A method for calculating and modeling the inclination of an offshore platform structure

Abstract

The application provides a kind of ocean platform structure inclination calculation and modeling method, belongs to marine petroleum engineering technical field.Its technical scheme is: a kind of ocean platform structure inclination calculation and modeling method, including obtaining ocean platform structure parameters;With sea level as benchmark, the elevation data of each layer of the ocean platform jacket cross brace pipe and platform deck are measured;The spatial inclination angle of the jacket structure is calculated;A three-dimensional coordinate system is established, and the design coordinates of the key nodes are determined in combination with the structure parameters;The inclined coordinates of the key nodes are calculated in combination with the design coordinates and the spatial inclination angle;The ocean platform structure is modeled with the inclined coordinates.The application establishes three-dimensional coordinates of key nodes of ocean platform jacket, pile leg and platform deck for three-pile jacket and four-pile jacket two kinds of platform structures, solves the technical problem of existing inclined ocean platform jacket structure detection modeling, and the method has high precision and reliable calculation results.

Description

Technical Field

[0001] This invention relates to the field of marine oil engineering technology, and in particular to a method for calculating and modeling the tilt of marine platform structures. Background Technology

[0002] In recent years, with the increasing demand for oil and natural gas resources from my country's industries, the development and utilization of offshore oil and natural gas resources have become increasingly important. Statistics show that over 70% of fixed platforms globally have reached, exceeded, or far exceeded their design lifespan. The aging of offshore platform structures has become a key issue facing global offshore oil and gas extraction. Conducting structural safety assessments of aging offshore platforms is of great significance for ensuring the continuous and safe production of offshore oil and gas. Due to environmental corrosion, material aging, component defects, mechanical impacts, fatigue fractures, and other factors, the structural components and overall resistance of aging platforms exhibit varying degrees of decline. To ensure the safety of aging offshore platforms, it is necessary to carry out structural inspection and safety assessments.

[0003] The structural safety assessment of offshore platforms primarily employs finite element modeling for numerical simulation. On one hand, early construction of offshore platforms was often substandard, leading to tilting of some jacket platforms during construction while the deck remained stable. On the other hand, even when the platform structure did not tilt during construction, external impacts and uneven settlement of the pile foundations during later operation caused overall tilting of the jacket structure and deck. Conducting a structural safety assessment requires the tilt angle of the platform structure and the three-dimensional coordinates of key nodes. Currently, there are no dedicated tools for detecting the tilt of offshore platform structures, making it impossible to obtain these parameters.

[0004] This invention proposes a method for calculating and modeling the tilt of marine platform structures, which can solve the technical problems of platform tilt detection and modeling, and provide data support for the safety assessment and modeling of marine platform structures. Summary of the Invention

[0005] To address the problems in the prior art, the present invention aims to provide a method for calculating and modeling the tilt of an offshore platform structure. This method can directly calculate the tilt angle of the jacket structure based on the elevation detection data of multiple detection points on the waterborne cross brace of the jacket. Furthermore, it can calculate the spatial three-dimensional coordinate values ​​of all key nodes of the platform jacket structure. By inputting the tilt angle or platform node coordinate values ​​into offshore platform structure modeling software, accurate modeling of the tilt state of the offshore platform jacket structure can be achieved.

[0006] This invention is achieved through the following technical solution: a method for calculating and modeling the tilt of an offshore platform structure, comprising the following steps;

[0007] S1, Obtain the structural parameters of each part of the offshore platform and determine the location of key nodes;

[0008] S2, using sea level as a reference, measures the elevation data of each layer of the jacket of the offshore platform and the platform deck;

[0009] S3. Establish a rectangular coordinate system with the center point of the area enclosed by the uppermost horizontal support pipe of the jacket as the origin, and calculate the spatial tilt angle of the jacket structure based on the structural parameters and elevation data.

[0010] S4. Establish a three-dimensional coordinate system with the center point of the interface between the jacket structure of the offshore platform and the sea level as the origin and the vertical above the sea level as the Z-axis. Combine the structural parameters to determine the design coordinates of the key nodes.

