Seabed multi-layer oil and gas conveying pipeline

Abstract

The seabed multi-layer oil and gas conveying pipeline comprises pipeline bodies and pipeline assemblies, the pipeline bodies are combined through the pipeline assemblies, each pipeline assembly comprises a concrete balance weight layer, a corrugated compression-resistant layer, an anti-corrosion protection layer, a steel pipe layer, an anti-attrition coating and spiral fins, the concrete balance weight layers are welded to the outer sides of the pipeline bodies, and the corrugated compression-resistant layers are welded to the outer sides of the pipeline bodies. A corrugated compression-resistant layer is arranged on the inner side of the concrete counterweight layer, an anti-corrosion protection layer is arranged on the inner side of the corrugated compression-resistant layer, a steel pipe layer is installed on the inner side of the anti-corrosion protection layer in an inserted connection mode, the inner side of the steel pipe layer is coated with an anti-attrition coating, and multiple sets of spiral fins are arranged on the outer side of the concrete counterweight layer. According to the composite structure, through multi-level collaborative design, the impact resistance and deformation self-adaptability of the pipeline under deep sea high pressure, ocean current impact and geological displacement are remarkably improved, the structural stability is enhanced through coupling of the honeycomb framework and the corrugated layer, the material redundancy is reduced, and the construction cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas transportation, and particularly to a subsea multi-layer oil and gas transportation pipeline. Background Art

[0002] As a core facility for deep-sea resource development, the performance of subsea oil and gas transportation pipelines directly determines the safety and economy of oil and gas transportation. Traditional pipelines mostly adopt single or simple multi-layer structures, but they face significant technical bottlenecks in complex deep-sea environments, with insufficient compressive resistance and deformation adaptability. Although conventional concrete counterweight layers can provide stability through their own weight, their rigid structures are prone to stress concentration under ocean current impact or geological displacement, resulting in pipeline fracture or plastic deformation failure. The contradiction between structural redundancy and cost is prominent. To improve compressive resistance in the prior art, it is often achieved by increasing the thickness of steel pipes or adding external reinforcement structures, which not only greatly increases material costs but also increases construction complexity and is difficult to meet the high-efficiency requirements of long-distance laying in the deep sea. The anti-corrosion and anti-friction performances have limitations. Traditional anti-corrosion coatings have insufficient corrosion resistance and are prone to local peeling under long-term seawater erosion, while the poor anti-friction performance of the pipeline inner wall leads to an increase in the resistance of crude oil transportation and significantly increases pumping energy consumption.

[0003] In Chinese Patent No. 202420695847.5, there is a lack of thermodynamic co-design. Although some composite pipelines introduce a heat tracing layer to solve the problem of crude oil fluidity, they fail to organically combine structural compressive resistance and thermal stress dispersion, resulting in local thermal expansion causing structural deformation or even leakage risks. Therefore, the present invention proposes a subsea multi-layer oil and gas transportation pipeline to solve the problems existing in the prior art. Summary of the Invention

[0004] In view of the above problems, the object of the present invention is to propose a subsea multi-layer oil and gas transportation pipeline. The composite structure of this subsea multi-layer oil and gas transportation pipeline significantly improves the impact resistance and deformation self-adaptability of the pipeline under deep-sea high pressure, ocean current impact, and geological displacement through multi-level collaborative design. The coupling of the honeycomb skeleton and the corrugated layer not only enhances the structural stability but also reduces material redundancy and construction costs; the combined solution of the anti-corrosion and anti-friction coatings extends the pipeline life and reduces the full-life cycle maintenance cost.

