Dynamic response model establishment method, prediction method, system and device for marine riser multi-structure fully coupled system

Abstract

The present invention relates to the technical field of ocean development, and discloses a method for establishing a dynamic response model of a multi-structure fully coupled system of an ocean riser, a prediction method, a system and a device. The model establishing method comprises: S101, defining and describing parameters of the multi-structure fully coupled system of an ocean riser; S102, establishing a subsystem model of the multi-structure fully coupled system of an ocean riser, wherein the subsystem comprises an anchor positioning system, a dynamic positioning system, a platform system, a tensioner system, and a riser-underwater wellhead-shallow wellbore system; S103, connecting the various subsystems through node sharing, integrating to obtain an overall load vector, an overall stiffness matrix and an overall mass matrix, and solving an overall damping matrix; S104, establishing a dynamic response model of the multi-structure fully coupled system of an ocean riser based on the overall stiffness matrix, the overall mass matrix, the overall damping matrix and the overall load vector; the present invention has high precision, high efficiency and full functions, and can realize dynamic response analysis and prediction in multiple modes.

Description

Technical Field

[0001] The present invention relates to the field of ocean development technology, and in particular to a model building method, prediction method, system and device for the dynamic response of a multi-structure fully coupled system of an ocean riser. Background Art

[0002] In the prior art, the marine riser system includes a platform, an anchor positioning system, a dynamic positioning system, a tensioner system, a riser system, an underwater wellhead system and a shallow wellbore system. The upper end of the riser system is connected to the platform through an upper flexible joint and a tensioner. The platform is equipped with a dynamic positioning system or connected to the anchor system. The lower end of the riser is connected to the underwater wellhead system through a lower flexible joint and a bottom assembly of the riser system. The lower part of the underwater wellhead system is connected to the shallow wellbore system. The structures of each system are closely connected to each other, forming a marine riser multi-structure fully coupled system. The multi-structure fully coupled system is subjected to the dynamic load of the marine environment during the process of marine oil and gas exploration and development. As the depth of the marine oil and gas exploration operation increases, its stress condition becomes more severe and complex, and it may encounter various forms of damage, such as riser rupture, underwater wellhead instability, etc. Any kind of damage will lead to the interruption or even failure of the marine oil and gas exploration and development operation, causing huge losses. Therefore, accurately predicting the dynamic response of the marine riser multi-structure fully coupled system is of great significance to the safe and smooth progress of marine oil and gas exploration and development.

[0003] The existing dynamic response prediction model of the marine riser system only takes the platform wave frequency response motion as the top boundary input of the riser system. The information transmission from the platform to the riser system is one-way transmission, and the coupling between the platform and the riser system cannot be considered. In the actual operation process, the platform movement is the superposition of the wave frequency response motion and the low-frequency response motion, and is affected by the mooring positioning system or the dynamic positioning system. There is a real-time coupling between the riser system and the traditional dynamic model of the riser system cannot simulate the real-time coupling between the platform movement, the mooring positioning system, the dynamic positioning system and the riser system; the bottom boundary condition of the riser adopts a fixed connection or is connected to the underwater wellhead system, ignoring the impact of the shallow wellbore on the entire marine riser system. That is, the existing dynamic response prediction model of the marine riser cannot consider the coupling effect between the platform, the mooring system or the dynamic positioning system, the riser, the underwater wellhead and the shallow wellbore, resulting in low analysis accuracy, affecting the dynamic response analysis and safety design of the marine riser system. Therefore, it is necessary to consider the coupling effect between the multi-structure systems of marine risers, and propose a dynamic response prediction method, system and device for the multi-structure fully coupled system of marine risers. Summary of the invention

[0004] In order to adapt to the actual needs in the field of marine development technology, the present invention overcomes the shortcomings of the existing technology and the technical problem to be solved is: to provide a model establishment method, prediction method, system and device for the dynamic response of a multi-structure fully coupled system of a marine riser, so as to effectively improve the dynamic response prediction accuracy of the multi-structure fully coupled system of a marine riser, and provide a new dynamic response prediction model and prediction method for marine oil and gas exploration and development.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for establishing a model of the dynamic response of a multi-structure fully coupled system of a marine riser, comprising the following steps:

[0006] S101. Define and describe the parameters of the fully coupled system of multi-structures of marine riser, including environmental parameters and structural physical parameters;

[0007] S102, establishing a subsystem model of a marine riser multi-structure fully coupled system, wherein the subsystem includes an anchor positioning system, a dynamic positioning system, a platform system, a tensioner system, and a riser-underwater wellhead-shallow wellbore system;

[0008] S103. Based on the subsystem models established in step S102, the subsystems are connected through node sharing: taking the platform as the central coupling point, the top node of the mooring and positioning system forms a coupling point with the platform and the top node of the riser-underwater wellhead-shallow wellbore system, the top node of the tensioner system forms a coupling point with the platform, the bottom node of the tensioner system is connected with the upper node of the riser-underwater wellhead-shallow wellbore system, and the bottom nodes of the mooring and positioning system and the riser-underwater wellhead-shallow wellbore system are both set as fixed connections. This connection is the boundary condition of the fully coupled system. Based on the unit stiffness matrix, unit mass matrix and unit load vector established in the local coordinate system of each subsystem, they are converted to the global coordinate system through the coordinate transformation matrix, and the overall stiffness matrix, the overall mass matrix and the overall load vector are integrated. Then, the overall damping matrix is ​​solved by Rayleigh damping using the overall stiffness matrix and the overall mass matrix;

[0009] S104. Based on the overall stiffness matrix K, overall mass matrix M, overall damping matrix C and overall load vector F of the marine riser multi-structure fully coupled system, a dynamic response model of the marine riser multi-structure fully coupled system is established. The dynamic response equations of the marine riser multi-structure fully coupled system are as follows:

[0010]

[0011] in, is the overall acceleration vector of the marine riser multi-structure fully coupled system; is the overall velocity vector of the marine riser multi-structure fully coupled system; δ is the overall displacement vector of the marine riser multi-structure fully coupled system.