[0011] S5. Calculate the tilted coordinates of the key nodes by combining the design coordinates and the spatial tilt angle.

[0012] S6. Model the marine platform structure using the tilted coordinates to obtain a marine platform safety assessment model.

[0013] Furthermore, the structural parameters include the length of each layer of cross bracing pipe, the radius of the cross bracing pipe, the radius of the jacket column, the length between each connection point of the platform deck and the jacket, and the distance from each node of the bottom layer of cross bracing pipe of the jacket to the mud surface, etc.

[0014] Furthermore, the key nodes include the connection point between the cross brace pipe and the center of the pile leg, the connection points between the platform deck and the guide frame, the junction point between the pile leg and the mud surface, and the bottom node of the pile leg.

[0015] Furthermore, the jacket is divided into a three-pile jacket or a four-pile jacket.

[0016] Furthermore, step S3 specifically includes:

[0017] S31: Establish a rectangular coordinate system with the center point of the area formed by the uppermost horizontal support tube of the jacket as the origin O and the axis of symmetry as the Y-axis;

[0018] S32: In the rectangular coordinate system, with the center point of each pile leg as the measurement point, measure the elevation of the top surface of the top two nodes of each cross brace tube near the center point of the pile leg.

[0019] S33: Calculate the X-axis rotation angle and Y-axis rotation angle .

[0020] Furthermore, S4 specifically involves: establishing a three-dimensional coordinate system with the center point of the interface between the jacket structure and the sea level as the origin, the vertical direction above the sea level as the Z-axis, and the axis of symmetry of the area enclosed by the cross bracing pipes as the Y-axis; combining structural parameters, and through coordinate transformation calculations, obtaining the design coordinates of the connection points between each layer of cross bracing pipes and the center of the pile legs before the overall tilt of the jacket, denoted as X. in Y in Z in , where i represents the letter number of the pile leg, starting from A according to the letter markings, and n represents the corresponding number of layers of the cross bracing pipe.

[0021] Furthermore, in S51, calculate the coordinates of the connection points between the horizontal bracing pipes of each layer and the center of the pile leg after the overall tilt of the jacket structure:

[0022] First, rotate around the X-axis:

[0023]

[0024] Then rotate around the Y-axis:

[0025]

[0026] Where i corresponds to the letter number of the pile leg; n is the number of layers of the corresponding cross bracing tube;

[0027] S52. Based on the coordinates of any two points of the inclined pile leg and the elevation data of the mud surface, the coordinates of the node where the corresponding pile leg intersects with the mud surface can be obtained by matrix solving.

[0028] S53. Obtain the equation of the straight line based on the coordinates of any two points of the inclined pile leg, and obtain the distance equation based on the distance between one of the points and the bottom end of the pile leg. Solve the system of three quadratic equations to obtain the coordinates of the bottom end of the pile leg.

[0029] Furthermore, when the pile legs and jacket structure are tilted, but the platform deck is not tilted, the coordinates of the connection point between the platform deck and the jacket are calculated using the platform deck elevation data, as follows: the equations of two planes are obtained using the coordinates of any two points of pile leg A, the plane equation of the platform deck is obtained based on the platform elevation data, and the coordinates of the intersection of the three planes are obtained by using a matrix to solve for the coordinates of the connection point between the platform deck and the jacket corresponding to pile leg A; the coordinates of other connection points between the platform deck and the jacket are solved in the same way.

[0030] The following is the detailed calculation process for three-pile and four-pile jacket structures:

[0031] 1. Three-pile jacket:

[0032] (1) Basic parameters:

[0033] (a) Establish a rectangular coordinate system with the center point of the equilateral triangle formed by the uppermost horizontal support tubes of the jacket as the origin O and the axis of symmetry as the Y-axis, to calculate the inclination angle of the jacket structure;

[0034] (b) Let the center points of the three pile legs be A, B, and C. Measure the elevation of the top surface of the 6 nodes on the cross brace near the center point: A1, A2, B1, B2, C1, C2; platform deck elevation detection data H5; the design elevation of the center line of each cross brace from bottom to top are H1, H2, H3, H4; the vertical distance from the bottom surface of the lowest cross brace node of the jacket structure to the mud surface is A3, B3, C3; the distance from the lowest cross brace node of the jacket structure to the bottom of the pile leg is H7.