[0005] To achieve the object of the present invention, the present invention is realized through the following technical solutions: A subsea multi-layer oil and gas transmission pipeline includes a pipeline body and pipeline components. The pipeline body is combined through the pipeline components. The pipeline components include a concrete counterweight layer, a corrugated compression layer, an anti-corrosion protection layer, a steel pipe layer, an anti-friction coating, and spiral fins. The concrete counterweight layer is welded to the outside of the pipeline body. The corrugated compression layer is arranged inside the concrete counterweight layer. The anti-corrosion protection layer is arranged inside the corrugated compression layer. The steel pipe layer is inserted and installed inside the anti-corrosion protection layer. The anti-friction coating is applied inside the steel pipe layer. Multiple groups of spiral fins are arranged on the outside of the concrete counterweight layer. The concrete counterweight layer is formed by cross-arranging and welding the spiral fins to form a quadrilateral honeycomb-like skeleton. Concrete is filled inside the honeycomb-like skeleton to form a composite counterweight structure. The corrugated configuration of the corrugated compression layer is connected with the honeycomb nodes of the concrete counterweight layer through spatial coupling and matching.

[0006] Further improvement lies in: The cross-welding angle of the spiral fins is 45° - 60°. The thickness of the spiral fins is 1 / 5 - 1 / 3 of the total thickness of the concrete counterweight layer. The side length of adjacent honeycomb units of the spiral fins is 30mm - 100mm.

[0007] Further improvement lies in: The ratio of the corrugation period of the corrugated compression layer to the side length of the honeycomb units of the concrete counterweight layer is 1:1.5 - 1:5. The corrugation height is 1 / 10 - 1 / 6 of the side length of the honeycomb units.

[0008] Further improvement lies in: A glass fiber reinforced layer is arranged inside the anti-corrosion protection layer. The anti-corrosion protection layer is composed of an epoxy resin-based composite material and the glass fiber reinforced layer 8 alternately laid. The thickness of the glass fiber reinforced layer is 2mm - 5mm.

[0009] Further improvement lies in: The anti-friction coating is a polyurethane graphene composite coating. The surface roughness Ra of the anti-friction coating is ≤0.8μm.

[0010] Further improvement lies in: An elastic buffer layer is provided at the coupling interface between the concrete counterweight layer and the corrugated compression layer.

[0011] Further improvement lies in: The thickness of the anti-friction coating is 0.5mm - 1.2mm.

[0012] Further improvement lies in: The thickness of the elastic buffer layer is 5 - 10mm. The material of the elastic buffer layer is chloroprene rubber.

[0013] Further improvement lies in: An installation base is fixedly installed at the bottom of the pipeline body. Multiple installation slots are opened inside the installation base. The size specifications of each group of installation slots are the same.

[0014] The beneficial effects of the present invention are as follows: Through the combined use of the concrete counterweight layer, corrugated compression layer, anti-corrosion protection layer, steel pipe layer, and anti-friction coating, the composite structure is designed through multi-level coordination, significantly enhancing the impact resistance and deformation self-adaptability of the pipeline under deep-sea high pressure, ocean current impact, and geological displacement. The coupling of the honeycomb skeleton and the corrugated layer not only enhances the structural stability but also reduces material redundancy and construction costs; the combined solution of the anti-corrosion and anti-friction coatings extends the pipeline life and reduces the full-life cycle maintenance cost. The introduction of the elastic buffer layer further optimizes the structural response under dynamic loads, avoiding the brittle failure caused by rigid connections in traditional pipelines, solving the problem of the difficult balance among compressive resistance, anti-corrosion performance, anti-friction performance, and economy in the prior art, providing reliable technical support for the efficient development of deep-sea oil and gas resources, and having significant engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 It is a front view schematic diagram of the pipeline body of the present invention; Figure 2 It is an internal view schematic diagram of the pipeline body of the present invention; Figure 3 It is a stress analysis diagram of the pipeline body of the present invention; Figure 4 It is a strain analysis diagram of the pipeline body of the present invention.