[0012] Preferably, in step S101, the environmental parameters include water depth, ocean current, wave and soil parameters;

[0013] Among the structural physical parameters, the structural physical parameters of the platform include platform RAO data, platform mass, moment of inertia, additional mass caused by platform surge, sway and pitch motion, additional mass coupled by surge-pitch motion, additional mass coupled by sway-pitch motion, platform surge and sway speeds, wind force coefficients, flow force coefficients and second-order wave force coefficients in the platform surge, sway and pitch directions;

[0014] The physical parameters of the mooring positioning system structure are the outer diameter of the structure, the length of the anchor chain, the density, the wet weight, the elastic modulus, the Poisson's ratio, the additional mass coefficient, the inertia force coefficient and the drag force coefficient;

[0015] The structural physical parameters of the dynamic positioning system are the number of thrusters and the basic parameters of the thrusters;

[0016] The physical parameters of the tensioner system structure include the initial pressure and volume of the high-pressure and low-pressure gas cylinders, the area of ​​the rod chamber and rodless chamber of the hydraulic cylinder, the weight of the piston and piston rod, and the tensioner stiffness;

[0017] The structural physical parameters of the riser system include the structural physical parameters of the upper flexible joint, the single riser, the lower flexible joint and the bottom assembly; the structural physical parameters of the upper flexible joint are the joint weight and length; the structural physical parameters of the single riser and the bottom assembly are the structural outer diameter, hydrodynamic outer diameter, wall thickness, pipe string length, pipe string density, wet weight, elastic modulus, Poisson's ratio, additional mass coefficient, inertia force coefficient and drag force coefficient; the structural physical parameters of the lower flexible joint are the joint weight, length and rotational stiffness;

[0018] The physical parameters of the underwater wellhead system structure include the structural outer diameter, hydrodynamic outer diameter, wall thickness, tubing length, tubing density, wet weight, elastic modulus, Poisson's ratio, additional mass coefficient, inertia force coefficient and drag force coefficient;

[0019] The physical parameters of the shallow wellbore system structure are the structure outer diameter, wall thickness, string length, string density, weight, elastic modulus, and Poisson’s ratio;

[0020] Preferably, in step S102,

[0021] The model establishment method of the mooring positioning system is as follows: based on the physical parameters of the mooring positioning system structure, the outer diameter, length, elastic modulus and Poisson's ratio of the anchor chain structure, the axial stiffness, bending stiffness and torsional stiffness of the mooring system are calculated, and a unit stiffness matrix is ​​formed; based on the physical parameters of the mooring positioning system structure, the outer diameter, length and density of the anchor chain structure are calculated, and a unit mass matrix is ​​formed; based on the wave parameters and current parameters in the environmental parameters and the hydrodynamic outer diameter, additional mass coefficient, inertia force coefficient and drag force coefficient of the physical parameters of the mooring positioning system structure, the combined force of waves and currents is calculated, and the unit node load vector is calculated in combination with the wet weight of the mooring system;

[0022] The model establishment method of the dynamic positioning system is as follows: based on the number of thrusters and basic parameters of the dynamic positioning system structure physical parameters, the thrusters are calculated to form a unit node load vector;

[0023] The model establishment method of the platform system is as follows: the platform is set as a six-degree-of-freedom rigid body, and the platform mass matrix is ​​formed based on the platform mass, moment of inertia, additional mass caused by platform surge, sway and bow pitch motion, additional mass coupled by surge-bow pitch motion, and additional mass coupled by sway-bow pitch motion of the platform structure physical parameters; the platform Coriolis force matrix is ​​established based on the platform's own mass, platform surge and sway velocity; the current force, wind load and wave force load vectors are established based on the wind, current and wave parameters in the environmental parameters and the wind force coefficient, flow force coefficient and second-order wave force coefficient in the platform surge, sway and bow pitch directions of the platform structure physical parameters, so as to form the platform low-frequency response motion model; the platform wave frequency response motion model is established based on the wave parameters and platform RAO data; the platform dynamic response motion model is formed by superposition based on the above platform low-frequency response motion model and platform wave frequency response motion model;

[0024] The model establishment method of the tensioner system is as follows: based on the tensioner stiffness, a physical parameter of the tensioner system structure, a unit stiffness matrix is ​​formed; based on the initial pressure and volume of the high-pressure and low-pressure gas cylinders, the area of ​​the rod cavity and the rodless cavity of the hydraulic cylinder, and the weight of the piston and the piston rod, the top tension of the fully coupled system is calculated to form a unit node load vector;

[0025] The model establishment method of the riser-underwater wellhead-shallow wellbore system is as follows: the riser system, the underwater wellhead system and the shallow wellbore system are modeled as a riser-underwater wellhead-shallow wellbore system, and the axial stiffness, bending stiffness and torsional stiffness of the riser-underwater wellhead-shallow wellbore system are calculated based on its structural physical parameters such as structural outer diameter, wall thickness, pipe string length, elastic modulus and Poisson's ratio, and a unit stiffness matrix is ​​formed, in which the unit stiffness matrix of the lower flexible joint only considers its axial stiffness and rotational stiffness; based on the riser-underwater wellhead-shallow wellbore system The unit length mass of the riser-underwater wellhead-shallow wellbore system is calculated based on the outer diameter, pipe string length and density of the system structure, and a unit mass matrix is ​​formed. The wave and current combined force is calculated based on the hydrodynamic outer diameter, additional mass coefficient, inertia force coefficient and drag force coefficient of the physical parameters of the riser-underwater wellhead-shallow wellbore system structure in the environmental parameters. The soil reaction force and vertical friction force are calculated based on the soil parameters in the environmental parameters, and the unit node load vector is calculated in combination with the wet weight of the riser-underwater wellhead-shallow wellbore system.

[0026] In addition, the present invention also provides a method for predicting the dynamic response of a marine riser multi-structure fully coupled system, which comprises the following steps:

[0027] S1. Establishing a dynamic response model of a multi-structure fully coupled system of a marine riser;

[0028] S2. Set the initial value of system displacement δ s0 and the convergence tolerance threshold in the convergence criterion;

[0029] S3, calculating the static load vector in the load model of the marine riser multi-structure fully coupled system;

[0030] S4. According to the displacement convergence criterion and the unbalanced convergence criterion, solve the initial displacement and set the initial velocity of the fully coupled system. Initial acceleration and selecting calculation parameters of the system and calculating the integral constant; the calculation parameters include the time step △t, the first parameter α, and the second parameter β;

[0031] S5. Calculate and update the overall load vector F in the load model of the marine riser multi-structure fully coupled system;

[0032] S6. Calculate the overall stiffness matrix K, overall mass matrix M and overall damping matrix C of the dynamic response model of the marine riser multi-structure fully coupled system;

[0033] S7. Calculate the effective stiffness matrix The calculation formula is:

[0034] Wherein, K, M, C represent the overall stiffness matrix, mass matrix and damping matrix of the dynamic response model of the multi-structure fully coupled system of the marine riser, respectively; a1 represents the first integral constant, and a2 represents the second integral constant;

[0035] S8. Calculate the effective load vector at time t+△t. The calculation formula is:

[0036]

[0037] in, represents the effective load vector at time t+△t, F t+△t represents the overall load vector at time t+△t, δ t represents the system displacement at time t, represents the system speed at time t, represents the system acceleration at time t, a1 represents the first integral constant, a2 represents the second integral constant, a3 represents the third integral constant, a4 represents the fourth integral constant, a5 represents the fifth integral constant, and a6 represents the sixth integral constant;

[0038] S9, calculating displacement value, velocity value and acceleration value according to the effective stiffness matrix and the effective load vector;

[0039] S10. Use the displacement value, velocity value and acceleration value obtained in step S9 as the initial value for the next iteration, return to step S5, and re-execute steps S5 to S9 until the operation is completed.