[0035] (c) Radius value of the cross brace R1, radius value of the guide frame column R2;

[0036] (d) The lengths of each cross brace of the jacket from bottom to top are L1, L2, L3, and L4, and the length between each connection point of the top node of the jacket and the platform is L5;

[0037] (e) A three-dimensional coordinate system is established with the center point of the interface between the jacket structure and the sea level as the origin, the vertical above the sea level as the Z-axis, and the symmetry axis of the platform cross brace as the Y-axis, to calculate the coordinates of key nodes after tilting.

[0038] (2) Calculation steps:

[0039] (a) Estimating the elevation of the center point of the pile leg using the elevation of the measurement points:

[0040]

[0041] (b) X-axis rotation angle :

[0042]

[0043] Elevation difference between points A and C:

[0044]

[0045] (c) Y-axis rotation angle :

[0046] The elevation difference between points A and C:

[0047]

[0048] (d) Coordinates of nodes before the overall tilt of the jacket:

[0049] A-leg:

[0050]

[0051] B-leg:

[0052]

[0053] C-leg:

[0054]

[0055] (e) Node coordinates after the overall jacket structure is tilted:

[0056] First, rotate around the X-axis:

[0057]

[0058] Then rotate around the Y-axis:

[0059]

[0060] (f) Node coordinates of the connection points between the non-inclined platform deck and the jacket, and the intersection points between the pile legs and the mud surface: The equations of the two planes are obtained using the coordinates of any two points on pile leg A. The equation of the platform plane is obtained based on the platform elevation data H5. The coordinates of the intersection points of the three planes are solved using a matrix (the following calculations take the coordinates of points 01 and 03 on pile leg A as an example):

[0061]

[0062] Similarly, using the coordinates of any two points on pile leg A and the mud surface elevation data, the coordinates of the node where the pile leg intersects the mud surface can be obtained using matrix solving (the following calculations take the coordinates of points 02 and 04 on pile leg A as an example):

[0063]

[0064]

[0065] (g) Coordinates of the lowest node of the pile leg:

[0066] Using the coordinates of any two points on pile leg A (the following calculations use the coordinates of points 01 and 03 on pile leg A as an example), the equation of the straight line is obtained. Simultaneously, based on the distance H7 between one of these points and the bottom endpoint of the pile leg, the distance equation is obtained. Solving the system of three quadratic equations yields the coordinates of the bottom endpoint of the pile leg (X). A7 Y A7 Z A7 )

[0067]

[0068]

[0069] (h) Finally, the coordinates of all key points of any pile leg are obtained:

[0070] .

[0071] 2. Four-pile jacket:

[0072] (1) Basic parameters

[0073] (a) Establish a rectangular coordinate system with the center point of the rectangle formed by the four horizontal braces as the origin O and the axis of symmetry as the Y-axis, in order to calculate the tilt angle of the jacket structure;

[0074] (b) Let the center points of the four pile legs be A, B, C, and D. Measure the elevations of the eight nodes on the cross brace closest to the center points: A1, A2, B1, B2, C1, C2, D1, D2;

[0075] (c) The radius value R1 of the cross brace and the length L of the cross brace 1n L 2n 1. The radius of the jacket support column, R2;

[0076] (d) The lengths of each cross brace of the jacket from bottom to top are L1, L2, L3, and L4, and the length between each connection point of the top node of the jacket and the platform is L5;

[0077] (e) A three-dimensional coordinate system is established with the center point of the interface between the jacket structure and the sea level as the origin, the vertical above the sea level as the Z-axis, and the symmetry axis of the platform cross brace as the Y-axis, to calculate the coordinates of key nodes after tilting.

