Design method of deep-sea non-adhesive flexible riser

Abstract

The invention discloses a deep-sea non-adhesive flexible riser design method, which comprises the following steps of: firstly, determining the use condition and the installation requirement of a deep-sea non-adhesive flexible riser, fully considering the influence of the use time and the annular environment of the non-adhesive flexible riser, and calculating the load performance requirement of the deep-sea non-adhesive flexible riser; main technical parameters of the deep-sea non-adhesive flexible riser are determined, structural size design from each layer to the whole is carried out, and static strength and dynamic load strength checking is completed; and carrying out a dynamic fatigue test on the deep-sea non-adhesive flexible riser, obtaining fatigue analysis check, and ensuring the service performance of the non-adhesive flexible riser. According to the method, through working condition analysis, structural design, strength check and fatigue check and in combination with experimental testing, the service safety of the non-adhesive flexible riser is ensured, and a more sufficient basis is provided for design.

Description

Technical Field

[0001] The invention relates to a deep-sea non-bonded flexible riser design method, and belongs to the field of marine oil and gas equipment technology development. Background Art

[0002] With the continuous growth of global energy demand and the gradual depletion of terrestrial oil and gas resources, the development of marine oil and gas resources has become increasingly important. Especially in deep-sea areas, due to the large oil and gas reserves and huge mining potential, deep-sea oil and gas development has become an important trend in the global energy field. In order to meet the needs of deep-sea oil and gas resource development, it is necessary to design and manufacture pipeline systems that can adapt to the deep-sea environment. Among them, non-bonded flexible risers have attracted much attention due to their unique performance advantages.

[0003] The oil and gas resources in my country's sea areas are mainly composed of offshore oil and gas resources and deep-sea oil and gas resources. Among them, deep-sea oil and gas resources account for 70% of the total. Therefore, the development of deep-sea oil and gas resources has become an important task in my country's energy development. Non-bonded flexible risers are the "blood vessels" of deepwater development systems, but their mechanical behavior is complex and difficult to design and analyze. In addition, the existing design schemes basically do not consider the impact of service time and annular environment on material properties, which may cause the non-bonded flexible risers to fail prematurely and endanger service safety. Therefore, it is of great significance to carry out reliable riser design. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a deep-sea non-bonded flexible riser design method, which is simple, has a short process, and is easy for relevant engineering personnel to understand.

[0005] The design of the present invention is achieved through the following technical solutions:

[0006] A method for designing a deep-sea non-bonded flexible riser, the method mainly comprising the following steps:

[0007] ① Clarify the use conditions, installation methods and layout of deep-sea non-bonded flexible risers, and calculate the load performance requirements;

[0008] ② Determine the main technical parameters of deep-sea non-bonded flexible risers, including inner and outer diameters, design internal pressure and bursting pressure, strength and stiffness, and operating temperature;

[0009] ③ Carry out the structural and dimensional design of each layer of deep-sea non-bonded flexible riser, including the materials used, winding form, and cross-sectional shape of each layer, and then design the overall structure and size, and conduct static strength verification through theoretical or finite element analysis. At the same time, the influence of the non-bonded flexible riser over the service time and the annular environment should be considered. If the verification fails, the overall structure and size should be redesigned;

[0010] ④ Conduct dynamic load analysis on deep-sea non-bonded flexible risers, and consider the coupling between ship, pipeline and seabed soil, pipeline laying plan, the influence of non-bonded flexible risers over time and annular environment, and conduct dynamic load strength verification. If the verification fails, redesign the overall structure and size;

[0011] ⑤ Formulate a dynamic fatigue simulation test plan for deep-sea non-bonded flexible risers, carry out tests with different cyclic loads, different numbers of cycles and frequencies, and consider the influence of non-bonded flexible risers over time and annular environment, obtain fatigue analysis verification, and redesign the overall structure and dimensions if the verification fails;

[0012] ⑥After completing the above steps, design is carried out based on the analyzed and verified data results to determine the final design product.

