A method for deep-sea riser spatial configuration inversion

Abstract

The present application belongs to the technical field of ocean engineering, and provides a deep-sea riser space configuration inversion method. An inclination sensor is used as a node, and the deep-sea riser is divided into a plurality of pipe segment units; each pipe segment unit is discretized into a plurality of micro-segment units, and each micro-segment unit is projected in a horizontal coordinate system and a vertical coordinate system to obtain a space curve length equation of each pipe segment unit; in combination with inclination information, a projection expression of the space curve of each pipe segment unit in the horizontal coordinate system and the vertical coordinate system is constructed; the relative coordinates of the upper end point and the lower end point of each pipe segment unit in the local coordinate system of the pipe segment unit are iteratively solved; the relative coordinates of each pipe segment unit in the local coordinate system of each pipe segment unit are converted into absolute coordinates in a global coordinate system, and the absolute coordinates of each pipe segment unit in the global coordinate system are integrated to obtain the space configuration of the deep-sea riser. The method realizes the reconstruction of the space configuration of the riser in a complex marine environment, and has higher robustness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ocean engineering, in particular to a deep-sea riser spatial configuration inversion method. BACKGROUND

[0002] As an important part of the ocean oil and gas and mineral development system, the marine riser is used to connect the offshore platform and the subsea wellhead, and is the necessary throat component for all types of platform structures to transport oil and gas and mineral materials. It is also the most complex type of equipment in deep-sea production systems. In the development process of deep-sea resources at home and abroad, the offshore demonstration and operation of resource development has been suspended several times due to sudden conditions such as marine riser winding and kinking. Therefore, the development of structural health monitoring technology plays a significant role in the vibration monitoring and intelligent control of marine risers, and real-time inversion of riser spatial configuration is a key link in the health monitoring and intelligent control technology of deep-sea resource development systems.

[0003] In the prior art, the traditional modal analysis method reconstructs the structure displacement based on the strain response using the mode superposition principle, cannot realize the coupled solution of three-dimensional spatial configuration, and is seriously dependent on the accurate expression of the structure mode function, and cannot be applied to super-slim flexible structures such as deep-sea risers with complex boundary conditions. The discrete curvature method converts the strain measured by the sensor into curvature through the linear relationship between strain and curvature, and then obtains the position coordinates of the end points of each section by piecewise integration and recursion. Since it is based on fixed constraint coordinate points, and the tangent direction of the starting point is a specific direction, it cannot be applied to deep-sea mining risers and other structures with top dynamic boundary and bottom weak constraint boundary conditions. Secondly, in actual kilometer-level deep-sea riser system engineering, due to the extreme conditions of deep-sea environment and technical limitations, sensor installation is mainly concentrated in the top range of the riser, which leads to a monitoring blind area at the bottom end of the riser. This wired sensor arrangement poses a higher challenge to the inversion of the spatial configuration of the riser, and requires accurate inversion of the overall configuration of the riser under the condition of insufficient sensor information.

[0004] Therefore, in view of the limitations of the traditional modal analysis method and the discrete curvature method in dealing with complex boundary conditions and actual engineering sensor monitoring blind areas, it is urgent to develop a new type of riser spatial configuration inversion technology to overcome the shortcomings of the prior art and solve the key challenges in deep-sea engineering practice. SUMMARY

[0005] The purpose of the present application is to solve the above technical problems and provide a deep-sea riser spatial configuration inversion method.

[0006] In order to achieve the above purpose, in some embodiments of the present application, the following technical solutions are provided:

[0007] A deep-sea riser spatial configuration inversion method, comprising the following steps:

[0008] N inclination sensors are installed on the deep-sea riser at intervals, the deep-sea riser is divided into a plurality of pipe segment units with the inclination sensors as nodes, and each pipe segment unit is a pipe segment spatial curve;

[0009] A global coordinate system is established at the top end point of the deep-sea riser, and a pipe segment unit local coordinate system is established at the upper end point of each pipe segment unit;

[0010] Each pipe segment unit is discretized into a plurality of micro-segment units along the length direction of each pipe segment unit, the micro-segment units are projected in the horizontal coordinate system and the vertical coordinate system respectively, and a projection curve of the micro-segment units in the horizontal coordinate system and the vertical coordinate system is obtained; and a spatial curve length equation of each pipe segment unit is obtained based on the corresponding relationship between the arc length of the micro-segment spatial curve and the projection of the micro-segment in the horizontal coordinate system and the vertical coordinate system;

[0011] The inclination information collected by the inclination sensors of each pipe segment unit is combined to construct a projection expression of each pipe segment spatial curve in the horizontal coordinate system and the vertical coordinate system; and the relative coordinates of the upper end point and the lower end point of each pipe segment unit in the pipe segment unit local coordinate system are iteratively solved based on the spatial curve length equation of each pipe segment unit and the projection expression.

[0012] The relative coordinates of each pipe segment unit in the pipe segment unit local coordinate system are converted into absolute coordinates in the global coordinate system, and the absolute coordinates of each pipe segment unit in the global coordinate system are integrated to obtain the spatial configuration of the deep-sea riser.

[0013] In some embodiments of the present application, the method of dividing the deep-sea riser into a plurality of pipe segment units with the inclination sensors as nodes comprises:

[0014] The pipe segment between adjacent inclination sensors is divided into one pipe segment unit, or the pipe segment between interval inclination sensors is divided into one pipe segment unit.