[0078] (2) Calculation steps

[0079] (a) Estimating the elevation of the center point of the pile leg using the elevation of the measurement points:

[0080]

[0081] (b) X-axis rotation angle :

[0082] Elevation difference between the center points of AB and CD:

[0083]

[0084] (c) Y-axis rotation angle :

[0085] Elevation difference between the center points of AD and BC:

[0086]

[0087] (d) Coordinates of nodes before the overall tilt of the jacket:

[0088] A-leg:

[0089]

[0090] B-leg:

[0091]

[0092] C-leg:

[0093]

[0094] D-leg:

[0095]

[0096] (e) Coordinates of nodes after the overall tilt of the jacket: Refer to the calculation steps (e) of the three-pile jacket, formulas 1-12 to 1-19, and similarly calculate the coordinates of the nodes before tilt, the nodes after tilt, the interface nodes, and the bottom node of the pile leg according to the tilt angle.

[0097] The beneficial effects of this invention are as follows: Based on the elevation detection data of the selected points of the jacket structure of the offshore platform, and combined with parameters such as the radius of the jacket tube, the length of the jacket, and the radius of the pile leg, this invention establishes three-dimensional coordinates of key nodes of the jacket structure, pile leg, and platform deck for both three-pile jacket and four-pile jacket platform structures, solving the technical difficulties of existing inclined offshore platform jacket structure detection and modeling. This method does not require high-performance computers or professional structural engineers, is convenient and simple to calculate, fast, and low in cost. Finally, modeling tests prove that this method has high accuracy and reliable calculation results, and can meet the needs of engineering applications. Attached Figure Description

[0098] Figure 1 This is a schematic diagram of the key nodes and coordinate system.

[0099] Figure 2 This is a schematic diagram of a jacket structure for an offshore platform.

[0100] Figure 3 The coordinate system is a rectangular coordinate system for the cross bracing of the three-pile guide frame.

[0101] Figure 4 The coordinate system is a rectangular coordinate system for the cross bracing of the four-pile guide frame.

[0102] Figure 5 A schematic diagram for calculating the tilt angle of the CBG1 platform.

[0103] Figure 6 A node-line graph generated based on coordinate values.

[0104] Figure 7 For the corresponding Figure 6 Modeling diagram.

[0105] The attached diagram is labeled as follows: 101, jacket support column; 102, pile leg; 103, cross brace pipe; 104, platform deck. Detailed Implementation

[0106] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0107] Example 1, see Figures 1-2 The present invention is achieved through the following technical solution: a method for calculating and modeling the tilt of a marine platform structure, comprising the following steps;

[0108] S1, Obtain the structural parameters of each part of the offshore platform and determine the location of key nodes;

[0109] S2, using sea level as a reference, measures the elevation data of each layer of the jacket of the offshore platform and the platform deck;

[0110] S3. Establish a rectangular coordinate system with the center point of the area enclosed by the uppermost horizontal support pipe of the jacket as the origin, and calculate the spatial tilt angle of the jacket structure based on the structural parameters and elevation data.

[0111] S4. Establish a three-dimensional coordinate system with the center point of the interface between the jacket structure of the offshore platform and the sea level as the origin and the vertical above the sea level as the Z-axis. Combine the structural parameters to determine the design coordinates of the key nodes.

[0112] S5. Calculate the tilted coordinates of the key nodes by combining the design coordinates and the spatial tilt angle.

[0113] S6. Model the marine platform structure using the tilted coordinates to obtain a marine platform safety assessment model.

[0114] Example 2, as Figure 1-4 As shown, the present invention is achieved through the following technical solution: a method for calculating and modeling the tilt of a marine platform structure, comprising the following steps;

[0115] S1, Obtain the structural parameters of each part of the offshore platform and determine the location of key nodes;

[0116] The structural parameters include the length of each layer of cross bracing pipe, the radius of the cross bracing pipe, the radius of the jacket column, the length between each connection point between the platform deck and the jacket, and the distance from each node of the bottom layer of cross bracing pipe of the jacket to the mud surface.

