Optimization method of floating production storage and offloading (FPSO) extra-heavy module structure based on offshore floating hoisting

Abstract

The invention discloses a floating production storage and offloading (FPSO) extra-heavy type module structure optimization method based on offshore floating type hoisting, and belongs to the technical field of FPSO extra-heavy type module structure optimization. S2, establishing an overall mass model of the extra-heavy module; s3, establishing a floating hoisting model of the extra-heavy module; s4, calculating an equivalent load under the coupling action of various loads; s5, boundary conditions of floating hoisting of the modular structure are obtained; s6, calculating the stress distribution of the overall structure of the extra-heavy module; and S7, the overall structure of the extra-heavy module is strengthened. By implementing refined structural strength calculation and key part optimization design, the potential failure mode in the floating hoisting process can be pre-judged and prevented and controlled in advance, the safety of floating hoisting of the extra-heavy module is improved, the risks of structural failure and accidents are reduced, and the safety of personnel and the environment is protected.

Description

Technical Field

[0001] This invention relates to the field of FPSO ultra-heavy module structure optimization technology, specifically to an optimization method for FPSO ultra-heavy module structures based on offshore floating hoisting. Background Technology

[0002] In recent years, the share of oil and natural gas in global energy has increased significantly. With dwindling onshore oil and gas reserves, interest in offshore resources has grown considerably. The Earth's oceans cover more than twice the area of ​​land, containing approximately 140 to 200 billion tons of seabed oil and about 14 billion cubic meters of marine natural gas. Offshore oil and gas fields are increasingly becoming a focus of energy production, possessing the potential to meet the growing global energy demand.

[0003] Floating Production Storage and Offloading (FPSO) vessels are integrated offshore bases for crude oil processing, encompassing oil-water separation, oily wastewater treatment, heating, power generation, oil storage and offloading, provision of living quarters, and a comprehensive production command system. An FPSO consists of a hull system, a production process system (modular system), a dedicated mooring system, and a unique offloading system. The installation of modular systems involves module weighing, transportation, hoisting, and cable and conduit connections. The hoisting process demands higher technical precision and carries greater safety risks. With the rapid development of the marine engineering industry, offshore modules are becoming increasingly complex and large-scale. The significant increase in module weight complicates hoisting scheme design, increases construction difficulty and risks, and presents new challenges to the overall module hoisting operation. Offshore module hoisting is a high-risk engineering task; even minor design errors, construction defects, or operational mistakes can lead to serious consequences and huge losses. Therefore, it is urgent to standardize the design, implementation, and operation of floating cranes for such projects.

[0004] In FPSO (Floating Production Station) systems, ultra-heavy modules refer to modules weighing over 3,800 tons. During offshore lifting, these modules are subjected to various loads, including waves, wind, cargo, and equipment handling. The complex coupling of these loads leads to vibration, deformation, and stress concentration in the ultra-heavy module, threatening the structural strength and stability during the floating lifting process. Summary of the Invention

[0005] The purpose of this invention is to provide an optimization method for FPSO ultra-heavy modular structures based on offshore floating hoisting, so as to improve the reliability and safety of the modular structure during the floating hoisting process.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: An optimization method for FPSO ultra-heavy modular structures based on offshore floating installation includes the following steps: Step S1: Establishment of the overall structural model of the ultra-heavy module; Step S2: Establishment of the overall quality model of the super-heavy module: Based on the overall structural model of the super-heavy module, use mass points to simulate large equipment on the module, so that the model quality of the super-heavy module matches the actual quality. Step S3: Establishment of the floating hoisting model of the ultra-heavy module: Using the overall mass model of the ultra-heavy module, the six-degree-of-freedom motion response spectrum of the ultra-heavy module during the hoisting process is obtained through experiments. Based on the six-degree-of-freedom motion response spectrum of the ultra-heavy module, a composite model including the sling model is established. Step S4: Calculation of equivalent load under multiple load coupling: Set the working load and environmental load sections of the super-heavy module, calculate the load parameters corresponding to the load components under the coupling of working load and environmental load at each section parameter when they reach the maximum, and calculate the equivalent load amplitude under the coupling of working load and environmental load based on the load parameters and long-term forecast values. Step S5: Obtain the boundary conditions for the floating hoisting of the module structure: The equivalent load is transferred to the overall structural model of the ultra-heavy module through the solver and the calculation is performed. The boundary conditions for the floating hoisting in the calculation results of the overall structure under the equivalent load are obtained through the stress response of the overall structure to the equivalent load. Step S6: Calculate the stress distribution of the overall structure of the super-heavy module: Use a solver to perform calculations to obtain the stress distribution of the overall structure of the super-heavy module under the coupled action of working load and environmental load; Step S7: Overall structural reinforcement of the super-heavy module: Set the allowable normal stress value and allowable shear stress value of the overall structure of the super-heavy module. In the stress distribution of the overall structure of the super-heavy module, select the parts that are higher than the allowable stress value, and optimize and strengthen the structure of the selected parts.

