Double-pipeline laying method capable of welding while constructing

Abstract

The invention provides a double-pipeline laying method capable of welding while construction, which belongs to the technical field of marine oil and gas engineering and comprises the following steps: step 1, executing a dynamic welding and double-pipeline collaborative laying method; 2, executing a mechanical and deformation control method of the pipeline structure; and step 3, executing the land-sea collaborative operation and partition management and control method. The defect that in the prior art, due to the fact that the working space of a pipe laying ship is relatively narrow, the high-efficiency and high-quality double-pipe welding requirement is difficult to meet through traditional welding equipment and technology is effectively overcome.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of offshore oil and gas engineering, and particularly relates to a double-pipeline laying method with simultaneous construction and welding. BACKGROUND

[0002] In the field of offshore oil and gas development, submarine pipelines bear the heavy responsibility of efficiently transporting the extracted oil and gas resources to land or offshore processing facilities. The increasing global demand for energy drives the development of offshore oil and gas fields, and the importance of submarine pipelines, as the key link connecting offshore production facilities and land terminals, is increasingly prominent. In many submarine pipeline projects, a single-pipeline laying vessel is used to lay double pipelines, and double pipelines are widely used due to their ability to meet complex requirements such as different medium transportation and redundancy backup.

[0003] In the evolution of offshore engineering technology, submarine pipeline laying technology has undergone several innovations. With the development of pipeline laying vessels and other specialized equipment, the single-pipeline laying mode with simultaneous construction and welding has gradually become the mainstream. In this mode, the pipeline laying vessel welds and lays single pipelines one by one during the journey, significantly improving construction efficiency and pipeline laying quality. For the pipeline laying system, how to achieve precise synchronous laying, efficient welding, and stable installation of two pipelines during the simultaneous construction and welding process has become a key and difficult point for technical research and development.

[0004] As disclosed in the patent announcement No. CN222960030U, the technical requirements of the double-pipeline laying method come from multiple aspects. In terms of pipeline structure design, the spacing, support method, and interaction of the two pipelines need to be considered. How to optimize the structure design to ensure that the two pipelines can be simultaneously welded and laid. In the field of welding technology, due to the relatively narrow working space of the pipeline laying vessel, it is difficult to meet the requirements of efficient and high-quality double-pipeline welding using traditional welding equipment and technology. SUMMARY

[0005] The purpose of the present application is to provide a double-pipeline laying method with simultaneous construction and welding, which effectively avoids the defects in the prior art that the use of traditional welding equipment and technology cannot meet the requirements of efficient and high-quality double-pipeline welding due to the relatively narrow working space of the pipeline laying vessel.

[0006] The present application employs the following technical solutions.

[0007] A double-pipeline laying method with simultaneous construction and welding, comprising:

[0008] Step 1: Perform a dynamic welding and double-pipeline coordinated laying method;

[0009] In step 1, the dynamic welding and double-pipe cooperative laying method comprises: welding while laying the double pipes, in the guiding and assembling link in the construction, combining the automatic butt joint method and the high-precision positioning system to ensure that the axis alignment error of the double pipes in the hoisting and lowering process is controlled within 2 mm; in the welding process, in view of the high humidity and high salt environment by the sea and the hot climate on land, a semi-automatic welding device is used to assist manual welding, and a real-time monitoring system is matched to realize dynamic regulation of the temperature and shape in the welding process and to guarantee the weld strength.

[0010] Further, step 1 specifically comprises:

[0011] Step 1-1: Perform guiding and assembling of the double pipes;

[0012] Step 1-2: Perform the welding process;

[0013] Further, step 1-2 specifically comprises:

[0014] In view of the high humidity and high salt environment by the sea and the hot source climate on land, a semi-automatic welding device is used to assist manual welding, and a real-time monitoring system is matched to dynamically regulate the welding temperature and weld shape and guarantee the weld strength to reach the design standard.

[0015] Step 1-3: Perform the land-sea segmented construction process;

[0016] Further, step 1-3 specifically comprises:

[0017] Land segment: adopt the "double-pipe overall welding + pushing" process, reduce the on-site operation time through modularized assembly, and control the pushing speed at 0.5-1 m / min.

[0018] Sea segment: combined with the laying by the main work ship and the adjustment assisted by the underwater robot, the pipe shaking caused by the waves and the sea current is coped with to ensure that the laying position deviation is not more than 50 cm.

[0019] Step 1-4: Perform synchronous coordination control: develop a double-pipe synchronous laying coordination control system, that is, realize that the speed difference of the two pipes is ≤0.5 m / min and the angle deviation is consistent through the polyurethane roller platform.

[0020] Further, step 1-1 specifically comprises:

[0021] Step 1-1-1: Perform the positioning system fusion scheme, that is, the land-sea environment differentiated positioning;

[0022] Step 1-1-2: Implement the automatic butt joint execution mechanism;

[0023] Step 1-1-3: Perform dynamic adjustment and error compensation.

[0024] Further, step 1-1-1 specifically includes:

[0025] Land segment positioning: taking centimeter-level differential GPS as the core, combined with a laser tracker, real-time collection of three-dimensional coordinates of both ends of the double pipeline, and sending to the central control system connected with the wireless transmission module through the connection of GPS and laser tracker;

[0026] Sea segment positioning: using an underwater ultra-short baseline acoustic positioning system, combined with a hydroacoustic transponder installed on the surface of the pipeline connected with the acoustic positioning system, real-time tracking of the spatial attitude of the double pipeline in the seawater environment; at the same time, an inertial measurement unit is matched to compensate for the high-frequency shaking caused by waves and ocean currents;

[0027] Data fusion processing: through Kalman filtering algorithm to fuse GPS, laser tracking, acoustic positioning and IMU data transmitted to the central control system, output the real-time relative position of the double pipeline axis.

[0028] Further, step 1-1-2 specifically includes:

[0029] Hoisting stage guidance: the double pipeline hoisting equipment is equipped with a servo-controlled lifting point adjustment mechanism connected with the central control system, according to the relative position of the double pipeline feedback by the positioning system, the central control system adjusts the length and angle of the hoisting ropes on both sides of the double pipeline hoisting equipment in real time through the servo-controlled lifting point adjustment mechanism connected with it, so that the double pipeline remains parallel during hoisting, and the alignment error is preliminarily controlled within 5mm;

[0030] Lowering stage docking: guide tool is installed at the end of the double pipeline, which includes a conical positioning pin and a matching positioning hole, as well as 3 groups of hydraulic micro-adjusting push rods distributed in the circumferential direction. When the double pipeline is lowered to the docking distance, the positioning pin guides the preliminary alignment of the pipeline, and the hydraulic push rod adjusts the position in real time. The final alignment error of the central axis is controlled within 2mm;

[0031] Land docking reinforcement: the land segment uses a fixed docking platform, the surface of which is installed with polyurethane rollers, and the roller speed is driven by a servo motor to ensure that the double pipeline does not slide relative during pushing.

