Buoy arrangement method for marine dynamic umbilical wave-shaped linear uniform curvature transition

Abstract

The application discloses a kind of marine dynamic umbilical wave form linear uniform curvature transition float arrangement method, it is applied to marine umbilical cable technical field. Including the following steps: establishing the proxy model between float design variable and objective function and constraint function;In given value constraint range, the value of each design variable of float section is initialized;The value of each design variable of float section is input into proxy model, and objective function and constraint function are solved;Current float section design variable value, objective function value and constraint function value are substituted into genetic algorithm, and update is carried out;Whether current optimization iteration converges is judged, if convergence then post-processing is carried out, otherwise reinitialization is carried out;Optimization result is post-processed, and according to optimization result, the geometric model of each buoyancy block constituting float section is generated.The application can guarantee that marine dynamic umbilical cable has more uniform curvature transition locally, prevent structural damage failure caused by excessive bending curvature, and improve the safety of umbilical cable in service.

Description

Technical Field

[0001] This invention relates to the field of marine umbilical cable technology, and more specifically to a method for buoy arrangement of marine dynamic umbilical cables with uniform curvature transition of waveform lines. Background Technology

[0002] The umbilical cable of an underwater production system is crucial to the underwater control system, transmitting hydraulic, electrical, control signals, and chemical agents between the upper structure and underwater production, thus ensuring the development and production of offshore oil and gas resources. With the increasing demand for deep-sea energy development, higher requirements are being placed on the design and development of umbilical cables. At each stage of the overall umbilical cable alignment design, a mechanical model needs to be established and the design analyzed to evaluate whether it meets the design criteria; therefore, overall alignment analysis is an important design tool.

[0003] The overall design of an umbilical cable includes parameters such as selecting the hull type and accessories, designing the umbilical cable length, float dimensions, and system layout. The hull type refers to the shape of the umbilical cable between the seabed and the floating platform, which, under its own weight and buoyancy, utilizes accessories to provide additional buoyancy or constraint. The corrugated hull type is one of the commonly used hull types for marine dynamic umbilical cables in deep-sea engineering applications. It exhibits good compliance characteristics with the movement and displacement of the floating body and hydrodynamic loads, significantly reducing the impact of the floating body's movement on the contact point. Floats are one of the accessories required in corrugated hull type design. They are mainly used in ultra-deepwater hull type design to reduce the structural tension of the umbilical cable. The buoyancy provided by the floats can offset part of the umbilical cable's own weight, thereby reducing the tension at the top and bottom of the umbilical cable, preventing end damage caused by excessive self-weight, and improving the safety and reliability of the umbilical cable. The design of the floats requires determining the magnitude, number, and distribution of buoyancy. Increasing the length and buoyancy of the buoy will increase the curvature of the umbilical cable and decrease its effective tension, and vice versa. In other words, the design of the buoy directly affects the changes in the curvature and effective tension of the umbilical cable.

[0004] Currently, both domestic and international manufacturers use the same type of floats, evenly distributed, to meet the requirements of reducing the effective tension of the umbilical cable's waveform design. However, arranging floats of the same type leads to excessive curvature at the midpoint of the float section in the waveform of the marine flexible cable, causing damage to the umbilical cable structure. Current float designs only utilize hydrodynamic simulation analysis software for trial calculations. This method clearly cannot simultaneously meet the requirements of effectively reducing the maximum bending curvature of the umbilical cable and reducing effective tension. Therefore, how to provide a float arrangement method with a uniform curvature transition for the waveform of marine dynamic umbilical cables is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method for buoy arrangement to achieve uniform curvature transition of the waveform of a marine dynamic umbilical cable. The buoy arrangement adopts a non-uniform buoyancy block arrangement of different sizes and models. By adjusting the volume of the buoyancy blocks, the buoyancy distribution of the L2 section is controlled, so as to achieve uniform curvature transition of the waveform when the marine dynamic umbilical cable is arranged.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for arranging pontoons with uniform curvature transition of the waveform of a marine dynamic umbilical cable includes the following steps:

[0008] S1. Establish a proxy model between the pontoon design variables and the objective function and constraint functions;

[0009] S2. Within the given value constraints, initialize the values ​​of each pontoon design variable;

[0010] S3. Input the values ​​of the pontoon design variables into the surrogate model and solve for the values ​​of the corresponding objective function and constraint function;

[0011] S4. Substitute the current design variable values, objective function values, and constraint function values ​​of the pontoon into the genetic algorithm to update the design variables;

[0012] S5. Determine whether the current optimization iteration has converged. If it has converged, continue to S6; otherwise, jump to S2 and start a new round of optimization iteration.