[0007] Further, step S1 specifically includes the following steps: Step S1.1: Establish a structural model based on the actual structure of the super-heavy module, with a total length of 29.67m, a total width of 46.56m, and a total height of 29.69m; Step S1.2, Modeling the main structure of the super-heavy module: including the main platform layer, the main steel structure space frame and large equipment, modeled using plate and shell units; Step S1.3: Modeling of secondary structures of the heavy-duty module: including columns and supports, using beam elements for modeling.

[0008] Furthermore, a clamping limiting plate is fixed on one side of the dual-output clamping hydraulic cylinder, which is used to limit the clamping position of the automatic pile head clamp on the pile.

[0009] Furthermore, step S2 specifically includes the following steps: Step S2.1: Assign material properties to the structural model of the module. The overall material of the super-heavy module is high-strength structural steel with a density of 7850 kg / m3, Young's modulus of 206000 MPa, and Poisson's ratio of 0.3. Step S2.2: Use mass points to simulate large equipment on a super-heavy module; Step S2.3: By adjusting the density of the structural materials of each part, the load and mass generated by some unmodeled small equipment, electrical instruments and mechanical handling of the super heavy module are simulated, so that the model mass of the super heavy module matches the actual mass. The model mass of the super heavy module is 3876.79t.

[0010] Furthermore, in step S3, the sling model is composed of beam units with a diameter of 2 meters, which represents the connection state between the lifting point and the lifting equipment, ensuring that the nodes do not translate during the lifting process, while allowing free rotation to adapt to dynamic changes during the lifting process.

[0011] Furthermore, the specific steps of step S4 are as follows: Step S4.1: Under ideal operating conditions, the loads generated by the equipment and its operation are called working loads, which include static loads and dynamic loads. Static loads mainly involve the weight of the module itself and the weight of the equipment it carries, while dynamic loads include the loads of each liquid storage tank, the loads generated during module hoisting operations, and the weight of other supplies such as living materials. Environmental loads include the loads from wind, waves and ocean currents borne by the heavy-duty module, as well as wave inertial force loads generated due to dynamic response. Step S4.2: Set the load section of the floating hoisting model of the ultra-heavy module, and transfer each load component to the floating hoisting model of the ultra-heavy module through the solver to calculate the load parameters corresponding to the maximum load component under the multi-load coupling action of each section parameter. Step S4.3: Obtain long-term forecast values ​​for the sea area where the ultra-heavy modules are hoisted through statistical and long-term forecasting methods; Step S4.4: Calculate the equivalent load amplitude under multiple load coupling based on the load parameters and long-term forecast values.

[0012] Furthermore, the specific steps of step S6 are as follows: Step S6.1: Solve the structural stress response using a nonlinear contact algorithm, wherein an adaptive mesh refinement layer is set in the contact area of ​​the suspension point, with a minimum mesh size of 50mm; Step S6.2: Virtual spring supports were used at the bottom of the module support column to ensure that the model would not rotate infinitely due to imbalance of the center of gravity during hoisting, thus ensuring the stability of the module during the analysis process; Step S6.3: Use the solver to perform calculations to obtain the stress distribution of the overall structure of the super-heavy module under the coupling of multiple loads during the floating hoisting process.

[0013] Furthermore, in step S7, the method for strengthening the structure of the selected corresponding parts is as follows: reduce the spacing between the truss support columns of each layer of the module to increase the overall strength and stiffness; add tubular support columns between the crossbeam below the main lifting point and the mid-span of the truss below the crossbeam, so that the stress at the lifting point is more evenly distributed on the entire structure during the lifting process, rather than concentrated on a specific point, effectively reducing local stress concentration and controlling deflection, thereby ensuring the structural integrity of the module during the lifting process.

[0014] Furthermore, in step S7, the allowable normal stress does not exceed 355 MPa.

[0015] Furthermore, in step S7, the allowable shear stress does not exceed 213 MPa.

