Subsea Pipe Buckling Control via Buoyancy-Driven Lateral Force
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Solution Overview
Problem
Existing solutions fail to reliably and economically regulate the buckling of rigid subsea hydrocarbon pipes under axial compression stresses from temperature and pressure variations, particularly in deep-sea environments, as they either do not control the shape, amplitude, or reproducibility of buckling effectively, and often require costly and complex implementations.
Innovation Solution
A device that applies a constant, predetermined horizontal force perpendicular to the pipe axis, using a combination of force application devices to control lateral buckling, allowing for diversion of axial expansion into lateral expansion, thereby limiting displacements and loads, and comprising a collar with a linear lateral traction element connected to a buoy or motorized winch, facilitating controlled buckling modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lateral buckling initiating devices are installed to control buckling, then buckling initiation becomes more reliable, but device complexity and installation cost increase
Solution Approach 1:
The patent applies local quality by creating zones with different friction characteristics along the pipe. Low-friction zones are strategically positioned to initiate buckling, while high-friction zones control and limit buckling propagation. This spatial variation in friction properties allows reliable buckling control without complex active devices.
Solution Approach 2:
The patent uses simple, passive friction control elements rather than complex active devices. These elements are inexpensive to install and maintain, providing reliable buckling control through their friction properties alone, without requiring power sources, sensors, or complex control systems.
2Ease of operation
If buoys are used to reduce lateral friction and promote buckling, then buckling initiation is facilitated, but control over buckling shape and amplitude is lost
Solution Approach 1:
The patent combines low-friction zones for buckling initiation with high-friction zones for buckling control. The high-friction zones act as boundaries that confine the buckling shape and amplitude, providing precise control over the buckling characteristics while maintaining easy initiation through the low-friction zones.
3Reliability
If sliding spans are installed to reduce lateral friction, then buckling initiation is improved, but control over buckling position and reproducibility is reduced
Solution Approach 1:
The patent creates a structured pattern of alternating low-friction and high-friction zones along the pipe. The low-friction zones serve as predetermined buckling initiation points, ensuring reproducible buckling positions. The high-friction zones between them control the buckling shape and prevent propagation, achieving reliable and reproducible buckling control.
4Reliability
If the pipe is buried in a trench to prevent lateral buckling, then lateral buckling is eliminated, but vertical buckling remains possible and implementation becomes difficult in deep sea
Solution Approach 1:
The patent extracts the pipe from the seabed by using buoyancy forces to lift it, creating a suspended configuration. This eliminates the need for trenching while preventing lateral buckling through controlled friction zones. The pipe is held in position by tension and friction rather than burial, making implementation feasible in deep sea environments.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise control of buckling location and mode, reducing the intensity of forces required to initiate and manage buckling, ensuring pipe integrity and equipment safety while being simple and economical to implement.
Implementation Method 1
The force application device comprises a collar, advantageously in two parts, surrounding the pipe to fix one end of a linear lateral traction element. The other end of the linear lateral traction element is linked to an actuator of the buoy, mass or motorized winch type.
Implementation Method 2
The other end of the linear lateral traction element is linked to an actuator of the buoy, mass or motorized winch type.
Implementation Method 3
The force application device comprises a collar, advantageously in two parts, surrounding the pipe to fix one end of a linear lateral traction element.
Data Source
Figure 1A~1B
Figure 2
Figure 3~4
AI summary
The invention concerns a device for regulating lateral buckling of a pipe section (10) comprising at least one device (11-15) for permanently applying a force on one spot of said pipe section, said force being preferably substantially horizontal and perpendicular to the axis of the pipe. Preferably, there are provided two devices for applying an equal and opposed force arranged at a specific distance from each other along the pipe section, each of the devices comprising a collar (15), a cable (12), a bell crank (14) and a buoy (11) or a weight.