[0040] Preferably, in step S10, after the operation is completed, the following steps are further included:

[0041] S11. Extract and output the dynamic response value of the marine riser multi-structure fully coupled system, wherein the dynamic response value includes system displacement, velocity, and acceleration.

[0042] Preferably, in step S9, the calculation formulas for the displacement value, the velocity value and the acceleration value are:

[0043]

[0044]

[0045]

[0046] in, represents the effective stiffness matrix, δ t , represents the system displacement, system velocity and system acceleration at time t, δ t+△t represents the system displacement at time t+△t, represents the system speed at time t+△t, represents the system acceleration at time t+△t, represents the effective load vector at time t+△t, a3 represents the third integral constant, a4 represents the fourth integral constant, a7 represents the seventh integral constant, and a8 represents the eighth integral constant.

[0047] Preferably, in step S4, the initial displacement is calculated as follows:

[0048] S401, by δ n Obtain the tangent stiffness matrix K Tn , and apply boundary conditions; δ n represents the initial displacement at the nth iteration;

[0049] S402, calculate the unbalance value ψ n , and further obtain the displacement correction △δ n , the specific calculation method is as follows:

[0050] ψ n =K Tn δ n -F n ;

[0051] △δ n =-(K Tn ) -1 ψ n ;

[0052] Among them, F n represents the overall load vector used in the nth iteration;

[0053] S403, the displacement value δ n and its correction value △δ n Add together to get the n+1th displacement iteration approximation δ n+1 :

[0054] δ n+1 =δ n +△δ n ;

[0055] S404, calculating the displacement convergence tolerance and the unbalanced force convergence tolerance, and determining whether they are less than the set displacement convergence tolerance threshold and the unbalanced force convergence tolerance threshold, respectively. If so, the iteration ends, and the calculated displacement iterative approximation is used as the initial displacement, and the process proceeds to step S5; if not, the process returns to step S401 to continue iterative calculation until the result converges;

[0056] The displacement convergence tolerance is calculated as:

[0057]

[0058] The calculation formula for the unbalanced force convergence tolerance is:

[0059]

[0060] Where C1 represents the displacement convergence tolerance, N represents the total number of iterations, and δ n represents the displacement obtained at the nth iteration; C2 represents the convergence tolerance of the unbalanced force, K Tn δ n -F n represents the unbalanced force at the nth iteration.

[0061] Preferably, in step S4, the setting conditions of the first parameter α and the second parameter β are:

[0062] β≥0.5, α=0.25(0.5+β) 2 ;

[0063] The integral constant is calculated as:

[0064]

[0065] a7=Δt(1-β), a8=βΔt.

[0066] Furthermore, the present invention also provides a dynamic response prediction system for a marine riser multi-structure fully coupled system, which is used in the above-mentioned prediction method, comprising:

[0067] Fully coupled system parameter definition module, used for users to define and select system parameters;

[0068] A fully coupled system model generation module includes a substructure model generation module and a fully coupled system model generation module; the subsystem model generation module is used to generate a platform motion response model, a tensioner system model, an anchor positioning system model, a dynamic positioning system model, and a riser-underwater wellhead-shallow wellbore system model respectively; the fully coupled system model generation module is used to generate a fully coupled system model according to each subsystem generated by the subsystem model generation module;

[0069] A fully coupled system dynamic response analysis module is used to calculate the dynamic response value of the fully coupled system according to the parameters in the fully coupled system parameter definition module and the fully coupled system model generated by the fully coupled system model generation module;

[0070] The fully coupled system dynamic response result display module is used for outputting and displaying the dynamic response prediction results of the fully coupled system of the marine riser multi-structure.

[0071] Furthermore, the present invention also provides a dynamic response prediction device for a multi-structure fully coupled system of a marine riser, comprising a UI display, a memory and a processor; the UI display is used for human-computer interactive information transmission; the memory is used for storing computer programs; the processor is connected to the memory, and is used to run the computer program and execute the marine riser fully coupled dynamic response prediction method.

[0072] Compared with the prior art, the present invention has the following beneficial effects:

[0073] (1) High precision: The present invention provides a model establishment method, prediction method, system and device for the dynamic response of a marine riser multi-structure fully coupled system, which adopts a dynamic response model of a marine riser multi-structure fully coupled system. On the one hand, it fully considers the real-time coupling effects of various parts of the system under dynamic loads, including the coupling between the mooring positioning system and the platform, the coupling between the platform and the riser system, the coupling between the riser system and the underwater wellhead system, the coupling between the shallow wellbore system and the soil, etc. On the other hand, it takes into account the strong nonlinear effects involved in the system, thereby achieving high-precision prediction of the dynamic response of the marine riser multi-structure fully coupled system.

[0074] (2) High efficiency: The present invention adopts a direct coupling analysis solution method, that is, the dynamic responses of multiple structures are solved simultaneously in one time step, which avoids the extension of calculation time caused by information transmission between substructures during indirect solution, and can realize real-time coupling response calculation between substructures, with high solution efficiency.

[0075] (3) Comprehensive functions: The present invention is capable of realizing dynamic response analysis and prediction under various structural states, including dynamic response analysis of riser system, dynamic response analysis of underwater wellhead system, dynamic response analysis of mooring system, dynamic response analysis of multi-structure fully coupled system of marine riser under mooring positioning mode, dynamic response analysis of multi-structure fully coupled system of marine riser under dynamic positioning mode, and stability assessment of underwater wellhead system. It is comprehensive in functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 A schematic diagram of the structure of a multi-structure fully coupled system of a marine riser in an anchoring positioning mode provided by an embodiment of the present invention;

[0077] Figure 2 A schematic diagram of the structure of a multi-structure fully coupled system of a marine riser in a dynamic positioning mode provided by an embodiment of the present invention;

[0078] Figure 3 A structural diagram of a dynamic response model of a multi-structure fully coupled system of a marine riser provided in an embodiment of the present invention;

[0079] Figure 4A flow chart of a boundary processing method for solving dynamic equations of a multi-structure fully coupled system of a marine riser provided in an embodiment of the present invention;

[0080] Figure 5 A flow chart of a method for predicting dynamic response of a marine riser multi-structure fully coupled system provided by an embodiment of the present invention;

[0081] Figure 6 Schematic diagram of a dynamic response device for a marine riser multi-structure fully coupled system provided in an embodiment of the present invention.

[0082] Among them, 1 is the guide tube, 2 is the wellhead, 3 is the mud line, 4 is the blowout preventer group, 5 is the bottom watertight pipe assembly, 6 is the lower flexible joint, 7 is the watertight pipe, 8 is the tensioner, 9 is the upper flexible joint, 10 is the anchor chain, and 11 is the thruster.

