Shearable Riser Passive Fracture Section
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Solution Overview
Problem
Subsea riser structures in marine oil and gas applications are prone to causing damage to equipment during extreme events such as loss of control of vessels or platforms, extreme weather, and wave events, with little innovation to address these issues.
Innovation Solution
Incorporating a passive fracture section in the riser made of materials like titanium alloys, aluminum alloys, or composite materials that can shear or fracture under extreme loading conditions, allowing for localized disconnection and reducing damage to subsea equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the riser is made strong and rigid to withstand normal operating loads, then the strength and reliability are improved, but the risk of damage to subsea equipment during extreme events increases
Solution Approach 1:
The riser is divided into segments with different material properties: a passive fracture section made of shearable material (e.g., aluminum alloy) is inserted between sections of stronger material (e.g., steel). This segmentation allows the riser to maintain overall strength while having a designated weak point that can fail safely during extreme events, protecting subsea equipment from damage.
2Object-affected harmful factors
If the riser is designed to be flexible and shearable to protect equipment during extreme events, then the protection capability is improved, but the reliability and load-bearing capacity under normal operation deteriorates
Solution Approach 1:
Different sections of the riser are assigned different material qualities: the passive fracture section uses shearable material with lower strength for protection, while the adjacent riser sections use high-strength material for reliability. This local differentiation allows the riser to be both reliable during normal operation and protective during extreme events.
Data Source
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AI summary
A riser for a subsea well comprises a first riser section that may be similar to conventional risers in design and material specifications. A second riser section comprises a passive fracture section that is specifically designed to shear or fracture under design conditions, such as extreme events (e.g., extreme weather or waves, loss of control of a rig or vessel, a rig or vessel moving from a desired position). The passive fracture section is designed to fracture first to prevent or minimize damage to other well equipment, such as at the seabed.