[0015] In some embodiments of the present application, the method of dividing the deep-sea riser into a plurality of pipe segment units with the inclination sensors as nodes comprises:

[0016] The method of obtaining the spatial curve length equation of each pipe segment unit comprises:

[0017] The length initial equation of any micro-segment unit in the pipe segment unit is determined Q k-1 Q k is:

[0018]

[0019] wherein, the point is the lower end point of the micro-segment unit, and the coordinates of the point in the global coordinate system are , , ), Q k is the upper end point of the micro-element segment, whose coordinate in the global coordinate system is , , ), 、 、 are all intermediate variables, which have no actual meaning, , , ;

[0020] According to the Lagrange mean value theorem, the length of any micro-element segment Q k-1 Q k is obtained by the first rewriting equation:

[0021]

[0022] wherein:

[0023] ;

[0024] ;

[0025] 、 、 、 are all polynomial coefficients;

[0026] is the micro-element segment Q k-1 Q k is the derivative of the interpolation function in the horizontal coordinate system of the local coordinate system in which the micro-element segment is located, is the micro-element segment Q k-1 Q k is the derivative of the interpolation function in the vertical coordinate system of the local coordinate system in which the micro-element segment is located;

[0027] Substituting 、 into the first rewriting equation of the micro-element segment Q k-1 Q k , the length equation of the micro-element segment is further expressed as the second rewriting equation:

[0028]

[0029] wherein: , , is a parameter term, belongs to an intermediate variable, and has no actual meaning, ;

[0030] According to the second rewriting equation, the lengths of all micro-segments of each pipe segment unit are summed, and an initial equation of the pipe segment unit is obtained as follows:

[0031]

[0032] wherein, , is a parameter term, is a constant term, ;

[0033] The integral of the right side of the initial equation of the pipe segment unit is obtained, and a spatial curve length equation of the pipe segment unit is obtained as follows:

[0034]

[0035] wherein, S AB represents the length between two points A and B on the spatial curve, is a constant term.

[0036] In some embodiments of the present application: in combination with the inclination information collected by the inclination sensors of the pipe segment units, the method for constructing the projection expressions of the spatial curves of the pipe segment units in the horizontal coordinate system and the vertical coordinate system comprises:

[0037] The projection expression of the spatial curve of each pipe segment in the horizontal coordinate system is constructed as follows:

[0038]

[0039] The projection expression of the spatial curve of each pipe segment in the vertical coordinate system is constructed as follows:

[0040]

[0041] wherein, is the second-order term coefficient of the quadratic polynomial of the projection expression of the spatial curve in the horizontal coordinate system, is the first-order term coefficient of the quadratic polynomial of the projection expression of the spatial curve in the horizontal coordinate system, is the constant term of the quadratic polynomial of the projection expression of the spatial curve in the horizontal coordinate system, is the second-order term coefficient of the quadratic polynomial of the projection expression of the spatial curve in the vertical coordinate system, is the first-order term coefficient of the quadratic polynomial of the projection expression of the spatial curve in the vertical coordinate system, For the constant term of the quadratic polynomial in the expression of the projection of the space curve onto the vertical coordinate system;

[0042]

[0043]

[0044]

[0045] in, x A The upper endpoint of the pipe segment unit in the global coordinate system x The coordinates of the axis, x B The lower endpoint of the pipe segment unit in the global coordinate system x The coordinates of the axis, This is the angle by which the inclination information of the upper end point of the pipe segment unit is mapped onto the horizontal coordinate system. This is the angle mapped to the horizontal coordinate system by the inclination information of the lower end point of the pipe segment unit. This is the mapping angle of the inclination angle information of the upper end point of the pipe segment unit in the vertical coordinate system. The mapping angle of the inclination angle of the lower end point of the pipe segment unit in the vertical coordinate system; This is the two-dimensional projection expression of the pipe segment element in the horizontal coordinate system. This is the two-dimensional projection expression of the pipe segment element in the vertical coordinate system.

[0046] In some embodiments of this application, the method for iteratively solving the relative coordinates of the upper and lower endpoints of each pipe segment unit in the local coordinate system of the pipe segment unit, based on the spatial curve length equation of each pipe segment unit and the projection expression, includes:

[0047] In each segment of a deep-sea riser, assuming the coordinates of the upper endpoint of each segment in its local coordinate system are 0, solve for the coordinates of the lower endpoint of the segment in its local coordinate system. :

[0048]

[0049] in: ; The distance between the tilt sensor at the upper end of the pipe segment unit and the tilt sensor at the lower end of the pipe segment unit;

[0050] Solve , , , , , Furthermore, the coordinates of the lower endpoint of the pipe segment unit where the top point is located are solved. , , the three-dimensional space relative coordinates of the top end point of the pipe segment unit in the local coordinate system of the pipe segment unit are obtained ， ， );

[0051] The three-dimensional space relative coordinates of the top end point and the bottom end point of each pipe segment unit in the local coordinate system of each pipe segment unit are iteratively solved, until the three-dimensional space absolute coordinates of the top end point and the bottom end point of each pipe segment unit in the local coordinate system of the pipe segment unit are obtained.

[0052] In some embodiments of the present application, the method for converting the relative coordinates of each pipe segment unit in the local coordinate system of each pipe segment unit into absolute coordinates in the global coordinate system comprises:

[0053] Let the three-dimensional space absolute coordinates of the top end point of the deep-sea riser in the global coordinate system be , the three-dimensional space relative coordinates of the bottom end point B of the pipe segment unit in which the top end point is located in the local coordinate system are obtained ;

[0054] The three-dimensional space relative coordinates of the bottom end point of the pipe segment unit in which the top end point is located in the local coordinate system are superimposed with the three-dimensional space absolute coordinates of the top end point of the pipe segment unit in which the top end point is located in the global coordinate system, to obtain the three-dimensional space absolute coordinates of the bottom end point of the pipe segment unit in which the top end point is located in the global coordinate system ;

[0055] The bottom end point of the pipe segment unit in which the top end point is located is taken as the top end point of the adjacent pipe segment unit, and the three-dimensional space absolute coordinates of the bottom end point of the adjacent pipe segment unit are solved.

[0056] The three-dimensional space absolute coordinates of the top end point and the bottom end point of each pipe segment unit are iteratively solved, until the three-dimensional space absolute coordinates of the top end point and the bottom end point of each pipe segment unit are obtained.

[0057] In some embodiments of the present application, the inclination sensor collects real-time inclination information, and according to the inclination information at each time, the projection expressions of the spatial curves of each pipe segment in the horizontal coordinate system and the vertical coordinate system are updated, and the relative coordinates and the absolute coordinates are updated, and the spatial configuration of the deep-sea riser is updated.

[0058] Compared with the prior art, the technical scheme of the present application has the following beneficial effects:

[0059] The deep-sea riser spatial configuration inversion method disclosed by the present application has higher accuracy and reliability when reconstructing unknown position spatial configuration from known position inclination information of the riser, and has better universality for spatial configuration inversion of risers of different forms. Specifically, the method projects the three-dimensional spatial configuration of the riser onto two two-dimensional coordinate planes, divides the riser into a plurality of pipe segment units with a plurality of inclination sensors installed on the riser as nodes, uses a high-order interpolation function to describe the projection of each pipe segment unit on the two-dimensional plane, establishes a two-dimensional projection expression based on the inclination information, combines the spatial curve length equation of the pipe segment unit, obtains the three-dimensional spatial relative coordinates of each pipe segment unit in the corresponding local coordinate, and finally converts the three-dimensional spatial relative coordinates of each pipe segment unit in the corresponding local coordinate into three-dimensional spatial absolute coordinates in the global coordinate system, thereby completing the spatial configuration reconstruction of the riser.