[0117] The key nodes include the connection point between the cross brace and the center of the pile leg, the connection points between the platform deck and the jacket, the junction of the pile leg and the mud surface, and the bottom node of the pile leg.

[0118] S2, using sea level as a reference, measures the elevation data of each layer of the jacket of the offshore platform and the platform deck;

[0119] S3. Establish a rectangular coordinate system with the center point of the area enclosed by the uppermost horizontal support pipe of the jacket as the origin, and calculate the spatial tilt angle of the jacket structure based on the structural parameters and elevation data.

[0120] Specifically, S31: Establish a rectangular coordinate system with the center point of the area formed by the uppermost horizontal support tube of the jacket as the origin O and the axis of symmetry as the Y-axis;

[0121] S32: In the rectangular coordinate system, with the center point of each pile leg as the measurement point, measure the elevation of the top surface of the top two nodes of each cross brace tube near the center point of the pile leg.

[0122] S33: Calculate the X-axis rotation angle and Y-axis rotation angle ;

[0123] S4. Establish a three-dimensional coordinate system with the center point of the interface between the jacket structure and the sea level of the offshore platform as the origin and the vertical direction above the sea level as the Z-axis. Combine this with the structural parameters to determine the design coordinates of key nodes. Specifically: establish a three-dimensional coordinate system with the center point of the interface between the jacket structure and the sea level as the origin, the vertical direction above the sea level as the Z-axis, and the axis of symmetry of the area enclosed by the cross bracing pipes as the Y-axis. Combine this with the structural parameters and perform coordinate transformation calculations to obtain the design coordinates of the connection points between each layer of cross bracing pipes and the center of the pile legs before the overall tilt of the jacket, denoted as X. in Y in Z in , where i represents the letter number of the pile leg, starting from A according to the letter, and n represents the corresponding number of layers of cross bracing tube;

[0124] S5. Calculate the tilted coordinates of key nodes based on the design coordinates and the spatial tilt angle; S51. Calculate the coordinates of the connection points between the cross bracing pipes of each layer and the center of the pile leg after the overall tilt of the jacket structure:

[0125] First, rotate around the X-axis:

[0126]

[0127] Then rotate around the Y-axis:

[0128]

[0129] Where i corresponds to the letter number of the pile leg; n is the number of layers of the corresponding cross bracing tube;

[0130] S52. Based on the coordinates of any two points of the inclined pile leg and the elevation data of the mud surface, the coordinates of the node where the corresponding pile leg intersects with the mud surface can be obtained by matrix solving.

[0131] S53. Obtain the equation of the straight line based on the coordinates of any two points of the inclined pile leg, and obtain the distance equation based on the distance between one of the points and the bottom end of the pile leg. Solve the system of three quadratic equations to obtain the coordinates of the bottom end of the pile leg.

[0132] When the pile legs and jacket structure are tilted, but the platform deck is not tilted, the coordinates of the connection point between the platform deck and the jacket are calculated using the platform deck elevation data, as follows: The equations of two planes are obtained using the coordinates of any two points on pile leg A. The plane equation of the platform deck is obtained based on the platform elevation data. The coordinates of the intersection of the three planes are obtained using a matrix, which gives the coordinates of the connection point between the platform deck and the jacket corresponding to pile leg A. The coordinates of other platform deck and jacket connection points are calculated similarly.

[0133] S6. Model the marine platform structure using the tilted coordinates to obtain a marine platform safety assessment model.

[0134] The jacket is divided into three-pile jackets or four-pile jackets.

[0135] Based on the above method, the specific calculation process is as follows:

[0136] 1. Three-pile jacket:

[0137] like Figure 2 As shown, this is a three-pile guide pipe offshore platform, including three guide pipe support columns 101. The upper end of the pile leg 102 is inserted into the guide pipe support column 101, the lower end is inserted into the seawater and the bottom end is set below the mud surface. There are cross bracing pipes 103 between the guide pipe support columns, and there are four layers of cross bracing pipes from bottom to top. The top of the guide pipe support column 101 is provided with a platform deck 104.