[0013] S6. Post-process the optimization results and generate the geometric models of each buoyancy block that constitutes the pontoon section based on the optimization results.

[0014] Optionally, S1 is as follows:

[0015] S101. Within the range of values ​​for the pontoon design variables, the Latin hypercube sampling technique is used to generate sample points for the pontoon design variables.

[0016] S102. Solve the objective function and constraints for each sample point using Orcaflex.

[0017] S103. Import the design variable values, objective function values, and constraint function values ​​of the sample points into the Isight software. Use a radial basis function neural network to establish a surrogate model between the pontoon design variables and the objective function and constraint function. The input of the surrogate model is the pontoon design variable values ​​of each sample point, and the output is the values ​​of the objective function and constraint function.

[0018] Optionally, S102 specifically refers to:

[0019] S1021. In Orcaflex, based on the length L1 of the lower section of the umbilical cable catenary, the length L2 of the float section, the length L3 of the upper section of the catenary, and the length, inner diameter, and outer diameter of each buoyancy block, establish a finite element model of the umbilical cable applying the float section.

[0020] S1022. In Orcaflex, input the dimensions and material information of the umbilical cable cross-section, the material information of the buoy, and the boundary conditions, and submit the calculation.

[0021] S1023. After the Orcaflex calculation is completed, extract the curvature and stress information of each Line element in the umbilical cable, as well as the end tension of the umbilical cable, in order to solve for the values ​​of the objective function and constraint function.

[0022] Optional, the float design variables are:

[0023]

[0024] In the formula, x is the set of design variables for the pontoon section. Let be the length of the i-th buoyancy block. Let be the outer diameter of the i-th buoyancy block, and n be the total number of buoyancy blocks.

[0025] Optionally, the given value constraint range for the design variables of the pontoon section is:

[0026]

[0027]

[0028] In the formula, This represents the lower limit of the length of the buoyancy block. This represents the upper limit of the possible length values ​​for the buoyancy block. This represents the lower limit of the outer diameter of the buoyancy block. This represents the upper limit of the outer diameter of the buoyancy block.

[0029] Optionally, the objective function for optimization is:

[0030] Minf(x=max(κ j ),j=1,2,…,n e

[0031] In the formula, κ j Let n be the curvature of the j-th Line unit in the umbilical cable profile. e Let x be the number of Line units, and Minf(x) denotes the minimization of the maximum curvature of the umbilical cable type.

[0032] Optionally, the constraint functions include the total mass constraint of the pontoon, the total length constraint of the pontoon, and the end tension constraint of the umbilical cable pontoon section;

[0033]

[0034]

[0035] i≤f0

[0036] In the formula, m is the total mass constraint of the pontoon, m i Let be the mass of the i-th buoyancy block, n be the total number of buoyancy blocks, m0 be the given upper limit of the total mass of the pontoons, and s be the total length constraint of the pontoons. s0 is the length of the i-th buoyancy block, and s0 is the upper limit of the total length of the buoy; f is the end tension of the umbilical cable, and f0 is the limit of the end tension.

[0037] Optionally, the geometric models of the individual pontoons in S6 can be generated using one of the following modeling software: Pro / E, SolidWorks, or Catia.

[0038] As can be seen from the above technical solution, compared with the prior art, the present invention provides a method for buoy arrangement with uniform curvature transition of the waveform of a marine dynamic umbilical cable, which has the following beneficial effects: In the waveform design of the present invention, the buoy arrangement adopts a non-uniform arrangement of different specifications. Using the proposed optimization design method, the configuration of each buoyancy block and the magnitude of buoyancy are first determined, and then the volume of each buoyancy block is determined according to the magnitude of buoyancy. By adjusting the volume of the buoyancy blocks, the distribution of buoyancy in section L2 is controlled, thereby realizing the adjustment and control of local bending curvature, overall waveform, and end tension. When realizing the waveform control of the marine dynamic umbilical cable, it can ensure that the waveform of the umbilical cable has a more uniform curvature transition, prevent structural damage and failure caused by excessive bending curvature, and improve the safety of the umbilical cable in-situ service. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0040] Figure 1 This is a flowchart of the pontoon arrangement method of the present invention;

