Marine oil and gas subsea pipeline three-dimensional path obstacle avoidance calculation method
By constructing a three-dimensional topographic surface and obstacle model of the seabed, combining neighborhood search and heuristic algorithms, the three-dimensional path of the seabed pipeline is calculated, which solves the problem that traditional methods cannot be effectively applied to three-dimensional planning, and achieves rapid and accurate path obstacle avoidance, reducing the risks and costs of seabed pipeline laying.
Patent Information
- Application Number
- CN202510319643.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-18
- Publication Date
- 2025-06-24
AI Technical Summary
The traditional two-dimensional obstacle avoidance path calculation method cannot be effectively applied to the three-dimensional planning of subsea pipelines, and the existing three-dimensional path calculation algorithms are cumbersome to calculate and are not efficient due to complex parameters.
A three-dimensional path obstacle avoidance calculation method is adopted for marine oil and gas subsea pipelines. By constructing a three-dimensional terrain surface and obstacle model, combining neighborhood search and heuristic algorithms, the three-dimensional path from the starting point to the target point is calculated, which satisfies the preset objective function, that is, the area specified by the obstacle avoidance model.
A fast and accurate path obstacle avoidance algorithm is realized, which improves the efficiency of submarine pipeline laying, reduces risks and costs, and provides scientific methods to guide the early layout optimization and line pipe laying of marine oil and gas fields.
Smart Images
Figure CN120197790A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of offshore oil and gas exploration and development, and particularly relates to a three-dimensional path obstacle avoidance calculation method for offshore oil and gas submarine pipelines. Background Art
[0002] The seabed terrain is complex and changeable, and the naturally existing obstacles have a direct impact on the laying of submarine pipelines and the installation of underwater equipment. For offshore oil and gas exploitation, during the overall underwater layout design process, these obstacles need to be avoided, and a reasonable pipeline obstacle avoidance path needs to be selected. This can not only effectively reduce the laying risk of offshore oil and gas field pipelines, but also play an important guiding role in optimizing the laying path of pipelines, etc.
[0003] It is found through research that the A-star obstacle avoidance path calculation method of traditional technologies can be well applied in two-dimensional scenarios, but cannot be effectively used for the planning of three-dimensional submarine pipelines; while the particle swarm optimization algorithm currently applied to three-dimensional scenarios has complex settings of parameters such as inertia weight, individual learning factor, and swarm learning factor, resulting in cumbersome algorithm calculations and low efficiency. Summary of the Invention
[0004] The present invention provides a three-dimensional path obstacle avoidance calculation method for offshore oil and gas submarine pipelines, which can be used for path optimization of pipeline laying in offshore oil and gas development, and can provide a fast and accurate path obstacle avoidance algorithm during overall underwater layout optimization, providing a scientific method guidance for the design of early layout optimization of offshore oil and gas fields and the laying of pipeline cables. At the same time, it can greatly improve the efficiency of obstacle avoidance, reduce the pipeline laying risk and cost.
[0005] To achieve the above object, the present invention adopts the following technical solutions:
[0006] In a first aspect, the present application provides a three-dimensional path obstacle avoidance calculation method for offshore oil and gas submarine pipelines, including:
[0007] S1, constructing a mathematical representation of the three-dimensional seabed terrain surface of the area where the submarine pipeline to be laid is located;
[0008] S2, constructing an obstacle model to be avoided on the three-dimensional seabed terrain curve;
[0009] S3, inputting the three-dimensional seabed terrain surface, the obstacle model, and the starting point and target point of the submarine pipeline to be laid into a three-dimensional path calculation model, and calculating a three-dimensional path from the starting point to the target point based on neighborhood search and heuristic algorithm, satisfying a preset objective function, that is, avoiding the area specified by the obstacle model.
[0010] In one implementation, in S1, the elevation data corresponding to two-dimensional grid points is used as the mathematical representation of the three-dimensional seabed terrain surface.
[0011] In one implementation, in the step S2, a preset functional relationship or the obstacle avoidance area specified by the obstacle model constructed by the polygon on the three-dimensional seabed terrain surface is used.
[0012] In one implementation, in the step S3, the three-dimensional path calculation model starts from the starting point, obtains the next expansion node by using neighborhood search, and based on the actual cost function between the starting point and the expansion node and the cost estimation function between the expansion node and the target point, determines each expansion node in sequence according to the preset objective function to obtain the final three-dimensional path.
[0013] In one implementation, the preset objective function is: the total length of the three-dimensional path connecting the starting point, each expansion node and the target point is the lowest.
[0014] In one implementation, the actual cost function between the starting point and the expansion node is: the three-dimensional path length of the pipeline from the starting point to the current expansion node.
[0015] In one implementation, the cost estimation function between the expansion node and the target point is: the Manhattan distance between the current expansion node and the target point.