[0016] The beneficial effects of this invention are as follows: This invention introduces a structural optimization method based on the multi-load coupling effect during the floating hoisting of ultra-heavy modules. It fully considers the working and environmental loads during the hoisting process, and through the implementation of refined structural strength calculation and key component optimization design, it can realize the early prediction and prevention and control of potential failure modes during the floating hoisting process, improve the safety of ultra-heavy module floating hoisting process, reduce the risk of structural failure and accidents, and protect the safety of personnel and the environment. Attached Figure Description

[0017] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort: Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0019] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper surface," "lower surface," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "forward," "reverse," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] Taking the TS011 module in an FPSO as an example, we will optimize its structure to improve the reliability and safety of the module during floating hoisting. The TS011 module weighs over 3,800 tons, classifying it as an ultra-heavy-duty module.

[0021] like Figure 1 As shown, an optimization method for FPSO ultra-heavy modular structures based on offshore floating installation is presented. Includes the following steps: Step S1: Establishment of the overall structural model of the TS011 module: Specifically, the following steps are included: Step S1.1: The structural model established according to the actual structure of the TS011 module has a total length of 29.67m, a total width of 46.56m, and a total height of 29.69m; Step S1.2: TS011 module main structure modeling: including the main platform layer, main steel structure space frame and large equipment, modeled using plate and shell units; Step S1.3: Modeling of secondary structures in TS011 module: including columns and supports, using beam elements for modeling.

[0022] Step S2: Establishment of the overall quality model of TS011 module: Based on the overall structural model of TS011 module, use mass points to simulate large equipment on the module, so that the model quality of the established TS011 module matches the actual quality.

[0023] Step S2 specifically includes the following steps: Step S2.1: Assign material properties to the structural model of the module. The overall material of the TS011 module is high-strength structural steel with a density of 7850 kg / m3, Young's modulus of 206000 MPa, and Poisson's ratio of 0.3. Step S2.2: Simulate large equipment on the TS011 module using mass points; Step S2.3: By adjusting the density of the structural materials of each part, the load and mass generated by some unmodeled small equipment, electrical instruments and mechanical handling of the TS011 module are simulated, so that the model mass of the built TS011 module matches the actual mass. The model mass of the TS011 module is 3876.79t.

[0024] Step S3: Establishment of the floating hoisting model of TS011 module: Using the overall mass model of TS011 module, the six-degree-of-freedom motion response spectrum of TS011 module during the hoisting process is obtained through experiments. Based on the six-degree-of-freedom motion response spectrum of TS011 module, a composite model including the sling model is established.

[0025] The sling model consists of beam units with a diameter of 2 meters. It typically represents the connection between the lifting point and the lifting equipment, ensuring that the nodes do not translate during the lifting process, while allowing free rotation to adapt to dynamic changes during the lifting process.

[0026] Step S4: Calculation of equivalent load under multiple load coupling effects: Set the working load and environmental load sections of the TS011 module, calculate the load parameters corresponding to the maximum load components under the coupling effect of working load and environmental load for each section parameter, and calculate the equivalent load amplitude under the coupling effect of working load and environmental load based on the load parameters and long-term forecast values.

[0027] The specific steps of step S4 are as follows: Step S4.1: Under ideal operating conditions, the loads generated by the equipment and its operation are called working loads, which include static loads and dynamic loads. Static loads mainly involve the weight of the module itself and the weight of the equipment it carries, while dynamic loads include the loads of each liquid storage tank, the loads generated during module hoisting operations, and the weight of other supplies such as living materials. Environmental loads include the loads borne by the TS011 module from wind, waves, and ocean currents, as well as wave inertial force loads generated due to dynamic response.

[0028] Step S4.2: Set the load section of the floating hoisting model of the TS011 module, and transfer each load component to the floating hoisting model of the TS011 module through the solver to calculate the load parameters corresponding to the maximum load component under the multi-load coupling action of each section parameter. Step S4.3: Obtain the long-term forecast value of the sea area for the hoisting of the TS011 module through statistical and long-term forecasting methods; Step S4.4: Calculate the equivalent load amplitude under multiple load coupling based on the load parameters and long-term forecast values; Step S5: Obtain the boundary conditions for the floating hoisting of the module structure: The equivalent load is transferred to the overall structural model of the TS011 module through the solver and the calculation is performed. The boundary conditions for the floating hoisting in the calculation results of the overall structure under the equivalent load are obtained through the stress response of the overall structure to the equivalent load.