[0138] (1) Basic parameters

[0139] (a) Establish a rectangular coordinate system with the center point O of the equilateral triangle formed by the uppermost horizontal support tubes of the jacket as the origin and the axis of symmetry as the Y-axis, to calculate the inclination angle of the jacket structure, such as Figure 3 As shown;

[0140] (b) Let the center points of the three pile legs be A, B, and C. Measure the elevation of the top surface of the 6 nodes on the cross brace near the center point: A1, A2, B1, B2, C1, C2; platform deck elevation detection data H5; the design elevation of the center line of each cross brace from bottom to top are H1, H2, H3, H4; the vertical distance from the bottom surface of the lowest cross brace node of the jacket structure to the mud surface is A3, B3, C3; the distance from the lowest cross brace node of the jacket structure to the bottom of the pile leg is H7.

[0141] (c) Radius value of the cross brace R1, radius value of the guide frame column R2;

[0142] (d) The lengths of each cross brace of the jacket from bottom to top are L1, L2, L3, and L4, and the length between each connection point of the top node of the jacket and the platform is L5;

[0143] (e) A three-dimensional coordinate system is established with the center point of the interface between the jacket structure and the sea level as the origin, the vertical above the sea level as the Z-axis, and the symmetry axis of the platform cross brace as the Y-axis, to calculate the coordinates of key nodes after tilting.

[0144] (2) Calculation steps

[0145] (a) Estimating the elevation of the center point of the pile leg using the elevation of the measurement points:

[0146]

[0147] (b) X-axis rotation angle :

[0148]

[0149] Elevation difference between points A and C:

[0150]

[0151] (c) Y-axis rotation angle :

[0152] The elevation difference between points A and C:

[0153]

[0154] (d) Coordinates of nodes before the overall tilt of the jacket:

[0155] A-leg:

[0156]

[0157] B-leg:

[0158]

[0159] C-leg:

[0160]

[0161] (e) Node coordinates after the overall jacket structure is tilted:

[0162] First, rotate around the X-axis:

[0163]

[0164] Then rotate around the Y-axis:

[0165] ;

[0166] (f) Node coordinates of the connection points between the non-inclined platform deck and the jacket, and the intersection points between the pile legs and the mud surface: The equations of the two planes are obtained using the coordinates of any two points on pile leg A. The equation of the platform plane is obtained based on the platform elevation data H5. The coordinates of the intersection points of the three planes are solved using a matrix (the following calculations take the coordinates of points 01 and 03 on pile leg A as an example):

[0167] ;

[0168] Similarly, using the coordinates of any two points on pile leg A and the mud surface elevation data, the coordinates of the node where the pile leg intersects the mud surface can be obtained using matrix solving (the following calculations take the coordinates of points 02 and 04 on pile leg A as an example):

[0169]

[0170] ;

[0171] (g) Coordinates of the lowest node of the pile leg:

[0172] Using the coordinates of any two points on pile leg A (the following calculations use the coordinates of points 01 and 03 on pile leg A as an example), the equation of the straight line is obtained. Simultaneously, based on the distance H7 between one of these points and the bottom endpoint of the pile leg, the distance equation is obtained. Solving the system of three quadratic equations yields the coordinates of the bottom endpoint of the pile leg (X). A7 Y A7 Z A7 )

[0173]

[0174]

[0175] (h) Finally, the coordinates of all key points of any pile leg are obtained:

[0176] .