[0017] Reference signs in the drawings: 1. Pipeline body; 2. Concrete counterweight layer; 3. Corrugated compression layer; 4. Anti-corrosion protection layer; 5. Steel pipe layer; 6. Anti-friction coating; 7. Spiral rib; 8. Glass fiber reinforced layer; 9. Elastic buffer layer; 10. Installation base; 11. Installation slot. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0019] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection" and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] In Document 202420695847.5, a counterweight block with a reinforced concrete casting structure is provided outside the pipe body. The buoyancy of seawater can be balanced by the counterweight block to ensure the reliable positioning and fixing of the submarine oil and gas transportation pipeline during laying and operation. Anti-slip particles are provided on the outer surface of the pipe body anti-corrosion layer to avoid relative sliding between the counterweight block and the pipe body, so that the counterweight block and the pipe body are closely integrated into one body, achieving the purpose of improving the laying work efficiency of the submarine oil and gas transportation pipeline and extending the service life of the submarine oil and gas transportation pipeline. However, this application has a leakage risk. In the present application, the coupling of the honeycomb skeleton and the corrugated layer not only enhances the structural stability but also reduces material redundancy, avoiding brittle failure caused by rigid connection in traditional pipelines.

[0021] According to Figure 1 、 Figure 2As shown in the figure, this embodiment provides a subsea multi-layer oil and gas transmission pipeline, which includes a pipeline body 1 and pipeline components. The pipeline body 1 is combined through the pipeline components. The pipeline components include a concrete counterweight layer 2, a corrugated compressive layer 3, an anti-corrosion protection layer 4, a steel pipe layer 5, an anti-friction coating 6, and spiral fins 7. The concrete counterweight layer 2 is welded to the outside of the pipeline body 1. The setting of the concrete counterweight layer 2 increases the weight of the pipeline, making it have sufficient negative buoyancy in seawater to ensure that the pipeline can be stably laid on the seabed. The corrugated compressive layer 3 is arranged inside the concrete counterweight layer 2. The setting of the corrugated compressive layer 3 increases the bending stiffness and compressive strength of the pipeline through the corrugated shape, which helps to resist external pressure and load. The anti-corrosion protection layer 4 is arranged inside the corrugated compressive layer 3. The anti-corrosion protection layer 4 can effectively isolate the direct contact between seawater and the metal surface of the pipeline, preventing electrochemical corrosion caused by salts and dissolved oxygen in seawater. The steel pipe layer 5 is inserted and installed inside the anti-corrosion protection layer 4. The steel pipe layer 5 is the direct channel for transporting oil and gas, with sufficient strength and sealing performance to withstand the pressure of the internal medium and the influence of the external environment. The anti-friction coating 6 is coated inside the steel pipe layer 5. The anti-friction coating 6 reduces the friction resistance when the fluid flows inside the pipeline through its smooth surface characteristics. Multiple groups of spiral fins 7 are arranged on the outside of the concrete counterweight layer 2. The concrete counterweight layer 2 is formed by cross-arranging and welding the spiral fins 7 to form a quadrilateral honeycomb skeleton. The honeycomb skeleton is filled with concrete to form a composite counterweight structure. The corrugated configuration of the corrugated compressive layer 3 is connected with the honeycomb nodes of the concrete counterweight layer 2 through spatial coupling and matching. It not only enhances the overall compressive strength through the geometric interlocking effect but also retains the freedom of bending deformation of the pipeline to adapt to complex terrains. The wave crests and wave troughs of the corrugated compressive layer 3 are coupled with the honeycomb skeleton nodes through spatial matching to construct an efficient stress dispersion network, evenly conducting the deep-sea high pressure and impact load to the counterweight layer and avoiding local stress concentration.

[0022] The cross-welding angle of the spiral fins 7 is 45° - 60°, the thickness of the spiral fins 7 is 1 / 5 - 1 / 3 of the total thickness of the concrete counterweight layer, and the side length of adjacent honeycomb units of the spiral fins 7 is 30mm - 100mm.

[0023] The ratio of the corrugation period of the corrugated compressive layer 3 to the side length of the honeycomb units of the concrete counterweight layer 2 is 1:1.5 - 1:5, and the corrugation height is 1 / 10 - 1 / 6 of the side length of the honeycomb units.