[0029] Step S6: Calculate the stress distribution of the overall structure of the TS011 module: Use the solver to perform calculations to obtain the stress distribution of the overall structure of the TS011 module under the coupled action of working load and environmental load.

[0030] The specific steps of step S6 are as follows: Step S6.1: Solve the structural stress response using a nonlinear contact algorithm, wherein an adaptive mesh refinement layer is set in the contact area of ​​the suspension point, with a minimum mesh size of 50mm; Step S6.2: Virtual spring supports were used at the bottom of the module support column to ensure that the model would not rotate infinitely due to imbalance of the center of gravity during hoisting, thus ensuring the stability of the module during the analysis process; Step S6.3: Use the solver to perform calculations to obtain the stress distribution of the overall structure of the TS011 module under the coupling of multiple loads during the floating hoisting process.

[0031] Step S7: Overall Structural Strengthening of the TS011 Module: Set the allowable normal stress and allowable shear stress values ​​for the overall structure of the TS011 module, wherein the allowable normal stress does not exceed 355 MPa and the allowable shear stress does not exceed 213 MPa. In the stress distribution of the overall structure of the TS011 module, select locations corresponding to stress values ​​higher than the allowable values, and strengthen the structure of these selected locations.

[0032] The following methods are used to strengthen the structure of the selected parts: reduce the spacing between the truss support columns of each layer of the module to increase the overall strength and stiffness; add tubular support columns between the crossbeam below the main lifting point and the middle span of the truss below the crossbeam to make the stress at the lifting point more evenly distributed on the entire structure during the lifting process, rather than concentrated on a specific point, effectively reducing local stress concentration and controlling deflection, thereby ensuring the structural integrity of the module during the lifting process.

[0033] Working Principle: During floating hoisting, the TS011 module is subjected to various environmental and operational loads, including waves, wind, cargo, and equipment handling. The complex coupling of these loads leads to vibration, deformation, and stress concentration, threatening the module's structural strength and stability. To ensure the safety of the TS011 module hoisting process, the impact of these loads must be fully considered during the design phase. Strength calculations of the overall TS011 module structure must be performed, and stress concentration areas must be appropriately reinforced. This allows for early prediction and prevention of potential failure modes during floating hoisting, improving the reliability and safety of the TS011 module structure, reducing the risk of structural failure and accidents, and protecting personnel and the environment.

[0034] Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of those embodiments or examples, without contradiction. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. An optimization method for FPSO ultra-heavy modular structure based on offshore floating installation, characterized in that, Includes the following steps: Step S1: Establishment of the overall structural model of the ultra-heavy module; Step S2: Establishment of the overall quality model of the super-heavy module: Based on the overall structural model of the super-heavy module, use mass points to simulate large equipment on the module, so that the model quality of the super-heavy module matches the actual quality. Step S3: Establishment of the floating hoisting model of the ultra-heavy module: Using the overall mass model of the ultra-heavy module, the six-degree-of-freedom motion response spectrum of the ultra-heavy module during the hoisting process is obtained through experiments. Based on the six-degree-of-freedom motion response spectrum of the ultra-heavy module, a composite model including the sling model is established. Step S4: Calculation of equivalent load under multiple load coupling: Set the working load and environmental load sections of the super-heavy module, calculate the load parameters corresponding to the load components under the coupling of working load and environmental load at each section parameter when they reach the maximum, and calculate the equivalent load amplitude under the coupling of working load and environmental load based on the load parameters and long-term forecast values. Step S5: Obtain the boundary conditions for the floating hoisting of the module structure: The equivalent load is transferred to the overall structural model of the ultra-heavy module through the solver and the calculation is performed. The boundary conditions for the floating hoisting in the calculation results of the overall structure under the equivalent load are obtained through the stress response of the overall structure to the equivalent load. Step S6: Calculate the stress distribution of the overall structure of the super-heavy module: Use a solver to perform calculations to obtain the stress distribution of the overall structure of the super-heavy module under the coupled action of working load and environmental load; Step S7: Overall structural reinforcement of the super-heavy module: Set the allowable normal stress value and allowable shear stress value of the overall structure of the super-heavy module. In the stress distribution of the overall structure of the super-heavy module, select the parts that are higher than the allowable stress value, and optimize and strengthen the structure of the selected parts.