[0177] 2. Four-pile jacket:

[0178] (1) Basic parameters

[0179] (a) Establish a rectangular coordinate system with the center point of the rectangle formed by the four horizontal braces as the origin O and the axis of symmetry as the Y-axis, to calculate the tilt angle of the jacket structure, such as... Figure 4 As shown;

[0180] (b) Let the center points of the four pile legs be A, B, C, and D. Measure the elevations of the eight nodes on the cross brace closest to the center points: A1, A2, B1, B2, C1, C2, D1, D2;

[0181] (c) The radius value R1 of the cross brace and the length L of the cross brace 1n L 2n 1. The radius of the jacket support column, R2;

[0182] (d) The lengths of each cross brace of the jacket from bottom to top are L1, L2, L3, and L4, and the length between each connection point of the top node of the jacket and the platform is L5;

[0183] (e) A three-dimensional coordinate system is established with the center point of the interface between the jacket structure and the sea level as the origin, the vertical above the sea level as the Z-axis, and the symmetry axis of the platform cross brace as the Y-axis, to calculate the coordinates of key nodes after tilting.

[0184] (2) Calculation steps

[0185] (a) Estimating the elevation of the center point of the pile leg using the elevation of the measurement points:

[0186]

[0187] (b) X-axis rotation angle :

[0188] Elevation difference between the center points of AB and CD:

[0189]

[0190] (c) Y-axis rotation angle :

[0191] Elevation difference between the center points of AD and BC:

[0192]

[0193] (d) Coordinates of nodes before the overall tilt of the jacket:

[0194] A-leg:

[0195]

[0196] B-leg:

[0197]

[0198] C-leg:

[0199]

[0200] D-leg:

[0201]

[0202] (e) Coordinates of nodes after the overall tilt of the jacket: Refer to the calculation steps (e) of the three-pile jacket, formulas 1-12 to 1-19, and similarly calculate the coordinates of the nodes before tilt, the nodes after tilt, the interface nodes, and the bottom node of the pile leg according to the tilt angle.

[0203] Example 3: Using the method of Example 2, the tilt angle of the Victory CBG1 platform is calculated as follows:

[0204] Basic structural parameters of the Victory CBG1 platform:

[0205] like Figure 5 As shown, the center points of the three pile legs are A, B, and C. The elevations of the top surfaces of the six nodes on the cross braces closest to the center points are measured as follows: A1=3.548m, A2=3.676m, B1=3.555m, B2=3.473m, C1=4.100m, C2=4.100m; the platform deck elevation measurement data is H5=6.6m; the design elevations of the centerlines of each cross brace from bottom to top are H1=-7.5m, H2=-2m, H3=2m. m, H4=5m, the bottom surface of the lowest horizontal support node of the jacket structure is 1.8m, B3=1.5m, C3=1.9m from the mud surface elevation; the straight-line distance between point 01 of pile leg A and the bottom end of the pile leg is 36m; the radius of the horizontal support pipe is R1=0.3m, the radius of the jacket structure column is R2=0.5m; the lengths of each horizontal support of the jacket structure from bottom to top are L1=6m, L2=5.02m, L3=4.31m, L4=3.78m.

[0206] The calculation steps are as follows:

[0207] 1. Calculate the rotation angle using the elevation of the measurement point:

[0208] (1) Rotation angle of X-axis : ; ; ;

[0209] (2) Y-axis rotation angle : ; .

[0210] 2. Calculate the coordinates of the nodes before the overall tilt of the jacket structure:

[0211] A-leg:

[0212] B-leg:

[0213] C-leg: .

[0214] 3. Calculate the coordinates of all key points of the three pile legs after tilting:

[0215] .

[0216] Import the tilted coordinates into the offshore platform structure modeling software, such as... Figure 6-7 As shown, the structure of the marine platform is modeled to obtain a marine platform safety assessment model.

[0217] The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0218] The technical features of this invention not described can be implemented by or using existing technology, and will not be repeated here. Of course, the above description is not a limitation of this invention, and this invention is not limited to the examples above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention should also be within the protection scope of this invention.