[0060] The method solves the limitation of the traditional modal decomposition method which depends on the structural mode function, realizes the spatial configuration reconstruction of the riser in the complex marine environment, has higher robustness, and has better universality for spatial configuration inversion of risers of different forms; the three-dimensional spatial configuration is projected onto a two-dimensional plane for spatial coordinate iteration, reducing the complexity of solving three-dimensional space problems; the inclination information of each measuring point at each time is used for iterative inversion, effectively avoiding the cumulative effect of inversion error over time. The spatial displacement of the riser can be accurately inverted under the condition of sparse inclination measuring points, greatly reducing the requirement for the number of sensors and reducing the dependence on high-cost and high-density sensors. BRIEF DESCRIPTION OF DRAWINGS

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0062] Figure 1 is the overall flowchart of the deep-sea riser spatial configuration inversion method provided by the present application;

[0063] Figure 2 is a schematic diagram of the numerical simulation of the steel catenary riser and the sensor arrangement form provided by the present application;

[0064] Figure 3 is a comparison diagram of the inversion displacement and the true displacement time history curve in the x-y-z direction of the middle part of the steel catenary riser provided by the present application;

[0065] Figure 4 is a displacement inversion error diagram of each position of the steel catenary riser provided by the present application;

[0066] wherein the reference signs are:

[0067] 10: riser;

[0068] 11: pipe section unit;

[0069] 20: inclination sensor. DETAILED DESCRIPTION

[0070] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects more clearly understood, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0071] The prefix words such as "first", "second" used in the embodiments of the present application are only used to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of ordinal words such as ordinal words in the embodiments of the present application does not limit the described objects, and the description of the described objects should be referred to the description of the context in the claims or embodiments, and should not be construed as redundant limitation because of the use of such prefix words. In addition, in the description of the embodiments, unless otherwise stated, the meaning of "multiple" is two or more.

[0072] The technical solutions in the embodiments of the present application will be described below in combination with the drawings in the embodiments of the present application. In the description of the embodiments of the present application, unless otherwise stated, " / " represents the meaning of or, for example, A / B can represent A or B; "and / or" in this paper is only a description of the association between the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can represent three cases of A alone, A and B together, and B alone.

[0073] It should be understood that the disclosed system and method can be implemented in other ways in several embodiments provided in the embodiments of the present application. For example, the above-described device embodiments are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed objects can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0074] The embodiments of the present application provide a deep-sea riser spatial configuration inversion method, Figure 1 The flow chart of the inversion method provided by the present application is shown, and specifically includes the following steps.

[0075] S1: N inclination sensors are installed on the deepwater riser at intervals, and the deepwater riser is divided into a plurality of pipe segment units with the inclination sensors as nodes, and each pipe segment unit is a spatial curve of the pipe segment.

[0076] The deepwater riser is a vertical passage device connecting a floating platform (such as FPSO, TLP, SPAR platform, etc.) on the sea and a subsea device (such as a subsea wellhead, a subsea pipeline terminal or a mining relay station), mainly used for transporting resources such as oil, gas, minerals or drilling fluid from the seabed to the offshore platform, and can also be used for injection, well repair and completion.

[0077] The deepwater riser needs to adapt to the platform movement caused by wind and waves due to the connection of the floating platform, and bears complex hydrodynamic load. The position or angle of the deepwater riser will be offset under the influence of the water load during work. By measuring the angle of the deepwater riser, the influence on it can be reflected.

[0078] Reference Figure 2 As shown in the reference, a plurality of inclination sensors 20 are arranged on the riser 10, and the inclination sensors 20 collect inclination information, i.e. inclination angle, at the corresponding position of the riser. In this embodiment, the deepwater riser is divided into a plurality of pipe segment units 11 with each inclination sensor placed on the riser as a node.

[0079] In some embodiments of the present application: the method of dividing the deepwater riser into a plurality of pipe segment units with inclination sensors as nodes includes:

[0080] Dividing the pipe segment between adjacent inclination sensors into a pipe segment unit, or dividing the pipe segment between interval inclination sensors into a pipe segment unit.

[0081] Specifically, in actual engineering, the division of each pipe segment unit can be between two adjacent inclination sensors, or between several interval inclination sensors, and the specific division is determined by factors such as the specific arrangement density of the inclination sensors. In addition, in some embodiments, each pipe segment unit can also be divided forward from the top end of the riser, or each pipe segment unit can also be divided reversely from the bottom end of the riser.

[0082] After the riser is divided into pipe segment units, each pipe segment unit includes at least two inclination sensors, and according to the inclination data collection values of each sensor, the inclination of the pipe segment unit can be reflected.

[0083] For example, if two adjacent inclination sensors are divided into one pipe segment unit, the data collected by the upper inclination sensor is the inclination of the upper end point of the pipe segment unit, and the data collected by the lower inclination sensor is the inclination of the lower end point of the pipe segment unit. If a plurality of inclination sensors are divided into one pipe segment unit, an inclination measurement rule can be set to select which data collected by the inclination sensor is used as the inclination data of each part of the riser according to the rule.

[0084] S2: A global coordinate system is established at the top end point of the deep-sea riser, and a pipe segment unit local coordinate system is established at the upper end point of each pipe segment unit. Each local coordinate system is divided into a horizontal coordinate system and a vertical coordinate system.

[0085] xoy The two-dimensional coordinate plane is the plane of the horizontal coordinate system of the local coordinate system, xoz, yoz and the two vertical coordinate planes are perpendicular to each other in the local coordinate system.

[0086] In the embodiments of the present application, the riser three-dimensional space configuration pipe segment unit is first projected onto the two two-dimensional coordinate planes of the local coordinate system. In a specific embodiment, the two two-dimensional coordinate planes are set as xoy the two-dimensional coordinate plane and xoz the two-dimensional coordinate plane, but the present application is not limited thereto, for example, it can also be xoy the two-dimensional coordinate plane and yoz the two-dimensional coordinate plane.

