Ocean platform-pipe column-seabed equipment multi-body coupling experiment device and method

Abstract

The invention discloses an ocean platform-pipe column-seabed equipment multi-body coupling experiment device and method, and the device comprises an experiment frame which comprises a top pedestal, a bottom pedestal, and a supporting mechanism disposed between the top pedestal and the bottom pedestal; the drilling simulation rotating system comprises a motor and a simulation drill rod, the motor is installed on the top base, the upper end of the simulation drill rod is detachably connected with the motor, and the lower end of the simulation drill rod is provided with a simulation underwater wellhead through a connecting device; seabed soil is contained in the soil box; and the detection device is used for detecting working parameters of the simulation drill rod, and the working parameters comprise any one or combination of the following parameters: stress parameters, rotation speed and torque. Experimental simulation requirements of deep-sea oil exploration and development can be met, so that actual production is guided, and the drilling efficiency and the success rate are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of deep-sea oil and gas simulation drilling, and particularly relates to a marine platform-pipe string-seafloor equipment multi-body coupling experimental device and method. BACKGROUND

[0002] With the growth of current energy demand and the increasing uncertainty of traditional fossil fuel supply, the development of deep-sea energy is increasingly valued. Deep-sea areas contain a large amount of oil resources, which are crucial to meet the growing energy demand. In the context of the exhaustion of onshore oil resources, the development and utilization of deep-sea oil has become a key way to maintain energy balance and alleviate the situation of energy supply shortage.

[0003] Advanced and reliable drilling platforms and related seafloor facilities are reliable guarantees for deep-sea oil exploration and development. With the development of drilling technology, a large number of new drilling processes, technologies and tools are proposed, so that experimental techniques and means must be adapted.

[0004] Therefore, it is necessary to propose a marine platform-pipe string-seafloor equipment multi-body coupling experimental device for adjustable simulation of platform-pipe string-seafloor equipment in the process of deep-sea oil and gas development, to meet the experimental simulation needs of deep-sea oil exploration and development.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely describing the technical solutions of the present application, and for the convenience of understanding by those skilled in the art. The above technical solutions cannot be considered as known to those skilled in the art only because they are described in the background section of the present application. SUMMARY

[0006] In view of the defects of the prior art, the present application provides a marine platform-pipe string-seafloor equipment multi-body coupling experimental device and method for adjustable simulation of platform-pipe string-seafloor equipment in the process of deep-sea oil and gas development, which can meet the experimental simulation needs of deep-sea oil exploration and development, thereby guiding actual production and improving drilling efficiency and success rate.

[0007] The specific technical solutions of the present application are as follows: The offshore platform-pipe column-seafloor equipment multi-body coupling experimental device comprises: an experimental frame, the experimental frame comprises a top base, a bottom base, and a supporting mechanism arranged between the top base and the bottom base; a drilling simulation rotating system, the drilling simulation rotating system comprises a motor and a simulation drill pipe, the motor is installed on the top base, the upper end of the simulation drill pipe is detachably connected with the motor, and the lower end is provided with a simulation underwater wellhead through a connecting device; a soil tank, the soil tank contains seafloor soil; and a detection device, the detection device is used for detecting working parameters of the simulation drill pipe, the working parameters comprising any one or a combination of the following: a force parameter, a rotating speed, and a torque.

[0008] In a preferred embodiment, the offshore platform-pipe column-seafloor equipment multi-body coupling experimental device further comprises: a bottom slide rail, the bottom slide rail at least comprises a first track extending longitudinally along a first direction, and the soil tank is movably installed on the first track.

[0009] In a preferred embodiment, the bottom slide rail further comprises a second track extending longitudinally along a second direction, the second direction being perpendicular to the first direction, and the first track is movably installed on the second track.

[0010] In a preferred embodiment, a first locking mechanism is arranged between the soil tank and the first track, and a second locking mechanism is arranged between the first track and the second track.

[0011] In a preferred embodiment, the supporting mechanism comprises: a main support frame and a lateral support frame, the main support frame extending longitudinally along a height direction as a whole, the upper end of the main support frame being connected with the top base, the lower end of the main support frame being connected with the bottom base, the upper end of the lateral support frame being connected with the top base, the lower end of the lateral support frame being connected with the bottom base, and the main support frame, the lateral support frame, and the bottom base cooperating to form a triangular mechanism.

[0012] In a preferred embodiment, the top base comprises a rectangular plate with a predetermined thickness, comprising opposite left and right sides and opposite front and back sides, and the projection length of the left and right sides towards the bottom base is located within the bottom base.

[0013] In a preferred embodiment, the offshore platform-pipe column-seafloor equipment multi-body coupling experimental device further comprises: a simulation riser sleeved outside the simulation drill pipe, and a simulation tensioner connected at the top of the simulation riser, the simulation tensioner being used for providing tension to the simulation riser.

[0014] In a preferred embodiment, the offshore platform-riser-seafloor equipment multi-body coupling experimental device further comprises a simulated blowout preventer, which is arranged on the simulated underwater wellhead at the lower end of the simulated riser and is capable of closing the annular space of the simulated underwater wellhead.

[0015] In a preferred embodiment, the offshore platform-riser-seafloor equipment multi-body coupling experimental device further comprises a simulated platform, and the support mechanism comprises a support frame sliding rail arranged longitudinally along the height direction, and the simulated platform is in sliding cooperation with the support frame sliding rail.

[0016] In a preferred embodiment, the simulated platform has a spatial three-dimensional vibration function, and the simulated platform comprises a vibration platform, a first support frame arranged above and below the vibration platform, a first spring arranged between the vibration platform and the first support frame, a second support frame arranged left and right of the vibration platform, a second spring arranged between the vibration platform and the second support frame, a third support frame arranged front and back of the vibration platform, and a third spring arranged between the vibration platform and the third support frame.

[0017] In a preferred embodiment, the offshore platform-riser-seafloor equipment multi-body coupling experimental device further comprises a simulated drill bit torque device, which is arranged at the bottom of the soil box and is used to simulate the drill bit penetration into rocks and soil with different hardness.