[0013] Furthermore, the load characteristics that need to be considered in step ① include tensile and compressive loads, bending loads, torsional loads, internal pressure and compressive loads, temperature loads, and corrosion loads.

[0014] Furthermore, the design pressure in step ② is designed to be 1.2 to 1.5 times greater than the actual working pressure.

[0015] Furthermore, the verification in steps ③, ④ and ⑤ refers to API RP 17B / API SPEC 17J or CCS standards.

[0016] Furthermore, in the dynamic fatigue test in step ⑤, the number of load cycles, the temperature and pressure inside the tube, and the temperature and pressure outside the tube should be continuously recorded.

[0017] Furthermore, the consideration of the influence of the non-bonded flexible riser over the service time and the annular environment in steps ③, ④ and ⑤ mainly involves the influence of the mechanical properties of metal materials and non-metal materials.

[0018] Furthermore, the designed product life in step ⑥ is designed according to a safety factor S=10.

[0019] The beneficial effects of the present invention are as follows:

[0020] (1) The method of the present invention fully considers the use conditions, installation methods, layout forms, and involves all-round verification of static strength, dynamic strength, and fatigue life to ensure the safety of the design;

[0021] (2) When checking the static strength, dynamic strength and fatigue life, the method of the present invention fully considers the influence of the service life of the non-bonded flexible riser and the annular environment on the mechanical properties of the metal material and the non-metallic material, thereby ensuring the safety of the non-bonded flexible riser during its entire life cycle and having higher design safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention is a flow chart of a method for designing a deep-sea non-bonded flexible riser.

[0023] Figure 2 It is a schematic structural diagram of a deep-sea non-bonded flexible riser according to the present invention.

[0024] The reference numerals are as follows:

[0025] 1. Skeleton layer; 2. Inner sheath layer; 3. Compression armor layer; 4. Anti-friction layer; 5. Inner tensile armor layer; 6. Outer tensile armor layer; 7. Outer sheath layer. DETAILED DESCRIPTION

[0026] In order to make the process and technical solution of the present invention more clear, the present invention is further described below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] refer to Figure 1 As shown, a deep-sea non-bonded flexible riser design method provided by the present invention mainly includes the following processes:

[0028] ① Clarify the use conditions, installation methods and layout of deep-sea non-bonded flexible risers, and calculate the load performance requirements;

[0029] ② Determine the main technical parameters of deep-sea non-bonded flexible risers, including inner and outer diameters, design internal pressure and bursting pressure, strength and stiffness, and operating temperature;

[0030] Before determining the main technical parameters in step ②, the environmental parameters under the working conditions of the flexible riser in step ① need to be tested, and the main technical parameters need to be analyzed and designed based on the environmental parameters to ensure that the parameters are reasonable when designing the flexible riser;

[0031] ③ Carry out the structural and dimensional design of each layer of deep-sea non-bonded flexible riser, including the materials used, winding form, and cross-sectional shape of each layer, and then design the overall structure and size, and conduct static strength verification through theoretical or finite element analysis. At the same time, the influence of the non-bonded flexible riser over the service time and the annular environment should be considered. If the verification fails, the overall structure and size should be redesigned;

[0032] In step ③, the inner sheath layer (2), anti-friction layer (4), and outer sheath layer (7) of the non-bonded flexible riser are made of high molecular polymer materials and are regarded as shell units in theoretical and finite element analysis; the skeleton layer (1), compression armor layer (3), inner tensile armor layer (5), and outer tensile armor layer (6) of the non-bonded flexible riser are composed of metal materials such as high-strength steel and are regarded as shell units or solid units in theoretical and finite element analysis. The mechanical properties under different loads are determined by numerical simulation, and strength verification is performed.

[0033] The cross-sectional shape of the non-bonded flexible riser compressive armor layer (3) is usually "Z", "C", or "T" type. Figure 2 The structure diagram adopts a "Z" shape. The cross-section shape of the inner tensile armor layer (5) and the outer tensile armor layer (6) is a rectangular steel strip, and the inner and outer layers are formed by spirally winding the rectangular steel strip in opposite directions.