[0083] Specific embodiment

[0084] In order to make the technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in combination with specific embodiments and drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0085] In the description of the present invention, it should be noted that the terms "displacement", "velocity", "acceleration" and "force" should be understood in a broad sense. "Displacement" can mean translational displacement or rotational angle, "velocity" can mean translational velocity or rotational angular velocity, "acceleration" can mean translational acceleration or rotational angular acceleration, and "force" can mean tensile / compressive load or bending moment. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0086] Embodiment 1

[0087] Embodiment 1 of the present invention provides a method for establishing a dynamic response model of a marine riser multi-structure fully coupled system. The model is not only applicable to Figure 1 The anchor positioning mode shown is also applicable to Figure 2 The dynamic positioning mode shown in the figure includes the following steps: defining the parameters of the marine riser multi-structure fully coupled system, establishing the substructure model of the marine riser multi-structure fully coupled system, and establishing the dynamic response model of the marine riser multi-structure fully coupled system. The following is a detailed description.

[0088] 1. Define the parameters describing the fully coupled system of multi-structure of marine riser, further including:

[0089] 1.1 Define the environmental parameter model, including water depth, ocean current, wave and soil parameters;

[0090] 1.2 Establish a structural physical parameter model. The structural physical parameters include the structural physical parameters of the platform, mooring positioning system, dynamic positioning system, tensioner system, riser system, underwater wellhead system and shallow wellbore system.

[0091] Among them, the physical parameters of the platform structure include platform RAO data, platform mass, moment of inertia, additional mass caused by platform surge, sway and pitch motion, additional mass coupled by surge-pitch motion, additional mass coupled by sway-pitch motion, platform surge and sway speeds, wind coefficient, flow coefficient and second-order wave force coefficient in the platform surge, sway and pitch directions.

[0092] The structural physical parameters of the mooring positioning system include the outer diameter of the structure, the length of the anchor chain, the density, the wet weight, the elastic modulus, the Poisson's ratio, the additional mass coefficient, the inertia force coefficient and the drag force coefficient;

[0093] The structural physical parameters of the dynamic positioning system include the number of thrusters and basic thruster parameters;

[0094] The physical parameters of the tensioner system structure include the initial pressure and volume of the high-pressure and low-pressure gas cylinders, the area of ​​the rod chamber and rodless chamber of the hydraulic cylinder, the weight of the piston and piston rod, and the tensioner stiffness;

[0095] The riser system includes an upper flexible joint, a single riser, a lower flexible joint, and a bottom assembly. The structural physical parameters of the upper flexible joint are the joint weight and length. The structural physical parameters of the single riser and the bottom assembly are the structural outer diameter, hydrodynamic outer diameter, wall thickness, pipe string length, pipe string density, wet weight, elastic modulus, Poisson's ratio, additional mass coefficient, inertia force coefficient, and drag force coefficient. The structural physical parameters of the lower flexible joint are the joint weight, length, and rotational stiffness.

[0096] The physical parameters of the underwater wellhead system structure include the outer diameter of the structure, the hydrodynamic outer diameter, the wall thickness, the length of the tubing, the density of the tubing, the wet weight, the elastic modulus, the Poisson's ratio, the additional mass coefficient, the inertia force coefficient and the drag force coefficient; the physical parameters of the shallow wellbore system structure include the outer diameter of the structure, the wall thickness, the length of the tubing, the density of the tubing, the weight, the elastic modulus and the Poisson's ratio.

[0097] 2. Establish a substructure model describing the fully coupled system of multiple structures of the marine riser, further including:

[0098] 2.1 Platform. The platform is set as a rigid body with six degrees of freedom. The platform mass matrix is ​​formed based on the platform mass, moment of inertia, additional mass caused by platform surge, sway and pitch motion, additional mass coupled by surge-sway motion, and additional mass coupled by sway-sway motion, based on the platform mass, surge and sway velocity, and the current force, wind load and wave force load vectors are established based on the wind, current and wave parameters in the environmental parameters and the wind force coefficient, flow force coefficient and second-order wave force coefficient in the platform surge, sway and pitch directions of the platform physical parameters, so as to form the platform low-frequency response motion model. The platform wave-frequency response motion model is established based on the wave parameters and platform RAO data. The platform dynamic response motion model is formed by superimposing the above platform low-frequency response motion model and platform wave-frequency response motion model.

[0099] 2.2 The riser system, underwater wellhead system and shallow wellbore system are modeled as a riser-underwater wellhead-shallow wellbore system. The axial stiffness, bending stiffness and torsional stiffness of the riser-underwater wellhead-shallow wellbore system are calculated based on its structural physical parameters, such as structural outer diameter, wall thickness, tubing length, elastic modulus and Poisson's ratio, and a unit stiffness matrix k is formed, in which the unit stiffness matrix of the lower flexible joint only considers its axial stiffness and rotational stiffness; based on the structural outer diameter, wall thickness, tubing length, elastic modulus and Poisson's ratio of the riser-underwater wellhead-shallow wellbore system, the axial stiffness, bending stiffness and torsional stiffness of the riser-underwater wellhead-shallow wellbore system are calculated, and the unit stiffness matrix k is formed, in which the unit stiffness matrix of the lower flexible joint only considers its axial stiffness and rotational stiffness; based on the structural outer diameter, wall thickness, tubing length, elastic modulus and Poisson's ratio of the riser-underwater wellhead-shallow wellbore system, the axial stiffness Density is used to calculate the unit length mass of the riser-underwater wellhead-shallow wellbore system, and a unit mass matrix m is formed; the wave and current combined force is calculated based on the wave parameters and current parameters in the environmental parameters and the hydrodynamic outer diameter, additional mass coefficient, inertia force coefficient and drag force coefficient of the physical parameters of the riser-underwater wellhead-shallow wellbore system structure; the soil reaction force and vertical friction force are calculated based on the soil parameters in the environmental parameters, and the unit node load vector f is calculated in combination with the wet weight of the riser-underwater wellhead-shallow wellbore system;

[0100] 2.3 Mooring positioning system, based on the physical parameters of the mooring positioning system structure, the outer diameter, length, elastic modulus, and Poisson's ratio of the anchor chain structure, the axial stiffness, bending stiffness, and torsional stiffness of the mooring system are calculated, and the unit stiffness matrix k is formed; based on the physical parameters of the mooring positioning system structure, the outer diameter, length, and density of the anchor chain structure, the unit length mass of the anchor chain is calculated, and the unit mass matrix m is formed; based on the wave parameters and current parameters in the environmental parameters and the hydrodynamic outer diameter, additional mass coefficient, inertia force coefficient, and drag force coefficient of the physical parameters of the mooring positioning system structure, the combined force of waves and currents is calculated, and the unit node load vector f is calculated in combination with the wet weight of the mooring system;

[0101] 2.4 Dynamic positioning system, based on the number of thrusters and basic parameters of the dynamic positioning system structure physical parameters, calculate the thruster thrust to form the unit node load vector f;

[0102] 2.5 Tensioner system, based on the tensioner stiffness of the tensioner system structure physical parameters, the unit stiffness matrix [k] is formed, and based on the initial pressure and volume of the high-pressure and low-pressure gas cylinders, the area of ​​the rod cavity and the rodless cavity of the hydraulic cylinder, and the weight of the piston and piston rod, the top tension of the fully coupled system is calculated to form the unit node load vector f;

[0103] 3. Establish a dynamic response model describing the multi-structure fully coupled system of the marine riser, further including:

[0104] Based on the substructure model of the marine riser multi-structure fully coupled system, a dynamic response model of the marine riser multi-structure fully coupled system is established.