[0018] An offshore platform-riser-seafloor equipment multi-body coupling experimental method is executed based on the offshore platform-riser-seafloor equipment multi-body coupling experimental device described above, the simulated underwater wellhead comprises a simulated surface conductor and a suction pile arranged outside the simulated surface conductor, and the offshore platform-riser-seafloor equipment multi-body coupling experimental method comprises: Starting the drilling simulation rotation system, simulating the suction pile filling process, judging whether the simulated surface conductor is sunk in place based on the detection signal obtained by the detection device, and establishing a first relationship for determining the ultimate bearing capacity of the suction pile before the simulated surface conductor is sunk in place, the first relationship being:

[0019] Judging whether the simulated surface conductor is sunk in place based on the detection signal obtained by the detection device, and establishing a second relationship for determining the ultimate bearing capacity of the suction pile after the simulated surface conductor is sunk in place, the second relationship being:

[0020] During the simulated second drilling, based on the detection signal acquired by the detection device, after identifying that the soil plug inside the simulated surface guide pipe has been drilled open, a third relationship is established to determine the ultimate bearing capacity of the suction pile. The third relationship is as follows:

[0021] in, F u The maximum load-bearing capacity of the overall structure is N; L The height of the suction pile skirt panel is in meters (m). d c To simulate the radius of the surface duct, in meters (m); d s Let be the radius of the suction pile, in meters. f co To simulate the force per unit area of ​​the surface conduit in the soil, Pa; f so The frictional force per unit area between the interior of the suction pile casing and the soil contact surface, expressed in Pa; f si The lateral frictional force per unit area of ​​the suction pile casing, expressed in Pa. f ci To simulate the frictional force per unit area at the contact surface between the surface guide pipe and the soil, Pa; A c To simulate the cross-sectional area of ​​the surface conduit, m 2 ; A cs To simulate the cross-sectional area of ​​the surface conduit after the formation of the soil plug, m 2 ; A s Let m be the cross-sectional area of ​​the suction pile. 2 ; A sb The area of ​​the top plate of the suction pile is m. 2 ; q c The resistance per unit area simulating the surface conduit, N / m 2 ; q cs To simulate the resistance per unit area of ​​the surface conduit after the formation of the soil plug, N / m 2 ; q s The resistance force per unit area of ​​the suction pile, in N / m. 2 ; q sb The resistance force per unit area of ​​the suction pile top plate, in N / m. 2 .

[0022] The technical solution of the present invention has the following significant beneficial effects: The multi-body coupling experimental device and method for offshore platform-tubing-subsea equipment provided in this application can simulate multiple working conditions: it can simulate various working conditions such as deep-water surface well construction, riser-drill pipe (pipe-in-pipe) dynamics, and platform-riser-drill pipe-bottom blowout preventer-subsea wellhead coupling, covering the core scenarios of deep-sea drilling; it supports the replacement of different types of wellheads (guide pipe, suction pile wellhead, cementing guide pipe, expansion guide pipe, etc.), and can simulate different geological conditions and platform movement states, with high experimental flexibility; it has extremely high engineering application value: it effectively verifies the structural design and mechanical model of the deep-sea drilling system, reducing engineering risks; it optimizes drilling parameters (such as drilling pressure, rotation speed, etc.) and structural design based on experimental data, improving drilling efficiency and success rate; it completes multi-working-condition testing in a laboratory environment, avoiding trial and error costs in actual engineering, and reducing material consumption and maintenance costs; the experimental process does not require actual offshore drilling operations, avoiding pollution to the marine environment.

[0023] Specific embodiments of the invention are disclosed in detail below with reference to the description and accompanying drawings, indicating how the principles of the invention can be employed. It should be understood that the embodiments of the invention are not therefore limited in scope. Features described and / or shown for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments. Attached Figure Description

[0024] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, can select various possible shapes and proportions to implement the invention according to specific circumstances.

[0025] Figure 1 This is a schematic diagram of the soil box and bottom slide rail assembly in a multi-body coupling experimental device for marine platform-tube string-subsea equipment provided in the embodiments of this application. Figure 2This is a bottom view of the soil box and bottom slide rail assembly in a multi-body coupling experimental device for marine platform-tube string-subsea equipment provided in the embodiments of this application. Figure 3 This is a schematic diagram of the structure of a multi-body coupling experimental device for a marine platform-tube gantry-subsea equipment under working condition 1 provided in the embodiments of this application. Figure 4 This is a schematic diagram of the structure of a multi-body coupling experimental device for marine platform-tube string-subsea equipment under working condition 2 provided in the embodiments of this application. Figure 5 This is a schematic diagram of the structure of a multi-body coupling experimental device for marine platform-tube string-subsea equipment under working condition 3 provided in the embodiments of this application. Figure 6 This is a side view of a multi-body coupling experimental device for a marine platform-tube gantry-subsea equipment under working condition 3 provided in the embodiments of this application. Figure 7 A schematic diagram of the longitudinal bearing capacity of a suction pile during its sinking process; Figure 8 This is a schematic diagram of the longitudinal bearing capacity of suction piles in the second stage of construction; Figure 9 A schematic diagram of the frictional resistance experienced by the soil plug.

[0026] The reference numerals in the above figures are as follows: 6. Earthen box; 61. First track; 62. First locking mechanism; 63. Simulated drill bit torque device; 64. Second track; 65. Second locking mechanism; 7. Drilling simulation rotary system; 8. Top base; 9. Lateral support frame; 10. Main support frame; 11. Bottom base; 12. Support base; 13. Simulated drill pipe; 15. Simulate an underwater wellhead; 16. Connecting device for guide pipe and drill pipe; 17. Simulated tensioner; 19. Tensioner clamping device for water-tightening pipe; 20. Simulated riser pipe; 21. Simulated blowout preventer; 22. Simulated drilling guide; 23. Support frame slide rail; 24. Second support frame; 25. The second spring; 27. Water-tightening pipe clamping device; 28. Simulate bottom blowout preventer; 29. The third spring; 30. Simulation platform; 31. Third support frame; 32. First support frame; 35. The first spring; X, first direction; Y, the second direction. Detailed Implementation

[0027] The details of the present invention can be more clearly understood by referring to the accompanying drawings and the description of specific embodiments. However, the specific embodiments of the present invention described herein are for illustrative purposes only and should not be construed as limiting the invention in any way. Under the teachings of this invention, those skilled in the art can conceive of any possible modifications based on the invention, all of which should be considered within the scope of the invention. It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there may be an intervening element. The terms "mounted," "connected," and "connected" should be interpreted broadly, for example, they can refer to mechanical or electrical connections, or internal communication between two elements, and can be direct or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] In oil drilling operations, mechanical analysis and calculation of the platform, riser, wellhead, and platform-drill pipe-wellhead system are very important, as they directly affect various aspects such as safety assessment, design optimization, determination of operating parameters, environmental adaptability, maintenance and repair.