[0032] Further, step 1-1-3 includes:

[0033] Real-time monitoring feedback: laser displacement sensors and inclination sensors connected with the central control system are uniformly arranged around the double pipeline docking surface, which can detect the inclination Δθ, radial gap ΔX and axial misalignment ΔY of the two pipeline ends in real time, and the data sampling frequency is ≥500Hz;

[0034] Dynamic compensation control: the central control system calculates the adjustment amount according to the data fed back by the sensors as error values through the PID algorithm, drives the hydraulic push rod, hanger point adjusting mechanism and roller platform connected with the central control system to coordinate, realizes the real-time closed-loop control of "error-adjustment";

[0035] Further, in step 1-1-3, the dynamic compensation control specifically includes:

[0036] Step 1-1-3-1: Real-time error detection is performed;

[0037] Step 1-1-3-2: Incremental PID control algorithm is applied to dynamically calculate the adjustment amount;

[0038] Step 1-1-3-3: Precise adjustment of the actuator is performed;

[0039] Step 1-1-3-4: Environmental disturbance suppression is performed: for land vibration and sea sway, a preset disturbance compensation model, i.e. a neural network algorithm trained by historical data, is used to predict the influence of environmental disturbance on the pipeline posture in advance, and the hydraulic push rod, hanger point adjusting mechanism and roller platform are driven to perform feedforward control.

[0040] Further, step 1-1-3-1 specifically includes:

[0041] Through the laser displacement sensor and the inclination sensor deployed at the double-pipeline butt joint end, the relative position deviation of the double-pipeline central axis is collected in real time, including:

[0042] Axial offset: X-axis deviation ΔX, Y-axis (vertical longitudinal) deviation ΔY;

[0043] Angular deviation: rotational angular deviation Δθ of the double-pipeline central axis.

[0044] Further, step 1-1-3-2 specifically includes:

[0045] An incremental PID control algorithm is used to calculate the adjustment amount of the actuator according to the real-time error, and the formula is as follows:

[0046] ;

[0047] Wherein represents the adjustment amount at the time point); represents the proportional coefficient; represents the integral coefficient; represents the differential coefficient; represents the error value at the time point; , represents the , Error value of time.

[0048] Further, step 1-1-3-3 specifically includes:

[0049] The central control system converts the calculated adjustment amount into an execution instruction to drive the corresponding mechanism to act:

[0050] For X, Y axis offset: control 3 groups of hydraulic push rods distributed circumferentially at the end of the double pipeline, and stretch and retract according to the stretching and retracting of ΔU(k), directly correcting the horizontal or vertical deviation;

[0051] For angle deviation Δθ: adjust the length difference of the hoisting ropes of the two sides of the hoisting equipment, so that the central axis of the double pipeline rotates to a parallel state.

[0052] To ensure that the error is stably controlled within ≤2mm, the PID parameters need to be dynamically adapted according to the construction scene (land / sea):

[0053] Land section: small environmental interference (mainly mechanical vibration), take smaller (0.1-0.2), to avoid excessive inhibition leading to adjustment lag;

[0054] Sea section: greatly affected by waves and currents, take larger (0.2-0.3), to enhance the anti-interference ability; at the same time, increase (1.0-1.2), to speed up the response speed to sudden deviation;

[0055] In addition, the system has built-in error threshold judgment logic: when the real-time error is ≤1mm, automatically reduce (to 0.05 or less), to reduce unnecessary fine-tuning actions; when the error is >1.5mm, trigger the fast adjustment mode, temporarily increase to 1.2, to ensure that the error is pulled back to ≤2mm range within 2 seconds.

[0056] Further, the double pipeline laying method of welding while constructing, further includes:

[0057] Step 2: execute the pipeline structure mechanics and deformation control method;

[0058] Step 3: execute the land-sea collaborative operation and partitioned control method.

[0059] Further, in step 2, the design stage simulation: use finite element analysis software such as ANSYS to establish a three-dimensional mechanical model, simulate the stress distribution under different working conditions, and ensure that the maximum deformation is ≤1% of the pipeline diameter, and the bending radius is not more than the limit bending radius of the pipeline;

[0060] Fatigue life prediction: based on the mechanical model data, combined with the fatigue characteristics of the material, the fatigue damage of the pipeline within the designed service life is predicted to ensure that the safety factor is greater than or equal to 1.2.

[0061] Real-time monitoring system: strain sensors and displacement monitoring devices connected to the central control system are installed at the key positions of the pipeline, and the data collected by the strain sensors and displacement monitoring devices are transmitted to the central control system in real time. When the deformation approaches the preset threshold, a warning is triggered, and the construction parameters can be adjusted in time.

[0062] Further, step 3 specifically includes:

[0063] Land area function division:

[0064] Group work area: configure digital cutting and bevel machining equipment to ensure that the precision error of the pipeline component is less than or equal to 1mm; welding work area: use semi-automatic welding equipment matched with dynamic welding process, and support real-time monitoring system;

[0065] Welding detection area: configure X-ray flaw detector and ultrasonic detector to perform 100% weld detection, and the unqualified product repair rate is controlled to be less than 5%;

[0066] Storage area: use intelligent scheduling system to optimize pipe stacking and transfer path to avoid pipe ovality deviation exceeding 0.5% due to collision;

[0067] Data sharing platform: establish a land-sea data sharing platform to synchronize construction progress, quality detection and environmental monitoring data in real time, and realize cross-regional collaborative decision response time less than or equal to 30 minutes.

[0068] The beneficial effects of the present application are that, compared with the prior art, the technical effects of the present application include:

[0069] (1) High construction efficiency: the method of the present application can usually complete welding and lengthening operations on the land prefabrication site, and through the flow line operation mode, the two pipes are lengthened side by side, and welding, inspection and corrosion prevention processes are performed at the same time, which reduces the time consumed by traditional prefabrication and overall installation. Moreover, double-pipe laying can complete more work in the same time compared with single-pipe laying, which greatly shortens the overall construction period.

[0070] (2) Good welding quality: during the construction and welding process, semi-automatic welding technology can be used for backing and surfacing. This technology can improve the welding efficiency and is also beneficial to improve the tensile properties and fracture toughness of the welded joint, so that the welding quality is more stable, the uniformity and consistency of the weld are better, and the welding defects can be effectively reduced, which meets the high sealing and high strength requirements of the submarine oil pipeline.

[0071] (3) Pipeline deformation and strength control optimization: During laying, the method of the application can apply appropriate tension to the pipeline through devices such as tensioners, better control the deformation of the pipeline, and make the pipeline maintain good shape and strength under the action of gravity, seawater pressure, etc., to ensure that the pipeline meets the design requirements and reduce the risk of pipeline damage or affecting the conveying performance due to excessive deformation.

[0072] (4) Strong adaptability to complex marine environment: The double pipeline laying method of simultaneous construction and welding can flexibly adjust the construction progress and method according to the marine environment conditions. When encountering bad weather, the pipeline can be abandoned at any time, and the work site can be left to anchor to avoid wind. After the weather improves, the construction can continue. Compared with some fixed site construction methods, the adaptability to the marine environment is stronger, and the construction range is expanded.

[0073] (5) Good economy: Double pipelines are laid at the same time, and some construction equipment and resources such as pipelaying vessels and welding equipment can be shared, reducing the repeated investment in equipment. Moreover, the improvement of construction efficiency also means the reduction of labor cost and time cost, and the reduction of multiple disturbances to the marine environment, which to some extent reduces the environmental restoration cost, and the overall economy is better.