[0105] 3.1 The subsystems are connected through node sharing: with the platform as the central coupling point, the top node of the mooring and positioning system forms a coupling point with the platform and the top node of the riser-underwater wellhead-shallow wellbore system, the top node of the tensioner system forms a coupling point with the platform, the bottom node of the tensioner system is connected to the upper node of the riser-underwater wellhead-shallow wellbore system, and the bottom nodes of the mooring and positioning system and the riser-underwater wellhead-shallow wellbore system are set as fixed connections. This connection is the boundary condition of the fully coupled system. This embodiment uses the zero-set-one method to calculate the boundary conditions, such as Figure 4 , the specific calculation method is:

[0106] 3.1.1 Given the displacement of a fully coupled system with v degrees of freedom, retain the elements on the corresponding main diagonal and change all other elements in the row (v) and column (v) to 0.

[0107] 3.1.2 In the load vector, let:

[0108] F(v)=K(v,v)×A; (1)

[0109] F′(i)=F(i)-K(i,v)×A(i≠v)

[0110] Among them, F(v) represents the load vector corresponding to the main diagonal of the system, F(i) represents the load vector corresponding to the i-th row of the stiffness matrix of the system, and F′(i) represents the load vector corresponding to the i-th row of the stiffness matrix calculated using the zero-one method. In this embodiment, the set of load vectors F′(i) calculated by the zero-one method is used as the load vector of the system.

[0111] 3.2 After each subsystem completes the common point connection, its stiffness matrix, mass matrix and load vector need to be integrated in the global coordinate system. The unit stiffness matrix, unit mass matrix and unit load vector of each subsystem are established in the local coordinate system, and need to be converted to the global coordinate system through the coordinate transformation matrix, and the overall stiffness matrix, overall mass matrix and overall load vector of the fully coupled system are assembled. Through the overall matrix assembly, the tensioner system, the mooring positioning system and the riser-underwater wellhead-shallow wellbore system realize the coupling between subsystems with the matrix unit where the common node is located, and the platform dynamic response motion model and the tensioner system, the mooring positioning system and the riser-underwater wellhead-shallow wellbore system realize the coupling between systems with the platform as the central coupling point. 3.3 After obtaining the overall stiffness matrix and the overall mass matrix, the overall damping matrix is ​​solved by Rayleigh damping. The specific solution method is as follows:

[0112] C=α r M+β r K; (2)

[0113] Among them, α r represents the first Rayleigh damping coefficient, β r represents the second Rayleigh damping coefficient, C represents the overall damping matrix of the marine riser multi-structure fully coupled system; M represents the overall mass matrix of the marine riser multi-structure fully coupled system; K represents the overall stiffness matrix of the marine riser multi-structure fully coupled system.

[0114] 3.4 Based on the above overall stiffness matrix, overall mass matrix, overall damping matrix and overall load vector, the dynamic response model of the marine riser multi-structure fully coupled system is established, and the dynamic response equation of the marine riser multi-structure fully coupled system is as follows:

[0115]

[0116] in, It represents the overall acceleration vector of the marine riser multi-structure fully coupled system; represents the overall velocity vector of the marine riser multi-structure fully coupled system; δ represents the overall displacement vector of the marine riser multi-structure fully coupled system; F represents the overall load vector of the marine riser multi-structure fully coupled system.

[0117] Embodiment 2

[0118] like Figure 5 As shown, the second embodiment of the present invention provides a method for analyzing the dynamic response model of a fully coupled system of a marine riser. Based on the dynamic response model of a fully coupled system of a multi-structure of a marine riser, the specific steps are as follows:

[0119] S1. Selecting a platform positioning mode (anchoring positioning mode or dynamic positioning mode) and establishing a dynamic response model of the marine riser multi-structure fully coupled system in the first embodiment;

[0120] S2. Set the initial value of system displacement δ s0 and convergence criteria convergence tolerance thresholds, which include displacement convergence criterion tolerance thresholds and unbalanced force convergence criterion tolerance thresholds.

[0121] S3. Calculate the static load vector in the load model of the marine riser multi-structure fully coupled system, namely, the combined wave and current force, soil reaction force and vertical friction force described in 2.2 of Example 1.

[0122] S4. According to the displacement convergence criterion and the unbalanced convergence criterion, solve the initial displacement and set the initial velocity of the fully coupled system. Initial acceleration Select the time step △t, the first parameter α, the second parameter β and the integration constant.

[0123] Wherein, solving the initial displacement specifically includes the following steps:

[0124] S401, by δ n Obtain the tangent stiffness matrix K Tn , and apply boundary conditions; δ n represents the initial displacement at the nth iteration; in the first iteration, δ n =δ s0 , during the 2nd to nth iterations, δ n =δ n-1 +Δδ n-1 ;

[0125] S402, calculate the unbalance value ψ n , and further obtain the displacement correction △δ n , the specific calculation method is as follows:

[0126] ψ n =K Tn δ n -F n ; (4);

[0127] △δ n =-(K Tn ) -1 ψ n ; (5)

[0128] Among them, F nRepresents the overall load vector used in the nth iteration. Specifically, in this step, the overall load vector includes the combined wave-current force, soil reaction force and vertical friction force, among which the soil reaction force is updated and calculated according to the displacement value, and the remaining forces are static loads, which are constants and remain unchanged in the calculation cycle of the initial displacement.

[0129] S403, the displacement value δ n and its correction value △δ n Add the displacement iteration approximation value and use it as the initial displacement value δ for the n+1th iteration. n+1 ,Right now:

[0130] δ n+1 =δ n +△δ n ; (6)

[0131] S404, calculate the displacement convergence tolerance and the unbalanced force convergence tolerance, and determine whether they are less than the set displacement convergence tolerance threshold and the unbalanced force convergence tolerance threshold respectively. If so, the iteration ends, and the calculated displacement iterative approximation is used as the initial displacement to proceed to the next step; if not, return to step S401 to continue the iterative calculation until the result converges.