[0024] A glass fiber reinforced layer 8 is arranged inside the anti-corrosion protection layer 4. The anti-corrosion protection layer 4 is composed of an epoxy resin-based composite material and the glass fiber reinforced layer 8 laid alternately. The thickness of the glass fiber reinforced layer 8 is 2mm - 5mm.

[0025] The anti-friction coating 6 is a polyurethane graphene composite coating, and the surface roughness Ra of the anti-friction coating 6 is ≤0.8μm.

[0026] An elastic buffer layer 9 is provided at the coupling interface between the concrete counterweight layer 2 and the corrugated compressive layer 3.

[0027] The thickness of the anti-friction coating 6 is 0.5 mm - 1.2 mm.

[0028] The thickness of the elastic buffer layer 9 is 5 - 10 mm, and the material of the elastic buffer layer 9 is chloroprene rubber.

[0029] An installation base 10 is fixedly installed at the bottom of the pipeline body 1. A plurality of installation slots 11 are opened inside the installation base 10, and the size specifications of each group of installation slots 11 are the same.

[0030] When the submarine multi-layer oil and gas transmission pipeline is in use, from the outside to the inside, the pipeline includes a concrete counterweight layer 2, a corrugated compressive layer 3, an anti-corrosion protection layer 4, a steel pipe layer 5 and an anti-friction coating 6. The concrete counterweight layer adopts a quadrilateral honeycomb skeleton formed by cross-welding spiral rib fins and is filled with concrete inside. It not only enhances the overall compressive strength through the geometric interlocking effect but also retains the freedom of pipeline bending deformation to adapt to complex terrains. The wave crests and wave troughs of the corrugated compressive layer 3 are coupled with the honeycomb skeleton nodes through spatial matching to construct an efficient stress dispersion network, evenly conducting the deep-sea high pressure and impact load to the counterweight layer to avoid local stress concentration. In the concrete counterweight layer, the spiral rib fins are welded at a cross angle of 45°–60°, and the thickness is 1 / 5–1 / 3 of the total thickness of the counterweight layer. The side length of the honeycomb unit is 30–100 mm, taking into account both lightweight and compressive requirements. The corrugation period of the corrugated compressive layer 3 and the honeycomb side length are designed in a ratio of 1:1.5–1:5, and the corrugation height is 1 / 10–1 / 6 of the honeycomb side length to ensure uniform stress distribution. The anti-corrosion protection layer 4 is alternately laid with an epoxy resin-based composite material and a glass fiber reinforced layer, with a thickness of 2–5 mm, having both long-term corrosion resistance and anti-shear performance; the anti-friction coating 6 is made of a polyurethane-graphene composite material, with a surface roughness Ra≤0.8 μm and a thickness of 0.5–1.2 mm, significantly reducing the frictional resistance of crude oil flow and reducing energy consumption. An elastic buffer layer 9 is added between the concrete counterweight layer 2 and the corrugated compressive layer, and the material is chloroprene rubber or silicone rubber, with a thickness of 5–10 mm. This layer can effectively absorb dynamic impact energy, avoid fatigue damage caused by interlayer stress concentration, and at the same time compensate for the thermal expansion difference and improve the structural durability.

[0031] To illustrate the technical effects of the present invention, please refer to Figure 3 The following shows the stress distribution nephogram of a submarine multi-layer oil and gas transmission pipeline provided by an embodiment of the present invention, and Figure 4The strain distribution nephogram of a subsea multi-layer oil and gas transmission pipeline provided by an embodiment of the present invention is shown. In this embodiment, a complete pipeline is intercepted for deep-sea pressure tests. The subsea depth is set at 2000 m, and the average pressure is set at 20 MPa. Through the synergistic effect of the honeycomb skeleton and the corrugated layer, the structural stability of the pipeline is significantly guaranteed, thereby enhancing its impact resistance and deformation self-adaptability in the deep-sea environment. From Figure 3 and Figure 4 of the stress and strain distribution nephograms, the stable effect of the structure can be directly seen. The collaborative effect of the concrete counterweight layer, the skeleton structure and the corrugated layer determines the compressive resistance of the pipeline. When the pressure acts on the pipeline surface, the stress and strain inside the pipeline show no obvious change. Through Figure 3 Figure 4 it can be seen that the excessive stress is mainly concentrated at the base slot holes. The excessive strain generated by the redundant design of the thickness of the installation slot holes does not affect the overall compressive performance of the pipeline. According to the actual application requirements, appropriately adjusting the slot hole design can effectively improve this situation.