[0074] (6) High precision: Some advanced laying systems are equipped with high-precision guiding and positioning devices, such as gyro-based guiding systems, which can realize accurate guidance at uphill, downhill and turning points, better control the laying position and spacing of double pipelines, and ensure that the pipelines are laid according to the design requirements, especially suitable for complex seabed terrain areas. BRIEF DESCRIPTION OF DRAWINGS

[0075] Figure 1 is a flow chart of the double pipeline laying method of simultaneous construction and welding in the application. DETAILED DESCRIPTION

[0076] In order to make the purpose, technical scheme and advantages of the application more clear, the technical scheme of the application will be expressed clearly and completely in combination with the drawings in the embodiments of the application. The embodiments expressed in this application are only part of the embodiments of the application, not all embodiments. According to the spirit of the application, other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0077] As shown in Figure 1 , the double pipeline laying method of simultaneous construction and welding comprises:

[0078] Step 1: Perform dynamic welding and double pipeline coordinated laying method;

[0079] In the preferred but non-limiting embodiment of the present application, in step 1, the dynamic welding and double-pipe cooperative laying method comprises: taking the "welding while constructing" as the core feature, focusing on solving the real-time splicing and accurate laying problems of the double pipes in the complex land and sea environment. In the guiding and assembling link in the construction, the automatic docking method and high-precision positioning system need to be combined to ensure that the axis alignment error of the double pipes in the hoisting and lowering process is controlled within 2 mm, thereby providing a stable foundation for subsequent welding. In the welding process, in view of the high humidity and high salt environment on the sea side and the hot climate conditions on land, semi-automatic welding equipment with strong adaptability is used to assist manual welding, and a real-time monitoring system is matched to realize dynamic regulation of temperature and shape in the welding process and guarantee the weld strength.

[0080] In the preferred but non-limiting embodiment of the present application, step 1 specifically comprises:

[0081] Step 1-1: performing guiding and assembling of the double pipes;

[0082] In the preferred but non-limiting embodiment of the present application, step 1-1 specifically comprises:

[0083] The specific method for realizing the axis alignment error ≤2 mm of the double pipes in the hoisting and lowering process by combining the automatic docking technology and the high-precision positioning system can be divided into three parts: executing the positioning system fusion scheme, implementing the automatic docking execution mechanism, and executing dynamic adjustment and error compensation, and the specific method is as follows:

[0084] Step 1-1-1: executing the positioning system fusion scheme, that is, land and sea environment differentiated positioning;

[0085] In the preferred but non-limiting embodiment of the present application, step 1-1-1 specifically comprises:

[0086] According to the different environmental characteristics of land and sea areas, a high-precision positioning system of "GPS + underwater acoustic positioning + multi-sensor fusion" is adopted to provide real-time coordinate reference for the alignment of the double pipes:

[0087] Land segment positioning: taking the centimeter-level differential GPS as the core, matching the laser tracker (precision ±0.1 mm / m), collecting the three-dimensional coordinates (X, Y, Z axes) of the two ends of the double pipes in real time, and sending them to the central control system connected with the wireless transmission module through the wireless transmission module (delay ≤10 ms) connected with the GPS and the laser tracker, so as to ensure that the position deviation of the pipes in the assembling and pushing process can be perceived in real time; the central control system can be a computer, and the wireless transmission module can be a 4G module.

[0088] Sea section positioning: Adopting underwater ultra-short baseline (USBL) acoustic positioning system (positioning accuracy ±5 cm @ 1000 m water depth), combined with the pipeline surface-mounted acoustic transponder connected with the acoustic positioning system, real-time tracking of the spatial attitude of the double pipeline in seawater environment; At the same time, matched with inertial measurement unit (IMU), compensating for the high-frequency shaking caused by waves and ocean currents (sampling frequency ≥100 Hz), providing stable coordinate reference for underwater docking;

[0089] Sea section positioning specifically includes:

[0090] Real-time tracking of the spatial attitude of the double pipeline in seawater environment and compensation of high-frequency shaking caused by waves and ocean currents through inertial measurement unit (IMU) are the key links of sea section dynamic welding and double pipeline cooperative laying technology, the specific method is as follows:

[0091] I. Real-time tracking system of spatial attitude

[0092] Based on the high-precision positioning system of "GPS combined with underwater acoustic positioning", matched with IMU to form a tracking scheme of multi-source data fusion, the core components include:

[0093] Underwater acoustic positioning subsystem: Adopting ultra-short baseline (USBL) acoustic positioning system, through the acoustic transducer connected with the central control system deployed on the pipelaying ship or operation platform, emitting detection signal to the underwater acoustic transponder mounted on the surface of the double pipeline, real-time receiving echo and obtaining three-dimensional coordinates (X, Y, Z axis absolute position) of the pipeline, positioning accuracy up to ±5 cm @ 1000 m water depth, sampling frequency ≥10 Hz, providing absolute position reference for attitude tracking.

[0094] Inertial measurement unit (IMU) connected with the central control system: High-precision IMU (such as fiber-optic gyroscope) is installed at the end and middle key nodes (every 50 m interval) of the double pipeline, real-time collecting angular velocity (rotation rate around X, Y, Z axis) and acceleration (linear acceleration) of the pipeline, sampling frequency ≥100 Hz, capturing high-frequency shaking (period 0.1-5 s) caused by waves and ocean currents, outputting real-time attitude angle (roll angle, pitch angle, heading angle) of the pipeline.

[0095] II. High-frequency shaking compensation mechanism

[0096] For the high-frequency vibration of the pipeline caused by waves and ocean currents (manifested as rapid fluctuation of attitude angle and slight deviation of position), error correction is realized through real-time analysis and dynamic compensation algorithm of IMU data, the specific steps are as follows:

[0097] Shaking feature extraction: Fourier transform of acceleration and angular velocity data collected by IMU, identifying the main frequency of high-frequency shaking (such as 2-3 Hz vibration caused by waves, 5-10 Hz jitter caused by ocean current turbulence), establishing shaking interference model.

[0098] Real-time filter compensation: using Kalman filter algorithm, low-frequency stable data of acoustic positioning as reference, combined with high-frequency dynamic data of IMU, real-time correction of pipeline posture:

[0099] For the attitude angle error caused by high-frequency vibration (such as ±0.5°), the instantaneous angular velocity data of IMU is used for reverse compensation, so that the output attitude angle accuracy is controlled within ±0.1°;

[0100] For the position micro-offset (such as ±10cm), based on the acceleration integration calculation of IMU, the displacement change is calculated, and after fusion with the acoustic positioning data, the position error is corrected to within ±2cm.

[0101] Feedback control linkage: the compensated attitude data is transmitted to the double-pipeline synchronous coordination control system in real time, driving the polyurethane roller platform and the hydraulic fine adjustment device:

[0102] When the axial deviation (>1mm) of the pipeline due to shaking is detected, the roller platform adjusts the speed difference (≤0.05m / min) for correction;

[0103] When the radial offset (>1mm) is detected, the hydraulic push rod triggers the fine adjustment (extension amount ±0.02mm), ensuring that the alignment error of the central axis is always ≤2mm.

