer (18 , 20).

According to another exemplary embodiment, the internal sheath (14) is inside the anti-corrosion barrier (16). According to this example, the internal sheath (14) is formed before the step by which the anti-corrosion barrier (16) is arranged.

According to yet another exemplary embodiment, a step of connecting the internal sheath (14) is carried out when the latter is present with the anti-corrosion barrier (16). For example, a step of bonding the internal sheath (14) with the anti-corrosion barrier (16) is carried out. For this, after the formation of the anti-corrosion barrier (16) or of the internal sheath (14), the external surface of the anti-corrosion barrier (16) or of the internal sheath (14) is coated with an adhesive. then the anti-corrosion barrier (16) is formed around the internal sheath (14) or vice versa. Alternatively, the internal sheath (14) is coextruded with the anti-corrosion barrier (16) to bond them by fusion.

The polyetheretherketone forming the fillers (26) is for example the grade Ketaspire® PEEK XT produced by Solvay. According to another example, the Ketaspire® XT 920 P grade produced by Solvay is chosen to form the fillers (26) in the form of powder particles (28). According to yet another example, the Ketaspire® XT 920 NT grade produced by Solvay is for example chosen to form the fillers (26) in the form of fibers (30).

Claims

1. Flexible pipe (10) with central axis (A) intended for the transport, within a body of water, of a hydrocarbon fluid comprising gas particles, said flexible pipe (10) comprising:

- an internal passage for circulation of the hydrocarbon fluid,

- A tubular anti-corrosion barrier (16) intended to limit the passage of gas particles from the internal passage towards the outside of the flexible pipe (10), said anti-corrosion barrier (16) comprising a polymer matrix (24) formed of a first material having a melting temperature Tf 1 and fillers (26) in the solid state arranged within the polymer matrix, comprising a second material having a melting temperature Tf2 higher than the melting temperature Tf 1,

- at least one external reinforcing layer (18, 20) of metal arranged around the anti-corrosion barrier (16) and intended to reinforce the flexible pipe (10) against axial forces and / or internal radial forces exerted on the flexible pipe (10),

- a tubular external sheath (22) arranged coaxially around the external reinforcing layer (18, 20) making it possible to limit the penetration of water from the body of water within the flexible pipe (10), characterized in that that the second material of the fillers (26) is chosen from semi-crystalline thermoplastic polymer materials.

2. Flexible pipe according to claim 1 characterized in that the melting temperature Tf2 of the second filler material (26) is greater than or equal to 300 ° C and preferably between 300 ° C and 400 ° C.

3. Flexible pipe according to claim 1 or 2 characterized in that the second filler material (26) is chosen from a polyaryletherketone such as a polyetherketone or a polyetheretherketone or a polyetherketoneketone or a polyetheretherketoneketone, or a polyetherketoneetherketoneketone.

4. Flexible pipe according to any one of the preceding claims, characterized in that the fillers (26) are in the form of powder particles (28).

5. Flexible pipe according to claim 4 characterized in that the powder particles (28) have a diameter D _v 50 less than 1 mm.

6. Flexible pipe according to one of claims 1 to 3 characterized in that the fillers (26) are in the form of fibers (30) having an average length of less than 1 mm.

7. Flexible pipe according to any one of the preceding claims, characterized in that the volume concentration of the charges (26) within the anti-corrosion barrier (16) is at least 30%, advantageously between 30% and 70 % and preferably between 30% and 50%.

8. Flexible pipe according to any one of the preceding claims, characterized in that the loads (26) comprise an external metallic coating.

9. Flexible pipe according to any one of the preceding claims, characterized in that the first material of the polymer matrix (24) is chosen from polyolefins such as polypropylene or polyethylene.

10. Flexible pipe according to any one of the preceding claims, characterized in that it comprises an internal tubular sheath (14) arranged inside or around the anti-corrosion barrier (16).

1 1. Flexible pipe according to claim 10 characterized in that the anti-corrosion barrier (16) and the internal sheath (14) are linked.

12. Flexible pipe according to claim 1 1 characterized in that the anti-corrosion barrier (16) and the internal sheath (14) are bonded or bonded.

13. Flexible pipe according to any one of the preceding claims, characterized in that it comprises an internal reinforcement structure (12) making it possible to limit the crushing of the flexible pipe (10) under the effect of external radial forces s '' acting on the flexible pipe (10).

14. Flexible pipe according to any one of the preceding claims, characterized in that the external reinforcing layer (18, 20) comprises an anti-burst sheet (18) intended to reinforce the flexible pipe (10) against the internal radial forces around from which is wound a superposition of at least two plies of tensile armor (20) intended to reinforce the flexible pipe (10) against the axial forces exerted on the flexible pipe (10).

15. Flexible pipe according to any one of the preceding claims, characterized in that the external reinforcing layer (18, 20) is configured to move longitudinally relative to any one of the layers of the flexible pipe (10) during bending of the flexible pipe.

16. Method for manufacturing a flexible pipe (10) with a central axis (A) intended for transporting, within a body of water, a hydrocarbon fluid comprising gas particles, said flexible pipe ( 10) comprising an internal passage for circulation of the hydrocarbon fluid, the method comprising the following steps: forming a tubular anti-corrosion barrier (16) intended to limit the passage of gas particles from the internal passage towards the outside of the flexible pipe (10), said anti-corrosion barrier (16) comprising a polymer matrix (24) formed of a first material having a melting temperature Tfi and fillers (26) in the solid state arranged within the polymer matrix (24) comprising a second material having a melting temperature Tf higher than the melting temperature Tfi ,

- have around the anti-corrosion barrier (16) an external reinforcing layer (18, 20) of metal intended to reinforce the flexible pipe (10) against axial forces and / or internal radial forces exerted on the flexible pipe (10), - arranging coaxially around the external reinforcing layer (18, 20) an external tubular sheath (22) intended to limit the penetration of water within the flexible pipe (10), characterized in that the second filler material (26) is chosen from semi-crystalline thermoplastic polymers.