[0087] In the embodiments of the present application, after each pipe segment unit is divided, a local coordinate system is established at the upper end point of each pipe segment unit, and a global coordinate system is established at the top of the riser. Here, the local coordinate system and the global coordinate system refer to three-dimensional space coordinate systems.

[0088] S3: Along the length direction of each pipe segment unit, each pipe segment unit is discretized into a plurality of micro-segments, each micro-segment is projected in the horizontal coordinate system and the vertical coordinate system to obtain the projection curve of the micro-segment in the horizontal coordinate system and the vertical coordinate system, and based on the corresponding relationship between the arc length of the micro-segment space curve and the projection of the micro-segment in the horizontal coordinate system and the vertical coordinate system projection curve, the space curve length equation of each pipe segment unit is obtained. The arc length of the micro-segment space curve can be obtained according to the actual construction situation of the riser.

[0089] In the embodiments of the present application, the space curve of each pipe segment unit is discretized in length, and a high-order interpolation function is used to represent the projection of the discretized space curve in the two two-dimensional coordinate planes to establish the relationship between the length of the space curve and the projection, so as to obtain the space curve length equation of each pipe segment unit.

[0090] In some embodiments of the present application, the method of dividing the deep-sea riser into a plurality of pipe segment units with the inclination sensor as the node comprises: dividing the pipe segment between adjacent inclination sensors into one pipe segment unit.

[0091] Specifically, if the interval between the two adjacent inclination sensors in the actual project is S AB The spatial curve length of the pipe segment unit between the two inclination sensors is simplified to the spatial straight line length composed of n one infinitesimal segment formed by n- 1 discrete point, which approximates the true configuration of the pipe segment curve.

[0092] The method for obtaining the spatial curve length equation of each pipe segment unit comprises:

[0093] determining the length initial equation of any infinitesimal segment Q k-1 Q k is:

[0094] (1)

[0095] wherein, the lower end point of the infinitesimal segment is , whose coordinates in the global coordinate system are , , , Q k the upper end point of the infinitesimal segment is , whose coordinates in the global coordinate system are , , , , all are intermediate variables without actual meaning, , , ; n is the number of discrete points, .

[0096] According to the Lagrange mean value theorem, combined with the interpolation function decomposed in the xoz and xoy two-dimensional coordinate planes, the relationship between the length of the spatial curve and the projection of the spatial curve on the two two-dimensional coordinate planes is established, and the infinitesimal segment length equation (1) is further expressed as equation (2), to obtain the length first rewritten equation of any infinitesimal segment Q k-1 Q k is:

[0097] (2)

[0098] wherein:

[0099] ;

[0100] ;

[0101] , , , are polynomial coefficients;

[0102] is the micro-element segment Q k-1 Q k the derivative of the interpolation function in the horizontal coordinate system of the local coordinate system in which the micro-element segment is located, is the micro-element segment Q k-1 Q k the derivative of the interpolation function in the vertical coordinate system of the local coordinate system in which the micro-element segment is located; the obtaining of the interpolation function belongs to the prior art, and can be obtained based on the projection curve of the micro-element segment in the horizontal coordinate system and the vertical coordinate system, and thus is not described in detail.

[0103] substitute , into the micro-element segment Q k-1 Q k The first rewritten equation of the micro-element segment length equation is further expressed as the second rewritten equation:

[0104] (3)

[0105] wherein, , , is an intermediate variable and has no actual meaning, ;

[0106] According to the second rewritten equation, the lengths of all micro-element segments of each pipe segment unit are summed up, and the initial equation of the pipe segment unit is obtained as:

[0107] (4)

[0108] wherein, , is a parameter term, is a constant term, ;

[0109] The integral of the right side of the initial equation of the pipe segment unit is obtained, and the spatial curve length equation of the pipe segment unit is:

[0110] (5)

[0111] wherein, S AB denotes the length between two points on a spatial curve, A and B is a constant term.

[0112] S4: combine the inclination information collected by the inclination sensor of each pipe segment unit, construct the two-dimensional projection expression of the spatial curve of each pipe segment in the horizontal coordinate system and the vertical coordinate system; based on the spatial curve length equation of each pipe segment unit and the projection expression, iteratively solve the relative coordinates of the upper end point and the lower end point of each pipe segment unit in the local coordinate system of the pipe segment unit, and obtain the three-dimensional relative coordinates of each pipe segment unit in the corresponding local coordinate.

[0113] Based on the given displacement boundary condition and the slope boundary condition, a quadratic polynomial interpolation function is used to establish a two-dimensional projection expression of the inclination information in the xoy two-dimensional coordinate plane and the xoz two-dimensional coordinate plane, which is represented by a quadratic interpolation function. In some embodiments of the present application, the method for constructing the projection expression of the spatial curve of each pipe segment in the horizontal coordinate system and the vertical coordinate system in combination with the inclination information collected by the inclination sensor of each pipe segment unit comprises:

[0114] constructing the projection expression of the spatial curve of each pipe segment in the horizontal coordinate system:

[0115] (6-1)

[0116] constructing the projection expression of the spatial curve of each pipe segment in the vertical coordinate system:

[0117] (6-2)

[0118] wherein, is the quadratic polynomial second-order term coefficient of the projection expression of the spatial curve in the horizontal coordinate system, is the quadratic polynomial first-order term coefficient of the projection expression of the spatial curve in the horizontal coordinate system, is the constant term of the quadratic polynomial of the projection expression of the spatial curve in the horizontal coordinate system, is the quadratic polynomial second-order term coefficient of the projection expression of the spatial curve in the vertical coordinate system, is the quadratic polynomial first-order term coefficient of the projection expression of the spatial curve in the vertical coordinate system, is the constant term of the quadratic polynomial of the projection expression of the spatial curve in the vertical coordinate system; ​

[0119] According to the boundary conditions, the coefficient expression is:

[0120]

[0121] (7)

[0122]

[0123] wherein, x A is the upper end point of the pipe segment unit in the global coordinate system x axis, x B is the lower end point of the pipe segment unit in the global coordinate system x axis, is the mapping angle of the inclination information of the upper end point of the pipe segment unit in the horizontal coordinate system, is the mapping angle of the inclination information of the lower end point of the pipe segment unit in the horizontal coordinate system, is the mapping angle of the inclination information of the upper end point of the pipe segment unit in the vertical coordinate system, is the mapping angle of the inclination information of the lower end point of the pipe segment unit in the vertical coordinate system. is the two-dimensional projection expression of the pipe segment unit in the horizontal coordinate system xoy , is the two-dimensional projection expression of the pipe segment unit in the vertical coordinate system xoz .