[0030] For example, the specific impact on security assessment is as follows: Structural Integrity: Mechanical calculations can assess the structural integrity and durability of drilling platforms and related subsea facilities under operational and extreme environmental conditions, ensuring operational safety.

[0031] Accident prevention: Through mechanical analysis, structural failures caused by overload, fatigue, resonance, etc. can be predicted and prevented, thereby avoiding accidents.

[0032] The specific impacts on design optimization are as follows: Material selection: Mechanical calculations can help engineers select appropriate materials and structural designs to withstand expected loads and environmental impacts.

[0033] Cost-effectiveness: By optimizing the design, it is possible to reduce the use of materials, thereby lowering construction and maintenance costs while ensuring safety.

[0034] The specific impact on the determination of operating parameters is as follows: Drilling parameters: Mechanical calculations help determine the optimal drilling parameters, such as drilling pressure and rotation speed, to improve drilling efficiency and success rate.

[0035] Dynamic response: Understanding the dynamic response of the platform and drill pipe system helps in developing reasonable operating procedures and avoiding structural damage caused by improper operation.

[0036] The specific impacts on environmental adaptability are as follows: Wind, wave and current effects: Mechanical calculations can assess the stability of platforms and wellhead systems under different environmental conditions (such as storms, waves and currents), ensuring safe operation under various climatic conditions.

[0037] Geological conditions: Considering the impact of geological conditions on the wellhead and drill pipe system, mechanical calculations help to develop drilling strategies that adapt to different formation characteristics.

[0038] The specific impacts on maintenance and repair are as follows: Fatigue life prediction: The fatigue life of key components can be predicted through mechanical calculations, providing a scientific basis for regular inspection and maintenance.

[0039] Fault diagnosis: Mechanical analysis helps diagnose abnormal behavior of a system, identify potential faults in a timely manner, and take corrective measures.

[0040] Reliable drilling platforms and related subsea facilities are crucial for deep-sea oil exploration and development. In oil drilling operations, the mechanical analysis and calculation of the platform, riser, wellhead, and platform-drill pipe-wellhead system directly impact several key aspects, including safety assessment, design optimization, determination of operating parameters, environmental adaptability, maintenance, and repair. However, current numerical calculations face numerous difficulties in addressing these mechanical problems: Model complexity: The actual drilling system includes multiple parts such as platform, riser, wellhead, drill pipe, etc., and each part has unique mechanical properties, which makes model construction extremely difficult; Multiphysics coupling: The coupling effects of multiple physical fields such as fluid mechanics, structural mechanics, and thermodynamics need to be considered comprehensively, making the analysis process complex; Nonlinear analysis: Material nonlinearity and geometric nonlinearity further increase the difficulty of analysis; Uncertainty analysis: The unpredictability of environmental conditions and geological structures reduces the reliability of the analysis results; Computational resource requirements: High-precision simulations require a large amount of computing resources and are very costly; Model validation: There is a lack of sufficient experimental data to validate the accuracy of the numerical model.

[0041] With the development of drilling technology, a large number of new drilling processes, technologies and tools have emerged, and existing experimental technologies and methods are no longer sufficient to meet the experimental simulation needs of deep-sea oil exploration and development.

[0042] This invention provides an adjustable simulation of the platform-tubing-subsea equipment multi-body coupling experimental device and method for deep-sea oil and gas development processes. It can meet the experimental simulation needs of deep-sea oil exploration and development, thereby guiding actual production and improving drilling efficiency and success rate.

[0043] Please refer to the following for comprehensive information. Figures 1 to 6 The embodiments of this application provide a multi-body coupling experimental device for marine platform-tubing-subsea equipment. The multi-body coupling experimental device for marine platform-tubing-subsea equipment may include: an experimental frame, a drilling simulation rotation system 7, a soil box 6 and a bottom slide rail assembly, a tubing simulation assembly, a simulation platform assembly and a detection device, etc.

[0044] The experimental frame provides stable support for the entire device, including a top base 8, a bottom base 11, and a support mechanism set between the two.

[0045] The top base 8 is a rectangular plate with a predetermined thickness, including opposite left and right sides, opposite front and rear sides, and the projected length of the left and right sides toward the bottom base 11 is located within the bottom base 11 to ensure support stability.

[0046] The bottom base 11 is used to support the soil box 6, the slide rail and other auxiliary components, providing a stable installation foundation.

[0047] The support mechanism includes a main support frame 10 and a side support frame 9. The main support frame 10 extends longitudinally along the height direction, with its upper end connected to the top base 8 and its lower end connected to the bottom base 11. The upper end of the side support frame 9 is connected to the top base 8 and its lower end is connected to the bottom base 11. The main support frame 10, the side support frame 9, and the bottom base 11 work together to form a triangular mechanism, which significantly improves the structural stability and load-bearing capacity of the experimental frame.

[0048] The drilling simulation rotation system 7 is used to simulate the rotational motion and stress state of the drill pipe during the drilling process, including a motor and a simulated drill pipe 13. The motor is mounted on the top base 8 to provide power for the simulated drilling; the upper end of the simulated drill pipe 13 is detachably connected to the motor for easy maintenance and replacement, and the lower end is equipped with a simulated subsea wellhead 15 through a connecting device, which can be replaced with different types of wellhead structures (such as guide pipes, suction pile wellheads, etc.) according to experimental needs.

[0049] Please refer to the following: Figures 1 to 2 The soil tank 6 is used to simulate the seabed geological environment, and the bottom sliding rail assembly enables multi-directional position adjustment of the soil tank 6. The soil tank 6 contains seabed soil, and different geological conditions can be simulated by adjusting the composition and ratio of the seabed soil. A simulated drill bit torque device 63 can be installed at the bottom of the soil tank 6. This device controls the torque by rotation, and automatically rotates when the torque accumulates to the design value, which is used to simulate the process of the drill bit cutting into rocks and soils of different hardness.

[0050] The bottom slide rail includes at least a first track 61 extending longitudinally along the first direction X and a second track 64 extending longitudinally along the second direction Y (perpendicular to the first direction X); the soil box 6 is movably mounted on the first track 61, and the first track 61 is movably mounted on the second track 64, so as to realize the flexible movement of the soil box 6 in the XY plane.

[0051] Furthermore, a first locking mechanism 62 is provided between the soil box 6 and the first track 61, and a second locking mechanism 65 is provided between the first track 61 and the second track 64, which can be fixed after the soil box 6 is moved to the target position to ensure the stability of the position during the experiment.