[0032] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A subsea multi-layer oil and gas transmission pipeline, comprising a pipeline body (1) and pipeline components, characterized in that: The pipeline body (1) is combined through pipeline components. The pipeline components include a concrete counterweight layer (2), a corrugated compression layer (3), an anti-corrosion protection layer (4), a steel pipe layer (5), an anti-friction coating (6), and spiral fins (7). The concrete counterweight layer (2) is welded to the outer side of the pipeline body (1). The corrugated compression layer (3) is arranged inside the concrete counterweight layer (2). The anti-corrosion protection layer (4) is arranged inside the corrugated compression layer (3). The steel pipe layer (5) is inserted and installed inside the anti-corrosion protection layer (4). The anti-friction coating (6) is coated inside the steel pipe layer (5). Multiple groups of spiral fins (7) are arranged on the outer side of the concrete counterweight layer (2). The concrete counterweight layer (2) is formed by cross-arranging and welding the spiral fins (7) to form a quadrilateral honeycomb-like skeleton, and the honeycomb-like skeleton is filled with concrete to form a composite counterweight structure. The corrugation configuration of the corrugated compression layer (3) is connected to the honeycomb nodes of the concrete counterweight layer (2) through spatial coupling and matching.

2. The submarine multi-layer oil and gas transmission pipeline according to claim 1, characterized in that: The cross-welding angle of the spiral fins (7) is 45° - 60°. The thickness of the spiral fins (7) is 1 / 5 - 1 / 3 of the total thickness of the concrete counterweight layer. The side length of adjacent honeycomb units of the spiral fins (7) is 30 mm - 100 mm.

3. The undersea multi-layer oil and gas transmission pipeline according to claim 1, characterized in that: The ratio of the corrugation period of the corrugated compression layer (3) to the side length of the honeycomb unit of the concrete counterweight layer (2) is 1:1.5 - 1:

5. The corrugation height is 1 / 10 - 1 / 6 of the side length of the honeycomb unit.

4. A subsea multi-layer oil and gas pipeline according to claim 1, characterized in that: A glass fiber reinforced layer (8) is arranged inside the anti-corrosion protection layer (4). The anti-corrosion protection layer (4) is composed of alternately laying an epoxy resin-based composite material and the glass fiber reinforced layer (8). The thickness of the glass fiber reinforced layer (8) is 2 mm - 5 mm.

5. A subsea multi-layer oil and gas pipeline according to claim 1, characterized in that: The anti-friction coating (6) is a polyurethane graphene composite coating, and the surface roughness Ra of the anti-friction coating (6) is ≤ 0.8 μm.

6. A subsea multi-layer oil and gas pipeline according to claim 1, characterized in that: An elastic buffer layer (9) is provided at the coupling interface between the concrete counterweight layer (2) and the corrugated compression layer (3).

7. The submarine multi-layer oil and gas transmission pipeline according to claim 1, characterized in that: The thickness of the anti-friction coating (6) is 0.5 mm - 1.2 mm.

8. The submarine multi-layer oil and gas transmission pipeline according to claim 6, characterized in that: The thickness of the elastic buffer layer (9) is 5 - 10 mm, and the material of the elastic buffer layer (9) is chloroprene rubber.

9. A subsea multi-layer oil and gas pipeline according to claim 1, characterized in that: An installation base (10) is fixedly installed at the bottom of the pipeline body (1). Multiple groups of installation slots (11) are opened inside the installation base (10), and the size specifications of each group of installation slots (11) are the same.

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