[0034] ④ Conduct dynamic load analysis on deep-sea non-bonded flexible risers, and consider the coupling between ship, pipeline and seabed soil, pipeline laying plan, the influence of non-bonded flexible risers over time and annular environment, and conduct dynamic load strength verification. If the verification fails, redesign the overall structure and size;

[0035] ⑤ Formulate a dynamic fatigue simulation test plan for deep-sea non-bonded flexible risers, carry out tests with different cyclic loads, different numbers of cycles and frequencies, and consider the influence of non-bonded flexible risers over time and annular environment, obtain fatigue analysis verification, and redesign the overall structure and dimensions if the verification fails;

[0036] In the dynamic fatigue simulation test in step ⑤, the number of load cycles, the temperature and pressure inside the pipe, and the temperature and pressure outside the pipe should be continuously recorded.

[0037] ⑥After completing the above steps, design is carried out based on the analyzed and verified data results to determine the final design product.

Claims

1. A method for designing a deep-sea non-bonded flexible riser, characterized in that: The method mainly includes the following steps: ① Clarify the use conditions, installation methods and layout of deep-sea non-bonded flexible risers, and calculate the load performance requirements; ② Determine the main technical parameters of deep-sea non-bonded flexible risers, including inner and outer diameters, design internal pressure and bursting pressure, strength and stiffness, and operating temperature; ③ Carry out the structural and dimensional design of each layer of deep-sea non-bonded flexible riser, including the materials used, winding form, and cross-sectional shape of each layer, and then design the overall structure and size, and conduct static strength verification through theoretical or finite element analysis. At the same time, the influence of the non-bonded flexible riser over the service time and the annular environment should be considered. If the verification fails, the overall structure and size should be redesigned; ④ Conduct dynamic load analysis on deep-sea non-bonded flexible risers, and consider the coupling between ship, pipeline and seabed soil, pipeline laying plan, the influence of non-bonded flexible risers over time and annular environment, and conduct dynamic load strength verification. If the verification fails, redesign the overall structure and size; ⑤ Formulate a dynamic fatigue simulation test plan for deep-sea non-bonded flexible risers, carry out tests with different cyclic loads, different numbers of cycles and frequencies, and consider the influence of non-bonded flexible risers over time and annular environment, obtain fatigue analysis verification, and redesign the overall structure and dimensions if the verification fails; ⑥After completing the above steps, design is carried out based on the analyzed and verified data results to determine the final design product.

2. A method for designing a deep-sea non-bonded flexible riser according to claim 1, characterized in that: The load characteristics that need to be considered in step ① include tensile and compressive loads, bending loads, torsion loads, internal pressure and compressive loads, temperature loads, and corrosion loads.

3. A method for designing a deep-sea non-bonded flexible riser according to claim 1, characterized in that: The design pressure in step ② is designed to be 1.2 to 1.5 times greater than the actual working pressure.

4. A method for designing a deep-sea non-bonded flexible riser according to claim 1, characterized in that: The calibration in steps ③, ④ and ⑤ shall refer to APIRP 17B / APISPEC 17J or CCS standards.

5. A method for designing a deep-sea non-bonded flexible riser according to claim 1, characterized in that: In the dynamic fatigue test in step ⑤, the number of load cycles, the temperature and pressure inside the pipe, and the temperature and pressure outside the pipe should be continuously recorded.

6. A method for designing a deep-sea non-bonded flexible riser according to claim 1, characterized in that: The consideration of the influence of the non-bonded flexible riser over the service time and the annular environment in step ③, step ④ and step ⑤ mainly involves the influence of the mechanical properties of metal materials and non-metal materials.

7. A method for designing a deep-sea non-bonded flexible riser according to claim 1, characterized in that: The designed product life in step ⑥ is designed according to the safety factor S=10.

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