[0052] The tubing string simulation assembly is used to simulate the riser 20-drill pipe (tube-in-tube) structure, including a simulated riser 20, a simulated tensioner 17, and a simulated blowout preventer 21. The simulated riser 20 is fitted over the simulated drill pipe 13, simulating the riser structure in actual drilling. The simulated tensioner 17 is connected to the top of the simulated riser 20 to provide stable tension, simulating the stress state of the riser in a deep-sea environment. The simulated blowout preventer 21 is installed on the simulated subsea wellhead 15, located at the lower end of the simulated riser 20, and can be used to seal the annular space of the simulated subsea wellhead 15, simulating the blowout prevention function in actual drilling.

[0053] The simulation platform assembly is used to simulate the vibration and offset states of a drilling platform, and includes a simulation platform 30 and a support frame slide rail 23. The support frame slide rail 23 is arranged longitudinally along the height direction, and the simulation platform 30 slides in conjunction with the support frame slide rail 23, allowing for adjustment of the height of the simulation platform 30.

[0054] The simulation platform 30 has a three-dimensional (XYZ direction) vibration function and includes a vibration platform, a first support frame 32, a first spring 35, a second support frame 24, a second spring 25, a third support frame 31, and a third spring 29. The first support frame 32 is arranged vertically along the vibration platform, and the first spring 35 is located between the vibration platform and the first support frame 32; the second support frame 24 is arranged horizontally along the vibration platform, and the second spring 25 is located between the vibration platform and the second support frame 24; the third support frame 31 is arranged front-to-back along the vibration platform, and the third spring 29 is located between the vibration platform and the third support frame 31. The vibration of the simulation platform 30 in three dimensions is achieved through the elastic deformation of the springs, accurately simulating the impact of the platform 30's vibration on the entire drilling system.

[0055] The detection device is used to detect the working parameters of the simulated drill pipe 13 in real time, providing data support for experimental analysis and model verification. The detection parameters include any one or a combination of force parameters, rotational speed and torque.

[0056] The multibody coupling experimental device for marine platform-tube gantry-subsea equipment can be applied to different simulated working conditions. The following will explain the application of the multibody coupling experimental device for marine platform-tube gantry-subsea equipment to different working conditions.

[0057] Operating Condition 1: Simulating Deep Water Surface Well Construction

[0058] Experimental steps: Preparation: Adjust the composition and ratio of seabed soil in soil box 6 according to experimental requirements to simulate the geological conditions of the target sea area; adjust the position of soil box 6 through the bottom slide rail and fix it with the locking mechanism; according to Figure 3 The components and their fit are shown for device installation: The simulated subsea wellhead 15 (which can be selected as a guide pipe, suction pile wellhead, cementing guide pipe, expansion guide pipe, etc.) is connected to the lower end of the simulated drill pipe 13 through the connecting device to ensure a firm connection; Simulation platform 30 adjustment: The offset of platform 30 is simulated by adjusting the pulleys on the bottom slide rail; Experimental operation: Start the drilling simulation rotation system 7 to simulate the drilling process, and collect the force, rotation speed and torque data of the simulated drill pipe 13 in real time through the detection device; Data recording and analysis: Record experimental data under different geological conditions and different platform offsets, and analyze the impact of platform offset on wellhead stability.

[0059] The installation of the experimental apparatus may specifically include the following installation operations: Assemble the experimental frame: Connect and fix the top base 8, bottom base 11, main support frame 10 and side support frame 9 to form a triangular support structure; wherein, the bottom base 11 is installed on the support base 12; Install the soil box 6 assembly: Install the soil box 6 on the first track 61 through the first locking mechanism 62, and install the first track 61 on the second track 64 through the second locking mechanism 65. Install the simulated drill bit torque device 63 at the bottom of the soil box 6, and fill the soil box 6 with seabed soil of a preset ratio. Install the drilling simulation rotation system 7: Fix the motor on the top base 8, connect the upper end of the simulated drill rod 13 to the motor, and install the simulated underwater wellhead 15 at the lower end through the guide pipe and drill rod connection device 16 (the type of guide pipe can be selected according to the experimental requirements). Set up detection devices: Install force sensors, speed sensors and torque sensors on key parts of the simulated drill pipe 13, and connect them to data acquisition equipment.

[0060] Considering the complex and variable geological conditions in the deep sea, and the threats that wind, waves and ocean currents pose to the position control and stability of drilling platforms, the multi-body coupling experimental device for offshore platforms-tube string-seabed equipment provided in this application can improve the integrity and comprehensiveness of the experiment by adjusting the seabed soil that makes up various combinations; and by adjusting the pulley below, it can accurately simulate the impact of the platform 30's offset on the wellhead.

[0061] When conducting experiments under working condition 1, the process of drilling wells on the surface of the deep sea can be simulated to study the impact of complex geological conditions in the deep sea and platform offset on the wellhead.

[0062] Specifically, the factors that can be measured during the experiment in operating condition 1 include the following: I. Dynamic response of the riser pipe: Tension of the riser pipe: The tension change at the top and bottom of the riser pipe is measured by a tension sensor.

[0063] Bending and twisting of the riser: Use strain gauges or other displacement sensors to monitor the degree of bending and twisting of the riser.

[0064] Vibration frequency and amplitude of the riser pipe: measured by accelerometer or other vibration monitoring equipment.

[0065] II. Dynamic behavior of underwater wellheads: Wellhead displacement: Use underwater positioning systems or visual monitoring technology to track changes in the position of the wellhead.

[0066] Wellhead load: Various loads acting on the wellhead are measured by force sensors installed on the underwater wellhead.

[0067] Wellhead pressure: Pressure changes at the wellhead are monitored using pressure sensors.

[0068] III. Performance of Coupled Systems: The natural frequency of the system: The natural frequency of the entire coupled system is determined through dynamic analysis in order to assess the risk of resonance.

[0069] Damping characteristics of the system: The damping ratio of the system is determined through dynamic testing, which is very important for controlling vibration.

[0070] System fatigue life: The fatigue life of the system is evaluated by using a cumulative damage model and the actual load spectrum.

[0071] IV. Safety-related parameters: The safety factor of the riser pipe in case of fracture is assessed by calculating the stress state of the riser pipe and the fracture toughness of the material.

[0072] When conducting the experiment under working condition 1, the bearing capacity of the surface guide pipe can be calculated. Specifically, the empirical formula for the ultimate bearing capacity of a single pile axial bearing capacity can be used to calculate the ultimate bearing capacity.