[0041] Figure 2 This is a schematic diagram of the arrangement of the pontoon sections in this invention;

[0042] Figure 3 This is a schematic diagram of the waveform line type design in the prior art;

[0043] Figure 4This is a schematic diagram of a float line unit in the prior art;

[0044] Figure 5 This is a schematic diagram illustrating the change in the overall linear curvature of the umbilical cable in the prior art. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] This invention discloses a method for pontoon arrangement with uniform curvature transition of the waveform line of a marine dynamic umbilical cable, such as... Figure 1 As shown, it includes the following steps:

[0047] S1. Establish a proxy model between the pontoon design variables and the objective function and constraint functions;

[0048] S2. Within the given value constraints, initialize the values ​​of each pontoon design variable;

[0049] S3. Input the values ​​of the pontoon design variables into the surrogate model and solve for the values ​​of the corresponding objective function and constraint function;

[0050] S4. Substitute the current design variable values, objective function values, and constraint function values ​​of the pontoon into the genetic algorithm to update the design variables;

[0051] S5. Determine whether the current optimization iteration has converged. If it has converged, continue to S6; otherwise, jump to S2 and start a new round of optimization iteration.

[0052] S6. Post-process the optimization results and generate the geometric models of each buoyancy block that constitutes the pontoon section based on the optimization results.

[0053] In this embodiment of the invention, if the change in the average objective function in five consecutive iterations during the optimization process is less than the given convergence tolerance (0.001), the optimization iteration is considered to have converged.

[0054] Furthermore, S1 specifically refers to:

[0055] S101. Within the range of values ​​for the pontoon design variables, the Latin hypercube sampling technique is used to generate sample points for the pontoon design variables.

[0056] S102. Solve the objective function and constraints for each sample point using Orcaflex.

[0057] S103. Import the design variable values, objective function values, and constraint function values ​​of the sample points into the Isight software. Use a radial basis function neural network to establish a surrogate model between the pontoon design variables and the objective function and constraint function. The input of the surrogate model is the pontoon design variable values ​​of each sample point, and the output is the values ​​of the objective function and constraint function.

[0058] In the optimization process of this embodiment, it is necessary to start with the initial values ​​of the given buoy design variables and gradually approach the optimal direction through optimization iterations. In each process, the values ​​of the buoy design variables in the next iteration need to be updated using an optimization algorithm based on the values ​​of the objective function and constraints, until the convergence criterion of the optimization iteration is met.

[0059] As the above process shows, the optimization process requires continuous calls to the finite element method in Orcaflex, leading to significant computational costs. This is especially true when the number of optimization iterations is excessive, making the computational cost of Orcaflex analysis unbearable. Therefore, before optimization, this embodiment establishes a surrogate model of the objective function and constraints. This involves using a small amount of Orcaflex calculations to establish an approximate functional mapping relationship (i.e., a surrogate model) between the design variables and the design objectives and constraints. During optimization, this approximate mapping relationship allows for the direct determination of the values ​​of the objective and constraint functions corresponding to the design variables, eliminating the need for further Orcaflex calculations and thus improving optimization efficiency.

[0060] Furthermore, S102 specifically refers to:

[0061] S1021. In Orcaflex, based on the length L1 of the lower section of the umbilical cable catenary, the length L2 of the float section, the length L3 of the upper section of the catenary, and the length, inner diameter, and outer diameter of each buoyancy block, establish a finite element model of the umbilical cable applying the float section.

[0062] S1022. In Orcaflex, input the dimensions and material information of the umbilical cable cross-section, the material information of the buoy, and the boundary conditions, and submit the calculation.

[0063] S1023. After the Orcaflex calculation is completed, extract the curvature and stress information of each Line element in the umbilical cable, as well as the end tension of the umbilical cable, in order to solve for the values ​​of the objective function and constraint function.

[0064] In this embodiment of the invention, the boundary conditions include boundary fixed constraints, gravity loads, and hydrodynamic loads.

[0065] Furthermore, the design variables for the pontoons are:

[0066]

[0067] In the formula, x is the set of design variables for the pontoon section. Let be the length of the i-th buoyancy block. Let be the outer diameter of the i-th buoyancy block, and n be the total number of buoyancy blocks.