[0132] The displacement convergence tolerance is calculated as:

[0133]

[0134] The calculation formula for the unbalanced force convergence tolerance is:

[0135]

[0136] Where C1 represents the displacement convergence tolerance, N represents the total number of iterations, and δ n represents the displacement obtained at the nth iteration, C2 represents the convergence tolerance of the unbalanced force, and K Tn represents the global tangent stiffness matrix, F n represents the loading matrix used in the nth iteration, K Tn δ n -F n Represents the imbalance amount at the nth iteration.

[0137] Specifically, in this embodiment, after the initial displacement δ0 is calculated through steps S401 to S404, the initial velocity of the fully coupled system needs to be set. Initial acceleration This embodiment adopts the Newmark-β integration method to solve the dynamic response value of the marine riser multi-structure fully coupled system.

[0138] Specifically, step S4 also includes selecting a time step Δt, a first parameter α and a second parameter β, and calculating each integral constant, as follows:

[0139] β≥0.5, α=0.25(0.5+β) 2 ,

[0140] a7=△t(1-β), a8=β△t; (9)

[0141] Among them, α represents the first parameter, β represents the second parameter, a1 represents the first integral constant, a2 represents the second integral constant, a3 represents the third integral constant, a4 represents the fourth integral constant, a5 represents the fifth integral constant, a6 represents the sixth integral constant, a7 represents the seventh integral constant, and a8 represents the eighth integral constant.

[0142] S5. Calculate and update the overall load vector F in the load model of the marine riser multi-structure fully coupled system.

[0143] S6. Calculate the overall stiffness matrix K, mass matrix M and damping matrix C of the marine riser multi-structure fully coupled system analysis model respectively.

[0144] S7. Calculate the effective stiffness matrix based on step S4 and step S6 And apply the boundary conditions. The specific calculation method is as follows:

[0145]

[0146] Wherein, K, M, C represent the overall stiffness matrix, mass matrix and damping matrix of the dynamic response model of the multi-structure fully coupled system of the marine riser, respectively; a1 represents the first integral constant, and a2 represents the second integral constant;

[0147] S8. Calculate the effective load at time t+Δt based on steps S4, S5 and S6. The specific calculation method is as follows:

[0148]

[0149] in, represents the effective load vector at time t+△t, F t+△t represents the overall load vector at time t+△t, δ t represents the system displacement at time t, represents the system speed at time t, represents the system acceleration at time t, a1 represents the first integral constant, a2 represents the second integral constant, a3 represents the third integral constant, a4 represents the fourth integral constant, a5 represents the fifth integral constant, a6 represents the sixth integral constant, M represents the overall mass matrix, and C represents the overall damping matrix.

[0150] S9. Calculate the displacement value according to the effective stiffness matrix calculated in step S7 and the effective load vector calculated in step S8, and solve the velocity value and the acceleration value. The specific calculation process is as follows:

[0151]

[0152] in, represents the effective stiffness matrix, δ t , represents the system displacement, system velocity and system acceleration at time t, δ t+△t represents the system displacement at time t+△t, represents the system speed at time t+△t, represents the system acceleration at time t+△t, represents the effective load vector at time t+△t, a3 represents the third integral constant, a4 represents the fourth integral constant, a7 represents the seventh integral constant, and a8 represents the eighth integral constant.

[0153] S10. Based on the displacement value, velocity value and acceleration value obtained in step S9 as the initial value for the next iteration, return to step S5 for calculation until the operation is completed, and then go to step S11.

[0154] S11. Extract the dynamic response values ​​of the marine riser multi-structure fully coupled system, including but not limited to system displacement, velocity, acceleration, etc.

[0155] Embodiment 3

[0156] The above-mentioned second embodiment provides a method for predicting the dynamic response of a marine riser multi-structure fully coupled system. Correspondingly, this embodiment provides a system for predicting the dynamic response of a marine riser multi-structure fully coupled system. The dynamic response prediction system provided in this embodiment can implement the method for predicting the dynamic response of a marine riser multi-structure fully coupled system of the second embodiment, and the system includes the dynamic response model of the marine riser multi-structure fully coupled system established in the first embodiment. The prediction system of the embodiment of the present invention can be implemented by software, hardware, or a combination of software and hardware. For example, the prediction system may include integrated or separate functional modules or functional units to execute the corresponding steps in the method of the second embodiment.

[0157] like Figure 6As shown, this embodiment provides a dynamic response prediction system for a marine riser multi-structure fully coupled system, comprising:

[0158] The fully coupled system parameter definition module is used by the user to define and select system parameters. Specifically, it may include a basic parameter definition module and a platform positioning mode selection module. The former is used to define basic parameters, and the latter is used to select the platform positioning mode.

[0159] The fully coupled system model generation module includes a subsystem model generation module and a fully coupled system model generation module. The subsystem model generation module includes a platform motion response model generation module, a tensioner system model generation module, an anchor positioning system model generation module, a dynamic positioning system model generation module, and a riser-underwater wellhead-shallow wellbore system model generation module, each of which is used to generate a corresponding subsystem. Each module corresponds to the fully coupled system model. Based on the substructure model generation module, a fully coupled system model generation module is integrated;

[0160] A fully coupled system dynamic response analysis module is used to calculate the dynamic response value of the fully coupled system according to the parameters in the fully coupled system parameter definition module and the fully coupled system model generated by the fully coupled system model generation module;

[0161] The fully coupled system dynamic response result display module is used for outputting and displaying the dynamic response prediction results of the fully coupled system of the marine riser multi-structure.

[0162] The fully coupled system parameter definition module allows the user to define environmental parameters and system structure physical parameters that match the actual sea conditions and the fully coupled system through the basic parameter definition module, and select the mooring positioning mode or the dynamic positioning mode through the platform positioning mode selection module. The fully coupled system model generation module generates a platform motion response model, a tensioner system model, a mooring positioning system model or a dynamic positioning system model, and a riser-underwater wellhead-shallow wellbore system model according to the basic parameters in the basic parameter definition module, and integrates them to form a marine riser multi-structure fully coupled system model. The fully coupled system dynamic response analysis module is used to predict the dynamic response of the marine riser multi-structure fully coupled system.

[0163] Embodiment 4

[0164] Correspondingly, this embodiment provides a dynamic response prediction device for a marine riser multi-structure fully coupled system, which is used to implement the dynamic response prediction method for a marine riser multi-structure fully coupled system provided in the second embodiment.

[0165] Specifically, the marine riser multi-structure fully coupled system dynamic response device includes a UI display, a memory and a processor. The UI display is used for human-computer interaction information transmission; the memory is used to store computer programs; the processor is connected to the memory and is used to run the computer program to implement the marine riser multi-structure fully coupled system dynamic response prediction method and system described in Embodiment 2 and Embodiment 3.