2. The optimization method for FPSO ultra-heavy modular structure based on offshore floating hoisting as described in claim 1, characterized in that, Step S1 specifically includes the following steps: Step S1.1: Establish a structural model based on the actual structure of the super-heavy module, with a total length of 29.67m, a total width of 46.56m, and a total height of 29.69m; Step S1.2, Modeling the main structure of the super-heavy module: including the main platform layer, the main steel structure space frame and large equipment, modeled using plate and shell units; Step S1.3: Modeling of secondary structures of the heavy-duty module: including columns and supports, using beam elements for modeling.

3. The optimization method for FPSO ultra-heavy modular structure based on offshore floating hoisting as described in claim 1, characterized in that, Step S2 specifically includes the following steps: Step S2.1: Assign material properties to the structural model of the module. The overall material of the super-heavy module is high-strength structural steel with a density of 7850 kg / m3, Young's modulus of 206000 MPa, and Poisson's ratio of 0.

3. Step S2.2: Use mass points to simulate large equipment on a super-heavy module; Step S2.3: By adjusting the density of the structural materials of each part, the load and mass generated by some unmodeled small equipment, electrical instruments and mechanical handling of the super heavy module are simulated, so that the model mass of the super heavy module matches the actual mass. The model mass of the super heavy module is 3876.79t.

4. The optimization method for FPSO ultra-heavy modular structure based on offshore floating hoisting as described in claim 1, characterized in that: In step S3, the sling model is composed of beam units with a diameter of 2 meters. It represents the connection state between the lifting point and the lifting equipment, ensuring that the nodes do not translate during the lifting process, while allowing free rotation to adapt to dynamic changes during the lifting process.

5. The optimization method for FPSO ultra-heavy modular structure based on offshore floating hoisting as described in claim 1, characterized in that, The specific steps of step S4 are as follows: Step S4.1: Under ideal operating conditions, the loads generated by the equipment and its operation are called working loads, which include static loads and dynamic loads. Static loads mainly involve the weight of the module itself and the weight of the equipment it carries, while dynamic loads include the loads of each liquid storage tank, the loads generated during module hoisting operations, and the weight of other supplies such as living materials. Environmental loads include the loads from wind, waves and ocean currents borne by the heavy-duty module, as well as wave inertial force loads generated due to dynamic response. Step S4.2: Set the load section of the floating hoisting model of the ultra-heavy module, and transfer each load component to the floating hoisting model of the ultra-heavy module through the solver to calculate the load parameters corresponding to the maximum load component under the multi-load coupling action of each section parameter. Step S4.3: Obtain long-term forecast values ​​for the sea area where the ultra-heavy modules are hoisted through statistical and long-term forecasting methods; Step S4.4: Calculate the equivalent load amplitude under multiple load coupling based on the load parameters and long-term forecast values.

6. The optimization method for FPSO ultra-heavy modular structure based on offshore floating hoisting as described in claim 1, characterized in that, The specific steps of step S6 are as follows: Step S6.1: Solve the structural stress response using a nonlinear contact algorithm, wherein an adaptive mesh refinement layer is set in the contact area of ​​the suspension point, with a minimum mesh size of 50mm; Step S6.2: Virtual spring supports were used at the bottom of the module support column to ensure that the model would not rotate infinitely due to imbalance of the center of gravity during hoisting, thus ensuring the stability of the module during the analysis process; Step S6.3: Use the solver to perform calculations to obtain the stress distribution of the overall structure of the super-heavy module under the coupling of multiple loads during the floating hoisting process.

7. The optimization method for FPSO ultra-heavy modular structure based on offshore floating hoisting as described in claim 1, characterized in that: In step S7, the method for strengthening the structure of the selected corresponding parts is as follows: reduce the spacing between the truss support columns of each layer of the module to increase the overall strength and stiffness; add tubular support columns between the crossbeam below the main lifting point and the middle span of the truss below the crossbeam, so that the stress at the lifting point is more evenly distributed on the entire structure during the lifting process, rather than concentrated on a specific point, effectively reducing local stress concentration and controlling deflection, thereby ensuring the structural integrity of the module during the lifting process.

8. The optimization method for FPSO ultra-heavy modular structure based on offshore floating hoisting as described in claim 1, characterized in that: In step S7, the allowable normal stress does not exceed 355 MPa.

9. The optimization method for FPSO ultra-heavy modular structure based on offshore floating hoisting as described in claim 1, characterized in that: In step S7, the allowable shear stress does not exceed 213 MPa.

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