[0124] Through the aforementioned calculation steps of the curve interpolation function and the boundary conditions, the unknowns are respectively the coefficients , , , , , and the three-dimensional space relative coordinates of the lower end point of the pipe segment unit in the local coordinate system ， ， . The embodiments of the present application adopt an iterative solving method, and the coordinates of each pipe segment unit are solved step by step from the pipe segment unit located at the top of the riser.

[0125] In some embodiments of the present application, based on the space curve length equation of each pipe segment unit and the projection expression, the method for iteratively solving the relative coordinates of the upper end point and the lower end point of each pipe segment unit in the local coordinate system of the pipe segment unit includes the following steps.

[0126] Based on the spatial curve length equation of each pipe segment unit and the aforementioned projection expression, the method for iteratively solving the relative coordinates of the upper and lower endpoints of each pipe segment unit in the local coordinate system of the pipe segment unit includes:

[0127] In each segment of a deep-sea riser, assuming the coordinates of the upper endpoint of each segment in its local coordinate system are 0, solve for the coordinates of the lower endpoint of the segment in its local coordinate system. :

[0128] Solve , , , , , Furthermore, the coordinates of the lower endpoint of the pipe segment unit where the top point is located are solved. , The three-dimensional spatial relative coordinates of the pipe segment element where the top point is located in its local coordinate system are obtained. ， ， );

[0129] The relative coordinates of the upper and lower endpoints of each pipe segment unit in their respective local coordinate systems are solved iteratively until the relative coordinates of the upper and lower endpoints of each pipe segment unit in the local coordinate system of the pipe segment unit are obtained.

[0130] For example, in this embodiment of the application, the endpoint coordinates of each pipe segment unit are solved iteratively from top to bottom. First, the three-dimensional spatial coordinates of the upper endpoint of the first pipe segment unit can be obtained through the shipborne GPS. , , ). The three-dimensional spatial coordinates ( , , The relative value is zero, and the three-dimensional spatial coordinates of the upper endpoint are ( , , The coordinates of the top point of the deep-sea riser are set to 0, which means the coordinates of the upper end point of the pipe segment unit where the top point is located are 0.

[0131] Thus, formula (7) is simplified to formula (8):

[0132] (8)

[0133] Combining the space curve length equation with the two-dimensional projection expression, i.e. combining equations (5)-(8), the three-dimensional space relative coordinates of the lower end point of the first pipe segment unit in the corresponding local coordinate system can be obtained ， ， The relative coordinate of the X axis of the lower end point of the pipe segment unit in which the top end point is located is solved as The relative coordinate of the Y axis of the lower end point of the pipe segment unit in which the top end point is located is solved as

[0134] (9)

[0135] Wherein: ; is the distance between the inclination sensor at the upper end point of the pipe segment unit and the inclination sensor at the lower end point of the pipe segment unit;

[0136] Solve , , , , , , and further solve the coordinates of the lower end point of the pipe segment unit in which the top end point is located , , to obtain the three-dimensional space relative coordinates of the pipe segment unit in which the top end point is located in its local coordinate system ， ， . Specifically, by applying a numerical iteration method, the value of the relative coordinate of the X axis of the lower end point of the pipe segment unit in which the top end point is located in equation (9) is determined within a given error range, to obtain all the coefficients in the interpolation function X , , , , , , , . Through the curve interpolation function of the two-dimensional coordinate plane and the two-dimensional coordinate plane, the relative coordinate of the X axis of the lower end point xoy and the relative coordinate of the Y axis of the lower end point xoz are solved, to obtain the three-dimensional space relative coordinates of the lower end point of the pipe segment unit in the local coordinate system Y . Z ， ，

[0137] ​​​​For each pipe segment unit of the riser, the three-dimensional space relative coordinates of the upper end point of each pipe segment unit in the corresponding local coordinate system can be determined according to the method for determining the three-dimensional space relative coordinates of the first pipe segment unit in the local coordinate system, and the three-dimensional space relative coordinates of the lower end point of each pipe segment unit in the corresponding local coordinate system are determined by combining the space curve length equation and the two-dimensional projection expression, and the three-dimensional space relative coordinates of the lower end point of each pipe segment unit in the corresponding local coordinate system are obtained. , , ) are zero, and the three-dimensional space relative coordinates of the lower end point of each pipe segment unit in the corresponding local coordinate system are determined by combining the space curve length equation and the two-dimensional projection expression. The three-dimensional space relative coordinates of each subsequent pipe segment unit in the corresponding local coordinate system are sequentially determined, and finally the three-dimensional space relative coordinates of all pipe segment units of the riser in the corresponding local coordinate system are obtained.

[0138] S5: converting the relative coordinates of each pipe segment unit in the local coordinate system of each pipe segment unit into absolute coordinates in the global coordinate system, and obtaining the spatial configuration of the deep-sea riser by comprehensively considering the absolute coordinates of each pipe segment unit in the global coordinate system.

[0139] In some embodiments of the present application, the method for converting the relative coordinates of each pipe segment unit in the local coordinate system of each pipe segment unit into absolute coordinates in the global coordinate system comprises:

[0140] The first pipe segment unit of the riser is the top end point of the deep-sea riser, and for the first pipe segment unit, the three-dimensional space absolute coordinates of the top end point of the deep-sea riser in the global coordinate system are , and the three-dimensional space relative coordinates of the lower end point B of the pipe segment unit where the top end point is located in the local coordinate system are obtained by solving ;

[0141] The three-dimensional space absolute coordinates of the lower end point of the pipe segment unit where the top end point is located in the global coordinate system are obtained by superimposing the three-dimensional space relative coordinates of the lower end point of the pipe segment unit where the top end point is located in the local coordinate system and the three-dimensional space absolute coordinates of the upper end point of the pipe segment unit where the top end point is located in the global coordinate system ;

[0142] The lower end point of the pipe segment unit where the top end point is located is taken as the upper end point of the adjacent pipe segment unit, and the three-dimensional space absolute coordinates of the lower end point of the adjacent pipe segment unit are solved.