[0104] Through the above method, the real-time and accurate tracking of the spatial posture of the double pipeline in seawater environment can be realized, the high-frequency shaking interference can be effectively compensated, the stable position and posture reference for the dynamic welding of the sea area section can be provided, and the precision and efficiency of the double pipeline coordinated laying can be ensured.

[0105] Data fusion processing: through Kalman filter algorithm, the GPS, laser tracking, acoustic positioning and IMU data transmitted to the central control system are fused, the measurement noise of single sensor is eliminated, and the real-time relative position of the double pipeline central axis (error ≤0.5mm) is output, which provides accurate position reference for automatic docking.

[0106] Step 1-1-2: implement the automatic docking execution mechanism, that is, mechanical guidance and accurate alignment;

[0107] In the preferred but non-limiting embodiment of the present application, step 1-1-2 specifically includes:

[0108] Through the modular mechanical structure and servo drive system, the automatic adjustment of the physical posture of the double pipeline is realized, and the central axis alignment of the double pipeline is ensured:

[0109] Hoisting stage guidance: double pipeline hoisting equipment (such as synchronous hydraulic crane) is equipped with servo-controlled lifting point adjusting mechanism (adjusting accuracy ±0.1mm) connected with the central control system, according to the relative position of the double pipeline feedback by the positioning system, the central control system adjusts the length and angle of the two sides of the double pipeline hoisting equipment through the servo-controlled lifting point adjusting mechanism connected with it, so that the double pipeline keeps parallel (axis angle ≤0.01°) during hoisting, and the alignment error is controlled within 5mm;

[0110] Lowering stage docking: guide tool is installed at the end of the double pipeline, the guide tool includes conical positioning pin (diameter tolerance ±0.05mm) and matched positioning hole (clearance ≤0.1mm), and 3 groups of hydraulic fine adjustment push rods (pushing force ≥50kN, adjusting accuracy ±0.02mm) distributed in the circumferential direction, when the double pipeline is lowered to the docking distance (≤10cm), the positioning pin guides the preliminary alignment of the pipeline, the hydraulic push rod adjusts in real time according to the position deviation (X, Y axis translation and rotation angle), and finally the center axis alignment error is controlled within 2mm;

[0111] Land group strengthening: the fixed docking platform (flatness ≤0.05mm / m) is used in the land section, the polyurethane roller (friction coefficient ≤0.02) is installed on the surface of the platform, the roller speed is driven by the servo motor (synchronization accuracy ±0.1r / min), so that the double pipeline does not slide relative during pushing, and the alignment accuracy is further stabilized.

[0112] Step 1-1-3: dynamic adjustment and error compensation, that is, real-time monitoring and closed-loop control.

[0113] In the preferred but non-limiting embodiment of the application, step 1-1-3 includes:

[0114] A "perception-decision-execution" closed-loop control system is constructed to continuously compensate for position deviation caused by external interference:

[0115] Real-time monitoring feedback: laser displacement sensors (measurement range 0-50mm, accuracy ±0.01mm) and inclination sensors connected with the central control system are arranged uniformly around the double pipeline docking surface, which can detect the inclination Δθ, radial gap ΔX and axial misalignment ΔY of the two pipeline ends in real time, the data sampling frequency is ≥500Hz, which ensures that small deviations can be captured in time;

[0116] Dynamic compensation control: The central control system calculates the adjustment amount using a PID algorithm based on the error data (ΔX, ΔY, Δθ) fed back by the sensors. This drives the hydraulic push rod, lifting point adjustment mechanism, and roller platform connected to the central control system to work together (response time ≤ 50ms), achieving real-time closed-loop control of "deviation-adjustment". For example, when a 1.5mm deviation is detected in the X-axis direction, the central control system immediately drives the hydraulic push rod on one side to extend by 1.5mm, and at the same time fine-tunes the height of the corresponding lifting point to quickly eliminate the deviation.

[0117] In a preferred but non-limiting embodiment of the present invention, in step 1-1-3, the dynamic compensation control specifically includes:

[0118] Step 1-1-3-1: Perform real-time error detection;

[0119] In a preferred but non-limiting embodiment of the present invention, step 1-1-3-1 specifically includes:

[0120] By deploying laser displacement and tilt sensors at the joint of the two pipes, the relative positional deviation of the central axis of the two pipes is collected in real time, including:

[0121] Axial offset: X-axis (horizontal) deviation ΔX, Y-axis (vertical) deviation ΔY (unit: mm);

[0122] Angular deviation: Rotational angular deviation Δθ of the central axis of the two pipes (unit: °);

[0123] The sensor sampling frequency is ≥500Hz to ensure that tiny error changes are captured at the millisecond level. The data is filtered (to eliminate interference from sea waves and mechanical vibrations) and then used as input parameters for compensation control.

[0124] Step 1-1-3-2: Apply incremental PID control algorithm to dynamically calculate the adjustment amount;

[0125] In a preferred but non-limiting embodiment of the present invention, step 1-1-3-2 specifically includes:

[0126] An incremental PID control algorithm is used to calculate the adjustment amount of the actuator (such as a hydraulic push rod or lifting point adjustment device) based on the real-time error (ΔX, ΔY, Δθ), as shown in the following formula:

[0127] ;

[0128] in Indicates the first Adjustments at any given time (such as the extension or retraction of the hydraulic actuator, or the change in the length of the suspension rope, in mm). This represents the proportionality coefficient (ranging from 0.8 to 1.2, dynamically adjusted according to the pipe diameter; the larger the diameter, the larger the value, ensuring rapid response to errors). This represents the integral coefficient (ranging from 0.05 to 0.1, used to eliminate long-term accumulated errors and avoid static bias). This represents the differential coefficient (ranging from 0.1 to 0.3, used to suppress overshoot during adjustment and prevent secondary deviations caused by frequent pipe vibrations). Indicates the first Error values ​​at any given time (ΔX, ΔY, or Δθ); , Indicates the first , Error value at any given time (historical error, used to predict error trends).

[0129] Step 1-1-3-3: Precise adjustment of the implementing mechanism;

[0130] In a preferred but non-limiting embodiment of the present invention, step 1-1-3-3 specifically includes:

[0131] The central control system will calculate the adjustment amount Transformed into execution instructions, driving the corresponding mechanism to perform actions:

[0132] For X and Y axis offset: control the three sets of hydraulic push rods (adjustment accuracy ±0.02mm) circumferentially distributed at the ends of the dual pipes, and extend and retract according to the extension and retraction of ΔU(k) ​​to directly correct the lateral or longitudinal deviation;

[0133] For the angular deviation Δθ: Adjust the difference in the length of the hoisting ropes on both sides of the hoisting equipment (controlled by a servo motor, with a length adjustment accuracy of ±0.1mm) to rotate the central axis of the two pipes to a parallel state.