[0068] Furthermore, the given range of values ​​for the pontoon design variables is as follows:

[0069]

[0070]

[0071] In the formula, This represents the lower limit of the length of the buoyancy block. This represents the upper limit of the possible length values ​​for the buoyancy block. This represents the lower limit of the outer diameter of the buoyancy block. This represents the upper limit of the outer diameter of the buoyancy block.

[0072] In this embodiment of the invention, the water depth is 1300m, the lower limit of the length of the buoyancy block is 1m, the upper limit of the length of the buoyancy block is 5m, the lower limit of the outer diameter of the buoyancy block is 0.13m (outer diameter of the umbilical cable), and the upper limit of the outer diameter of the buoyancy block is 0.39m (3 times the outer diameter of the umbilical cable).

[0073] Furthermore, the objective function for optimization is:

[0074] Minf(x) = max(κ) j ),j=1,2,…,n e

[0075] In the formula, κ j Let n be the curvature of the j-th Line unit in the umbilical cable profile. e Let x be the number of Line units, and Minf(x) denotes the minimization of the maximum curvature of the umbilical cable type.

[0076] Furthermore, the constraint functions include the total mass constraint of the pontoon, the total length constraint of the pontoon, and the end tension constraint of the umbilical cable pontoon section;

[0077]

[0078]

[0079] f≤f0

[0080] In the formula, m is the total mass constraint of the pontoon, m i Let be the mass of the i-th buoyancy block, n be the total number of buoyancy blocks, m0 be the given upper limit of the total mass of the pontoons, and s be the total length constraint of the pontoons. s0 is the length of the i-th buoyancy block, and s0 is the upper limit of the total length of the buoy; f is the end tension of the umbilical cable, and f0 is the limit of the end tension.

[0081] In this embodiment of the invention, the wet weight of the umbilical cable is 15 kg / m, the maximum total mass of the float is 15,000 kg, the maximum total length of the float is 250 m, and the end tension limit of the umbilical cable is 900 kN.

[0082] Furthermore, the geometric models of the individual pontoons in S6 are generated using one of the following modeling software: Pro / E, SolidWorks, or Catia.

[0083] Furthermore, in one embodiment of the present invention, the proxy model may also be one of the Kriging model and the response surface model, and the proxy model may be constructed using one of the third-party libraries such as Matlab and Python.

[0084] Furthermore, in one embodiment of the present invention, the total length of the pontoon is used as the objective function, and the maximum curvature of the pontoon, the total mass of the pontoon, and the end tension of the umbilical cable are used as constraint functions for optimization. The optimized L2 segment is more economical.

[0085] Furthermore, in one embodiment of the present invention, the total mass of the pontoon is minimized as the objective function, and the maximum curvature of the pontoon, the total length of the pontoon, and the end tension of the umbilical cable are optimized as constraint functions.

[0086] Furthermore, in one embodiment of the present invention, S4 uses either the particle swarm optimization algorithm or the ant colony optimization algorithm for updating.

[0087] Furthermore, in one embodiment of the present invention, the optimized pontoon section arrangement is as follows: Figure 2 As shown, a non-uniform arrangement of buoyancy blocks of different specifications is used.

[0088] Waveform patterns in existing technologies, such as Figure 3 As shown, the waveform design can be divided into three segments: the lower catenary L1, the pontoon section L2, and the upper catenary L3. Given the pontoon material, the buoyancy of the pontoon section is D. f S f and L f The buoy hull shape design in traditional umbilical cable design, controlled by three variables, is mainly carried out using Orcaflex software:

[0089] (1) Structural analysis: The suspension section, descent section and streamline section of the umbilical cable model are simulated using Line elements, and the float section is simulated using the Buoyancy modules attached to a line (Line with Floats) method in Line elements.

[0090] (2) Float design variables: The basic configuration of Line with Floats is as follows Figure 4 As shown, and all buoyancy blocks use the same specifications, in the design, by optimizing D f S f and L f Three buoyancy control parameters are used to design the pontoon section.