[0219] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

Claims

1. A method for calculating and modeling the tilt of an offshore platform structure, characterized in that, Includes the following steps; S1, Obtain the structural parameters of each part of the offshore platform and determine the location of key nodes; S2, using sea level as a reference, measures the elevation data of each layer of the jacket of the offshore platform and the platform deck; S3. Establish a rectangular coordinate system with the center point of the area enclosed by the uppermost horizontal support pipe of the jacket as the origin, and calculate the spatial tilt angle of the jacket structure based on the structural parameters and elevation data. S4. Establish a three-dimensional coordinate system with the center point of the interface between the jacket structure of the offshore platform and the sea level as the origin and the vertical above the sea level as the Z-axis. Combine the structural parameters to determine the design coordinates of the key nodes. S5. Calculate the tilted coordinates of the key nodes by combining the design coordinates and the spatial tilt angle. S6. Model the marine platform structure using the tilted coordinates to obtain a marine platform safety assessment model; Step S3 specifically involves: S31: Establish a rectangular coordinate system with the center point of the area formed by the uppermost horizontal support tube of the jacket as the origin O and the axis of symmetry as the Y-axis; S32: In the rectangular coordinate system, with the center point of each pile leg as the measurement point, measure the elevation of the top surface of the top two nodes of each cross brace tube near the center point of the pile leg. S33: Calculate the X-axis rotation angle and Y-axis rotation angle ; Specifically, S4 is: A three-dimensional coordinate system is established with the center point of the interface between the jacket structure and the sea level as the origin, the vertical distance above the sea level as the Z-axis, and the axis of symmetry of the area enclosed by the cross bracing pipes as the Y-axis. Combining structural parameters, and through coordinate transformation calculations, the design coordinates of the connection points between each layer of cross bracing pipes and the center of the pile legs before the overall tilt of the jacket are obtained, denoted as X. in Y in Z in , where i represents the letter number of the pile leg, starting from A according to the letter, and n represents the corresponding number of layers of cross bracing tube; S51, Calculate the coordinates of the connection points between the center of each layer of horizontal bracing pipe and the center of the pile leg after the overall tilt of the jacket: First, rotate around the X-axis: Then rotate around the Y-axis: Where i corresponds to the letter number of the pile leg; n is the number of layers of the corresponding cross bracing tube; S52. Based on the coordinates of any two points of the inclined pile leg and the elevation data of the mud surface, the coordinates of the node where the corresponding pile leg intersects with the mud surface can be obtained by matrix solving. S53. Obtain the equation of the straight line based on the coordinates of any two points of the inclined pile leg, and obtain the distance equation based on the distance between one of the points and the bottom end of the pile leg. Solve the system of three quadratic equations to obtain the coordinates of the bottom end of the pile leg.

2. The method for calculating and modeling the tilt of a marine platform structure according to claim 1, characterized in that, The structural parameters include the length of each layer of cross bracing pipe, the radius of the cross bracing pipe, the radius of the jacket support column, the length between each connection point of the platform deck and the jacket support, and the distance from each node of the bottom layer of cross bracing pipe of the jacket support to the mud surface.

3. The method for calculating and modeling the tilt of a marine platform structure according to claim 2, characterized in that, The key nodes include the connection point between the cross brace and the center of the pile leg, the connection points between the platform deck and the guide frame, the junction of the pile leg and the mud surface, and the bottom node of the pile leg.

4. The method for calculating and modeling the tilt of a marine platform structure according to claim 3, characterized in that, The jacket is divided into three-pile jackets or four-pile jackets.

5. The method for calculating and modeling the tilt of a marine platform structure according to claim 4, characterized in that, When the pile legs and jacket structure are tilted, but the platform deck is not tilted, the coordinates of the connection point between the platform deck and the jacket are calculated by combining the platform deck elevation data. Specifically, the equations of two planes are obtained by using the coordinates of any two points of pile leg A. The plane equation of the platform deck is obtained based on the platform elevation data. The coordinates of the intersection of the three planes are obtained by using a matrix. The coordinates of the intersection point of the three planes are the coordinates of pile leg A. The coordinates of the other connection points between the platform deck and the jacket are calculated in the same way.

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