[0073] When the surface guide pipe is lowered into the soil layer, the frictional resistance between the soil and the pile leg surface can be calculated by the following formula: .

[0074] In the above formula: : Formation lateral pressure coefficient, under axial compressive load ; Effective overburden pressure, ; The friction angle between the soil and the pile is generally taken as... ; : Angle of internal friction of soil.

[0075] Pile end resistance: .

[0076] In the formula: : Bearing capacity coefficient.

[0077] The simulated underwater wellhead 15 includes a simulated surface guide pipe and a suction pile disposed outside the simulated surface guide pipe. During the driving process of the suction pile, the friction between the inner and outer walls of the suction pile skirt is an important component of its bearing capacity. Especially when the suction pile drives into the seabed soil, the effective stress of the soil inside the suction pile and the seepage in the soil have a great influence on the friction of the suction pile.

[0078] The multi-body coupling experimental method for offshore platform-tubing-subsea equipment may include a method for calculating the bearing capacity of suction pile wellheads; specifically, it may include: The drilling simulation rotation system 7 is activated to simulate the suction pile injection process. Based on the detection signal obtained by the detection device, it is determined whether the simulated surface guide pipe has penetrated into place. Before the simulated surface guide pipe penetrates into place, a soil plug has not yet formed inside the simulated surface guide pipe. A first relationship is established to determine the ultimate bearing capacity of the suction pile. The first relationship is:

[0079] Based on the detection signal acquired by the detection device, it is determined whether the simulated surface guide pipe has penetrated into place. After the simulated surface guide pipe has penetrated into place, a soil plug is formed inside the simulated surface guide pipe. A second relationship is established to determine the ultimate bearing capacity of the suction pile. The second relationship is:

[0080] During the simulated second drilling, based on the detection signal acquired by the detection device, after identifying that the soil plug inside the simulated surface guide pipe has been drilled open, a third relationship is established to determine the ultimate bearing capacity of the suction pile. The third relationship is as follows:

[0081] in, F u The maximum load-bearing capacity of the overall structure is N; L The height of the suction pile skirt panel is in meters (m). d c To simulate the radius of the surface duct, in meters (m); d s Let be the radius of the suction pile, in meters. f co To simulate the force per unit area of ​​the surface conduit in the soil, Pa; f so The frictional force per unit area between the interior of the suction pile casing and the soil contact surface, expressed in Pa; f si The lateral frictional force per unit area of ​​the suction pile casing, expressed in Pa. f ci To simulate the frictional force per unit area at the contact surface between the surface guide pipe and the soil, Pa; A c To simulate the cross-sectional area of ​​the surface conduit, m2 ; A cs To simulate the cross-sectional area of ​​the surface conduit after the formation of the soil plug, m 2 ; A s Let m be the cross-sectional area of ​​the suction pile. 2 ; A sb The area of ​​the top plate of the suction pile is m. 2 ; q c The resistance per unit area simulating the surface conduit, N / m 2 ; q cs To simulate the resistance per unit area of ​​the surface conduit after the formation of the soil plug, N / m 2 ; q s The resistance force per unit area of ​​the suction pile, in N / m. 2 ; q sb The resistance force per unit area of ​​the suction pile top plate, in N / m. 2 .

[0082] Due to seepage, the frictional force between the soil and the inner wall of the suction pile differs significantly from that between the soil and the outer wall of the pile casing, causing a tendency for the soil outside the suction pile to flow into the pile casing. After the suction pile is driven to the designated position, it relies on the soil inside the pile casing for bearing capacity. Simultaneously, because the soil is disturbed during driving, the bearing capacity outside the pile casing gradually recovers as the pile reaches its final position. Longitudinally, the suction pile is supported by the lateral frictional forces from the inside and outside of the suction pile skirt and the lateral frictional forces from the inside and outside of the guide pipe, as well as the self-weight of the guide pipe and suction pile, the supporting force of the top plate between the suction pile and the guide pipe, and the supporting force of the top plate between the suction pile and the guide pipe. These factors work together to support the guide pipe, the upper equipment, and the lower pipe string. Figure 7 As shown.

[0083] During the second drilling phase, the drill bit breaks through the soil plug inside the guide pipe, changing the bearing capacity of the suction pile from its previous stress state to a stress state lacking the support of the soil plug inside the guide pipe. Figure 8 As shown.

[0084] After the suction pile is driven into the seabed mud surface, to maintain vertical stability, then:

[0085] in, Figure 7 and Figure 8 middleN cv For the support force at the end of the catheter, N co The frictional resistance on the outer surface of the catheter. N ci The frictional resistance on the inner surface of the catheter. N sv This is the end support force of the suction pile. N so The frictional resistance on the outer side of the skirt plate of the suction pile. N si The frictional resistance on the inner side of the skirt plate of the suction pile. N sb The bearing capacity of the bottom plate at the top of the suction pile. Q c For the weight of the catheter, Q b The weight of the suction pile. F u This represents the overall ultimate bearing capacity of the suction pile.

[0086] Based on the pile-soil interaction theory, the ultimate bearing capacity models for the inner and outer sides of the suction pile and the outer side of the tremie pipe are obtained as follows: Ultimate bearing capacity model of the outer side of the duct:

[0087] Ultimate bearing capacity model of suction pile on the outside:

[0088] Model of the ultimate bearing capacity of the inner side of a suction pile:

[0089] Based on the pile-soil interaction theory, the ultimate bearing capacity models for the end of the guide pipe, the end of the suction pile, and the bottom plate of the suction pile top are as follows: Ultimate bearing capacity model of catheter tip:

[0090] Ultimate bearing capacity model of suction pile end:

[0091] Ultimate bearing capacity model of suction pile base plate:

[0092] According to the soil arching effect in pile-soil systems, when the soil in the tremie pipe is subjected to pressure, the soil will be compressed and a soil plug will form as the load is pressed in. When the pressure is too great, the soil arch will be destroyed and a new soil arch will form. At this time, the resistance of the soil arch exceeds the upward pressure. The soil arching effect converts the resistance of the soil at the pile bottom into the normal compressive force of the inner wall of the tremie pipe, which greatly enhances the friction between the seabed soil and the inner wall of the tremie pipe. During the penetration of suction piles, the seabed soil pressed into the tremie pipe undergoes a cycle of arching and failure. When no soil plug forms in the seabed soil inside the tremie pipe, the bearing capacity is the friction force of the seabed soil inside the tremie pipe. When an elastic soil plug forms inside the tremie pipe, it is equivalent to forming a closed pile, and the resistance is the end resistance.