[0016] In one implementation, the neighborhood search adopts octal neighborhood search.
[0017] The technical solution of the present invention can be used for the path optimization of pipeline laying in offshore oil and gas development, and can provide a fast and accurate path obstacle avoidance algorithm during the underwater overall layout optimization, providing a scientific method guidance for the design of the early layout optimization of offshore oil and gas fields and the pipeline laying, and at the same time can greatly improve the efficiency of obstacle avoidance, reduce the risk and cost of pipeline laying. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic diagram of discrete terrain data points under the three-dimensional seabed in the embodiment of the present application;
[0019] Figure 2 It is a schematic diagram of the three-dimensional terrain surface in the embodiment of the present application;
[0020] Figure 3 It is a schematic diagram of obstacle characterization in the embodiment of the present application;
[0021] Figure 4 It is a schematic diagram of neighborhood search in the embodiment;
[0022] Figure 5 It is a schematic diagram of the calculation process of the three-dimensional path calculation model;
[0023] Figure 6 It is a schematic diagram of three-dimensional pipeline length calculation. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.
[0025] In view of the deficiencies and problems of the prior art, the present application provides a three-dimensional path obstacle avoidance calculation method for offshore oil and gas submarine pipelines, including:
[0026] S1, constructing a mathematical representation of the three-dimensional seabed terrain surface of the area where the submarine pipeline to be laid is located;
[0027] S2, constructing an obstacle model to be avoided on the three-dimensional seabed terrain curve;
[0028] S3, inputting the three-dimensional seabed terrain surface, the obstacle model, and the starting point and target point of the submarine pipeline to be laid into a three-dimensional path calculation model, and calculating the three-dimensional path from the starting point to the target point based on neighborhood search and heuristic algorithms, satisfying a preset objective function, that is, avoiding the area specified by the obstacle model.
[0029] The above method will be described in a more detailed embodiment below with reference to more accompanying drawings.
[0030] Combined Figures 1 to 6 , in one embodiment, the method flow includes:
[0031] Step 1, constructing a three-dimensional terrain surface
[0032] The three-dimensional terrain is essentially represented by a set of discrete elevation data points to represent complex terrain. To facilitate the management and invocation of discrete elevation data, the discrete elevation data is stored in a matrix, and its mathematical expression is as follows:
[0033] z i = f(x i , y i ), i = 1, 2,..., n
[0034] In the formula, z i is the elevation value of the i-th grid position point, and (x i , y i ) is the plane coordinate of the i-th grid position. These discrete data points form a finite sequence of three-dimensional digital vectors, and the mathematical expression is as follows:
[0035] V i = (x i , y i , z i), i = 1, 2, ..., n
[0036] To construct a three-dimensional terrain, the three-dimensional vectors in the finite sequence need to be arranged orderly at the regular grid. All the three-dimensional vectors can be simplified to form a two-dimensional vector sequence, and the discrete data points here can be directly obtained from the DEM (Digital Elevation Model) data.
[0037] The DEM data of the seabed terrain can be downloaded from the international public seabed sounding data website. The seabed sounding DEM data of a certain area in the South China Sea is obtained from the NOAA website as a tiff format file. In this method, a seabed area with a length and width of 240 grids is selected as a case. The resolution of the grid is 90m, that is, a rectangular area with a length and width of 21.6km. The GDAL library of Python is used to read the DEM data, and the data includes: the starting longitude and latitude coordinates of the upper left corner of the rectangular area, the resolution, and a two-dimensional array. The values in the array are the elevation values of the corresponding grids. Since the scatter plot of the original DEM data 240*240 is too dense, the three-dimensional seabed scatter plot after sampling to 20*20 is as Figure 1 shown. Each point in the figure is the discrete terrain data point under the three-dimensional seabed.
[0038] According to the Python program to read the two-dimensional array of the DEM data with a size of 240*240, the three-dimensional terrain surface is generated by using the cubic spline interpolation method. The generated surface is as Figure 2 shown.
[0039] Step 2, establish an obstacle model
[0040] The obstacle area of the three-dimensional obstacle in the real seabed environment is an area where pipelines are not allowed to pass through and underwater equipment cannot be installed. If there are obstacles in the area where the deep-sea oil and gas field is located, the distance function of the three-dimensional pipeline in the underwater production control system layout model should be the optimal path considering the obstacles, and the underwater equipment cannot be installed in the obstacle area. It is difficult to describe the three-dimensional obstacle with an exact mathematical function. However, there are two types of mathematical methods that can generally describe the obstacle area. The first type is the elementary function superposition method, that is, the obstacle area can be generally described by superimposing multiple elementary functions; the second type is the polygon approximation method, that is, the obstacle area is represented by a polygon. The more sides the polygon has, the more accurate the description of the obstacle area. However, in actual engineering applications, many obstacle areas are irregular and cannot be formed by superimposing multiple elementary functions or cannot be described by mathematical methods. Therefore, the polygon approximation method is mostly used to describe the obstacle area.