[0143] The three-dimensional space absolute coordinates of the upper end point and the lower end point of each pipe segment unit are iteratively solved until the three-dimensional space absolute coordinates of the upper end point and the lower end point of each pipe segment unit are obtained.

[0144] This process is sequentially performed until the last pipe segment unit, and the three-dimensional space absolute coordinates of the lower end point N of the last pipe segment unit relative to the global coordinate system are obtained as , , Finally, the absolute three-dimensional spatial coordinates of the upper and lower endpoints of all riser segments in the global coordinate system are obtained:

[0145] (10)

[0146] In the formula, γ x γ y γ z They are respectively x , y , z The deformation coefficient of risers in different directions can be calibrated using sensors. , , These are dynamic deformation variables, which are solved using the following formulas:

[0147] (11)

[0148] In the formula, q x , q y for x and y Lateral load distribution direction L B The length of the pipe segment unit. E The elastic modulus of the riser material. I Let the moment of inertia of the cross section be... F z for z axial resultant force in the direction, A This represents the cross-sectional area of ​​the pipe section.

[0149] Due to the rapidly changing seabed environment, the inclination information of the riser can change at any time, and the riser configuration may change when the inclination changes. To address this issue, some embodiments of this application further include: an inclination sensor collecting real-time inclination information, updating the projection representation of the spatial curve of each pipe segment in the horizontal and vertical coordinate systems based on the inclination information at each moment, and updating the relative and absolute coordinates to update the spatial configuration of the deep-sea riser.

[0150] Furthermore, in one embodiment, for any two adjacent pipe segment units, the relative three-dimensional coordinates of the current pipe segment unit in the corresponding local coordinate system are added to the absolute three-dimensional coordinates of the lower end point of the previous pipe segment unit in the global coordinate system, thus converting the current pipe segment unit into its absolute displacement in the global coordinate system. In this way, combined with this absolute displacement, the absolute three-dimensional coordinates of any position on the riser can be reconstructed using a spline interpolation function.

[0151] In an embodiment, the visualization of the three-dimensional absolute coordinates of the riser at any position is achieved in an encrypted manner by using a cubic spline interpolation method. The coefficients of the spline interpolation function are determined by interpolation conditions, continuity conditions, first-order derivative continuity conditions, and second-order derivative continuity conditions.

[0152] In addition, in an embodiment, to further improve the accuracy of the configuration inversion, a spatial position sensor is installed at the bottom end of the riser to obtain the three-dimensional absolute coordinates of the bottom end of the riser in the global coordinate system. Then, the pipe segment units are divided in reverse from the bottom end of the riser, and the three-dimensional absolute coordinates of the upper end point of the pipe segment unit at the bottom end of the riser are solved in combination with the spatial curve length equation and the two-dimensional projection expression, with reference to the solving method of the above-mentioned forward division of the pipe segment units from the top end of the riser, to obtain the three-dimensional absolute coordinates of the upper end point and the lower end point of each pipe segment unit in the global coordinate system. The three-dimensional absolute coordinates of the upper end point and the lower end point of each pipe segment unit in the global coordinate system obtained under the reverse division condition are used to correct the three-dimensional absolute coordinates of the upper end point and the lower end point of each pipe segment unit in the global coordinate system obtained under the forward division condition.

[0153] In some embodiments, the iterative solving of the coordinates of the pipe segment units can adopt the forward division method and the reverse division method. The forward division method refers to starting from the top of the pipe segment unit to iteratively solve the coordinates of the upper end point and the lower end point of each pipe segment unit, and the reverse division method refers to starting from the bottom of the pipe segment unit to iteratively solve the coordinates of the upper end point and the lower end point of each pipe segment unit.

[0154] In some embodiments, the three-dimensional absolute coordinates of the upper end point and the lower end point of each pipe segment unit in the global coordinate system obtained under the reverse division condition (x1, y1, z1) and the three-dimensional absolute coordinates of the upper end point and the lower end point of each pipe segment unit in the global coordinate system obtained under the forward division condition (x2, y2, z2) are fused to solve, adaptive weighted fusion is introduced, the weight is dynamically adjusted in combination with Kalman filtering, and the three-dimensional absolute coordinates of the upper end point and the lower end point of each pipe segment unit in the global coordinate system are updated to (x, y, z). ​​​​​​​​​​​​​​​​​), finally the three-dimensional absolute coordinates of the upper end point and the lower end point of all pipe segment units of the riser in the global coordinate system are obtained as:

[0155] (11)

[0156] wherein, w* and w r is the weight coefficient of forward deduction and reverse deduction, σ is the coordinate variance of deduction.

[0157] Since the above-mentioned three-dimensional absolute coordinates of each pipe segment unit are solved, only the coordinate change of the upper end point of the pipe segment unit is taken into account, and the time change is not taken into account. Therefore, by repeating the above-mentioned operation steps for the inclination data at each time, the spatial coordinate information of the riser in a given time domain can be solved and obtained. In this way, in an embodiment, the overall spatial configuration of the riser is further updated according to the inclination information collected by each pipe segment unit at different times, and the change trend of the overall spatial configuration of the riser at different times is obtained.

[0158] To verify the effect of the deep-sea riser spatial configuration inversion method, the following simulation verification is performed:

[0159] A steel catenary riser model is established by using a commercial software OrcaFlex. The upper floating body has a total length of 120.0 m, a designed draft of 7.5 m, a total tonnage of 12625.0 t, a riser total length of 1200.0 m, an inner diameter of 193.68 mm, an outer diameter of 219.08 mm, and a unit length mass of 65.56 kg / m. Secondly, for the sensor arrangement form, the inclination sensors are uniformly arranged, and the inclination sensor spacing s =30.0m( s / L =1 / 40) is taken as an example, wherein s is the adjacent inclination sensor spacing, L is the total length of the riser, as shown in Figure 2 In this simulation, wave and current loads are applied to the riser system, and the simulation time is 150.0 s.

[0160] Firstly, two-direction inclination data and three-dimensional spatial displacement data of the riser at each measuring point are obtained based on the numerical simulation results of the commercial software OrcaFlex. The inclination information obtained by numerical simulation is taken as input, and the spatial displacement data obtained by output is compared with the displacement data obtained by numerical simulation. As Figure 3 the middle part of the steel catenary riser x-y-z the time history curve comparison diagram of the inverted displacement and the true displacement in the direction.