[0134] To ensure that the error is stably controlled within ≤2mm, the PID parameters need to be dynamically adapted according to the construction scenario (land / sea):

[0135] Land section: Minimal environmental disturbance (mainly mechanical vibration), smaller value selected. (0.1-0.2), to avoid excessive suppression leading to adjustment lag;

[0136] Sea area: Greatly affected by waves and currents, take the larger [area / area]... (0.2-0.3), enhancing anti-interference capability; simultaneously improving (1.0-1.2) to accelerate the response speed to sudden deviations.

[0137] In addition, the system has built-in error threshold judgment logic: when the real-time error is ≤1mm, it automatically reduces the threshold. (less than 0.05), reducing unnecessary fine adjustment actions; when the error is greater than 1.5 mm, triggering a fast adjustment mode, temporarily increasing to 1.2, ensuring that the error is pulled back to a range of less than or equal to 2 mm within 2 seconds.

[0138] By the above method, the dynamic compensation of the center axis alignment error during the hoisting and lowering of the double pipeline can be realized, a stable physical reference for subsequent welding is provided, and the core technical requirement of "high-precision butt joint" in the document is met.

[0139] Step 1-1-3-4: Perform environmental interference suppression: For land vibration (such as construction machinery vibration) and sea sway (wave period 3-10s), a disturbance compensation model is preset, i.e. a neural network algorithm trained by historical data, to predict the influence of environmental disturbance on the pipeline posture in advance (prediction accuracy ≥ 95%), and drive the hydraulic push rod, hoisting point adjustment mechanism and roller platform such as the actuator to perform feedforward control, reducing dynamic error (compensation efficiency ≥ 80%).

[0140] By the above method, the center axis alignment error of less than or equal to 2 mm during the hoisting and lowering of the double pipeline in the complex land and sea environment can be realized, a stable physical basis for subsequent welding is provided, and the welding quality and pipeline laying precision are guaranteed.

[0141] Step 1-2: Perform welding process;

[0142] In the preferred but non-limiting embodiments of the present application, step 1-2 specifically includes:

[0143] For the high-humidity and high-salt environment at the seaside and the multi-heat-source climate on land, semi-automatic welding equipment is used to assist manual welding, and a real-time monitoring system (temperature sensor, shape scanner) is provided to dynamically control the welding temperature (controlled within the material phase transition temperature range) and the weld shape, ensuring that the weld strength meets the design standard (such as tensile strength ≥ 80% of the base material).

[0144] Step 1-3: Perform land-sea segmented construction process;

[0145] In the preferred but non-limiting embodiments of the present application, step 1-3 specifically includes:

[0146] Land segment: adopt "double pipeline integral welding + pushing" process, reduce on-site operation time through modularized tool assembly, and control the pushing speed at 0.5-1 m / min.

[0147] The "double pipeline integral welding + pushing" process includes:

[0148] Construct a double-station parallel welding system:

[0149] Synchronous operation design: Symmetrical double-station layout is adopted to support positioning and clamping of two pipes at the same time. The work station is automatically switched through a servo motor driven rotary workbench, and the single-station switching time is less than or equal to 15 seconds.

[0150] Precise positioning control: The pneumatic clamp realizes axial and radial positioning (deviation less than or equal to 0.2 mm), and is suitable for pipes of different materials (red copper, brass) and wall thicknesses (0.5-2 mm).

[0151] Performing full-automatic welding process:

[0152] Push-pull wire double-power wire feeding: The double-power wire feeding mechanism ensures welding stability, and combined with a small and intensive welding trolley, it realizes 360° continuous circle welding of the pipe, solving the problem of low efficiency of small-bore pipe welding.

[0153] Double-welding-torch collaborative operation: In the joint welding, the double-welding-torch synchronous filling technology is adopted to replace the traditional manual argon arc welding, which makes the welding efficiency increase by more than 50%.

[0154] Performing mechanized pushing and grouping:

[0155] External jointing root welding device: The external jointing device of the automatic welding machine is used to solve the problem of pipe grouping in complex terrain, realize the integrated operation of "pushing-positioning-welding", and reduce manual intervention.

[0156] Closed-loop temperature control: The high-frequency welding system cooperates with an infrared temperature measuring instrument (accuracy ±1℃) to dynamically adjust the power, ensuring that the welding point temperature fluctuation during pushing is less than or equal to ±3℃.

[0157] Offshore section: Combined with the laying of the main operation ship and the auxiliary adjustment of the underwater robot (ROV), the pipe shaking caused by waves and currents is dealt with, and the laying position deviation is ensured to be less than or equal to 50 cm.

[0158] Steps 1-4: Perform synchronous coordination control: Develop a double-pipe synchronous laying coordination control system, that is, through the polyurethane roller platform, the speed difference between the two pipes is less than or equal to 0.5 m / min, and the angle deviation is consistent, avoiding pipe distortion caused by uneven force.

[0159] In the preferred but non-limiting embodiment of the present application, the double-pipe laying method of welding while constructing further comprises:

[0160] Step 2: Perform pipe structure mechanics and deformation control method;

[0161] In the preferred but non-limiting embodiment of the present application, in step 2, for the deformation and bending problem of the double-pipe under load, the following technologies are integrated:

[0162] Design stage simulation: Use finite element analysis software such as ANSYS to establish a three-dimensional mechanical model, simulate stress distribution under different working conditions (self weight, medium pressure, wave force, current force), ensure that the maximum deformation is ≤1% of the pipe diameter, and the bending radius is not more than the limit bending radius of the pipe (such as API standard value);

[0163] Design stage simulation is the core link of pipeline structural mechanics and deformation control technology, aiming to predict the deformation, stress distribution and safety performance of double pipes under various loads through three-dimensional mechanical modeling and multi-condition simulation, ensure that the maximum deformation is controlled within 1% of the pipe diameter, and the bending radius is not more than the limit bending radius of the pipe. The specific method is as follows:

[0164] I. Modeling basis and parameter setting

[0165] Geometric model construction

[0166] Based on the design parameters of double pipes (diameter, wall thickness, length, spacing and support method), use finite element analysis software such as ANSYS to establish a three-dimensional solid model. The model needs to accurately include the details of the pipe body, welded joints, support structures (such as pipe clamps, pads) and other details, among which the welded area is divided into fine mesh (element size ≤5mm) to ensure the accuracy of stress analysis.

[0167] Material property definition

[0168] Input the mechanical parameters of the main material of the pipe (such as API5LX65 steel) and the welding material, including:

[0169] Elastic modulus (E≈206GPa)

[0170] Poisson's ratio (μ≈0.3)

[0171] Yield strength (≥448MPa)

[0172] Tensile strength (≥530MPa)

[0173] At the same time, consider the plastic properties of the material to provide data basis for subsequent limit condition simulation.

[0174] Boundary condition setting

[0175] According to the construction and operation scene, define the constraint conditions:

[0176] Land section: fixed constraints are set at both ends of the pipe (simulate the clamping action of the pushing device), and the support points are set as sliding constraints (allow axial displacement and limit radial sway);

[0177] Sea section: simulate the tension effect of the tensioner of the pipe-laying ship (apply axial tension, value range 50-200 kN, dynamically adjusted according to the pipe diameter), and set a current load action surface on the underwater part (reference the measured current velocity in the sea area of the project, and convert it into a uniform force load).