[0093] Assuming that after penetration, frictional resistance of the inner wall of the conduit takes effect, such as... Figure 9 As shown.

[0094] When the soil penetrates the conduit to a depth of... When it is at this point, its total ultimate bearing capacity is:

[0095] Assuming that a soil plug forms inside the guide pipe after the penetration is completed, the ultimate bearing capacity model is as follows:

[0096] When the soil penetrates the conduit to a depth of... When it is at this point, its total ultimate bearing capacity is: (8) Assuming that a soil plug forms inside the guide pipe after the penetration is completed, the ultimate bearing capacity model is as follows: (9) The ultimate bearing capacity of a suction pile is the superposition of several forces: the specific formula for calculating the ultimate bearing capacity of a suction pile can be found in the first relation.

[0097] When a soil plug is formed during the sinking process, the ultimate bearing capacity of the suction pile is determined according to the second relationship mentioned above.

[0098] During the second opening, the soil inside the guide pipe will be drilled away, and the ultimate bearing capacity will be determined according to the third relationship mentioned above.

[0099] The above experiment was conducted as follows: The data acquisition equipment was activated to ensure all sensors were functioning correctly; then, the motor was started to rotate the simulated drill rod 13 and the simulated subsea wellhead 15, simulating the drilling process. The simulated drill bit torque device 63 automatically adjusted the torque based on the soil sample hardness. Experiments were conducted at different platform offsets, with each condition lasting for a predetermined duration, such as 30 minutes, recording the force, rotational speed, and torque data of the simulated drill rod 13. After the experiment, the motor and data acquisition equipment were turned off. Subsequently, based on the formula for calculating the bearing capacity of the surface guide pipe, the ultimate bearing capacity of the surface guide pipe under different platform offsets was calculated; the experimental data under different conditions were compared to analyze the influence of platform offset on wellhead stability; the accuracy of the numerical model was verified, and the model parameters were adjusted.

[0100] By establishing the calculation relationship of the ultimate bearing capacity of suction piles in stages (simulating the absence of soil plug before the surface guide pipe is driven into place, the formation of soil plug after driving into place, and the removal of soil plug during the second drilling), the core construction stages of deep-sea suction pile wellhead from installation to drilling are fully covered. This fills the gap in the existing technology that ignores the impact of soil plug formation and removal on bearing capacity, realizes the accurate quantification of the bearing capacity change trend at different construction stages, and solves the technical defect that the traditional single bearing capacity model cannot adapt to the entire construction process.

[0101] Operating Condition 2: Simulation of the dynamic state of riser 20-drill rod (pipe-in-pipe)

[0102] Experimental steps: like Figure 4 As shown, the device is assembled as follows: a simulated riser 20 is fitted over the simulated drill pipe 13, a simulated tensioner 17 is installed at the top and adjusted to the set tension, and then the riser device 19 is clamped by the tensioner to achieve the clamping of the top of the simulated riser 20. A simulated blowout preventer 21 and a simulated drilling guide 22 are installed at the bottom. Parameter settings: Set parameters such as ocean current velocity and drill pipe rotation speed according to experimental requirements; Experimental operation: Start the drilling simulation rotation system 7 to simulate the rotation of drill pipe 13 and fluid flow state, and collect data such as force and displacement of the system through the detection device; Data analysis: Based on the pipe-in-pipe mechanical model, the mechanical parameters such as the collision force and effective axial force of the drill pipe on the riser are analyzed to verify the rationality of the design and optimize the technical solution.

[0103] When setting up the experimental setup under operating condition 2: Based on working condition 1, a simulated riser 20 is fitted over the simulated drill pipe 13, a simulated tensioner 17 is installed at the top, and a simulated blowout preventer 21 is installed at the bottom; the tension of the simulated tensioner 17 is set, and the simulated riser 20 and the simulated drill pipe 13 are fitted with a clearance.

[0104] Using this experimental setup for deepwater drilling pipe-in-pipe simulation can effectively verify designs, assess risks, optimize technologies, save costs, protect the environment, collect data, improve emergency response, and support education and research, thereby promoting the development of deepwater drilling technology while ensuring safety and efficiency.

[0105] A simulation experiment was conducted under operating condition 2 to study the mechanical effects of tubing rotation on the riser-drill pipe system and to verify the mechanical principles of the tube-in-tube interaction. The mechanical analysis of the tube-in-tube is as follows: Assuming the well riser is filled with flowing fluid, and neglecting the angle between the riser's axis and the vertical direction, the effective axial force can be calculated using the following formula:

[0106] In the formula: The effective axial force of the drilling riser, Tension at the top of the riser pipe This is the effective weight of the drilling riser; This refers to the weight caused by the density difference between the drilling fluid inside the riser and the seawater outside the riser. The resistance to fluid flow inside the pipe, Provide buoyancy to the buoyancy block.

[0107] Analytical models for the kinetic energy, variable properties, and external work of the riser:

[0108] In the formula, This refers to the force exerted by the drill pipe on the riser.

[0109] The introduced step function is:

[0110] In the formula, and These represent the x-direction displacement of the riser and the displacement of the drill string, respectively. Let be the outer diameter of the drill string. When the lateral displacement distance between the riser and the drill string is equal to the outer diameter of the drill string, it is assumed that there is no gap between them, and a collision occurs. Therefore, the collision force of the drill pipe on the riser... It can be represented as:

[0111] For ease of calculation, it is assumed that the drill string follows its rotation period at the wellhead position (x=Lr), and the horizontal displacement of the drill string at the rotary table position (x=0) is equal to the platform drift. The initial boundary and control boundary of the drill string are:

[0112] The initial boundary and control boundary of the riser are:

[0113] The current velocity profile is based on the flow profile formula recommended by the American Bureau of Shipping (ABS).

[0114] In the formula, For ocean current speed, For the speed of the trend.

[0115] Analytical models for the kinetic energy, variable properties, and external work of the riser:

[0116] In the formula, This refers to the force exerted by the drill pipe on the riser.