[0161] Then, the local coordinate system and the global coordinate system are established, and the origin of the global coordinate system is located at the initial time when the upper floating body contacts the riser t=0s). In the global coordinate system, X The axis pointing to the right is positive, Y The axis pointing to the back is positive, Z The axis vertically extending upwards is positive; the local coordinate system is established with the upper end point of each pipe segment unit as the origin, and x The axis pointing to the right is positive, y The axis pointing to the back is positive, z The axis vertically extending upwards is positive. θ xy The angle between the projection tangent of the three-dimensional riser on the horizontal plane and the axis is positive in the counterclockwise direction from above the horizontal plane; xoy The angle between the projection tangent of the three-dimensional riser on the horizontal plane and the axis is positive in the counterclockwise direction from above the horizontal plane; x The angle between the projection tangent of the three-dimensional riser on the horizontal plane and the axis is positive in the counterclockwise direction from above the horizontal plane; xoy The angle between the projection tangent of the three-dimensional riser on the horizontal plane and the axis is positive in the counterclockwise direction from above the horizontal plane; θ xz The angle between the projection tangent of the three-dimensional riser on the horizontal plane and the axis is positive in the counterclockwise direction from above the horizontal plane; xoz The angle between the projection tangent of the three-dimensional riser on the horizontal plane and the axis is positive in the counterclockwise direction from above the horizontal plane; x The angle between the projection tangent of the three-dimensional riser on the horizontal plane and the axis is positive in the counterclockwise direction from above the horizontal plane; xoz The angle between the projection tangent of the three-dimensional riser on the horizontal plane and the axis is positive in the counterclockwise direction from above the horizontal plane.

[0162] Further, the inclination information of each measuring point obtained is substituted into formula (9), and the spatial coordinates of each pipe segment unit node in the local coordinate system are solved according to the above step S3, and then the three-dimensional spatial relative coordinates of all pipe segment units on the riser in the corresponding local coordinate system are obtained. At the same time, the coordinates in the local coordinate system are converted into the coordinates in the global coordinate system according to step S4.

[0163] Through the above process, the spatial coordinate values of each measuring point of the riser can be obtained, and the spatial coordinate values at any position can be visualized in an encrypted manner by using the cubic spline interpolation method.

[0164] By repeating the above operation steps for the inclination information at each time, the riser spatial coordinate information in the given time domain can be solved and obtained. Among them, Figure 4 is the displacement inversion error diagram of each position of the steel catenary riser provided by the embodiment of the present application.

[0165] It can be seen that the deep-sea riser space configuration inversion method has high accuracy and reliability when reconstructing unknown position space configuration from known position inclination information of the riser, and has good versatility for space configuration inversion of risers of different forms. Specifically, the method projects the three-dimensional space configuration of the riser onto two two-dimensional coordinate planes, divides the riser into a plurality of pipe segment units with a plurality of inclination sensors installed on the riser as nodes, uses a high-order interpolation function to describe the projection of each pipe segment unit on the two-dimensional plane, establishes a two-dimensional projection expression based on the inclination information, combines the spatial curve length equation of the pipe segment unit, obtains the three-dimensional space relative coordinates of each pipe segment unit in the corresponding local coordinate, and finally converts the three-dimensional space relative coordinates of each pipe segment unit in the corresponding local coordinate into three-dimensional space absolute coordinates in the global coordinate system, thereby completing the reconstruction of the space configuration of the riser.

[0166] The deep-sea riser space configuration inversion method solves the limitation of the traditional modal decomposition method driven by strain data, realizes the reconstruction of the space configuration of the riser in a complex marine environment under dynamic boundary conditions, and has higher robustness; the three-dimensional space configuration is projected onto a two-dimensional plane for space coordinate iteration, reducing the complexity of solving three-dimensional space problems; in addition, the method iteratively inverts the inclination information at each measurement point at each time, effectively avoiding the cumulative effect of inversion errors over time; and the space displacement of the riser can be accurately inverted under the condition of sparse inclination measurement points, greatly reducing the requirement for the number of sensors and reducing the dependence on high-cost and high-density sensors.

[0167] The above specific embodiments do not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

[0168] The above description is only the preferred embodiment of the present application and should not be used to limit the present application. It should be pointed out that for ordinary skilled in the art, any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the appended claims.

Claims

1. A method of deep-sea riser spatial configuration inversion, characterized in that, The method comprises the following steps: N inclination sensors are installed on the deep-sea riser at intervals, the deep-sea riser is divided into a plurality of pipe segment units with the inclination sensors as nodes, and each pipe segment unit is a pipe segment spatial curve; A global coordinate system is established at a top end point of the deep-sea riser, and a pipe segment unit local coordinate system is established at an upper end point of each pipe segment unit; Each pipe segment unit is discretized into a plurality of micro-segment units along the length direction of the pipe segment unit, the micro-segment units are projected in a horizontal coordinate system and a vertical coordinate system respectively, and a projection curve of the micro-segment units in the horizontal coordinate system and the vertical coordinate system is obtained; and a spatial curve length equation of each pipe segment unit is obtained based on the corresponding relationship between the arc length of the micro-segment unit spatial curve and the projection of the micro-segment unit in the horizontal coordinate system and the vertical coordinate system. The inclination information collected by the inclination sensors of each pipe segment unit is combined to construct a projection expression of the spatial curve of each pipe segment unit in the horizontal coordinate system and the vertical coordinate system; and the relative coordinates of the upper end point and the lower end point of each pipe segment unit in the pipe segment unit local coordinate system are iteratively solved based on the spatial curve length equation of each pipe segment unit and the projection expression. The relative coordinates of each pipe segment unit in the pipe segment unit local coordinate system are converted into absolute coordinates in the global coordinate system, the absolute coordinates of each pipe segment unit in the global coordinate system are integrated, and the spatial configuration of the deep-sea riser is obtained.

2. The deep-water riser spatial configuration inversion method of claim 1, wherein: The method for dividing the deep-sea riser into a plurality of pipe segment units with the inclination sensors as nodes comprises: The pipe segment between adjacent inclination sensors is divided into one pipe segment unit, or the pipe segment between interval inclination sensors is divided into one pipe segment unit.