[0166] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for establishing a model of dynamic response of a marine riser multi-structure fully coupled system, characterized in that: It includes the following steps: S101. Define and describe the parameters of the fully coupled system of multi-structures of marine riser, including environmental parameters and structural physical parameters; S102, establishing a subsystem model of a marine riser multi-structure fully coupled system, wherein the subsystem includes an anchor positioning system, a dynamic positioning system, a platform system, a tensioner system, and a riser-underwater wellhead-shallow wellbore system; S103. Based on the subsystem models established in step S102, the subsystems are connected through node sharing: taking the platform as the central coupling point, the top node of the mooring and positioning system forms a coupling point with the platform and the top node of the riser-underwater wellhead-shallow wellbore system, the top node of the tensioner system forms a coupling point with the platform, the bottom node of the tensioner system is connected with the upper node of the riser-underwater wellhead-shallow wellbore system, and the bottom nodes of the mooring and positioning system and the riser-underwater wellhead-shallow wellbore system are both set as fixed connections. This connection is the boundary condition of the fully coupled system. Based on the unit stiffness matrix, unit mass matrix and unit load vector established in the local coordinate system of each subsystem, they are converted to the global coordinate system through the coordinate transformation matrix, and the overall stiffness matrix, the overall mass matrix and the overall load vector are integrated. Then, the overall damping matrix is ​​solved by Rayleigh damping using the overall stiffness matrix and the overall mass matrix; S104. Based on the overall stiffness matrix K, overall mass matrix M, overall damping matrix C and overall load vector F of the marine riser multi-structure fully coupled system, a dynamic response model of the marine riser multi-structure fully coupled system is established. The dynamic response equations of the marine riser multi-structure fully coupled system are as follows: In the formula, is the overall acceleration vector of the marine riser multi-structure fully coupled system; is the overall velocity vector of the marine riser multi-structure fully coupled system; δ is the overall displacement vector of the marine riser multi-structure fully coupled system.

2. The method for establishing a model of dynamic response of a marine riser multi-structure fully coupled system according to claim 1, characterized in that: In step S101, the environmental parameters include water depth, ocean current, wave and soil parameters; Among the structural physical parameters, the structural physical parameters of the platform include platform RAO data, platform mass, moment of inertia, additional mass caused by platform surge, sway and pitch motion, additional mass coupled by surge-pitch motion, additional mass coupled by sway-pitch motion, platform surge and sway speeds, wind force coefficients, flow force coefficients and second-order wave force coefficients in the platform surge, sway and pitch directions; The physical parameters of the mooring positioning system structure are the outer diameter of the structure, the length of the anchor chain, the density, the wet weight, the elastic modulus, the Poisson's ratio, the additional mass coefficient, the inertia force coefficient and the drag force coefficient; The structural physical parameters of the dynamic positioning system are the number of thrusters and the basic parameters of the thrusters; The physical parameters of the tensioner system structure include the initial pressure and volume of the high-pressure and low-pressure gas cylinders, the area of ​​the rod chamber and rodless chamber of the hydraulic cylinder, the weight of the piston and piston rod, and the tensioner stiffness; The structural physical parameters of the riser system include the structural physical parameters of the upper flexible joint, the single riser, the lower flexible joint and the bottom assembly; the structural physical parameters of the upper flexible joint are the joint weight and length; the structural physical parameters of the single riser and the bottom assembly are the structural outer diameter, hydrodynamic outer diameter, wall thickness, pipe string length, pipe string density, wet weight, elastic modulus, Poisson's ratio, additional mass coefficient, inertia force coefficient and drag force coefficient; the structural physical parameters of the lower flexible joint are the joint weight, length and rotational stiffness; The physical parameters of the underwater wellhead system structure include the structural outer diameter, hydrodynamic outer diameter, wall thickness, tubing length, tubing density, wet weight, elastic modulus, Poisson's ratio, additional mass coefficient, inertia force coefficient and drag force coefficient; The physical parameters of the shallow wellbore system structure are the outer diameter of the structure, wall thickness, tubing length, tubing density, weight, elastic modulus, and Poisson's ratio.

3. The method for establishing a model of dynamic response of a marine riser multi-structure fully coupled system according to claim 1, characterized in that: In step S102, The model establishment method of the mooring positioning system is as follows: based on the physical parameters of the mooring positioning system structure, the outer diameter, length, elastic modulus and Poisson's ratio of the anchor chain structure, the axial stiffness, bending stiffness and torsional stiffness of the mooring system are calculated, and a unit stiffness matrix is ​​formed; based on the physical parameters of the mooring positioning system structure, the outer diameter, length and density of the anchor chain structure are calculated, and a unit mass matrix is ​​formed; based on the wave parameters and current parameters in the environmental parameters and the hydrodynamic outer diameter, additional mass coefficient, inertia force coefficient and drag force coefficient of the physical parameters of the mooring positioning system structure, the combined force of waves and currents is calculated, and the unit node load vector is calculated in combination with the wet weight of the mooring system; The model establishment method of the dynamic positioning system is as follows: based on the number of thrusters and basic parameters of the dynamic positioning system structure physical parameters, the thrusters are calculated to form a unit node load vector; The model establishment method of the platform system is as follows: the platform is set as a six-degree-of-freedom rigid body, and the platform mass matrix is ​​formed based on the platform mass, moment of inertia, additional mass caused by platform surge, sway and bow pitch motion, additional mass coupled by surge-bow pitch motion, and additional mass coupled by sway-bow pitch motion of the platform structure physical parameters; the platform Coriolis force matrix is ​​established based on the platform's own mass, platform surge and sway velocity; the current force, wind load and wave force load vectors are established based on the wind, current and wave parameters in the environmental parameters and the wind force coefficient, flow force coefficient and second-order wave force coefficient in the platform surge, sway and bow pitch directions of the platform structure physical parameters, so as to form the platform low-frequency response motion model; the platform wave frequency response motion model is established based on the wave parameters and platform RAO data; the platform dynamic response motion model is formed by superposition based on the above platform low-frequency response motion model and platform wave frequency response motion model; The model establishment method of the tensioner system is as follows: based on the tensioner stiffness, a physical parameter of the tensioner system structure, a unit stiffness matrix is ​​formed; based on the initial pressure and volume of the high-pressure and low-pressure gas cylinders, the area of ​​the rod cavity and the rodless cavity of the hydraulic cylinder, and the weight of the piston and the piston rod, the top tension of the fully coupled system is calculated to form a unit node load vector; The model establishment method of the riser-underwater wellhead-shallow wellbore system is as follows: the riser system, the underwater wellhead system and the shallow wellbore system are modeled as a riser-underwater wellhead-shallow wellbore system, and the axial stiffness, bending stiffness and torsional stiffness of the riser-underwater wellhead-shallow wellbore system are calculated based on its structural physical parameters such as structural outer diameter, wall thickness, pipe string length, elastic modulus and Poisson's ratio, and a unit stiffness matrix is ​​formed, in which the unit stiffness matrix of the lower flexible joint only considers its axial stiffness and rotational stiffness; based on the riser-underwater wellhead-shallow wellbore system The unit length mass of the riser-underwater wellhead-shallow wellbore system is calculated based on the outer diameter, pipe string length and density of the system structure, and a unit mass matrix is ​​formed. The wave and current combined force is calculated based on the hydrodynamic outer diameter, additional mass coefficient, inertia force coefficient and drag force coefficient of the physical parameters of the riser-underwater wellhead-shallow wellbore system structure in the environmental parameters. The soil reaction force and vertical friction force are calculated based on the soil parameters in the environmental parameters, and the unit node load vector is calculated in combination with the wet weight of the riser-underwater wellhead-shallow wellbore system.