[0178] II. Multi-condition simulation and analysis

[0179] In view of the typical loads that the double pipe may face in the construction and operation stages, the following conditions are simulated:

[0180] Self-weight and medium pressure condition

[0181] Loading method: apply a gravity load to the pipe model (density calculated according to the steel density 7850 kg / m³), and at the same time, apply a design working pressure (such as 10 MPa, simulating oil and gas transmission pressure) inside the pipe.

[0182] Analysis target: calculate the axial stress and radial deformation of the pipe under the combined action of self-weight sag and internal pressure, to ensure that the maximum radial deformation is ≤1% of the pipe diameter (such as a pipe with a diameter of 1 m, the deformation is ≤10 mm).

[0183] Environmental load condition

[0184] Wave load: according to the wave parameters (wave height, period) in the sea area of the project, calculate the impact force of the wave on the underwater pipe by using the Morison equation, convert it into a transient load and apply it to the outer surface of the pipe, simulate the vibration response caused by wave impact;

[0185] Current load: calculate the drag force of the current on the pipe according to a constant flow rate (such as 1.5 m / s), and analyze the pipe deviation and stress accumulation under the long-term flow action;

[0186] Temperature load: consider the temperature difference between the high-temperature environment on land (such as 60℃ in summer) and the low-temperature environment on the seabed (such as 10℃), apply temperature strain (thermal expansion coefficient taken as 12×10 -6 / ℃), and evaluate the influence of temperature stress on the weld.

[0187] Construction dynamic load condition

[0188] Hoisting and lowering: simulate the force on the hoisting point when the double pipe is hoisted (consider the force distribution of 2-4 hoisting points), analyze the bending stress of the pipe during hoisting, and ensure that the bending radius is not less than the material limit value (such as the limit bending radius of X65 steel pipe ≥300D, D is the pipe diameter);

[0189] Synchronous pushing: simulate the pushing process of the double pipe on the polyurethane roller platform, apply an axial pushing force (converted into a dynamic load according to the pushing speed of 0.5 m / min), analyze the local stress at the contact part of the pipe and the roller, and avoid indentation or plastic deformation.

[0190] III. Simulation Result Verification and Optimization

[0191] Result Output and Criteria

[0192] Output the stress contour, deformation vector diagram, and stress value of key parts (welds, support points, and lifting points) under each working condition to verify whether the following criteria are met:

[0193] Maximum stress ≤ 80% of material yield strength (to ensure a safety factor ≥ 1.25);

[0194] Maximum deformation ≤ 1% of the pipe diameter;

[0195] Bending radius ≥ 1.1 times the pipe's ultimate bending radius (with a safety margin).

[0196] Parameter Optimization Iteration

[0197] If the simulation results do not meet the criteria, optimize through the following methods:

[0198] Adjust the pipe wall thickness (thicken the stress concentration area locally);

[0199] Optimize the support spacing (shorten the spacing to reduce bending caused by self-weight);

[0200] Improve the lifting point position (to make the lifting force distribution more uniform).

[0201] Repeat the simulation process until all parameters meet the design requirements.

[0202] Through the above simulation methods in the design phase, the mechanical properties of the double pipe can be accurately predicted before construction, providing a scientific basis for pipe structure design and construction parameter optimization, ensuring the safety and durability of the double pipe throughout its life cycle.

[0203] Fatigue Life Prediction: Based on the mechanical model data and material fatigue characteristics, predict the fatigue damage of the pipe within the designed service life to ensure a safety factor ≥ 1.2;

[0204] Fatigue life prediction is an important part of pipe structure mechanics and deformation control technology, aiming to predict the fatigue life of the double pipe within the designed service life by integrating finite element analysis, material property data, and fatigue damage theory, ensuring that it meets the requirements of safety and durability. Combined with the core requirements of "Pipe Structure Mechanics and Deformation Control Technology" in the document, the specific method is as follows:

[0205] I. Fatigue Load and Stress Analysis

[0206] Fatigue Load Identification

[0207] Identify the main fatigue inducers for the dynamic loads that the double pipe will bear during construction and operation:

[0208] Construction phase: stress fluctuation of lifting point during lifting and lowering, contact vibration between roller and pipeline during synchronous pushing, periodic fluctuation load caused by wave / current in sea section;

[0209] Operation phase: pulse fluctuation of medium transmission pressure (such as pressure change caused by pump start / stop), periodic load of ocean environment (pipeline vibration caused by wave, tide).

[0210] Based on the finite element model in the design phase (such as the three-dimensional mechanical model established by ANSYS), the stress time history curve (stress data changing with time) of the key parts of the pipeline (weld, elbow, support point) under the above loads is extracted.

[0211] Stress concentration factor calculation

[0212] The stress concentration area (such as the geometric discontinuity of the weld reinforcement and the pipe butt joint) is analyzed, and the stress concentration factor (SCF) is calculated by finite element simulation, which is the ratio of the maximum stress to the nominal stress. For the butt weld commonly used in submarine pipelines, the SCF usually takes the value range of 1.2-2.0 (according to the dynamic adjustment of weld forming quality, the upper limit for manual welding cover, and the lower limit for semi-automatic welding backing), to ensure the stress input accuracy of fatigue analysis.

[0213] II. Material fatigue property parameter acquisition

[0214] Basic data collection

[0215] For the main material of the pipeline (such as API5LX65 steel) and the weld material, the fatigue performance parameters are obtained through material testing:

[0216] S-N curve: using standard fatigue test method (such as GB / T3075), the fatigue life of the material under different stress amplitudes is measured, the relationship curve of stress amplitude (S) and cycle number (N) is drawn, and the fatigue limit of the material (usually the stress amplitude corresponding to 10 7 cycles) is determined;

[0217] Fatigue strength coefficient (σ_f') and fatigue ductility coefficient (ε_f'): obtained by low-cycle fatigue test, used to correct the fatigue damage calculation under complex stress state.

[0218] Environmental correction

[0219] Considering the weakening effect of high salt and high humidity environment on the fatigue performance of the material, the environmental correction coefficient (K_env) is introduced:

[0220] Land section: K_env=1.0 in dry environment;

[0221] Intertidal / shallow sea segment: high humidity + salt spray corrosion, K_env=0.8-0.9;

[0222] Deep sea segment: seawater immersion environment, K_env=0.7-0.8 (adjust according to the measured value of seawater salinity).

[0223] III. Fatigue damage calculation and life prediction

[0224] Application of Miner linear cumulative damage theory

[0225] Cumulative fatigue damage under multiple load conditions is calculated using the Miner rule, as follows:

[0226] ;

[0227] Where: is the cumulative fatigue damage (D≤1, the pipeline meets the fatigue life requirements);

[0228] is the stress cycle number under the i-th load condition (calculated according to the construction period, operation life and load frequency, such as wave load counted as 1000 cycles per day);

[0229] is the material fatigue life corresponding to the i-th stress amplitude (obtained from the S-N curve).