[0091] Currently, the use of the same specifications for the float sections, while reducing end tension to some extent, can lead to excessive local curvature of the umbilical cable during the design process. Figure 5 As shown, the area between the dashed lines represents the curvature of the pontoon section. This is because traditional single-specification pontoon designs and methods struggle to fully utilize the pontoon's ability to adjust its shape, tension, and curvature. This is particularly true in adjusting local curvature. It can be seen that the pontoon arrangement in this embodiment employs a non-uniform arrangement of different specifications. This ensures a more uniform curvature transition in the local area of ​​the umbilical cable when controlling its waveform, preventing structural damage and failure due to excessive bending curvature, and improving the safety of the umbilical cable during in-situ service.

[0092] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0093] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for arranging buoys with uniform curvature transition of the waveform line of a marine dynamic umbilical cable, characterized in that, Includes the following steps: S1. Establish a proxy model between the pontoon design variables and the objective function and constraint functions; S2. Within the given value constraints, initialize the values ​​of each pontoon design variable; S3. Input the values ​​of the pontoon design variables into the surrogate model and solve for the values ​​of the corresponding objective function and constraint function; S4. Substitute the current design variable values, objective function values, and constraint function values ​​of the pontoon into the genetic algorithm to update the design variables; S5. Determine whether the current optimization iteration has converged. If it has converged, continue to S6; otherwise, jump to S2 and start a new round of optimization iteration. S6. Post-process the optimization results and generate the geometric model of each buoyancy block that constitutes the pontoon section based on the optimization results; S1 specifically refers to: S101. Within the range of values ​​for the pontoon design variables, the Latin hypercube sampling technique is used to generate sample points for the pontoon design variables. S102. Solve the objective function and constraints for each sample point using Orcaflex. S103. Import the design variable values, objective function values, and constraint function values ​​of the sample points into the Isight software. Use a radial basis function neural network to establish a surrogate model between the pontoon design variables and the objective function and constraint function. The input of the surrogate model is the pontoon design variable values ​​of each sample point, and the output is the values ​​of the objective function and constraint function. S102 specifically refers to: S1021. In Orcaflex, based on the length L1 of the lower section of the umbilical cable catenary, the length L2 of the float section, the length L3 of the upper section of the catenary, and the length, inner diameter, and outer diameter of each buoyancy block, establish a finite element model of the umbilical cable applying the float section. S1022. In Orcaflex, input the dimensions and material information of the umbilical cable cross-section, the material information of the buoy, and the boundary conditions, and submit the calculation. S1023. After the Orcaflex calculation is completed, extract the curvature and stress information of each Line element in the umbilical cable, as well as the end tension of the umbilical cable, in order to solve for the values ​​of the objective function and constraint function. The constraint functions include the total mass constraint of the pontoon, the total length constraint of the pontoon, and the end tension constraint of the umbilical cable pontoon section; In the formula, The total mass constraint of the pontoons, For the first The mass of each buoyant block This represents the total number of buoyancy blocks. Given the maximum total mass of the pontoons; The total length of the pontoons is constrained. For the first The length of each buoyancy block The upper limit of the total length of the given pontoons; For the end tension of the umbilical cable, This represents the limit of the end tension.

2. The method for pontoon arrangement with uniform curvature transition of the waveform line of a marine dynamic umbilical cable according to claim 1, characterized in that, The design variables for the pontoon are: In the formula, Design the set of variables for the pontoon section. For the first The length of each buoyancy block For the first The outer diameter of each buoyancy block This represents the total number of buoyancy blocks.

3. The method for pontoon arrangement with uniform curvature transition of the waveform line of a marine dynamic umbilical cable according to claim 2, characterized in that, The given range of values ​​for the design variables of the pontoon section is as follows: In the formula, This represents the lower limit of the length of the buoyancy block. This represents the upper limit of the possible length values ​​for the buoyancy block. This represents the lower limit of the outer diameter of the buoyancy block. This represents the upper limit of the outer diameter of the buoyancy block.

4. The method for pontoon arrangement with uniform curvature transition of the waveform line of a marine dynamic umbilical cable according to claim 1, characterized in that, The objective function to be optimized is: Min In the formula, The first type of umbilical cable The curvature of a Line unit Min is the number of Line units. This represents the minimization of the maximum curvature of the umbilical cable profile.

5. The method for pontoon arrangement with uniform curvature transition of the waveform line of a marine dynamic umbilical cable according to claim 1, characterized in that, The geometric models of the individual pontoons in S6 were generated using one of the following modeling software: Pro / E, SolidWorks, or Catia.

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