[0117] To study the effect of the drill string on the riser, the force applied by the drill string is set as a step function, applied to the riser in a jump manner. The introduced step function is:

[0118] In the formula, and These represent the x-direction displacement of the riser and the displacement of the drill string, respectively. Let be the outer diameter of the drill string. When the lateral displacement distance between the riser and the drill string is equal to the outer diameter of the drill string, it is assumed that there is no gap between them, and a collision occurs. Therefore, the collision force of the drill pipe on the riser... It can be represented as:

[0119] For ease of calculation, it is assumed that the drill string follows its rotation period at the wellhead position (x=Lr), and the horizontal displacement of the drill string at the rotary table position (x=0) is equal to the platform drift. The initial boundary and control boundary of the drill string are:

[0120] The initial boundary and control boundary of the riser are:

[0121] The current velocity profile is based on the flow profile formula recommended by the American Bureau of Shipping (ABS).

[0122] In the formula, For ocean current speed, For the speed of the trend.

[0123] The specific process of conducting the experiment for operating condition 2 includes: Start the data acquisition equipment to collect the force and displacement data of the simulated riser 20 and the simulated drill rod 13; Start the motor to rotate the simulated drill rod 13, and at the same time simulate the action of ocean currents through external equipment; The ocean current speed and drill pipe rotation speed were changed sequentially, and each working condition was maintained for a predetermined duration (e.g., 20 minutes), and the experimental data were recorded. After the experiment, the tubular assembly was disassembled and the experimental apparatus was cleaned.

[0124] Data analysis was conducted after the experiment. Specifically, based on the aforementioned pipe-in-pipe mechanical calculation method, the effective axial force of the riser and the collision force of the drill pipe on the riser were calculated; the influence of ocean current velocity and drill pipe rotation speed on the mechanical properties of the tubing system was analyzed, and the tubing structure design was optimized; the experimental data and numerical simulation results were compared to verify the rationality of the multiphysics coupling model.

[0125] Operating Condition 3: Simulation Platform 30 - Riser - Drill Pipe - Bottom Blowout Preventer - Subsea Wellhead Status

[0126] Experimental steps: like Figure 5 and Figure 6 As shown, the system setup includes: assembling the simulation platform 30, simulation riser 20, simulation drill pipe 13, simulation bottom blowout preventer 28, and submersible wellhead, ensuring reliable connection of each component; Vibration parameter setting: The vibration parameters in the XYZ directions are set by simulating the spring assembly of platform 30 (based on the platform motion displacement model under linear wave or random wave). Experimental operation: The vibration function of the simulation platform 30 and the drilling simulation rotation system 7 were activated to simulate the platform vibration conditions during the actual drilling process. The detection device collected data such as the force, displacement, and vibration frequency of each component of the system in real time. Data processing: Based on the force model under horizontal load, analyze parameters such as lateral bending moment and axial force at the wellhead to evaluate the stability and safety of the system.

[0127] This experiment allows for the analysis of underwater wellhead stability.

[0128] The platform motion displacement model under the linear wave case can be simplified as follows:

[0129] In the formula, For drilling platform motion response, This is the platform offset. This represents the single-sided amplitude of the drilling platform's drift. The period of the drilling platform's drifting motion. This represents the phase difference between the drift motion and the wave (its value is usually taken as 0). Both the amplitude ratio and the phase difference are related to the wave period.

[0130] The calculation method for the longitudinal motion of a platform under random waves can refer to the calculation method for the platform motion under linear waves. The longitudinal motion model of a drilling platform under random waves incorporates the influence of the instantaneous response to irregular waves, including three aspects: the average offset of the drilling platform, the long-term drift motion of the platform positioning system, and the instantaneous response of the drilling vessel to irregular waves. The drilling platform motion model is as follows:

[0131] In the formula, For the first i The amplitude of each component wave.

[0132] The simulation experiment under operating condition 3 can obtain the impact of platform vibration on the stability, safety and efficiency of the entire drilling system.

[0133] When conducting the experiment for working condition 3, the simulation platform 30 can be installed on the experimental frame via the support frame slide rail 23 based on working condition 2. The simulation tensioner 17, the riser clamping device 27, the simulation riser 20, the simulation drill rod 13, the simulation bottom blowout preventer 28, and the simulation underwater wellhead 15 can be connected in sequence to ensure that the connection of each component is reliable.

[0134] Specifically, during the experiment in working condition 3: Start the vibration function of the simulation platform 30 and set the preset vibration frequency and amplitude; Start the motor and data acquisition equipment to simulate the platform vibration conditions during the drilling process; Real-time recording of vibration data of simulation platform 30, stress data of tubing system, displacement and bending moment data of wellhead; Repeat the experiment with different vibration parameters, each condition lasting for a predetermined duration (e.g., 25 minutes).

[0135] After the experiment, data analysis can be performed: Based on the platform vibration displacement model and the horizontal load force model, the lateral bending moment and axial force at the wellhead are calculated. Analyze the impact of platform vibration on the stability of the entire drilling system and assess the system's safety redundancy; By combining the calculation formula of the bearing capacity of suction pile wellhead, the bearing capacity of suction pile under platform vibration conditions is verified, and the structural design of suction pile is optimized.

[0136] The multi-body coupling experimental device and method for offshore platform-tubing-subsea equipment of the present invention has the following significant advantages: It enables multi-condition simulation: It can simulate various operating conditions such as deep-water surface well construction, riser-drill pipe (pipe-in-pipe) dynamics, and platform-riser-drill pipe-bottom blowout preventer-subsea wellhead coupling, covering core deep-sea drilling scenarios. It supports the replacement of different types of wellheads (guide pipe, suction pile wellhead, cementing guide pipe, expansion guide pipe, etc.), simulating different geological conditions and platform movement states, providing high experimental flexibility. It has extremely high engineering application value: It effectively verifies the structural design and mechanical model of the deep-sea drilling system, reducing engineering risks; it optimizes drilling parameters (such as drilling pressure, rotational speed, etc.) and structural design based on experimental data, improving drilling efficiency and success rate; it completes multi-condition testing in a laboratory environment, avoiding trial-and-error costs in actual engineering, and reducing material consumption and maintenance costs; the experimental process does not require actual offshore drilling operations, avoiding pollution to the marine environment.

[0137] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified element, component, part, or step, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute “may” include is optional. Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The disclosure of “a” or “an” used to describe an element, component, part, or step does not imply exclusion of other elements, components, parts, or steps.

[0138] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from the others. Similar or identical parts between embodiments can be referred to interchangeably. The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-body coupling experimental device for marine platform-tube gantry-seabed equipment, characterized in that, The marine platform-tube string-subsea equipment multibody coupling experimental device includes: An experimental frame, comprising a top base, a bottom base, and a support mechanism disposed between the top base and the bottom base; A drilling simulation rotation system includes a motor and a simulated drill pipe. The motor is mounted on the top base, and the upper end of the simulated drill pipe is detachably connected to the motor. The lower end is provided with a simulated underwater wellhead through a connecting device. A soil container, the contents of which contain seabed soil; A detection device is used to detect the working parameters of the simulated drill pipe, the working parameters including any one or a combination of the following: force parameters, rotational speed, and torque.