[0230] Key position life prediction

[0231] For weak positions such as welds and support points, fatigue life is calculated as follows:

[0232] (1) Extract the amplitude ( ) and cycle number ( ) of each stress cycle from the stress time history curve, and simplify it to several stress levels by rainflow counting method;

[0233] (2) Combined with the corrected S-N curve (considering the environmental coefficient K_env), the fatigue life corresponding to each stress level is obtained ;

[0234] (3) Substitute into the Miner rule to calculate the cumulative damage D, when D=1, the total cycle number corresponding to it is the fatigue life of the position;

[0235] (4) The predicted fatigue life is required to be ≥1.2 times the design service life (such as 20 years), to ensure a safety margin.

[0236] IV. Result verification and optimization

[0237] Verification method

[0238] By comparing the fatigue life measured data of similar projects (such as the detection results of double pipe projects that have been running for 10 years), the accuracy of the prediction model is verified, and if the deviation exceeds 10%, the S-N curve or environmental coefficient needs to be corrected.

[0239] Optimization measures

[0240] If the predicted fatigue life does not meet the requirements, the following methods can be used for optimization:

[0241] Improve the welding process (such as reducing the weld reinforcement and reducing the stress concentration factor);

[0242] Increase the density of pipeline support (reduce the vibration amplitude and reduce the number of stress cycles);

[0243] Use materials with better fatigue performance (such as high-strength low-alloy steel).

[0244] Through the above methods, the fatigue life of the double pipe can be accurately predicted in the design stage, providing a basis for pipeline structure optimization and operation scheme development, ensuring that it can resist fatigue failure risk throughout its life cycle and meet the "transport safety and durability requirements" in the document.

[0245] Real-time monitoring system: Install strain sensors and displacement monitoring devices connected to the central control system at the key positions of the pipeline (such as welds and bends), and transmit the data collected by the strain sensors and displacement monitoring devices to the central control system in real time. When the deformation approaches the preset threshold, a warning is triggered, which facilitates timely adjustment of construction parameters.

[0246] Step 3: Implement land-sea collaborative operation and partition control method.

[0247] In the preferred but non-limiting embodiments of the present application, step 3 specifically includes:

[0248] Construct a "land-sea linkage, partition responsibility, process connection" construction management system, which specifically includes:

[0249] Land area function division:

[0250] Grouping work area: configure digital cutting and bevel machining equipment to ensure that the accuracy error of pipeline components is ≤1mm; welding work area: use semi-automatic welding equipment matched with dynamic welding process, and support real-time monitoring system;

[0251] Welding detection area: configure X-ray flaw detector and ultrasonic detector to perform 100% weld detection, and the unqualified product repair rate is controlled below 5%;

[0252] Storage area: use intelligent scheduling system to optimize pipe material stacking and transfer path to avoid exceeding 0.5% deviation of pipeline ovality due to collision;

[0253] Key points of sea area operation: Solve technical problems such as underwater ditching (using underwater ditching machine, ditch depth meeting design burial depth requirement), pipeline laying (controlling laying tension through tensioner) and pipe stabilizing (using concrete counterweight or sandbag ballast).

[0254] Data sharing platform: Establish a land-sea data sharing platform to synchronize real-time construction progress, quality detection and environmental monitoring data (such as wind speed, wave height, seawater salinity), and realize cross-regional collaborative decision-making response time ≤30 minutes.

[0255] The beneficial effects of the present application are that, compared with the prior art, the technical effects of the present application include:

[0256] (1) High construction efficiency: The method of the present application can usually complete welding and lengthening operations on land precast yards, and through flow line operation, two pipes are lengthened side by side, and welding, inspection and corrosion prevention processes are carried out at the same time, reducing the time consumed by traditional precasting and overall installation. Moreover, double-pipe laying can complete more work in the same time compared to single-pipe laying, greatly shortening the overall construction period.

[0257] (2) Good welding quality: In the process of construction and welding, semi-automatic welding technology can be used for backing and surfacing. This technology can improve welding efficiency and is also beneficial to improving the tensile properties and fracture toughness of the welded joint, making the welding quality more stable and the uniformity and consistency of the weld better, which can effectively reduce welding defects and meet the high sealing and high strength requirements of submarine oil pipelines.

[0258] (3) Optimal pipe deformation and strength control: During laying, the method of the present application can apply appropriate tension to the pipe through devices such as tensioners to better control the deformation of the pipe, so that the pipe can maintain good shape and strength under the action of gravity, seawater pressure and other forces, ensuring that the pipe meets the design requirements and reducing the risk of pipe damage or affecting the conveying performance due to excessive deformation.

[0259] (4) Strong adaptability to complex marine environment: The method of double-pipe laying with simultaneous construction and welding using a pipelaying vessel can flexibly adjust the construction progress and method according to marine environmental conditions. When encountering bad weather, the pipe can be abandoned at any time, and the work site can be left to anchor for shelter from the wind. After the weather improves, construction can continue. Compared with some fixed site construction methods, the adaptability to the marine environment is stronger, and the construction range is expanded.

[0260] (5) Good economy: Double-pipe laying can share some construction equipment and resources, such as pipelaying vessels and welding equipment, reducing the repeated investment in equipment. Moreover, the improvement of construction efficiency also means the reduction of labor and time costs, while reducing the multiple disturbances to the marine environment, to some extent, reducing the environmental restoration cost, and the overall economy is better.

[0261] (6) High precision: Some advanced laying systems are equipped with high-precision guiding and positioning devices, such as gyro-based guiding systems, which can achieve accurate guidance at uphill, downhill and turning places, better control the laying position and spacing of the double pipes, and ensure the pipes are laid according to the design requirements, especially suitable for complex seabed terrain areas.

[0262] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the above examples, those skilled in the art will understand that modifications or equivalent replacements can still be made to the specific embodiments of the present application without departing from the spirit and scope of the present application. Any modifications or equivalent replacements should be covered within the protection scope of the claims of the present application.

Claims

1. A method of simultaneous construction and welding of a double pipeline laying, characterized in that, Comprise: Step 1: Perform dynamic welding and double-pipe collaborative laying method; In step 1, the dynamic welding and double-pipe collaborative laying method comprises: welding while constructing the double-pipe, and in the guiding and assembling link in the construction, the automatic docking method and high-precision positioning system are combined to ensure that the axis alignment error of the double-pipe is controlled within 2mm during hoisting and lowering; in the welding process, in view of the high humidity and high salt environment on the sea and the hot climate on land, semi-automatic welding equipment with strong adaptability is used to assist manual welding, and a real-time monitoring system is matched to realize dynamic regulation of temperature and shape during welding, and to ensure the strength of the weld.

2. The method of claim 1, wherein, Step 1 specifically comprises: Step 1-1: Perform guiding and assembling of the double-pipe; Step 1-2: Perform welding process; Step 1-3: Perform land-sea segmented construction process; Step 1-4: Perform synchronous coordination control: develop a double-pipe synchronous laying coordination control system, that is, through the polyurethane roller platform, the speed difference between the two pipes is ≤0.5m / min, and the angle deviation is consistent.

3. The method of claim 2, wherein, Step 1-1 specifically comprises: Step 1-1-1: Perform positioning system fusion scheme, that is, land-sea environment differentiated positioning; Step 1-1-2: Implement automatic docking execution mechanism; Step 1-1-3: Perform dynamic adjustment and error compensation.