[0041] After introducing the three-dimensional obstacle, the pipeline distance function in the three-dimensional path model for laying marine oil and gas submarine pipelines is the three-dimensional pipeline obstacle avoidance distance. First, use the polygon approximation method to establish an obstacle model. The schematic diagram of the obstacle environment is as Figure 3 shown.
[0042] Step 3, Solving the 3D path obstacle avoidance model
[0043] The 3D obstacle model includes a 3D digital terrain, a starting node, a target node, and all obstacle nodes. The A-star algorithm and the eight-neighborhood search model are used to solve the shortest obstacle avoidance path between the starting node and the target node, expanding outward from the starting node until the target node is reached.
[0044] Optimal path search based on a digital grid terrain is a search method of expanding neighborhood nodes. That is, when the current node expands to the next node, there are several nodes to be expanded around the current node. The more nodes to be expanded, the lower the search efficiency of the algorithm, and the smoother the path obtained; the fewer nodes to be expanded, the higher the search efficiency of the algorithm, and the rougher the path obtained. According to the number of nodes to be expanded around the current node, there are four-neighborhood expansion models, eight-neighborhood expansion models, and sixteen-neighborhood expansion models. Schematic diagrams of these three neighborhood expansion models are shown as Figure 4 shown.
[0045] The four-neighborhood expansion model has fewer nodes to be expanded, so the algorithm has a higher search efficiency and poorer path smoothness. The sixteen-neighborhood model has more expanded nodes, so the algorithm has a lower search efficiency and a smoother path. Weighing the algorithm search efficiency and path smoothness, this method selects the eight-neighborhood model for path optimization.
[0046] In this embodiment, the actual path information introduced before expanding the current node is used as the heuristic information of the current node to evaluate the position of the next optimal path node. By continuously evaluating the estimated values of the nodes on the path, adjacent nodes are heuristically searched, thereby constructing an optimal path. The heuristic function of the A-star algorithm is as follows:
[0047] f(n) = g(n) + h(n)
[0048] In the formula, g(n) is the actual cost from the starting point to the current node n, and h(n) is the estimated cost from the current node n to the target node. Since the purpose of this method is to find the shortest path, the value of the evaluation function is the distance value. The key of the A-star algorithm lies in the selection of the evaluation function h(n). Since there may be obstacles and the calculation efficiency can be improved, the Manhattan distance is used as the estimation function. The Manhattan distance is the sum of the distances generated by projecting the line segment between two points onto the coordinate axes. Its function is:
[0049] h(n) = |x1 - x2| + |y1 - y2| + |z1 - z2|
[0050] As Figure 5 , the steps for solving the 3D path obstacle avoidance model are as follows:
[0051] (1) Record the starting node and the target node, and store the nodes covered by the obstacle area in the obstacle matrix. Determine whether the starting and ending points are in the obstacle matrix. If the starting and ending points are in the obstacle matrix, change the positions of the starting and ending points; if not, deposit the starting node into the Openlist and calculate the evaluation function value of the starting node.
[0052] (2) If the Openlist is empty, the path search fails; otherwise, continue to the next step.
[0053] (3) Move the node with the minimum evaluation function value in the Openlist to the Closelist, and expand the node in eight neighborhoods. Retain the expanded nodes that are not in the obstacle matrix, and continue to the next step.
[0054] (4) If the expanded nodes contain the target node, the path search ends. Trace back from the target node to the parent nodes to the starting node to obtain the path nodes and output the path length; otherwise, continue.
[0055] (5) If the expanded node is in the Openlist and the evaluation function value of the expanded node is the minimum in the Openlist, set the previous node as the parent node of the expanded node; otherwise, execute step (2). If the expanded node is not in the Openlist and the Closelist, deposit it into the Openlist and execute step (2).