2. The multi-body coupling experimental device for marine platform-tube gantry-subsea equipment as described in claim 1, characterized in that, The marine platform-tube-subsea equipment multibody coupling experimental device further includes: a bottom slide rail, the bottom slide rail including at least a first track extending longitudinally along a first direction, and the soil box being movably installed on the first track.

3. The multi-body coupling experimental device for marine platform-tube gantry-subsea equipment as described in claim 2, characterized in that, The bottom slide rail also includes a second track extending longitudinally along a second direction, which is perpendicular to the first direction, and the first track is movably mounted on the second track.

4. The multi-body coupling experimental device for offshore platform-tube gantry-subsea equipment as described in claim 3, characterized in that, A first locking mechanism is provided between the soil box and the first track, and a second locking mechanism is provided between the first track and the second track.

5. The multi-body coupling experimental device for offshore platform-tube gantry-subsea equipment as described in claim 1, characterized in that, The support mechanism includes a main support frame and a side support frame. The main support frame extends longitudinally along the height direction. The upper end of the main support frame is connected to the top base, and the lower end of the main support frame is connected to the bottom base. The upper end of the side support frame is connected to the top base, and the lower end of the side support frame is connected to the bottom base. The main support frame, the side support frame, and the bottom base cooperate to form a triangular mechanism.

6. The multi-body coupling experimental device for offshore platform-tube gantry-subsea equipment as described in claim 5, characterized in that, The top base includes a rectangular plate with a predetermined thickness, including opposing left and right sides, and opposing front and rear sides, wherein the projected lengths of the left and right sides toward the bottom base are located within the bottom base.

7. The multi-body coupling experimental device for offshore platform-tube gantry-subsea equipment as described in claim 1, characterized in that, The multi-body coupling experimental device for marine platform-tube string-subsea equipment also includes: a simulated riser sleeved outside the simulated drill pipe, and a simulated tensioner connected to the top of the simulated riser, the simulated tensioner being used to provide tension to the simulated riser.

8. The multi-body coupling experimental device for offshore platform-tube gantry-subsea equipment as described in claim 7, characterized in that, The multi-body coupling experimental device for marine platform-tube string-subsea equipment also includes: a simulated blowout preventer, which is installed on the simulated subsea wellhead, located at the lower end of the simulated riser, and can be used to seal the annular space of the simulated subsea wellhead.

9. The multi-body coupling experimental device for marine platform-tube gantry-subsea equipment as described in claim 8, characterized in that, The marine platform-tube string-subsea equipment multibody coupling experimental device also includes: a simulation platform, the support mechanism including a support frame slide rail, the support frame slide rail being arranged longitudinally along the height direction, and the simulation platform slidingly engaging with the support frame slide rail.

10. The multi-body coupling experimental device for marine platform-tube gantry-subsea equipment as described in claim 9, characterized in that, The simulation platform has a three-dimensional spatial vibration function. The simulation platform includes: a vibration platform, a first support frame arranged vertically along the vibration platform, a first spring located between the vibration platform and the first support frame, a second support frame arranged horizontally along the vibration platform, a second spring located between the vibration platform and the second support frame, a third support frame arranged front-to-back along the vibration platform, and a third spring located between the vibration platform and the third support frame.

11. The multi-body coupling experimental device for offshore platform-tube gantry-subsea equipment as described in claim 1, characterized in that, The multi-body coupling experimental device for marine platform-tube string-subsea equipment also includes: a simulated drill bit torque device, which is located at the bottom of the soil box and is used to simulate the drill bit entering rocks and soils of different hardness.

12. A multi-body coupling experimental method for offshore platform-tube gantry-subsea equipment, characterized in that, The offshore platform-tub-subsea equipment multi-body coupling experimental method is performed based on the offshore platform-tub-subsea equipment multi-body coupling experimental device described in claim 1. The simulated subsea wellhead includes a simulated surface guide pipe and a suction pile disposed outside the simulated surface guide pipe. The offshore platform-tub-subsea equipment multi-body coupling experimental method includes: The drilling simulation rotation system is activated to simulate the suction pile driving process. Based on the detection signal acquired by the detection device, it is determined whether the simulated surface guide pipe has penetrated into place. Before the simulated surface guide pipe penetrates into place, a soil plug has not yet formed inside the simulated surface guide pipe. A first relationship is established to determine the ultimate bearing capacity of the suction pile. The first relationship is: Based on the detection signal acquired by the detection device, it is determined whether the simulated surface guide pipe has penetrated into place. After the simulated surface guide pipe has penetrated into place, a soil plug is formed inside the simulated surface guide pipe. A second relationship is established to determine the ultimate bearing capacity of the suction pile. The second relationship is: During the simulated second drilling, based on the detection signal acquired by the detection device, after identifying that the soil plug inside the simulated surface guide pipe has been drilled open, a third relationship is established to determine the ultimate bearing capacity of the suction pile. The third relationship is as follows: in, F u The maximum load-bearing capacity of the overall structure is N; L The height of the suction pile skirt panel is in meters (m). d c To simulate the radius of the surface duct, in meters (m); d s Let be the radius of the suction pile, in meters. f co To simulate the force per unit area of ​​the surface conduit in the soil, Pa; f so The frictional force per unit area between the interior of the suction pile casing and the soil contact surface, expressed in Pa; f si The lateral frictional force per unit area of ​​the suction pile casing, expressed in Pa. f ci To simulate the frictional force per unit area at the contact surface between the surface guide pipe and the soil, Pa; A c To simulate the cross-sectional area of ​​the surface conduit, m 2 ; A cs To simulate the cross-sectional area of ​​the surface conduit after the formation of the soil plug, m 2 ; A s Let m be the cross-sectional area of ​​the suction pile. 2 ; A sb The area of ​​the top plate of the suction pile is m. 2 ; q c The resistance per unit area simulating the surface conduit, N / m 2 ; q cs To simulate the resistance per unit area of ​​the surface conduit after the formation of the soil plug, N / m 2 ; q s The resistance force per unit area of ​​the suction pile, in N / m. 2 ; q sb The resistance force per unit area of ​​the suction pile top plate, in N / m. 2 .

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