4. The method of claim 3, wherein, Step 1-1-1 specifically comprises: Land segment positioning: taking centimeter-level differential GPS as the core, matched with a laser tracker, real-time collection of three-dimensional coordinates of both ends of the double-pipe is realized, and through a wireless transmission module connected with the GPS and the laser tracker, the three-dimensional coordinates are sent to a central control system connected with the wireless transmission module; Sea segment positioning: an underwater ultra-short baseline acoustic positioning system is used, combined with a hydroacoustic transponder installed on the surface of the pipe and connected with the acoustic positioning system, to real-time track the spatial posture of the double-pipe in the seawater environment; at the same time, an inertial measurement unit is matched to compensate for high-frequency shaking caused by waves and ocean currents; Data fusion processing: through Kalman filtering algorithm, the GPS, laser tracking, acoustic positioning and IMU data transmitted to the central control system are fused to output the real-time relative position of the double-pipe axis; Step 1-1-2 specifically comprises: Hoisting stage guiding: the double-pipe hoisting equipment is equipped with a hoisting point adjusting mechanism connected with the central control system, according to the relative position of the double-pipe fed back by the positioning system, the central control system adjusts the length and angle of the hoisting ropes on both sides of the double-pipe hoisting equipment in real time through the servo-controlled hoisting point adjusting mechanism connected therewith, so that the double-pipe remains parallel during hoisting, and the alignment error is preliminarily controlled within 5mm; Lowering stage docking: a guide tool is installed at the end of the double-pipe, the guide tool comprises a conical positioning pin and a matching positioning hole, and 3 groups of hydraulic fine-tuning push rods distributed in the circumference, when the double-pipe is lowered to the docking distance, the positioning pin guides the pipe to preliminarily align, and the hydraulic push rod adjusts in real time according to the real-time position deviation, finally the axis alignment error is controlled within 2mm; Land segment assembly strengthening: the fixed docking platform is used in the land segment, the polyurethane roller is installed on the surface of the platform, the roller speed is driven by a servo motor to ensure that the double-pipe does not slide relative during pushing; Step 1-1-3 comprises: Real-time monitoring feedback: Laser displacement sensors and inclination sensors are arranged uniformly around the docking surface of the double pipelines and connected to the central control system, which can detect the inclination Δθ, radial gap ΔX and axial misalignment ΔY of the two pipeline ends in real time, with a data sampling frequency ≥500Hz; Dynamic compensation control: The central control system calculates the adjustment amount through the PID algorithm based on the error data fed back by the sensors, and drives the hydraulic push rod, suspension point adjustment mechanism and roller platform connected to the central control system to realize real-time closed-loop control of "error-adjustment". In step 1-1-3, dynamic compensation control specifically includes: Step 1-1-3-1: Real-time error detection; Step 1-1-3-2: Dynamic calculation of adjustment amount by using incremental PID control algorithm; Step 1-1-3-3: Precise adjustment of actuator; Step 1-1-3-4: Environmental disturbance suppression: For land vibration and sea sway, a preset disturbance compensation model, i.e. a neural network algorithm trained by historical data, is used to predict the influence of environmental disturbance on pipeline posture in advance, and the actuator such as hydraulic push rod, suspension point adjustment mechanism and roller platform is driven for feedforward control.

5. The method of claim 4, wherein, Step 1-1-3-1 specifically includes: Through the laser displacement sensors and inclination sensors deployed at the docking end of the double pipelines, the relative position deviation of the central axes of the double pipelines is collected in real time, including: Axial offset: X-axis deviation ΔX, Y-axis (vertical longitudinal) deviation ΔY; Angular deviation: rotational angle deviation Δθ of the central axes of the double pipelines; Step 1-1-3-2 specifically includes: Using incremental PID control algorithm, the adjustment amount of the actuator is calculated according to the real-time error, and the formula is as follows: ； wherein represents the adjustment amount at the time point; represents a proportional coefficient; represents an integral coefficient; represents a differential coefficient; represents the error value at the time point; , represents the error value at the , time point; Step 1-1-3-3 specifically includes: The central control system converts the calculated adjustment amount into an execution instruction to drive the corresponding mechanism to act. For X and Y axis offset: Control the 3 groups of hydraulic push rods distributed circumferentially at the end of the double pipelines to stretch and contract according to ΔU(k), directly correcting the horizontal or vertical deviation; For angular deviation Δθ: Adjust the length difference of the lifting ropes of the two sides of the lifting equipment to make the central axes of the double pipelines rotate to the parallel state.

6. The method of pipelaying according to claim 5, wherein, Step 1-2 specifically includes: For high humidity and high salt environment at the sea side and multi-heat source climate on land, semi-automatic welding equipment is used to assist manual welding, and a real-time monitoring system is matched to dynamically regulate the welding temperature and weld shape, ensuring that the weld strength meets the design standard.

7. The method of pipelaying according to claim 6, wherein, Step 1-3 specifically includes: Land section: Using the "double pipeline overall welding + pushing" process, the on-site operation time is reduced by assembling the modular tooling, and the pushing speed is controlled at 0.5-1m / min synchronously; Sea section: Combined with the laying of the main work ship and the auxiliary adjustment of underwater robots, the pipeline sway caused by waves and currents is dealt with to ensure that the laying position deviation does not exceed 50cm.

8. The method of pipelaying according to claim 7, wherein, Also includes: Step 2: Perform pipeline structure mechanics and deformation control method; Step 3: Perform land-sea collaborative operation and partition control method.

9. The method of claim 8, wherein, In step 2, design stage simulation: Use finite element analysis software such as ANSYS to establish a three-dimensional mechanical model to simulate stress distribution under different working conditions, ensuring that the maximum deformation is ≤1% of the pipeline diameter and the bending radius is not more than the limit bending radius of the pipeline; Fatigue life prediction: Based on the mechanical model data, combined with the fatigue characteristics of the material, the fatigue damage of the pipeline within the designed service life is predicted to ensure that the safety factor is ≥1.2; Real-time monitoring system: Install strain sensors and displacement monitoring devices connected to the central control system at key positions of the pipeline, and transmit the data collected by the strain sensors and displacement monitoring devices to the central control system in real time. When the deformation approaches the preset threshold, an early warning is triggered, which facilitates timely adjustment of construction parameters.

10. The method of pipelaying according to claim 9, wherein, Step 3 specifically includes: Land area function division: Group pair work area: Configure digital cutting and bevel processing equipment to ensure that the precision error of the pipeline component is ≤1mm; Welding work area: Use semi-automatic welding equipment matched with dynamic welding process, and support real-time monitoring system; Welding detection area: Configure X-ray flaw detector and ultrasonic detector to perform 100% weld detection, with unqualified product repair rate controlled below 5%; Storage area: Use intelligent scheduling system to optimize pipe storage and transfer path to avoid pipeline ovality deviation exceeding 0.5% due to collision; Data sharing platform: Establish a land-sea data sharing platform to synchronize construction progress, quality detection and environmental monitoring data in real time, and realize cross-regional collaborative decision-making response time ≤30 minutes. ​

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