4. A method for predicting dynamic response of a marine riser multi-structure fully coupled system, characterized in that: It includes the following steps: S1. Establish a dynamic response model of a marine riser multi-structure fully coupled system as described in claim 1; S2. Set the initial value of system displacement δ s0 and the convergence tolerance threshold in the convergence criterion; S3, calculating the static load vector in the load model of the marine riser multi-structure fully coupled system; S4. According to the displacement convergence criterion and the unbalanced convergence criterion, solve the initial displacement and set the initial velocity of the fully coupled system. Initial acceleration and selecting calculation parameters of the system and calculating the integral constant; the calculation parameters include the time step △t, the first parameter α, and the second parameter β; S5. Calculate and update the overall load vector F in the load model of the marine riser multi-structure fully coupled system; S6. Calculate the overall stiffness matrix K, overall mass matrix M and overall damping matrix C of the dynamic response model of the marine riser multi-structure fully coupled system; S7. Calculate the effective stiffness matrix The calculation formula is: Wherein, K, M, C represent the overall stiffness matrix, mass matrix and damping matrix of the dynamic response model of the multi-structure fully coupled system of the marine riser, respectively; a1 represents the first integral constant, and a2 represents the second integral constant; S8. Calculate the effective load vector at time t+△t. The calculation formula is: in, represents the effective load vector at time t+△t, F t+△t represents the overall load vector at time t+△t, δ t represents the system displacement at time t, represents the system speed at time t, represents the system acceleration at time t, a1 represents the first integral constant, a2 represents the second integral constant, a3 represents the third integral constant, a4 represents the fourth integral constant, a5 represents the fifth integral constant, and a6 represents the sixth integral constant; S9, calculating displacement value, velocity value and acceleration value according to the effective stiffness matrix and the effective load vector; S10. Use the displacement value, velocity value and acceleration value obtained in step S9 as the initial value for the next iteration, return to step S5, and re-execute steps S5 to S9 until the operation is completed.

5. The method for predicting dynamic response of a marine riser multi-structure fully coupled system according to claim 4, characterized in that: In the step S10, after the operation is completed, the following steps are also included: S11. Extract and output the dynamic response value of the marine riser multi-structure fully coupled system, wherein the dynamic response value includes system displacement, velocity, and acceleration.

6. The method for predicting dynamic response of a marine riser multi-structure fully coupled system according to claim 4, characterized in that: In step S9, the calculation formulas for the displacement value, velocity value and acceleration value are: in, represents the effective stiffness matrix, δ t , represents the system displacement, system velocity and system acceleration at time t, δ t+△t represents the system displacement at time t+△t, represents the system speed at time t+△t, represents the system acceleration at time t+△t, represents the effective load vector at time t+△t, a3 represents the third integral constant, a4 represents the fourth integral constant, a7 represents the seventh integral constant, and a8 represents the eighth integral constant.

7. The method for predicting dynamic response of a marine riser multi-structure fully coupled system according to claim 4, characterized in that: In step S4, the calculation method of the initial displacement is: S401, by δ n Obtain the tangent stiffness matrix K Tn , and apply boundary conditions; δ n represents the initial displacement at the nth iteration; S402, calculate the unbalance value ψ n , and further obtain the displacement correction △δ n , the specific calculation method is as follows: ψ n =K Tn d n -F n ; △δ n =-(K Tn ) -1 ψ n ; Among them, F n represents the overall load vector used in the nth iteration; S403, the displacement value δ n and its correction value △δ n Add together to get the n+1th displacement iteration approximation δ n+1 : d n+1 =d n +△δ n ; S404, calculating the displacement convergence tolerance and the unbalanced force convergence tolerance, and determining whether they are less than the set displacement convergence tolerance threshold and the unbalanced force convergence tolerance threshold, respectively. If so, the iteration ends, and the calculated displacement iterative approximation is used as the initial displacement, and the process proceeds to step S5; if not, the process returns to step S401 to continue iterative calculation until the result converges; The displacement convergence tolerance is calculated as: The calculation formula for the unbalanced force convergence tolerance is: In the formula, C1 represents the displacement convergence tolerance, N represents the total number of iterations, and δ n represents the displacement obtained at the nth iteration; C2 represents the convergence tolerance of the unbalanced force, K Tn δ n -F n represents the unbalanced force at the nth iteration.

8. The method for predicting dynamic response of a marine riser multi-structure fully coupled system according to claim 4, characterized in that: In step S4, the setting conditions of the first parameter α and the second parameter β are: β≥0.5，α＝0.25(0.5+β) 2 ； The integral constant is calculated as: a7=△t(1-β), a8=β△t.

9. A dynamic response prediction system for a multi-structure fully coupled system of a marine riser, characterized in that: A prediction method for implementing claim 4, comprising: Fully coupled system parameter definition module, used for users to define and select system parameters; A fully coupled system model generation module includes a substructure model generation module and a fully coupled system model generation module; the subsystem model generation module is used to generate a platform motion response model, a tensioner system model, an anchor positioning system model, a dynamic positioning system model, and a riser-underwater wellhead-shallow wellbore system model respectively; the fully coupled system model generation module is used to generate a fully coupled system model according to each subsystem generated by the subsystem model generation module; A fully coupled system dynamic response analysis module is used to calculate the dynamic response value of the fully coupled system according to the parameters in the fully coupled system parameter definition module and the fully coupled system model generated by the fully coupled system model generation module; The fully coupled system dynamic response result display module is used for outputting and displaying the dynamic response prediction results of the fully coupled system of the marine riser multi-structure.

10. A dynamic response prediction device for a multi-structure fully coupled system of a marine riser, characterized in that: It comprises a UI display, a memory and a processor; the UI display is used for human-computer interaction information transmission; the memory is used for storing computer programs; the processor is connected to the memory and is used to run the computer program to implement the method for predicting the fully coupled dynamic response of the marine riser as described in any one of claims 4 to 8.

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