3. A deep-sea riser spatial configuration inversion method according to claim 1 or 2, characterized in that: The method for dividing the deep-sea riser into a plurality of pipe segment units with the inclination sensors as nodes comprises: the pipe segment between adjacent inclination sensors is divided into one pipe segment unit. The method for obtaining the spatial curve length equation of each pipe segment unit comprises: Determining the length of any elemental segment in the pipe segment unit Q k-1 Q k The initial equation for the length of the pipe segment unit is wherein the point is the lower end point of the microelement segment, and its coordinates in the global coordinate system are , , ), Q k is the upper end point of the microelement segment, and its coordinates in the global coordinate system are , , ), , , are all intermediate variables, and have no actual meaning, , , ; According to Lagrange's mean value theorem, the length of any infinitesimal segment Q k-1 Q k The first modified equation for the length of is Wherein: ; ; , , , are polynomial coefficients; is the microelement segment Q k-1 Q k is the derivative of the interpolation function in the horizontal coordinate system of the local coordinate system in which the microelement segment lies, is the microelement segment Q k-1 Q k is the derivative of the interpolation function in the vertical coordinate system of the local coordinate system in which the microelement segment lies, Will , Substitute the infinitesimal segment Q k-1 Q k The first rewritten equation is then further expressed as the second rewritten equation: wherein , , is a parameter term, which has no actual meaning, ; According to the second rewritten equation, the lengths of all micro-segment units of each pipe segment unit are summed to obtain an initial equation of the pipe segment unit as: wherein , is a parameter term, is a constant term, ; The integral on the right side of the initial equation of the pipe segment unit is obtained to obtain the spatial curve length equation of the pipe segment unit as: wherein, S AB denotes the length between two points A and B on a spatial curve, is a constant term.

4. The deepwater riser spatial configuration inversion method of claim 3, wherein: The method for constructing the projection expression of the spatial curve of each pipe segment unit in the horizontal coordinate system and the vertical coordinate system in combination with the inclination information collected by the inclination sensors of each pipe segment unit comprises: The projection expression of the spatial curve of each pipe segment unit in the horizontal coordinate system is constructed as: The projection expression of the spatial curve of each pipe segment unit in the vertical coordinate system is constructed as: wherein a is the second order term coefficient of the quadratic polynomial of the spatial curve projection expression in the horizontal coordinate system, b is the first order term coefficient of the quadratic polynomial of the spatial curve projection expression in the horizontal coordinate system, c is the constant term of the quadratic polynomial of the spatial curve projection expression in the horizontal coordinate system, a is the second order term coefficient of the quadratic polynomial of the spatial curve projection expression in the vertical coordinate system, b is the first order term coefficient of the quadratic polynomial of the spatial curve projection expression in the vertical coordinate system, c is the constant term of the quadratic polynomial of the spatial curve projection expression in the vertical coordinate system. wherein, x A is the upper end point of the pipe segment element in the global coordinate system x is the coordinate of the axis, x B is the lower end point of the pipe segment element in the global coordinate system x is the coordinate of the axis, is the mapped angle of the inclination information of the upper end point of the pipe segment element in the horizontal coordinate system, is the mapped angle of the inclination information of the lower end point of the pipe segment element in the horizontal coordinate system, is the mapped angle of the inclination information of the upper end point of the pipe segment element in the vertical coordinate system, is the mapped angle of the inclination information of the lower end point of the pipe segment element in the vertical coordinate system; is the two-dimensional projection expression of the pipe segment element in the horizontal coordinate system, is the two-dimensional projection expression of the pipe segment element in the vertical coordinate system.

5. The deepwater riser spatial configuration inversion method of claim 4, wherein: The method for iteratively solving the relative coordinates of the upper end point and the lower end point of each pipe segment unit in the pipe segment unit local coordinate system based on the spatial curve length equation of each pipe segment unit and the projection expression comprises: In the deep-sea riser pipe segment unit, the coordinate of the upper end point of the deep-sea riser pipe segment unit in the local coordinate system of the pipe segment unit is 0, and the coordinate of the lower end point of the pipe segment unit in the local coordinate system of the pipe segment unit is solved : wherein: ; is the distance between the upper end point inclination sensor and the lower end point inclination sensor of the pipe section unit. solving , , , , , , and further solving the coordinate of the lower end point of the pipe segment unit where the top end point is located , , to obtain the three-dimensional space relative coordinate of the pipe segment unit where the top end point is located in its local coordinate system ， ， ); The three-dimensional space relative coordinates of the upper end point and the lower end point of each pipe segment unit in the local coordinate system are iteratively solved until the relative coordinates of the upper end point and the lower end point of each pipe segment unit in the pipe segment unit local coordinate system are obtained.

6. The deepwater riser spatial configuration inversion method of claim 1, wherein: The method for converting the relative coordinates of each pipe segment unit in the pipe segment unit local coordinate system into absolute coordinates in the global coordinate system comprises: Let the three-dimensional absolute coordinate of the top end point of the deep-sea riser in the global coordinate system be , and the three-dimensional relative coordinate of the lower end point B of the pipe segment element where the top end point is located in the local coordinate system be ; superimpose the three-dimensional space relative coordinates of the lower end point of the pipe segment unit where the top end point is located in the local coordinate system with the three-dimensional space absolute coordinates of the upper end point of the pipe segment unit where the top end point is located in the global coordinate system, to obtain the three-dimensional space absolute coordinates of the lower end point of the pipe segment unit where the top end point is located in the global coordinate system ; The lower end point of the pipe segment unit at the top end point is taken as the upper end point of the adjacent pipe segment unit, and the absolute coordinates of the lower end point of the adjacent pipe segment unit in the three-dimensional space are solved. Iteratively solving the absolute coordinates of the upper end point and the lower end point of each pipe section unit in three-dimensional space until the absolute coordinates of the upper end point and the lower end point of each pipe section unit in three-dimensional space are obtained.

7. The deepwater riser spatial configuration inversion method of claim 1, wherein, Also comprising: The inclination sensor collects real-time inclination information, updates the projection expression of each pipe section space curve in the horizontal coordinate system and the vertical coordinate system according to the inclination information at each moment, and updates the relative coordinates and the absolute coordinates, and updates the deep-sea riser space configuration.

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