[0056] In this example, the core of calculating the three-dimensional pipeline length is the idea of infinitesimal elements, that is, cutting the pipeline into several segments, approximating the three-dimensional length of each segment by its straight-line length, and then summing up each segment to approximate the three-dimensional length of the entire pipeline. Therefore, the starting node coordinates of each segment need to be obtained. However, the starting node coordinates of each segment can be obtained from the two-dimensional vector sequence {V i , i = 1, 2,..., n}. The steps for calculating the three-dimensional pipeline length are as follows:
[0057] (1) As Figure 6 shown, the distance between adjacent pipelines is the same, which is m, that is, the resolution of the three-dimensional terrain is m. It can be seen from the figure that the more segments the pipeline is divided into, the higher the calculation accuracy, but the longer the calculation time;
[0058] (2) Obtain the coordinates (x i , y i , z i ) of the starting nodes of each segment from the vector sequence {V i , i = 1, 2,..., n};
[0059] (3) Assume that each segment of the pipeline is a straight line, and the length L 12 between node 1 and node 2 is:
[0060]
[0061] In the formula, L 12 is the length of the first section of pipeline, and (x1, y1, z1) and (x2, y2, z2) are the coordinates of the starting point of the pipeline respectively;
[0062] (4) The total length of the three-dimensional curve is the sum of the lengths of each section, and the formula is as follows:
[0063]
[0064] In an application embodiment, Figure 2 In the shown three-dimensional grid terrain, two obstacle areas in the shape of quadrilaterals are set for verification to verify the effect of the A* algorithm in practical applications. The starting point and ending point coordinates are (990, 1980, -1473) and (18000, 19980, -1486) respectively, with the unit of meters. The path optimization under three-dimensional obstacles is completed by using the eight-neighborhood A* algorithm. It can be seen from the calculation results that the straight-line distance between the starting node and the target node is 24.7588 kilometers, and the obstacle avoidance distance on the three-dimensional terrain is 26.6299 kilometers. The length when considering the three-dimensional terrain and obstacles increases by 7.56% compared with the straight-line length between the starting and ending points. Therefore, under the condition of considering the three-dimensional terrain and obstacles, it can not only provide guidance for the laying of pipelines, but also reliably estimate the investment cost of pipelines.
[0065] In summary, the present invention provides a three-dimensional path planning algorithm and method for the laying of offshore oil and gas submarine pipelines, which can be used for path optimization of pipeline laying in offshore oil and gas development, and can provide a fast and accurate path obstacle avoidance algorithm during underwater overall layout optimization, providing a scientific method guidance for the design of the early layout optimization of offshore oil and gas fields and the laying of pipeline tubes. At the same time, it can greatly improve the efficiency of obstacle avoidance and reduce the risk and cost of pipeline laying.
[0066] In several embodiments provided by the present invention, it should be understood that the disclosed method can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the above division of units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point, the displayed or discussed mutual coupling or direct coupling or communication connection can be through some interfaces, and the indirect coupling or communication connection of the device or unit can be in electrical, mechanical or other forms.
[0067] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.
Claims
1. A three-dimensional path obstacle avoidance calculation method for marine oil and gas submarine pipelines, characterized in that: include: S1, constructing a mathematical representation of the three-dimensional seabed topography surface in the area where the submarine pipeline is to be laid; S2, constructing obstacle models that need to be avoided on the three-dimensional seabed terrain curve; S3, input the three-dimensional seabed terrain surface, obstacle model, and the starting point and target point of the submarine pipeline to be laid into the three-dimensional path calculation model, and calculate the three-dimensional path from the starting point to the target point based on neighborhood search and heuristic algorithm to meet the preset objective function, that is, avoid the area specified by the obstacle model.
2. The three-dimensional path obstacle avoidance calculation method for marine oil and gas submarine pipelines according to claim 1 is characterized in that: In S1, the elevation data corresponding to the two-dimensional grid points are used as the mathematical representation of the three-dimensional seabed topographic surface.
3. The three-dimensional path obstacle avoidance calculation method for marine oil and gas submarine pipelines according to claim 2 is characterized in that: In S2, a preset functional relationship or polygon is used to construct an obstacle avoidance area specified by the obstacle model on the three-dimensional seabed terrain surface.
4. The three-dimensional path obstacle avoidance calculation method for marine oil and gas submarine pipelines according to claim 3 is characterized in that: In S3, the three-dimensional path calculation model starts from the starting point and uses neighborhood search to obtain the next extended node. Based on the actual cost function of the starting point and the extended node, and the cost estimation function of the extended node and the target point, each extended node is determined in turn according to the preset objective function to obtain the final three-dimensional path.
5. The three-dimensional path obstacle avoidance calculation method for marine oil and gas submarine pipelines according to claim 4 is characterized in that: The preset objective function is: the total length of the three-dimensional path connecting the starting point, each expansion node and the target point is the shortest.
6. The three-dimensional path obstacle avoidance calculation method for marine oil and gas submarine pipelines according to claim 5 is characterized in that: The actual cost function between the starting point and the expansion node is: the three-dimensional path length of the pipeline from the starting point to the current expansion node.
7. The three-dimensional path obstacle avoidance calculation method for marine oil and gas submarine pipelines according to claim 5 is characterized in that: The cost estimation function of the extended node and the target point is: the Manhattan distance between the current extended node and the target point.
8. The three-dimensional path obstacle avoidance calculation method for marine oil and gas submarine pipelines according to claim 4 is characterized in that: The neighborhood search uses eight-neighborhood search.